Road Traffic: Determination of Fitness to Drive – General

Road Traffic: Determination of Fitness to Drive – General CH Wecht, Private Practice, Pittsburgh, PA, USA SA Koehler, University of Pittsburgh, Pittsburgh, PA, USA r 2016 Elsevier Ltd. All rights reserved.

Abstract This chapter reviews medical conditions and medications that may impair a driver’s performance to operate a motor vehicle. The role of the physician in assessing the driver’s fitness, and methods of assessing and screening in the United States and other countries are also reviewed in this chapter. This chapter also provides an overview of the US population aged 65 and over, the causes of mortality among the elderly, and an analysis of elderly drivers.

Determination of Driver Fitness Driver’s Family and Caregiver’s Insight into Their Deficits

Drivers, especially those with cognitive disorders, such as dementia and Parkinson disease (PD), tend to overestimate their driving performance abilities and are less likely to report driving problems to their family members or physician. These drivers seldom stop driving of their own accord. More commonly, they cease driving only after intervention by family (24%), family and patient jointly (13%), actions of the family doctor (18%), or due to memory clinics (11%). Almost half the patients found to be demented while undergoing first-time evaluations in a geriatric clinic were still driving; younger and male demented drivers were less likely to stop driving despite significant cognitive impairment. A high percentage of individuals with Alzheimer disease (AD) who failed a road test for driving competency considered themselves to be safe drivers. Family and other caregivers also provided an unreliable assessment of the perceptions of the driving ability of impaired drivers. Studies have found long periods between the caregiver’s perception that the patient should stop driving and actual cessation – up to 4 years in some cases. Therefore, it is the role of the physician to determine the medical fitness of the driver (Gresset and Meyer, 1994). Role of the Medical Community in Assessing Driving Fitness

Physicians play a key role in determining whether their patients should continue their driving privileges. Therefore, they are required to have knowledge of driving reporting laws, skills in identifying risky drivers, and in counseling patients and family on strategies for driving cessation. In addition, they should know how to refer marginal drivers for driving training. When physicians are assessing the fitness of one of their patients, the physical examination should be directed toward the identification of any existing conditions and the degree of functional compromise. Medical or surgical control of

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the condition, duration of satisfactory control, and patient reliability are important considerations. However, it has been shown that the knowledge of doctors in reporting laws is weak. It has also been shown that 28% of all geriatricians do not know how to report patients with dementia who are potentially dangerous drivers (Simpson et al., 2000; Kakaiya et al., 2000; Physician’s Guide to Assessing and Counseling Older Drivers, 2010; Raedt and Krisoffersen, 2000). In 1999, the American Medical Association (AMA) adopted new ethical guideline stating that it is ‘desirable and ethical’ for physicians to notify a state licensing authority about patients who, because of a medical condition, may be unsafe to drive. State-by-state criteria for the medical conditions that physicians are required to report, where to obtain the forms, and where to mail are available on the AMA Website entitled ‘Physician’s Guide to Assessing and Counseling Older Drivers’ (Physician’s Guide to Assessing and Counseling Older Drivers, 2010). Below are some medical conditions that physicians should be aware of that may impair a driver’s ability to operate a motor vehicle safely.

Cardiovascular Medical Conditions that May Impair the Driver There are a number of cardiovascular conditions and some of these can place a driver at risk for a crash. To date, the collected data are still unclear as to the definite relationship between crash risk and cardiovascular diseases. Data have shown a modest increase in total crack risk for older driver with cardiac diseases (McGwin et al., 2000). In general, physicians should advise patients with cardiac diseases seek immediate medical attention if they experience the following symptomsprolonged chest discomfort, acute shortness of breath, syncope, presyncope, palpitations, or lightheadedness. A list of the major cardiovascular conditions that may impair driving ability are discussed below (Physician’s

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Road Traffic: Determination of Fitness to Drive – General

Guide to Assessing and Counseling Older Drivers, 2010). Cardiac Conditions that Cause Sudden, Unpredictable Loss of Consciousness

A number of cardiac conditions can precipitate a sudden an unpredictable loss of consciousness. These conditions include any arrhythmia (Epstein et al., 1996) can cause presynopy or syncope. Syncope is commonly due to either brady or tachyarrhythmia. The main consideration in determining medical fitness to drive for individuals with these cardiac conditions is the risk of presyncope or syncope. Where individuals have a known arrhythmia, the physician should identify and treat the underlying cause, if possible, and recommend temporary driving cessation until control of symptoms has been achieved. Cardiac conditions that can cause a sudden and unpredictable loss of consciousness include the following: atrial flutter/fibrillation with bradycardia or rapid ventricular response, paroxysmal supraventricular tachycardia (PSVT), including Wolff–Parkinson–White (WPW) syndrome, prolonged, nonsustained ventricular tachycardia (NSVT), sustained VT, high grade atrioventricluar (AV) block, and sick sinus syndrome: sinus bradycardial, sinus exit block, and sinus arrest (Physician’s Guide to Assessing and Counseling Older Drivers, 2010; Dobbs, 2005). Atrial flutter/fibrillation with bradycardia or rapid ventricular response

Atrial fibrillation (AF) or flutter is a common type of cardiac arrhythmia that causes an abnormal heartbeat in which the heart rhythm is fast and irregular (Atrial Fibrillation or Flutter). Symptoms may include tachycardia, fluttering, irregular, or bradycardia, heart palpitations, confusion, dizziness, lightheadedness, fainting, fatigue, and shortness of breath. The incidence and prevalence of AF increase with age. Data from the Framingham Heart study reported the prevalence of AF doubles with each decade of age in those 50 and older, with an estimated prevalence of approximately 10% for those 80 years and older (Kannel et al., 1998). Data also indicate that the incidence of AF is greater for men than for women. A number of studies have indicated that individuals with AF are at increased risk for cardiac morbidity and mortality, developing diabetes, left ventricular hypertrophy (LVH), coronary artery disease, valvular heart disease, heart failure, and stroke (Kannel et al., 1998; Dobbs, 2005). The presence of AF has the potential to affect driving performance because of its hemodynamic consequences (e.g., cerebral ischemia). However, there are no data available on the effects of AF on driving performance. Because the presence of AF is strongly associated with an increased risk for stroke, the most likely effects of AF on driving performance will be in terms of this

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complication. Epidemiological and clinical studies indicate that the presence of AF is associated with a four- to five-fold increased risk for stroke, after adjusting for other factors (Kannel et al., 1998; Dobbs, 2005). Recommendations from the CCS Consensus Conference (1996) for private drivers with chronic AF are: no restriction for private and commercial drivers with no underlying heart disease and no associated cerebral ischemia, no restriction for private drivers with underlying heart disease and no associated cerebral ischemia. Once the heart rate and symptoms have been treated, there should be no restrictions on driving privileges (Canadian Cardiovascular Society Consensus Conference, 1992; Dobbs, 2005). Paroxysmal supraventricular tachycardia or Wolff– Parkinson–White syndrome

PSVT is episodes of rapid heart rate that start in a part of the heart above the ventricles. Symptoms usually start and stop suddenly, and can last for a few minutes or several hours. They can include anxiety, chest tightness, palpitations, rapid pulse, shortness of breath, dizziness, and fainting (Paroxysmal supraventicular tachycardia, 2014). Individuals with a history of symptomatic tachycardia may resume driving after being asymptomatic for 6 months and on antiarrhythmic therapy. Drivers who undergo radiofrequency ablation may resume driving after 6 months, if there is no recurrence of symptoms, or sooner if no preexcitation or arrhythmias are detected on repeated electrophysiology testing. No restrictions apply if the individual is asymptomatic during documented episodes (Physician’s Guide to Assessing and Counseling Older Drivers, 2010; Dobbs, 2005). Ventricular tachycardia: Nonsustained ventricular tachycardia, sustained ventricular tachycardia

A significant number of sudden cardiac deaths in the United States are caused by VT, at an estimated rate of approximately 300 000 deaths per year (Chen et al., 1998). VT refers to any rhythm faster than 100 beats per minute, with three or more irregular beats in a row, arising distal to the bundle of his. The rhythm may arise from working ventricular myocardium and/or from the distal conduction system. The symptoms of VT include the following: palpitation, lightheadedness, syncope, chest pain, and anxiety. VT can also result in sudden death. VT includes NSVT and sustained VT (Compton, 2013). Nonsustained ventricular tachycardia

Individuals with symptomatic NSVT may resume driving after 3 months if they are on antiarrhythmic therapy – with or without an internal cardioverter defibrillator (ICD) – guided by invasive electrophysiologic (EP) testing, and the VT is noninducible at repeated EP testing.

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Drivers may resume driving after 6 months without arrhythmic events if they are on empiric antiarrhythmic therapy (with or without an ICD), or have an ICD alone without additional antiarrhythmic therapy. No restrictions apply if the individual is asymptomatic during documented episodes (Physician’s Guide to Assessing and Counseling Older Drivers, 2010). Sustained ventricular tachycardia

Individuals with VT may resume driving after 3 months if they are on antiarrhythmic therapy (with or without an ICD), guided by invasive EP testing, and VT is noninducible at repeated EP testing. Drivers may resume driving after 6 months without arrhythmic events if they are on empiric antiarrhythmic therapy (with and without an ICD), or have an ICD alone without additional antiarrythmic therapy (Physician’s Guide to Assessing and Counseling Older Drivers, 2010). Survivors of episode of ventricular tachycardia

Primary issues for driving safety among individuals that survived episodes of VT include (1) The likelihood of the arrhythmia recurring, (2) the likelihood that the arrhythmia will result in loss of consciousness, (3) the risk that the arrhythmia event will lead to a crash, and (4) the risk of harm to other road users (Dobbs, 2005). The recurrence of an arrhythmia

Older studies reveal that the survivors of sudden death caused by VT faced subsequent 1- and 2-year recurrence rates of 30% and 40%, respectively (Baum et al., 1974; Liberthson et al., 1974; Myerburg et al., 1982). However, with the advent of ambulatory electrocardiography (ECG) monitoring, programmed electrical stimulation to guide antiarrhythmic drug therapy, and the use of implantable cardioverter defibrillator devices, sudden death rates due to recurrent ventricular arrhythmias have declined significantly (Myerburg et al., 1987). Although the data are limited, those that are available suggest that the risk of recurrence of a ventricular arrhythmia is time-dependent with the highest risk occurring in the first 6–18 months following discharge from hospital following a first event (Furukawa et al., 1989; Myerburg et al., 1992). To determine when thesurvivors of VT and VF might safely return to driving, Larsen et al. (1994) followed 501 patients for 0–117 months (M¼ 26 months). Outcome events that could impair driving ability were analyzed. Those events included syncope, sudden death, recurrent VT, recurrent hemodynamically compromising VT, and ICD discharge. Results of that investigation revealed that the 1-year outcome event rate for all patients was 17%. Importantly, three distinct periods of risk were identified. The monthly hazard rate was highest in the first month following hospital discharge (4.22% per month), intermediate in months 2 through 7 (1.81% per month), and

lowest in months 8 through 12 (0.63% per month) (Larsen et al., 1994). Recommendations from the CCS Consensus Conference (1996) for private drivers with VT are: 1. A waiting period of 3 months for individuals: (1) with VT/VF noninducible by electrophysiologylogic studies (EPS), with or without ICD and (2) on EPSpredicted effective drug therapy, with or without ICD. 2. A waiting period of 6 months for individuals: (1) on Holter-predicted effective drug therapy, with or without ICD, (2) on empiric therapy with amiodarone, with or without ICD, and (3) on empiric therapy with other antiarrhythmic drugs, with ICD. 3. A waiting period of 12 months for individuals on empiric therapy with other antiarrhythmic drugs, without ICD. Atrioventricluar block

Heart block is a type of arrhythmia, which affects the electrical system affecting the rate or rhythm of the heartbeat. An atrioventricular block (AV block) involves the impairment of the conduction between the atria and the ventricles of the heart. AV block is grouped into First, Second, and third-degree AV block. First-degree AV block: generally not associated with any symptoms; it is usually an incidental finding on ECG. Second-degree AV block is divided into Type 1 (Mobitz 1, Wenckebach) and Type 2 (Mobitz 2). Second-degree AV block is usually asymptomatic, but in some patients, sensed irregularities of the heartbeat, presyncope, or syncope may occur; may manifest in physical examination as bradycardia (especially Mobitz II) and/or irregularity of heart rate (especially Mobitz I (Wenckebach)). Thirddegree AV block: frequently associated with symptoms, such as fatigue, dizziness, lightheadedness, presyncope, and syncope; associated with profound bradycardia unless the site of the block is located in the proximal portion of the atrioventricular node. Third-degree heart block requires prompt treatment because it can be fatal (Dobbs, 2005; Miles, 1997; Canadian Cardiovascular Society Consensus Conference, 1992). Syncope is aprimary symptom that places the driver with heart block at risk. The syncope symptoms are due to brady arrhythmias secondary to structural conduction system disease. Cardiac pacing is highly effective for individuals with heart block (Miles, 1997). Treatment is dictated by the degree to block. Firstdegree AV block and Mobitz I second-degree AV block do not generally require treatment unless they cause symptoms and are not due to a reversible cause. Implantation of a permanent pacemaker is the therapy of choice in advanced AV block. Second and third-degree AV block usually require temporary and/or permanent cardiac pacing. Patients with third-degree AV block with persistent bundle branch block and transient thirddegree AV block may benefit from permanent pacing

Road Traffic: Determination of Fitness to Drive – General

therapy, especially after anterior myocardial infarction (MI). Nonrandomized studies strongly suggest that permanent pacing improves survival in patients with third-degree AV block, especially if syncope has occurred. Individuals with symptomatic AV block managed with implant of pacemaker may resume driving according to pacemaker guidelines. Individuals with symptomatic AV block corrected without a pacemaker may only resume driving after they have been asymptomatic for 4 weeks and electrocardiogram (EKG) documentation shows resolution of the block. The CCS Consensus Conference (1996) makes the following recommendations from private drivers with heart block: There are no restrictions for private drivers with the following conditions: (1) isolated first-degree AV block, (2) isolated right-bundle branch block, (3) isolated leftanterior fascicular block, and (4) isolated left-posterior fascicular block. There are no restrictions for drivers with congenital third-degree AV block with no associated cerebral ischemia. There are no restrictions with no associated cerebral ischemia with: (1) left bundle branch block, (2) bifascicular block, (3) Mobitz type I AV block, and (4) first-degree AV block and bifascicular block. Conditions associated with disqualification of private drivers privileges include: (1) Mobitz type II AV block, (2) trifascicular block, and (3) first-degree AV block and bifascicular block (Canadian Cardiovascular Society Consensus Conference, 1992). Sick sinus syndrome: Sinus bradycardial, sinus exit block, and sinus arrest

Sick sinus syndrome is a collection of heart rhythm disorders that include sinus bradycardia – slow heart rates from the natural pacemaker of the heart; sinus pauses or arrest – when the natural pacemaker of the heart stops working for periods of time. Sick sinus syndrome is the name for a group of heart rhythm problems (arrhythmias) in which the sinus node – the heart’s natural pacemaker – doesn’t work properly. A person with sick sinus syndrome may have heart rhythms that are too fast, too slow, punctuated by long pauses, or an alternating combination of all of these rhythm problems. Sick sinus syndrome is relatively uncommon, but the risk of developing sick sinus syndrome increases with age. Many people with sick sinus syndrome eventually need a pacemaker to keep the heart in a regular rhythm (Sick sinus syndrome, 2011). Individuals with symptomatic disease can be managed with pacemaker implantation. Physicians should be alerted for clinically significant cognitive deficits that arise out of chronic cerebral ischemia. Those with significant cognitive changes should be referred to a driver rehabilitation specialist for a driver evaluation. No restrictions apply if the individual is asymptomatic during documented episodes. Regular medical

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follow-up is recommended to monitor cardiac rhythm and cognitive abilities (Physician’s Guide to Assessing and Counseling Older Drivers, 2010; Dobbs, 2005).

Cardiac Disease from Structural or Functional Abnormality

Two major considerations in determining medical fitness to drive are the risk of presyncope or syncope due to low cardiac output and the presence of cognitive deficits due to chronic cerebral ischemia. Drivers who experience presyncope, syncope, extreme fatigue, or dyspnea at rest or at the wheel should cease driving. Physicians should refer patients with clinically significant cognitive changes for cognitive testing and to a driving rehabilitation specialist (DRS) for evaluation. Cardiac diseases arising out of structural or functional abnormalities include congestive heart failure (CHF), hypertrophic obstructive cardiomyopathy (HOCM), and valvular diseases (Physician’s Guide to Assessing and Counseling Older Drivers, 2010). Congestive heart failure

CHF is a condition in which the heart’s function as a pump is inadequate to deliver oxygenated blood to the body. CHF can be caused by diseases that weaken the heart muscle, that cause stiffening of the heart muscles, or that increase oxygen demand by the body tissues beyond the capability of the heart to deliver adequate level of oxygenated blood. Approximately, 4.8 million individuals in the United States have CHF, with 400 000 new cases each year (National Institute of Health, 2000; National Health and Nutritional Examine Survey, 1991). The prevalence of CHF increases with age with the prevalence five times greater in individuals 70 years of age or older compared to those aged 40–59 (National Health and Nutritional Examine Survey, 1991). Common symptoms of CHF include shortness of breath, fatigue, and exercise intolerance. A decline in mental status is a common manifestation in CHF, an effect that may adversely affect driving performance. Studies have reported a positive relationship between CHF and cognitive impairment. An investigation in 1998 of the relationship between CHF and cognitive impairment measured by the mini mental state examination (MMSE) in an older population reported the following. A prevalence of CHF in subjects with cognitive impairment (MMSE below 24) of 20% compared to a prevalence of 4.6% among individuals with CHF with a MMSE424. Studies have also shown significant correlations between left ventricular ejection fractions and MMSE scores, with ejection fractionso30% associated with lower MMSE scores. Individuals with a diagnosis of CHF revealed significant differences in cognitive functioning between patients with CHF compared to those without CHF. Significant impairments were noted

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Road Traffic: Determination of Fitness to Drive – General

on the MMSE, verbal fluency, immediate and delayed recall (Rey test), and attention measures (Dobbs, 2005). The effects of CHF on driving performance are, unfortunately, largely unknown due to a paucity of research in the area. Fitness-to-drive guidelines for individuals with CHF have been published by the Canadian Cardiovascular Society (CCS). The CCS fitnessto-drive guidelines for individuals with CHF makes the following recommendations: no restrictions for private drivers that are functional class I-no functional limitations, (able to achieve 5–7 METS (1 MET equivalent to resting oxygen consumption in the seated position and equivalent to 3.5 ml kg1 min1)) or functional class II-mild functional limitations (able to achieve 5–7 METS), or functional class III LV class I-ejection fraction 50% or more, or LV class II-ejection fraction 35– 49% and Holter class II (no episodes of VT more than three beats in duration with an average cycle length 500 ms or less) (Canadian Cardiovascular Society Consensus Conference, 1992). Physicians should reassess a driver’s fitness with CHF every 6 months, or as needed depending on the clinical course and control of symptoms. Individuals with functional class III CHF (marked limitation of activity but no symptoms at rest, working capacity 2–4 METs (metabolic equivalents)) should be reassessed at least every 6 months (Physician’s Guide to Assessing and Counseling Older Drivers, 2010). Hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) was also known as HOCM. HCM is one of the most common inherited cardiac disorders (affecting B1 in 500 people) and is the number one cause of sudden cardiac death in young athletes. Annual mortality is estimated at 1–2%. The chief abnormality associated with HCM is LVH, occurring in the absence of any inciting stimulus such as hypertension or aortic stenosis. The degree and distribution of LVH is variable: mild hypertrophy (13–15 mm) or extreme myocardial thickening (30– 60 mm) may be seen. The most commonly observed pattern is asymmetrical thickening of the anterior interventricular septum (Hypertrophic Cardiomyopathy, 2013). Clinical symptoms: exertional syncope or presyncope – this is the most worrying symptom, suggesting dynamic left ventricular outflow tract obstruction7 ventricular dysrhythmia, with the potential for sudden cardiac death. Symptoms of pulmonary congestion (e.g., exertional dyspnea, fatigue, orthopnea, paroxysmal nocturnal dyspnea) due to left ventricular dysfunction. Chest pain – may be typical anginal pain due to increased demand (thicker myocardial walls) and reduced supply (aberrant coronary arteries). Palpitations due to supraventricular or ventricular arrhythmias. Drivers who experience syncope or presyncope should stop driving until they have been treated

(Physician’s Guide to Assessing and Counseling Older Drivers, 2010; Canadian Cardiovascular Society Consensus Conference, 1992). Valvular disease

Valvular heart disease is characterized by damage to defects in one of the four heart valves: the mitral, aortic, tricuspid, or pulmonary. Valve disease symptoms can occur suddenly or advances slowly. Note the severity of the symptoms does not necessarily correlate to the severity of the valve disease. An individual could have no symptoms at all, but have severe valve diseases. Conversely, severe symptoms could arise from even a small valve leak. Many of the symptoms are similar to those associated with CHF, such as shortness of breath and wheezing after limited physical exertion and swelling of the feet, ankles, hands, or abdomen (edema). Other symptoms include palpitations, fatigue, and dizziness or fainting (with aortic stenosis). Drivers who experience syncope or presyncope should stop driving until the underlying disease has been corrected (Physician’s Guide to Assessing and Counseling Older Drivers, 2010). Time-Limited Restrictions

The length of time of the driving restriction following cardiac procedures are based on the type of producer, the patient’s individual ability to recover from the procedure, and the initial underlying disease for which the procedure was performed. Cardiac procedures that may impact resuming driving include cardiac surgery involving median sternotomy, insertion of a pacemaker, and percutaneous transluminal coronary angioplasty (PTCA) (Physician’s Guide to Assessing and Counseling Older Drivers, 2010). Cardiac surgery involving median sternotomy

Individuals with heart diseases have a wide range of treatments such as bypass, valve replacement, and transplant. The length of driving cessation is primarily a function of the type of procedure and the length of recovery by the patient. Drivers may resume driving 4 weeks after coronary artery bypass grafting (CABG) and/or valve replacement surgery, and within 8 weeks of heart transplant, depending on resolution of cardiac symptoms and the patient’s course of recovery. In the absence of surgical and postsurgical complications, the main limitation to driving is the risk of sternal disruption following median sternotomy. If clinically significant cognitive changes persist following the patient’s physical recovery, cognitive testing, and fitness evaluated by a DRS are recommended before the patient is permitted to resume driving (Physician’s Guide to Assessing and Counseling Older Drivers, 2010).

Road Traffic: Determination of Fitness to Drive – General Pacemaker

Ever since the introduction of the pacemaker in 1958, millions have been implanted at a rate of 400 per million. Based on guidelines from the American College of Cardiology – American Heart Association Task Force (Dreifus et al., 1991), indications for pacemakers are: complete AV block (acquired, surgical, or congenital), second-degree AV block, sick sinus syndrome, carotid sinus hypersensitivity, and HCM. Approximately, 90% of all pacemakers are implanted because of either sinus node dysfunction or AV block. Syncope is the most common symptom prior to pacemaker implantation, and is seen in 40% of individuals. The second most frequent symptom is dizziness (25%) followed by symptomatic bradycardia (e.g., fatigue, lassitude, weakness, and visual disturbances) in 20% of individuals. The risk of syncope is essentially eliminated with cardiac pacing. Abrupt pacemaker system failure is rare, although problems with pacing leads have been reported (Miles, 1997). Bases on recommendations from the CCS Consensus Conference (1996) for private/commercial drivers with artificial cardiac pacemakers can resume driving under the following conditions: 1 week after pacemaker insertion if no longer experiencing presyncope or syncope, EKG shows normal sensing and capture, and the pacemaker is performing within the manufacturer’s specifications (Canadian Cardiovascular Society Consensus Conference, 1992). Percutaneous transluminal coronary angioplasty

PTCA is a minimally invasive procedure to open up blocked coronary arteries caused by coronary artery disease (CAD). A driver may resume driving 48 h to a week after successful PTCA and/or stenting procedures, depending on the patient’s baseline conditions and course of recovery from the procedure and underlying coronary artery disease (Physician’s Guide to Assessing and Counseling Older Drivers, 2010).

Unstable Coronary Syndrome (Unstable Angina or Myocardial Infarction)

Acute coronary syndrome defined here as unstable angina and non-ST elevation MI is characterized by episodes of chest pain at rest or with minimal exertion that are increasing in frequency or severity, often with dynamic ECG changes. Individuals with unstable coronary syndrome should not drive if they experience symptoms at rest or at the wheel. Drivers may resume driving when they are stable and asymptomatic for 1–4 weeks, as determined by a cardiologist following treatment of the underlying coronary disease. Drivers may resume within 1 week of successful revascularization by PTCA and 4 weeks after CABG (Physician’s Guide to Assessing and Counseling

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Older Drivers, 2010; Canadian Cardiovascular Society Consensus Conference, 1992). Sudden Death at the Wheel

Crashes due to sudden death while driving represent one possible tragic outcome for individuals with coronary heart disease, and is a source of potential danger to other road users. A review of the literature suggests that sudden or natural death while driving due to cardiac and other illnesses is a rare event. Early reports suggest that ‘sudden death while driving’ is a causal agent in less than 1% of all crashes (Baker and Spitz, 1970; Gratten and Jeffcoate, 1968; Herner et al., 1966; Peterson and Petty, 1962) and similar results were reported by Copeland in 1987. In the Copeland study, case files from the Medical Examiner’s office in Miami, Florida, were examined during the period of 1980–1984 (Copeland, 1987). Results reveal that less than 1% of all motor vehiclerelated accidental deaths were due to ‘sudden natural death at the wheel’. More recently, Halinen and Jaussi (1994) investigated the incidence of fatal traffic crashes caused by sudden incapacity of the driver due to cardiac and other illnesses in Finland and Switzerland. Results, based on a retrospective analysis from traffic accident data files in Finland (1984–1989) and police records of crashes from Vaud, Switzerland (1986–1989), reveal that sudden driver incapacity caused 1.5% of all traffic deaths in Finland, and 3.4% in Vaud. According to the authors, the higher rate of traffic deaths in Vaud due to sudden driver incapacity is likely due to higher traffic densities in the county of Vaud, which place heavier demands on the driver, and the more advanced age of drivers in Switzerland compared to Finland. Common causes of natural death while driving are MI, ventricular arrhythmia, and epilepsy (Halinen and Jaussi, 1994; Dobbs, 2005).

Neurological Conditions that May Impair the Driver While any medical condition that affects an individual’s ability to safely operate a motor vehicle requires attention neurological conditions, especially dementia demands greater attention for several reasons. First, dementia is a progressive disease and overtime individuals will lose their ability to drive safely. Second, dementia patients are more likely to drive even with visual and motor deficits. Neurological diseases can progress over time such as those caused by dementia, multiple sclerosis (MS), AD, and PD. While others occur rapidly, such as stroke, transient ischemic attacks (TIA), cerebrovascular accident, and seizures. Insults to the cerebral vascular system may cause a wide variety of symptoms, including sensory deficits, motor deficits, and cognitive impairment. These symptoms can range from mild to severe and may resolve almost immediately or

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persist for years (Campbell and Lutsep, 2003). During the evaluation process, the physician must take into account the individual’s unique constellation of symptoms, severity of symptoms, form of treatment, course of recovery, and baseline functions when making recommendations concerning driving privileges. The following neurological conditions and their impact on operating a motor vehicle will be discussed below: tumors, dementia, migraines, MS, PD, seizures, epilepsy, stroke, syncope, and TIA (Physician’s Guide to Assessing and Counseling Older Drivers, 2010; Canadian Cardiovascular Society Consensus Conference, 1992; Dobbs, 2005). Brain Tumors

A brain tumor is a mass or growth of abnormal cells in the brain. These growths can be classified as either benign or malignant and as primary or metastatic brain tumors. Treatment depends on the type, size, and location of the tumor. Recommendations on the continuation of driving should be based on the type of tumor, location, rate of growth, type of treatment, presence of seizure, and the presence of cognitive or perceptual impairment. Due to the progressive nature of certain types of tumors, the evaluation of fitness to drive needs to be done serially (Physician’s Guide to Assessing and Counseling Older Drivers, 2010). Dementia

Dementia is a general term describing loss of brain function that occurs with certain diseases primarily AD, PD, and stroke. It affects memory, thinking, language, judgment, and behavior. Individuals with dementia are often undetected and undiagnosed until late in the course of the disease. Initially, family and physicians may assume that the individual’s decline in cognitive function is part of the normal aging process. Physicians should be alert to the signs and symptoms of dementia and to pursue an early diagnosis. Early diagnosis is the first step in promoting driving safety for a dementia patient. The second step is intervention, which includes medication to slow the course of the disease, and counseling to prepare the individual for eventual driving cessation. When the assessment shows that the driver poses a significant safety risk, driving must cease. With early planning among the patient, family, and driver, the transition between driving and nondriving can be less traumatic (Physician’s Guide to Assessing and Counseling Older Drivers, 2010). The Alzheimer’s Association Policy Statement and the Canadian Consensus Conference on Dementia position statement on driving states: A diagnosis of dementia is not, on its own, a sufficient reason to withdraw driving privileges. A significant number of drivers with dementia are found to be

competent to drive during the early stages of the illness. Therefore, the determining factor in withdrawing driving privileges should be based on the individual’s driving ability. When the individual poses a serious risk to self or others, driving privileges must be withheld. Physicians with patients that have a history of dementia are recommended to perform a focused medical assessment that includes history of driving difficulty from family members or caregiver and an evaluation of cognitive abilities, including memory, attention, judgment, and visuospatial abilities. Physicians should be aware that patients with progressive dementia require serial assessment, including a formal assessment of driving skills consisting of an on-road driving assessment performed by a DRS (Canadian Cardiovascular Society Consensus Conference, 1992). Dementia of the Alzheimer type (DAT) individuals with DAT have an increased driving accident rate even with questionable or mild severity. Accident statistics show an increased risk for those with very mild and mild DAT. A number of studies have shown that individuals with even very mild or mild DAT are 2–3 times more likely to be in a crash compared to healthy age-matched controls, and that a high percentage of these individuals stopped driving only after having an accident. Among persons with AD, the increase in crash risk develops toward the end of the third year and more than doubles in the fourth year. Patients who have had AD for more than 2 years should have their driving ability closely monitored if they are to continue driving as the overall risk to society increases over time (Dubinsky et al., 2000). Optimum timing and type of screening for the cognitively impaired driver are still uncertain. Most recommend retesting every 6 months, although a clear-cut policy intended chiefly for primary care physicians is still lacking. In 1996, the California Department of Motor Vehicles revised its policy to revoke the driver’s license automatically only of persons with moderate or advanced dementia, and to enable those with very mild dementia to demonstrate the capacity to drive through a reexamination process (Physician’s Guide to Assessing and Counseling Older Drivers, 2010; Canadian Cardiovascular Society Consensus Conference, 1992; Dobbs, 2005). Migraine and Recurrent Headache Syndrome

Migraines are chronic neurological disorder characterized by recurrent moderate to severe headaches often in association with a number of autonomic nervous system symptoms, such as nausea, vomiting, photophobia (increased sensitivity to light), and phonophobia (increased sensitivity to sound). Typically, headache is unilateral lasting from 2 to 72 h. Up to one-third of people with migraine, headaches perceive an aura: a transient visual, sensory, language, or motor disturbance, which signals

Road Traffic: Determination of Fitness to Drive – General

that the headache will soon occur (Headache Classification Subcommittee of the International Headache Society, 2004). Individuals with recurrent headaches should be cautioned against driving when experiencing neurologic manifestations (visual disturbances or dizziness), when distracted by pain, and while on any barbiturate, narcotic, or narcotic-like analgesic. In addition, individuals that experience auras should as so as its safety possible pull off the road until the symptoms of the headache subside (Physician’s Guide to Assessing and Counseling Older Drivers, 2010). Multiple Sclerosis

MS is an autoimmune disease where the body’s immune system destroys the protective myelin sheath coving the nerves. This damage causes interference between the brain, spinal cord, and other regions of the body. MS also affects cognitive issues that can interfere with safe driving by reducing information processing speeds. Studies conducted in 2002 reported that drivers diagnozed with MS where involved in automobile accidents at a rate three times higher than healthy drivers of the same age (Lings, 2002; Schultheis et al., 2002). The Expanded Disability Status Scale (EDSS) is designed to provide a standardized measurement of global neurological impairment in patients with MS. Dr. Akinwuntan in Augusta, Georgia, reported that patients whose level of disability is low, scoring less than 2.5 are relatively good drivers and those above 7 are not fit to drive. Some have stated that the EDSS may not be a good measure of cognitive ability or impairment. Other research has shown that cognitive skills which may be negatively affected in individuals with MS can greatly hamper driving ability (Schultheis et al., 2001, 2010). The common MS symptoms that may affect driving include: sensory (touch) problems, such as tingling or numbness in hands and feet, visual problems, such as blurred or double vision, changes in your visual field or contrast sensitivity, or a temporary loss of sight caused by optic neuritis (inflammation of the optic nerve), fatigue which can make MS symptoms worse, loss of muscle strength, control and dexterity, and difficulty with memory, concentration, and thinking (Canadian Cardiovascular Society Consensus Conference, 1992). Driving recommendations should be based on the types of symptoms and level of symptom involvement. Physicians should be alerted for deficits that are subtle but have a strong potential to impair driving performance, such as muscle weakness, sensory loss, fatigue, cognitive or perceptual deficits, and symptoms of optic neuritis. Driver’s evaluation should include an on-road driving assessment performed by DRS and serial evaluation as the patient’s symptoms evolve and progress.

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Parkinson Disease

PD is a complex progressive neurodegenerative disorder of the central nervous system (CNS) recognized primarily as a motor disorder characterized by tremor and impaired muscular coordination. Cognitive and visual dysfunctions can also occur in the early stages of the disease. It is a common disorder affecting 3% of those 65 and older. Persons with mild PD experience problems with diminished visual contrast sensitivity, slower verbal learning, and slower set-shifting and executive tasks, all of which theoretically might affect driving. In moderately advanced PD, patients begin to suffer motor freezing, perform poorly on dual tasks; when quizzed while walking, both their stride length and verbal fluency decline, reflecting frontal lobe compromise. Individuals with advanced PD may lead to motor, cognitive, and visual impairments, all of which can affect a driver fitness to drive and increase the risk of motor vehicle crashes. Drivers typically complained particularly of difficulty managing pedals and assessing distances properly. Persons with PD may also develop cognitive impaired/dementia, emotional impairments (apathy and disinhibition), and visual-perceptual deficits that often do not respond to dopaminergic medications. In addition, PD patients have variability in response to the timing of dosage (on-off phenomenon) and side effects (daytime sleepiness) of their medications, these factors can impair driving ability and lead to an increased crash risk (Crizzle et al., 2012; Kahn, 2000; Uc et al., 2009). Limiting or complete driving cessation recommendations should be based on the level of motor and cognitive syndrome involvement, patient’s response to treatment, and presence and extent of any medication side effects. Currently, there are no evidence-based practice parameters to guide physicians in determining driver fitness with PD. The AMA recommends that physicians assessing driving privileges on motor and cognitive impairments, response to dopaminergic medications, and side effects. The National Highway Traffic Safety Administration (NHTSA) and Federal Motor Carrier Safety Administration both suggest a case-bycase, multidisciplinary evaluation focusing on the progression of the disease. Serial physical and cognitive evaluations are recommended every 6–12 months due to the progressive nature of the disease. The driver assessment should consist of an on-road driving assessment performed by a DRS. The United Parkinson Disease Rating Scale and the trial making B test results both correlated well with driving performance (Physician’s Guide to Assessing and Counseling Older Drivers, 2010).

Peripheral Neuropathy

Peripheral neuropathy is a term that refers to nerve damage; it leads to different ailments such as diabetes,

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traumatic injuries, infections, and metabolic problems. Typically, this condition results in weakness, numbness and pain, usually in hands and feet. At the same, it may occur in other areas of the body of patients. Lowerextremity deficits in sensation and proprioception may be exceedingly dangerous for driving, as the driver may be unable to control the foot pedals or may confuse the accelerator with the brake pedal. If deficits in sensation and proprioception are identified, referral to a DRS is recommended (Physician’s Guide to Assessing and Counseling Older Drivers, 2010). Seizure Disorders

A seizure is a paroxysmal uncontrolled abnormal discharge of electrical activity in the gray matter of the brain, causing clinical signs, and symptoms that interfere with normal functioning. A seizure is not a disease but is a symptom of underlying pathology. Numerous conditions can induce a seizure (e.g., CNS infections, hyperpyrexia, intracranial tumors, cerebral hypoxia, cerebral trauma, alcohol or drug withdrawal, etc.). It is estimated that up to 9% of the US population will have at least one seizure during their lifetimes and that the estimated risks of a recurrence following a single unprovoked seizure range from 23% to 71% (McLachlan, 1993; Dobbs, 2005). Patients with idiopathic seizures and normal electroencephalographies (EEGs) were found to have a low recurrence risk of about 24% at 2 years. Partial seizures were, in general, associated with an increased risk of seizure recurrence. Results of Berg and Shinnar’s metaanalysis may be useful when making decisions about licensing decisions for individuals with first unprovoked seizures. Specifically, results from this meta-analysis suggest that two commonly assessed patient characteristics (seizure etiology and EEG results) are helpful predictors for seizure recurrence (Berg and Shinnar, 1991). Healthcare providers must counsel their patients about the imperativeness and advantages of reporting the seizure disorder to the appropriate licensing authority. Patients should understand that this process not only improves public safety but also shields the driver from litigation should he/she have a seizure while driving, provided that individuals have not been otherwise negligent. If patients do not report their disorder and recurrent seizures, and do not obtain the physician’s statement, they may face civil liability and criminal prosecution in the event of an accident related to a seizure. In addition, if the physician believes that the patient has not self-reported and is endangering the public by driving, the physician should have the right to report the patient (with immunity). Moreover, the epileptic driver’s insurance company may deny coverage for the accident, particularly when the facts show that the individual failed to take the prescribed antiepileptic medication appropriately. For those patients who have

controlled their seizures successfully, the physician may offer a statement to the licensing authority, usually on specified forms, confirming that the individual’s seizures are controlled. With this statement, the physician asserts the opinion that, if licensed to drive, the person will not present an unreasonable risk to public safety. Generally, state medical review boards then review the driving application and physician statement and take a decision on whether to grant the license. State laws protect the physician from liability for violating patient confidentiality for statements about driving risk presented to the state, provided the statement is made in good faith and with reasonable belief of its accuracy. However, filling out the forms for the state authority is not enough. Providers may ask patients to sign in the medical record that they have received and understood counseling about driving risks and their obligations to report their disorder. Providers have an obligation to use reasonable care to protect potential victims and prevent harm to the public. Physicians who fail to counsel patients about driving risks from uncontrolled seizures, or who fail to document, such as counseling, may face future direct liability exposure, even to other individuals and third parties injured in seizure-related accidents (Physician’s Guide to Assessing and Counseling Older Drivers, 2010; Canadian Cardiovascular Society Consensus Conference, 1992; Dobbs, 2005). Epilepsy

Epilepsy, a common neurological disorder, characterized by recurrent seizures that can involve loss of consciousness, convulsive movements or other motor activity, sensory phenomena, or behavioral abnormalities. Epilepsy includes any recurrent loss of consciousness or conscious control arising from intermittent change in the brain function (Hansotia and Broste, 1999). Other disorders, which can also affect consciousness or control, such as syncope, cataplexy, narcolepsy, hypoglycemia, episodic vertigo interfering with function or drop attacks, also need to be considered in a similar fashion (Physician’s Guide to Assessing and Counseling Older Drivers, 2010; Dobbs, 2005). Epilepsy has a prevalence rate of 0.7% (McLachlan, 1993) and an overall incidence of about 50 per 100 000 (Hauser et al., 1996). The incidence of new-onset epilepsy is such that onset is highest in the first year of life, decreasing to a minimum during middle age (30s and 40s), and increasing again in individuals 60 years of age and older (Hauser, 1992). There are numerous classifications of epileptic seizures. The Commission on Classification and Terminology of the International League Against Epilepsy (1981) classified seizures as partial or generalized. The three most common types of seizures in adults are: (1) generalized tonic–clonic seizures, with convulsions (grand mal seizures), (2) complex partial seizures (CPSs),

Road Traffic: Determination of Fitness to Drive – General

with alterations of consciousness, and (3) simple partialseizures (SPSs) (Commission on Classification and Terminology of the International League Against Epilepsy, 1981). Approximately, one-third of all epileptic individuals have CPSs, with the prevalence increasing to approximately one-half in elderly epileptic individuals (Hauser, 1992). Epileptic seizures can also be classified by etiology into: (1) symptomatic or secondary epilepsy, and (2) idiopathic or primary epilepsy. In symptomatic or secondary epilepsy, the probable cause of the seizures, often, can be determined, whereas in idiopathic or primary epilepsy, specific causes cannot be found. Approximately, two-thirds of epilepsy in young adults is idiopathic in origin. However, more than 50% of epilepsy in elderly individuals have a known cause (Hauser, 1992), including cerebrovascular disorders (B33%), brain tumors (B10–15%), and infections, trauma, or other secondary lesions (B23%) (Luhdorf et al., 1986). Epidemiological studies have determined that the riskiest drivers with epilepsy are those that are most noncompliant with their prescribed medications and are the most likely to drive illegally without a license (Berg and Shinnar, 1994). Studies found that over 50% of persons with epilepsy drove illegally without completing a sufficiently long seizure-free interval or did not report breakthrough seizures to their physicians in states with mandatory doctor-reporting requirements. Those persons with epilepsy who abuse alcohol are clearly at much higher risk. According to the Consensus Statements on Driving Licensing in Epilepsy, from the American Academy of Neurology, American Epilepsy Society, and the Epilepsy Foundation of America, individuals with seizure disorder should not drive until they have been seizure-free for 3 months. The 3-month interval may be lengthened or shortened based on the presence of favorable or unfavorable modifiers. The following modifiers would increase the interval: noncompliance with medications, alcohol and/or drug abuse in the past 3 months, an increased number of seizures in the past 12 months, previous bad driving record, structure brain lesions, noncorrectable brain function or metabolic condition, frequent seizures after seizure-free interval, and previous crashes due to seizures in the past 5 years. The optimal minimal seizure-free interval to minimize seizure-related crashes is still unknown. In the United States, the seizure-free interval mandated by regulatory authorities varies from 2 years to as little as 3 months. Currently, six states in the United States and five provinces in Canada mandate that the physician reports to the state anyone with epilepsy (Physician’s Guide to Assessing and Counseling Older Drivers, 2010; Canadian Cardiovascular Society Consensus Conference, 1992; Dobbs, 2005). Epileptic seizures can result in an abrupt loss of consciousness or loss of body control. Further, if the

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seizure occurs while driving, the individual is placed in risk. Because of the potential for rapid incapacitation of the driver and the unpredictability of illness, epilepsy is one of the few medical conditions where restrictions on driving privileges are enforced in also every part of the world (Gastaut and Zifkin, 1987). The first report of a motor vehicle crash occurred due to a seizure was published in the early 1900s (Thalwitzer, 1906). Since then a number of studies have reported an increased risk of crashes in individuals with epilepsy, with rates of crashes for individuals with epilepsy ranging from 1.5 (Crancer and McMurray, 1968; Keys et al., 1961) to 1.95 (Waller, 1965) times greater than controls. Some studies have reported that individuals with epilepsy have a 40% increased risk of more severe crashes than nonepileptic individuals. More recent studies are equivocal: Taylor et al. (1996) suggested that the crash rates of individuals with epilepsy are not higher when compared to that of the general population, after adjusting for age, gender, driving experience, and mileage traveled, whereas results from Diller et al. (1998) suggested that crash rates are high for individuals with epilepsy (Taylor et al., 1996; Diller et al.,1998). Recent advances have resulted in improved medications for controlling seizures. Moreover, increased understanding by the medical community and by patients of the causes and effects of epilepsy has, undoubtedly, resulted in improved seizure control for many individuals with epilepsy. At one time, most developed countries prevented individuals with epilepsy from holding a driver’s license. Regulations, however, have gradually become less restrictive in many countries, such that individuals with epilepsy who have been seizure-free for a specified period of time are now granted the driver’s licenses. In a large number of states in the United States there are driving restrictions for individuals with epilepsy. However, there is considerable variability in the length of time required for the individual to be seizurefree before license renewal is allowed. In general, the seizure-free requirements range from 3 months to 2 years, with 1 year as the most common requirement. Although neuropsychological testing might be useful in identifying the presence or absence of cognitive impairments, more direct approach to evaluating driving competence would be through the assessment of on-road performance. Currently, the criteria for reinstating a driver’s license in individuals with epilepsy involves extended seizurefree intervals. This, however, leaves unanswered questions of driving competence for those treated with antiepileptic drugs. It may be that treatment with antiepileptic drugs reduces the risk of crashes due to seizures, but increases crash risks due to drug-related impairments in mental abilities. Despite extensive research in the last 25 years, the relative effects of antiepileptic drugs on cognition are controversial

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(Meador et al., 1995). In general, studies suggest that treatment with antiepileptic drugs can impair cognitive performance (Dodrill, 1988; Gallassi et al., 1987; Gallassi et al., 1988; Meador et al., 1995; Pulliainen and Jokelainen, 1994). Recent research suggests that the newer antiepileptic drugs (e.g., gabapentin, lamotrigine, and topirmate) produce fewer side effects than older antiepileptic drugs (e.g., phenytoin, carbamazepine). The significance of the cognitive impairments is, however, unclear (Leach et al., 1997; Martin et al., 1999). Future studies are needed to examine the effects of antiepileptic drug therapy on everyday activities, such as driving (Logan et al., 2000). Stroke

A stroke is an obstruction to or rupture of an artery resulting in complete or particle reduction in blood flow to a part of the brain leading to possible brain damage. There are two main types of strokes: ischemic stroke and hemorrhagic stroke. An ischemic stroke occurs when a blood clot or thrombus forms resulting in the blockage of blood flow to part of the brain. A hemorrhagic stroke occurs when a blood vessel on the brain’s surface ruptures and fills the space between the brain and skull with blood (subarachnoid hemorrhage) or when a defective artery in the brain bursts and fills the surrounding tissue with blood (cerebral hemorrhage). Symptoms associated within minutes of a stroke include: dizziness, trouble walking, loss of balance and coordination, speech problems, numbness, weakness, or paralysis on one side of the body, blurred, blackened, or double vision, and sudden severe headache (Physician’s Guide to Assessing and Counseling Older Drivers, 2010; Dobbs, 2005). Individuals with a history of stroke are at an increased driving-related risk due to decreased cognitive and psychomotor abilities. Individuals with acute motor, sensory, or cognitive deficits should not drive. Depending on the severity of residual symptoms and the degree of recovery, the driving restrictions may be permanent or temporary. All drivers with moderate to severe residual hemiparesis should be prohibited from driving until undergoing driving assessment. Even if symptoms improve to the extent that they are mild or completely resolved, the individual should undergo a driver assessment test, such as the Washington University Road Test, as reaction time may continue to be affected. Perceptual tests such as the motor-free visual perception test and trail making B test have also been shown to be predictive of on-road performance. Individuals with subarachnoid hemorrhage should not drive until symptoms have stabilized or resolved and a medical assessment is performed by a DRS (Physician’s Guide to Assessing and Counseling Older Drivers, 2010; Canadian Cardiovascular Society Consensus Conference, 1992; Dobbs 2005).

Syncope

Syncope is a temporary loss of consciousness, described as ‘fainting’ or ‘passing out.’ Syncope may result from various cardiovascular and noncardiovascular causes; it is recurrent in up to 33% of cases. The most common cause of syncope is cardiac arrhythmias. Driving restrictions for neurally mediated syncope should be based on the severity of the presenting event. No driving restrictions are necessary for infrequent syncope that occurs with warning and with clear precipitating causes. Individuals with severe syncope may resume driving after adequate control of the arrhythmia has been documented and/or pacemaker implantation. Driving cessation is recommended for individuals who continue to experience unpredictable symptoms after treatment with medications and pacemaker insertion (Physician’s Guide to Assessing and Counseling Older Drivers, 2010; Dobbs, 2005). Transient Ischemic Attacks

A TIA occurs when blood flow to a part of the brain stops for a brief period of time. Individuals who experience a single or recurrent TIA should refrain from driving until they have undergone medical assessment and appropriate treatment (Physician’s Guide to Assessing and Counseling Older Drivers, 2010). Traumatic Brain Injury that May Impair the Driver

Individuals with traumatic brain injury should not drive until symptoms have been stabilized or resolved. Traditionally, most driving rehabilitation programs have focused on the operational level, with emphasis on handling the vehicle and use of controls and mirrors, rather than tactical and strategic skills, where the deficits may lie for drivers with traumatic brain injury (Physician’s Guide to Assessing and Counseling Older Drivers, 2010). Vascular Malformation

Vascular malformations are abnormal clusters of blood vessels that occur during fetal development. These lesions while present from birth, they may not manifest until weeks or even years after birth. Following the detection of a brain aneurysm or arteriovenous malformation, the individual should cease driving until assessed by a neurosurgeon. The individual may resume driving if the risk of a bleed is small, an embolization procedure has been successfully completed, and/or the patient is free of medical contraindications to driving, such as uncontrolled seizures or significant perceptual or cognitive impairment (Physician’s Guide to Assessing and Counseling Older Drivers, 2010; Dobbs, 2005).

Road Traffic: Determination of Fitness to Drive – General

Metabolic Conditions that May Impair the Driver Disorders of the endocrine system include metabolic disorders that include diabetes, Cushing disease, Addison disease, and hyperfunction of the adrenal medulla. They also include thyroid disorders, parathyroid disease, pituitary disorders, and neuropathic disorders. Abnormalities of the endocrine system can cause altered consciousness, weakness, fatigue, lethargy, motor abnormalities, visual disturbances, tremors, or psychiatric disorders. Individuals with an acute condition of metabolic disorders may experience signs and symptoms that are incompatible with safe driving. Once one of these conditions has been diagnosed, evaluation should be undertaken by a physician to assess any degree of impairment (Dobbs, 2005; Cox et al., 2003). Diabetes Mellitus

Diabetes mellitus, one of the most common endocrine diseases, affects approximately 16 million Americans (Centers for Disease Control, 1998). Prevalence rates in the United States range from 2% to 6% (Centers for Disease Control, 1998; National Institute of Health, 1995). Statistics reveal that the prevalence of diabetes increases with age, and recent estimates are that 18–20% of those 65 and over in the United States have diabetes (Centers for Disease Control, 1998). Typically, the disease is categorized into two forms: insulin-dependent diabetes mellitus (IDDM or Type I diabetes) and noninsulindependent diabetes mellitus (NIDDM or Type II diabetes). The problems associated with diabetes, which may affect driving competency can be classified as either acute or chronic. Chronic effects of diabetes include cardiovascular disease (coronary artery disease, hypertension, cerebrovascular accidents, and microangiopathy), neuropathy, and diabetic retinopathy. Hypoglycemic reactions among diabetic drivers represent the most acute risk and are the primary causes of concern for traffic safety. Importantly, hypoglycemia does not occur in NIDDM treated only with diet and is unlikely to occur in those individuals with NIDDM treated with oral hypoglycemic (Hansotia and Broste, 1999). Hypoglycemic reactions are most likely to occur in insulin-treated individuals with IDDM, particularly those who are under tight glycemic control (The DCCT Research Group, 1987). Because of the importance for traffic safety, a detailed discussion of hypoglycemic reactions in the diabetic driver is provided below (Dobbs, 2005). Insulin-Dependent Diabetes Mellitus

IDDM is characterized by impairment in the ability to produce insulin. Daily insulin injections are required to manage the disease. IDDM may occur at any age, but it primarily appears before age 30 (Songer et al., 1988, 1993; Dobbs, 2005).

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Hypoglycemic reactions

Of all the metabolic complications of diabetes, hypoglycemia represents the most acute risk for traffic safety concerns. Hypoglycemia is common in diabetic individuals treated with insulin and also can occur in individuals treated with oral hypoglycemic sulfonylurea agents (Frier, 2000). Severity of hypoglycemia can range from very mild lowering of glycemia (60–70 mg dl1) with minimal or no symptoms to severe hypoglycemia with very low glucose levels (o40 mg dl1) and neurologic impairment (Gerich et al., 1991). A typical hierarchy of responses to decreases in plasma glucose concentrations has been described by Gerich in 1991. The initial response, occurring at approximately 70 mg dl1, involves an increase in the secretion of counter regulatory hormones (glucagon, epinephrine, growth hormone, and cortisol) and a concomitant increase in norepinephrine and acetylcholine release. If the initial responses are ineffective and further decreases in plasma glucose concentrations occur, the autonomic symptoms of sweating, tremor, hunger, anxiety, and palpitations occur, typically at blood glucose concentrations of 60 mg dl1. These autonomic symptoms usually act as a warning to the experienced individual to undertake protective measures (e.g., the intake of food) to ward off an impending hypoglycemic reaction. If the autonomic warning symptoms are ignored or unrecognized (hypoglycemic unawareness), with subsequent reductions in plasma glucose concentrations to around 50 mg dl1, symptoms of neuroglycopenia (weakness, lethargy, blurred vision, confusion, and dizziness) and signs of cognitive dysfunction usually occur (Gerich et al., 1991). Results from Pramming et al. (1991) revealed deteriorations in cognitive performance in IDDM individuals at blood glucose concentrations just below subnormal levels (54 mg dl1) (Pramming et al., 1991). An important finding in this investigation is that for all but one of the neuropsychological tests (finger tapping), there was a gradual deterioration in cognitive performance with decreasing blood glucose concentrations. Based on outcomes, the performance on everyday tasks that entail planning and control would be adversely affected even at subnormal blood glucose concentrations, concentrations that are usually not considered to be hypoglycemic. Significant disruptions in simulated driving behaviors during moderate hypoglycemia (2.6 þ 28 mM, B50 mg dl1) have been reported by Cox et al. (1993). Disrupted behaviors included more swerving, spinning, time over midline, time off road, and apparent compensatory slowing with an increase in ‘very slow’ driving (Cox et al., 1993). Despite the fact that hypoglycemia is the most common complication of insulin therapy in individuals with diabetes mellitus, the actual incidence of hypoglycemia is, however, difficult to ascertain. Ward et al. (1990) examined the prevalence of hypoglycemia in individuals randomly selected from outpatient clinics in Auckland,

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Australia (Ward et al., 1990). The results of the study indicated that majority (98%) of those surveyed had experienced hypoglycemia, with 73% reporting having had at least one mild episode of mild hypoglycemia monthly. Episodes of minor hypoglycemia have been estimated to occur twice per week in individuals with IDDM (The DCCT Research Group, 1991). Although short-term effects of mild hypoglycemia are troublesome for the individual, it is unlikely that episodes of mild hypoglycemia, if circumvented, pose much of a danger to individuals operating a motor vehicle. This is because signs of cognitive dysfunction generally begin to occur at plasma glucose concentrations around 50 mg dl1, which are below plasma glucose concentrations that initiate warning signs (Blackman et al., 1990; Ipp and Forster, 1987; Mitrakou et al., 1991; Widom and Simonson, 1990). Severe hypoglycemic reactions, on the other hand, represent the most significant short-term danger for the diabetic individual and particularly if the episode occurs during driving. Definitions of severe hypoglycemia vary and include hypoglycemia resulting in a seizure or a coma, reactions that require the intervention of another person, or a reaction that requires the administration of intravenous glucose, intramuscular glucagon, or hospitalization. Individuals that can demonstrate satisfactory control of their diabetes, have an ability to recognize the warning symptoms of hypoglycemia, and meet the visual standards, have no restrictions for operating a motor vehicle. Drivers should not drive during acute hypoglycemic and hyperglycemic episodes. Individuals who experience recurrent hypoglycemic or hyperglycemic attacks should not drive until they have been free of significant hypoglycemic or hyperglycemic attacks for 3 months (Physician’s Guide to Assessing and Counseling Older Drivers, 2010; Dobbs, 2005). Noninsulin-Dependent Diabetes Mellitus

NIDDM is a chronic condition that affects the way the body metabolizes glucose. It usually occurs in individuals over the age of 40. Therapeutic control often is achieved by diet alone or in combination with oral hypoglycemic agents. Of the two types of diabetes, NIDDM is the most common, with IDDM comprising only 5–10% of the total diabetic population (Canadian Diabetic Association, 2000; National Institute of Health, 1995). If the driver’s condition is managed by lifestyle changes and/or oral medication, there are no restrictions to driving privileges unless they develop disabilities such as diabetic retinopathy (Physician’s Guide to Assessing and Counseling Older Drivers, 2010). Thyroids Disorders: Hyperthyroidism/Hypothyroidism

Two common types of thyroid disorders include hyperthyroidism and hypothyroidisms.

Hyperthyroidism

Hyperthyroidism is the clinical expression of a group of disorders that produces elevated levels of free thyroxine and/or triiodothyronine (Goroll et al., 1987). This disorder includes toxic goiter (Grave’s disease), toxic multinodular goiter, and toxic uninodular goiter. While, the prevalence of hyperthyroidism is not known, it is estimated that the prevalence rate is 1.9% in women and 0.16% in men. Approximately, 15% of recognized cases occur in people older than 60 (Goroll et al., 1995). Clinical symptoms of hyperthyroidism include nervousness (anxiety), tremor, tachycardia, palpitations, muscle weakness, increased appetite, weight loss, and heat intolerance. In the elderly individuals, symptoms may be atypical, with the patient presenting with apathy, weight loss, and cardiovascular dysfunction (unexplained AF). A number of therapeutic agents are available for the treatment of hyperthyroidism. Driving should cease driving, if they experience symptoms associated with hyperthyroidism until symptoms are resolved or treated (Canadian Cardiovascular Society Consensus Conference, 1992; Dobbs, 2005). Hypothyroidism

Hypothyroidism is more common among thyroid disorders. The condition is caused decreased thyroid hormone production and secretion (Barnes, 1990). Causes include iodine deficiency in developed countries and chronic autoimmune thyroiditis (Barnes, 1990). Hypothyroidism affects women more than men. The prevalence of hypothyroidism increases with age. According to Goroll et al. (1987), as much as 5% of the elderly population show evidence of hypothyroidism. Subclinical hypothyroidism, on the other hand, is estimated to affect between 4% and 14% of people older than 60, with more females than males affected. Clinically, the patient with hypothyroidism presents with the following symptoms: fatigue, lethargy, sleepiness, drowsiness, dry skin, cognitive impairment, intolerance to cold, and weight gain. Fatigue, sleepiness, and cognitive impairment are the symptoms with the greatest relevance for driving. Once the diagnosis is established, treatment consists of thyroid hormone replacement therapy. Divers should not drive until their hypothyroidism has been treated. If residual cognitive deficits continue despite treatment, the individual may consider on-road assessment performed by a DRS (Physician’s Guide to Assessing and Counseling Older Drivers, 2010).

Respiratory Conditions that May Impair the Driver A number of respiratory diseases may interfere with the safe operation of a motor vehicle by causing reduced oxygen flow to the brain and subsequently cognitive impairment (e.g., impairments in judgment, decisionmaking, and attention). Respiratory diseases pertinent to

Road Traffic: Determination of Fitness to Drive – General

driving include asthma, chronic obstructive pulmonary disease (COPD), and carcinoma of the lungs. Asthma

Asthma is a chronic lung disease characterized by recurrent breathing problems (wheezing, shortness of breath, and chest tightness). Asthma is caused by inflammation of the lower airways. Triggers of asthma attacks include irritants in the air, respiratory infections, exercise, and changes in weather. It is estimated that over 14.6 million Americans suffer from asthma (Vital Health Statistics, 1995). Currently, there are no known studies that have examined the relationship between asthma and asthma related medications and motor vehicle crashes. Chronic Obstructive Pulmonary Disease

COPD refers to a group of diseases involving obstructed airflow, such as peripheral airway disease, emphysema, and chronic bronchitis. Emphysema and chronic bronchitis frequently coexist and the term COPD is often applied to individuals suffering from these two disorders. Complications of COPD include chronic hypercabia, corpulmonale (hypertrophy of the right ventricle), supraventricular and ventricular tachyarrhythmias, sleep hypoexmia, and acute respiratory failure (King, 1990). Approximately 16.4 million Americans suffer from COPD, which is the fourth leading cause of death in America (National Institute Health, 2000). Chronic bronchitis affects individuals of all ages. Emphysema, on the other hand, is more common among elderly individuals. Individuals with COPD should not drive if they suffer dyspnea at rest or at the wheel (even with supplemental oxygen), excessive fatigue, or have significant cognitive impairment. If individuals require supplemental oxygen to maintain a hemoglobin saturation of 90% or greater, they should use oxygen at all times while driving. Due to the often tenuous oxygenation status of these individuals, they should be counseled to avoid driving when they have other respiratory symptoms that may indicate concomitant illness or exacerbation of COPD (new cough, increased sputum production, change in sputum color, or fever). As COPD is a progressive disease, periodic reevaluations for symptoms and oxygenation status are required. Driver assessment should consist of an onroad driving assessment performed by a DRS with the driver’s oxygen saturation measured during the on-road assessment (Physician’s Guide to Assessing and Counseling Older Drivers, 2010; Canadian Cardiovascular Society Consensus Conference, 1992; Dobbs, 2005).

Renal Condition that May Impair the Driver Chronic Renal Disease

Chronic renal failure is a progressive disease involving deterioration and destruction of renal nephrons, with

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progressive loss of renal function. There are numerous causes of chronic renal failure, such as chronic glomerulone phritis, polycystic kidney disease, obstruction, and repeated bouts of pyelonephritis. Symptoms of chronic renal failure are absent during the early stages of the disease, as the disease progresses, however, the signs and symptoms of chronic renal failure appear. Symptoms include abnormal urinalysis, hypertension, weight loss, fatigue, malaise, and decreased mental acuity (Mayo Clinic, 1997). Drivers with chronic renal disease have no restrictions unless they experience symptoms such as cognitive impairment, impaired psychomotor function, seizures, or extreme fatigue from anemia. Individuals who require hemodialysis can drive without restriction, if they comply with nutrition and fluid restriction. Certain medications used to treat the side effects of hemodialysis may cause impairment to ones driving ability. In addition, the dialysis itself may result in hypotension, confusion, or agitation in many patients. These effects may require avoiding driving during the immediate postdialysis period. If the physician is concerned, the patient should take an on-road driving assessment performed by a DRS. Currently, there are no studies that have investigated the relationship between chronic renal failure and risk of motor vehicle crashes (Physician’s Guide to Assessing and Counseling Older Drivers, 2010; Canadian Cardiovascular Society Consensus Conference, 1992; Dobbs, 2005). End Stage Renal Disease

End stage renal disease (ESRD) is the final stage of chronic renal failure and is characterized by distinctive cardiovascular (e.g., hypertension, CHF, and anemia), gastrointestinal (e.g., anorexia, nausea, and vomiting), metabolic (e.g., increased blood urea nitrogen and serum creatinine levels), musculoskeletal (e.g., diffuse bone pain and bone abnormalities), and neurologic (e.g., peripheral neuropathy, cognitive impairment, and dementia) symptoms (Mayo Clinic, 1997). Individuals with irreversible kidney disease, management of the illness may include dialysis. There is a small body of literature, indicating that ESRD is associated with diminished perceptual motor coordination, impairments in intellectual functioning including decreased attention and concentration, and memory impairments (Baker et al., 1989; Ginn et al., 1975; Hart et al., 1983; Hagberg, 1974; McGee et al., 1982; Ryan et al., 1980; Kramer et al., 1996; Pliskin et al., 1996; Umans and Pliskin, 1998). There is little in the way of empirical literature to assist in fitness-to-drive decisions in individuals with renal failure. There is a small body of literature suggesting that cognitive impairment is associated with untreated renal disease. While a number of more recent studies

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(Buocristiani et al., 1993; Pliskin et al., 1996; Umans and Pliskin, 1998), however, have reported a lack of significant differences between dialyzed patients and healthy controls on various measures of cognitive performance. Improvements in the last decade or so in the management of ESRD may account for these findings. Future research with larger sample sizes and a more sensitive battery of cognitive testing would be instructive in this regard. Given the improvements in the quality of life of renal patients in recent years due to advances in patient care, it is likely that many patients with chronic renal disease can drive safely. However, directives from licensing agencies regarding the necessity for strict adherence to dialysis schedules may be prudent to ensure safety while driving.

Sleeping Disorders that May Impair the Driver Sleep disorders are thought to be responsible for a number of many motor vehicle crashes. However, it is difficult to establish reliable estimates of the contribution of sleepiness to motor vehicle crashes. The difficulty lies in identifying the role of sleepiness in crashes due to the multifactorial nature of many crashes, and the lack of objective and reliable measures for assessing driver sleepiness (Pack et al., 1995). According to recent estimates, 1–3 of all highway crashes are caused by driver sleepiness (Knipling and Wang, 1995; Wang et al., 1996; Webb, 1995). Narcolepsy and obstructive sleep apnea are two of the most common medical disorders that cause excessive daytime sleepiness, with obstructive sleep apnea the most common of the two disorders (Arbus et al., 1991; National Commission on Sleep Disorders Research Report, 1993). Both are believed to be associated with an increased risk of motor vehicle crashes. Literature relevant to both of these conditions is reviewed below. Individuals with sleeping disorders such as narcolepsy and sleep apnea should cease driving upon diagnosis but resume driving upon treatment. Only six US states – California, Maryland, North Carolina, Oregon, Texas, and Utah – have guidelines for narcolepsy. Physicians may consider using scoring tools, such as the Epworth Sleepiness Scale to assess the patient’s level of daytime drowsiness. In 1991, the US Federal Highway Administration recommended that drivers with suspected or untreated sleep apnea “not be medically qualified for commercial motor vehicle operation until the diagnosis has been eliminated or adequately treated.” Two states, California and Texas, currently have guidelines addressing sleep apnea. Currently, the impact of these regulations on crash rates or on the practice of sleep medicine has not been assessed (Physician’s Guide to Assessing and Counseling Older Drivers, 2010).

Narcolepsy

Narcolepsy is a chronic sleep disorder characterized by excessive daytime sleepiness, cataplexy, hallucinations, and sleep paralysis. Nocturnal polysomnograms and multiple sleep latency test are used to confirm the diagnosis of narcolepsy. Current estimates suggest that 0.03– 0.16% of the general population is affected, with men and women affected equally (Aldrich, 1990; Lyznicki et al., 1998). The condition usually starts in adolescence or early adulthood. Treatment of narcolepsy includes the use of stimulants (methylphenidate HCl (Ritalin) or dextroamphetamine) for sleepiness and tricyclic antidepressants for cataplexy and sleep paralysis (Green and Stillman, 1998). Excessive daytime sleepiness, which can affect driving performance, is generally believed to be the most debilitating of the symptoms (Green and Stillman, 1998). Cataplexy, a sudden episode of muscle weakness triggered by emotions (e.g., laughing, anger, and surprise), also may affect driving performance. More than onequarter of all narcoleptics may suffer from cataplexy (Broughton et al., 1981). Despite the potentially negative impact narcolepsy may have on driving performance, there are few studies investigating the relationship between narcolepsy and driving performance. A study in 1989 compared selfreports of crashes from individuals with narcolepsy to controls. Results of that investigation revealed that patients with narcolepsy have higher self-reported rates of crashes due to sleepiness than controls. Self-reported crashes were 11 times greater in females with narcolepsy compared to controls and seven times greater in males with narcolepsy compared to controls (Aldrich, 1989). George et al. (1996) investigated the performance of narcoleptics and controls on a divided attention driving test (DADT) involving tracking and visual search. Individuals with narcolepsy made significantly more tracking errors than controls. The differences between the two groups on the visual search test were less disparate. The pattern of findings suggests that individuals with narcolepsy have greater difficulty in dividing attention compared to controls (George et al., 1996). Despite the paucity of research in this area, most medical associations and driving agencies recommend that individuals who suffer from attacks of narcolepsy should not be allowed to drive. The Canadian Medical Association, Canadian Medical Association Staff (2000) specifically recommended that individuals with a diagnosis of narcolepsy supported by a sleep study and with uncontrolled episodes of cataplexy during the past 12 months (with or without treatment) not drive any type of motor vehicle. It is also recommended that those with a diagnosis of narcolepsy supported by a sleep study and with uncontrollable daytime sleep attacks or sleep paralysis during the past 12 months (with or without treatment) not drive any type of motor vehicle

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(Canadian Medical Association, Canadian Medical Association Staff, 2000). Sleep Apnea

Obstructive sleep apnea is a common disorder, affecting between two to 4% of the population (Young et al., 1993). Prevalence rates are higher in middle aged and older adults, and obese individuals (National Heart, Lung, Blood Institution Working Group on Sleep Apnea, 1996; Partinen, 1994; Strollo and Rogers, 1996). In sleep apnea, the upper airway repetitively collapses during sleep, resulting in sleep fragmentation, nocturnal hypoxemia, and lack of slow wave sleep. Cognitive impairments are thought to be frequent (Guilleminault et al., 1978; Strohl et al., 1984), with attention and concentration difficulties and impairments in vigilance the most common (Bédard et al., 1991; Findley et al., 1986; Greenberg et al., 1987). The cognitive deficits are believed to be due to hypoxemia during sleep, disruptions during sleep, and/or abnormal brain blood flow during wakefulness (Bédard et al., 1991; Guillemineault et al., 1988; Orr et al., 1979; Poceta et al., 1990). However, more research is needed to identify the underlying mechanism(s) responsible for the cognitive impairments. Nocturnal polysomnography is used to confirm the diagnosis of obstructive sleep apnea. With polysomnography, a number of physiological indices are monitored, including EEG, respiration, ECG, and oxygenation (American Thoracic Society, 1989). Generally, an individual is diagnosed with sleep apnea if they have greater than 10 apnea/hypopneas per hour of sleep. Apnea is defined as cessation of airflow lasting at least 10 s. Hypopnea is defined as a reduction in airflow lasting 10 s and is usually associated with a decline in blood oxygen level (American Thoracic Society, 1989). A number of treatments are available for sleep apnea including weight loss, alcohol abstinence, nasal continuous positive airway pressure (CPAP), and nasal and upper airway surgery (uvulopalatopharyngoplasty). CPAP is the most common treatment. Reduction in daytime sleepiness often is reported immediately with CPAP treatment, although studies indicate that approximately 6 weeks of treatment are required for maximum improvement in symptoms (Lamphere et al., 1989). Compliance rates differ as a function of measurement: subjective rates of patient compliance are higher than objectively determined values. Based on objective measures, Kribbs et al. (1993) reported acceptable compliance rates of 46% in patients treated with CPAP. Acceptable compliance was defined as the use of the CPAP machine for more than four hours per night for more than 70% of the observed nights (Kribbs et al., 1993). The literature reviewed suggests that both narcolepsy and obstructive sleep apnea may be associated with

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impaired driving performance. However, the limitations in the current literature are such that recommendations regarding licensure are likely to be based on an inadequate knowledge base. As noted by the American Thoracic Society (1994), sleep apnea is ‘undoubtedly a risk factor, but is not invariably linked with impaired driving.’ Thus, “efforts to reduce excessive driving risk should most sensibly be directed at selected patients with excessive daytime sleepiness, rather than categorically applied to anyone with apnea or with a certain number of sleep apnea events.” For example, results from Findley et al. (1988) revealed that more than two-thirds of individuals with sleep apnea were crash free during a 5-year study period. Currently, used measures of disease severity are inadequate in identifying those individuals with sleep apnea most at risk for motor vehicle crashes. Research is needed that will identify those individuals with sleep apnea who are most at risk for motor vehicle crashes. Finally, research examining the relationship between the results of simulated driving performance to real world on-road performance is needed. Currently, that relationship is not well defined.

Sensory Conditions that May Impair the Driver A driver receives visual and auditory inputs while operating a motor vehicle. Driving is a highly visual operation. Approximately, 90% of information used while driving is visual (Hills, 1980). Despite the apparent relationship between good visual function and safe driving performance, research has failed to find a strong relationship between the two. At least, five reasons are cited for the reported weak relationship between visual functioning and driving performance. These include: (1) vision is but one factor affecting driver performance, (2) the disparity between an individual’s visual capacities and the extent those capacities are used or needed in driving, (3) a lack of validity between tests used in research and the visual demands of driving, (4) the possibility of low reliability of the criterion measure of driving, and (5) methodological shortcomings of studies assessing the relationship between visual functioning and driving performance (Burg, 1971). A number of conditions can affect visual functioning and they include visual acuity, visual attention, and cataracts. Despite the importance of auditory information for driving (e.g., auditory feedback regarding operation of the motor vehicle, mechanical failure, awareness of other road users through detection of road noise, horn honking, etc.), there are limited data to indicate that impairments in hearing affect driving ability. Results from early studies conducted in 1963 (Coppin and Peck, 1963) indicated that deaf people, as a group, had poorer driving records compared to the nondeaf. However, more recent studies have failed to provide convincing evidence that individuals with hearing impairments are

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at a higher risk for motor vehicle crashes. In 1994, a population-based case control study that was undertaken to determine whether sensory impairments place older drivers at risk for collision injuries revealed no significant increase in risks of injury from motor vehicle collisions as a function of hearing impairment (McCloskey et al., 1994). However, those using hearing aids were at increased risk of an injury collision. It was speculated that feedback from the hearing aid while driving may create a distraction, placing the driver at an increased risk of crash involvement. However, no analysis was conducted to determine who was at-fault (McCloskey et al., 1994). Age and disease-related changes that may affect driving ability include visual acuity, visual fields, night vision, and contract sensitivity are discussed below. Visual Acuity

The most common type of visual disorder is errors of refraction. An individual with 20/20 vision is classified as having normal visual acuity. An individual with 20/ 70 vision or less (even when wearing corrective lenses) is classified as visually impaired. A person is legally blind when their vision is 20/200 or less, even when wearing glasses. On initial applications for a driver’s license, all United States and Canadian jurisdictions require vision testing (Keeney, 1993). In most states in the United States (42 States or 84%), an unrestricted private driver’s license requires visual acuity of 20/40 or better (corrected or uncorrected) in one eye alone. Results from a number of large-scale studies have indicated that individuals who have a history of eye conditions that may affect driving have a higher risk of crashes compared to controls matched on age, gender, and county of residence (Diller et al., 1998). Individuals with deceased far visual acuity may reduce its impact on dangerous driving by restricting driving in low-risk areas and conditions such as familiar surroundings, non-rush hour traffic, daytime, and good weather conditions. Individuals with a far visual acuity less than 20/70 should undergo an on-road assessment performed by a DRS. Individuals with a far visual acuity less than 20/100 should not drive until safe driving can be demonstrate by an on-road assessment performed by a DRS (Physician’s Guide to Assessing and Counseling Older Drivers, 2010). If the physician suspects visual acuity should referrer to an ophthalmologists for visual assessment for cataracts, macular degeneration, and glaucoma. Early evaluation is critical because many of these conditions can be improved and/or stabilized with treatment. A 1998 study to assess of the impact of vision-related relicensing policies on traffic fatalities in 48 contiguous States and the District of Columbia revealed lower vehicle occupant fatality rates of older drivers in those states with vision-related relicensing policies

(Shipp, 1998). State-level mandatory vision testing for relicensure may enhance traffic safety and reduce the economic costs of fatal crashes.

Dynamic Visual Acuity

The act of driving primarily involves the ability to discriminate an object when there is relative movement between the object and observer. Therefore, tests of dynamic visual acuity rather than static visual acuity would seem to be more relevant for assessments of safe driving performance. In contrast to static visual acuity, dynamic visual acuity is a reliable predictor of crash probability (Fox, 1989; Graca, 1986; Hills and Burg, 1977; Reuben et al., 1988; Ivers et al., 1999). Testing of dynamic visual acuity are seldom, if ever, included in traditional license renewal assessments. Importantly, declines in dynamic visual acuity and lateral motion detection start at an earlier age and accelerate faster, whereas deterioration in static visual acuity occurs later and progresses more slowly (Shinar and Schieber, 1991).

Low Vision and Telescopic Lens

Individuals with low vision have impaired vision that cannot be fully corrected by ordinary prescription lenses, medical treatment, or surgery. Low vision is defined as vision ranging from 20/200 to 20/50, or when the corrected vision becomes a disability to the point at which one cannot function at his or her vocation (Fonda, 1986). Recent estimates suggest that approximately 14 million (one in twenty) Americans have low vision (Kupfer, 1999). Low vision in older persons is most often the result of pathologies such as cataracts, macular degeneration, glaucoma, and diabetic retinopathy, or from a cerebrovascular accident. Individuals with low vision may experience one or more of the following: overall blurred vision, loss of central vision, and loss of peripheral vision. Telescopic spectacles and other low vision aids are used to assist individuals with low vision. Despite the importance of research in this area, there has been little research on the use of telescopic lenses and driving performance. The literature that is available generally discusses the benefits and drawbacks of the use of telescopic lenses while driving. However, there is little in the way of data to support the pros or cons of their use. Limitations of telescopic lens systems include small central fields, ring scotomas, nearness illusion, movement of the image in the opposite direction of any head movement, reduced resolving power due to vibration, and altered head posturing (Lippman, 1976; Scott, 1976). However, these cited limitations are over 25 years old and considerable improvements have been made in the technology of telescopic systems in recent years (Park et al., 1993).

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Advances in technology of telescopic systems include rear mounting, miniaturization, micro spiral galilean, vision enhancing systems, and bi-level telemicroscopic and behind the lens systems (Park et al., 1993). Research is needed, however, on the use of the new telescopic systems and driving performance. A driving program was developed in 1993 for visually handicapped telescopic drivers. The program is designed to ensure that every visually impaired telescopic driver meets the legal visual acuity and visual field requirements. In addition, the program is designed to improve the competency of telescopic lens use while driving. Details on the efficacy of the program are, however, lacking at this time. The NHTSA has established guidelines for unrestricted driver’s license and states that a driver must have 20/25 static near visual acuity in each eye (with correction less than 10 D), monocular visual fields of 120 in each eye, and binocular visual fields of 70 to the right and to the left in the horizontal meridian. Many common eye conditions require special consideration but lack set standards, including impairments of color vision and dark adaptation; heterophoria; stereopsis; monocular vision; refractive states; and telescopic lenses. Both dynamic visual acuity and static acuity decline with age, however, with dynamic acuity, the ability to resolve details of moving objects deteriorates more rapidly.

Visual Attention

Older drivers with 40% or greater impairment in their useful field of view (UFOV) – which stems from decline in visual sensory function, visual processing speed, and/ or visual attention skills – appear to be at an increased crash risk. Older adults who failed the UFOV task have been shown to have 3–4 times more accidents overall and 15 times more intersection accidents than older adults who passed the UFOV task. The NHSTA recommends that the UFOV protocol be incorporated as a diagnostic test of cognitive deficits, to predict driving impairments for license renewal applicants. The formal testing of UFOV can be performed at the physician’s office (Physician’s Guide to Assessing and Counseling Older Drivers, 2010; Dobbs, 2005). Visual field

While it is understood that an adequate visual field is important for safe driving, currently there is no definition defining what an ‘adequate visual field’ is nor what constitutes a standard test of visual field. There are significant state-to-state variations pertaining to visual field. Some states require a visual field of 100 degrees or more along the horizontal plane, other have lesser requirements, and some with no requirements. If the physician suspects a visual field defects they should refer the patient to an ophthalmogist for an evaluation.

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Cataracts

A cataract is a clouding of the lens of the eye, causing light from reaching the retina of the eye. Cataracts can result in compromised visual acuity (Mantyjarvi and Tuppurainen, 1999; Rubin et al., 1993), contrast sensitivity (Mantyjarvi and Tuppurainen, 1999; Rubin et al., 1993), and visual field sensitivity (Heuer et al., 1988). More than 12.9 million Americans age 40 and older have cataracts (Vision Problems US, 2000). Cataracts are the leading cause of vision impairment in older adults, affecting almost half of individuals 75–85 years of age (Kline et al., 1992). The main cause of cataract is aging process. Treatment of cataracts involves the removal of the clouded lens either through phacoemulsification or extra capsular surgery. Research reveals significant improvements in visual functioning following cataract surgery. Studies have reported that more than 85% of cataract cases achieve acuity of 20/40 or better following cataract treatment (Stark et al., 1983). Investigations revealed that individuals with cataracts have a higher risk of motor vehicle crashes. A 1999 investigation of the relationship between older drivers with and without cataracts and crash risk revealed that drivers with cataracts were 2.5 times more likely to have a history of at-fault crashes compared to those without cataracts. Individuals with moderately advanced cataracts (20/40–20/60) suffer more at-fault car crashes than individuals without cataracts (Owsley et al., 1999; Physician’s Guide to Assessing and Counseling Older Drivers, 2010). Individuals who have not undergone surgical treatment for cataract, assessments of visual functioning should include not only tests of visual acuity but also of contrast, glare, and visual field sensitivity. Although the data are limited, second-eye cataract surgery (if necessary) provides significant improvement in visual functioning and appears to be warranted. Future research is required to establish the parameters for safe resumption of driving following cataract surgery. Fortunately, visual impairment from cataracts is correctable with surgery to 20/40 acuity or better in most cases. An eye specialist should counsel patients regarding the dangers associated with driving with cataracts and suggest driving restrictions (e.g., at night/dusk, in reduced-visibility conditions such as rain, fog) until surgery has been performed (Physician’s Guide to Assessing and Counseling Older Drivers, 2010). Hearing Loss

There are very few studies that have examined the relationship between hearing impairment and the risk of a motor vehicle crash. Of these studies, none have demonstrated a clear and significant relationship between hearing impairment and the risk of crash. One study conducted in 1994 failed to find an association between hearing impairment and risk for injuries sustained in

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motor vehicle crashes. However, results of that investigation suggest that use of hearing aids by the hearing impaired while driving places the driver at an increased risk of motor vehicle crashes. Two studies conducted in 1994 and 1999 investigated the relationship between hearing impairment and risk of crash had mixed results. In most states, hearing loss traditionally has not precluded driving. The deaf driver (hearing loss 480 dB) and even those with hearing impairments (correctable to no better than 60 dB) lack a warning system that other drivers on the road assume to be present. While it is possible to compensate for lack of hearing with other sensory input, especially visual, some deaf drivers do have an increased accident rate. Currently, therefore, there is little evidence to warrant driving restrictions for individuals with hearing impairments from operating private vehicles (Physician’s Guide to Assessing and Counseling Older Drivers, 2010; Dobbs, 2005). Vertigo

Vertigo is a sensation of motion or spinning. The spinning sensation may cause nausea and vomiting. Other symptoms may include difficulty in focusing the eyes, dizziness, hearing loss, and loss of balance. Drivers with acute vertigo should cease driving until symptoms have fully resolved. Individuals with chronic vertiginous disorder are strongly recommended to undergo driver assessment consisting of an on-road driving assessment performed by a DRS before resuming driving. The medications commonly used to treat these conditions have a significant potential to impair driving skills (Physician’s Guide to Assessing and Counseling Older Drivers, 2010; Dobbs, 2005).

Deficits of the Extremities that May Impair the Driver Deformities of the feet (toenail irregularities, calluses, bunions, and hammertoes), impairment of gait and balance, and drivers who indicate that their feet or legs feel cold have all been shown to increase car collisions. Older drivers with poor flexibility of arms, legs, and neck are at increased crash risk. Epidemiological studies have reported that older women who could not extend their arms above shoulder height were more than twice as likely to crash their vehicles. In another study, limited neck range of motion was independently associated with adverse driving events.

Medications and Their Effects on Drivers’ Fitness Many of the commonly prescribed prescription and over-the-counter medications can impair driving performance. In general, any drug with prominent CNS

effects has the potential to impair an individual’s ability to operate a motor vehicle. The level of impairment is determined by the pharmacological actions and the side effects of medications. In addition, the actions of all medications must be examined alone and in combination with other medication, especially alcohol. Side effects that may affect driving performance range from drowsiness, blurred vision, and slow reaction time, to extrapyramida side effects. Potential driving impairing medication is a relatively new term that indentifies medications that have been associated with an increased crash risk. Physicians should make every effort to prescribe nonimpairing medications. However, if prescriptions that can impair driving needs to be prescribed, physicians should counsel the patient regarding the side effects. Therefore, physicians should counsel their patients on specific symptoms and side effects associated with the prescribed medication and suggest them to alert the physician, if such symptoms occur. When prescribing new medications, the physician should consider the present regimen of prescription, nonprescription, and seasonally prescribed medications. The combinations of drugs may affect drug metabolism and excretion, producing additive or synergistic interactions. A physician may consider formal psychomotor testing consisting of an on-road driving assessment performed by a DRS while off and on the medication to determine the extent of impairment. Many medications have been associated with increased crash risk and impairing the driver to operate a vehicle safety. A particle list includes alcohol, hypnotics, antiepileptic agents, antiemetic agents, narcotics, barbiturates, benzodiazepines, antihistamines, antidepressants, antipsychotics, and muscle relaxants. Below is a description of a number of medications, their effects on the driver, and recommendations regarding driving a motor vehicle (Physician’s Guide to Assessing and Counseling Older Drivers, 2010). Anticholinergics

Anticholinergic agents are substances that block the neurotransmitter acetylcholine in the central and the peripheral nervous system. Anticholinergic drugs are used in treating a variety of conditions, such as gastrointestinal disorders, genitourinary disorders, and respiratory disorders. The anticholinergic effects that can impair driving performance include blurred vision, double vision, sedation, confusion, ataxia, tremulousness, and myoclonic jerking. Individuals should also be advised that psychomotor and cognitive impairment might present even in the absence of subjective symptoms. Subtle deficits in attention, memory, and reasoning may occur with therapeutic dosage of anticholinergic drugs without signs of frank toxicity. These deficits have often been mistaken for symptoms of early dementia in elderly patients.

Road Traffic: Determination of Fitness to Drive – General Anticonvulsants

Drivers with epilepsy have an increased risk of an accident, due to their medical condition and from the side effects of medication. The traditional treatment for epilepsy is the use of anticonvulsant drugs that reduce the epileptic activity of nervous cells and decline or suppress epileptic discharges. The main anticonvulsive drugs and their adverse reactions are listed below. Phenytoin can lead to ataxia, lack of coordination, confusion, osteomalacia, and exanthema. Carbamazepine can cause ataxia, instability, diplopia, dizziness, gastrointestinal irritation, hepatotoxicity, and bone marrow suppression. Phenobarbital can cause ataxia, confusion, sedation, instability, depression, and exanthema, Primidone: can cause ataxia, confusion, sedation, instability, depression, and exanthema. Valproic acid can cause ataxia, sedation, tremor, hepatotoxicity, bone marrow suppression, and gastrointestinal irritation. Ethosuximide: can cause ataxia, lethargy, gastrointestinal irritation, skin exanthema, and bone marrow suppression. Clonazepam can cause ataxia, sedation, lethargy, and anorexia; it can precipitate a state of absence if administered with valproic acid. Trimethadione can cause blurred vision, sedation, skin rash, bone marrow suppression, nephrosis and hepatitis. Felbamate can cause insomnia, headache, instability, gastrointestinal irritation, nausea, and anorexia. Lamotrigine can cause headache, ataxia, instability, diplopia, exanthema, and nausea. Gabapentin can originate instability, somnolence, ataxia, and gastrointestinal irritation; it does not show pharmacological interactions (Driving and Medicines, 2013). Individuals should temporarily cease driving during the time of medication initiation, withdrawal, or dosage change due to the risk of recurrent seizure and potential medication side effects that may impair driving performance. If there is a significant risk of recurrent seizure during medication withdrawal or change, the individual should immediately cease driving for at least 3 months. If an individual experiences a seizure after medication withdrawal or change, he/she should not drive for 1 month after resuming a previously effective medication regimen. The main functions of a physician are to control the individual characteristics of epilepsy and to advise the epileptic patient on their limits related to driving. Patients should be advised against driving until the disease is stabilized, and should be made aware of the adverse events of his medication that can reduce his ability to drive. General guidelines for permitting driving privileges include; if the patient has no seizures or loss consciousness for 1 year, and approved by the patient’s physician. The patient with myoclonic shakes can demonstrate a minimum period of 3 months without shakes, and favorable report from the neurologist. Epileptic

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patients are advised against driving during treatment changes or if compliance is not adequate. All epileptic patients who despite treatment can be at risk of loss of consciousness cannot drive. Antidepressants

The degree of driving impairment varies among different classes of antidepressants and even within certain classes of antidepressants. In general, antidepressants that possess antagonistic activity at cholinergic, alpha1-adrenergic, and histaminergic receptors are the most impairing. Individuals should be advised not to drive during the initial phase of antidepressant dosage adjustment(s) if they experience drowsiness, lightheadedness, or other side effects that may impair driving performance (Sansone and Sansone, 2009). Below is a description of a number of common antidepressants and side effects that can impair driving. Bupropion

This antidepressant is used to treat depression, seasonal affective disorder, and acts as an aid in quitting smoking. Drugs in this class include Wellbutrin, Aplenzin, Zyban, Buproban, and Budeprion. The side effects of bupropion include anxiety, restlessness, and insomnia. Patients should be counseled on such side effects and their potential to impair driving performance. Bupropion may cause seizure in high doses and it should not be prescribed to individuals with a history of epilepsy, brain injury, or eating disorder. Mirtazapine

Mirtazapine is typically taken at night due to its sedating effects. However, is has been shown to cause substantial impairment for many hours after dosing. Patients should be advised not to drive if daytime sedation is noted. Monoamine oxidase inhibitors

Monoamine oxidase inhibitors (MAOI) are chemicals, which inhibit the activity of the monoamine oxidase enzyme family. They have a long history as a treatment for depression, panic attacks, OCD, generalized anxiety, PTSD, and social anxiety. Drugs in this class include Phenelzine, Selegiline, and Tranylcypromine. The side effects of MAOIs that may impair driving performance include blurred vision, overstimulation, insomnia, orthostatic hypotension (with transient cognitive deficits), and hypertensive crisis. Patients should be counseled on these side effects and their potential to impair driving. Tricyclic antidepressants

Tricyclic antidepressants (TCA) have been shown to impair psychomotor function, motor coordination, and open-road driving. Common side effects of tricyclic antidepressants that may impair driving performance

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include sedation, blurred vision, orthostatic hypotension, tremor, excitement, and heart palpitation. Studies have indicated an increase in the risk of drivers involved in motor vehicle crashes who take TCA due to impaired psychomotor functions and motor coordination. The pharmacological properties of the antidepressants that specifically account for potential driver impairment are antihistaminic and/or anticholinergic effects. These effects may initially cause somnolence or sedation, resulting in cognitive difficulties, attentional deficits, indecisiveness, and psychomotor impairment. A retrospective study on elderly individuals aged 65–84 in the Tennessee Medicaid program, found a greater relative risk for motor vehicle accidents (MVAs) among those on TCA (RR ¼2.2; 95% CI¼ 1.3–3.5). This risk increased with increasing TCA dose. An examination of older drivers in a Seattle-based health maintenance organization found that for those participants taking TCAs, there was an increased relative risk for a MVA of 2.3 (95% CI¼ 1.1–4.8). In a Japanese study, examining the effects of amitriptyline on healthy men showed that four hours after initial dosing, participants demonstrated significantly impaired road tracking and car-following performance as well as somnolence and reduced vigilance. In general, studies with TCAs and risk factors associated with impaired driving ability appear to be: (1) advanced age, (2) rapid escalation and/or high doses of TCAs, and (3) the initial dose as well as the initial treatment period with TCAs (i.e., first week). Studies with the newer antidepressants suggest that active depressive symptoms and the administration of comorbid psychotropic drugs, especially benzodiazepines, heighten the risks of MVAs. Tricyclic antidepressants should be avoided in individuals who wish to continue driving. If nonimpairing alternatives are not available, the physician should advise patients on the potential side effects and recommend temporary driving cessation during the initial phase of medication initiation/dosage adjustment. Selective serotonin reuptake inhibitors

Selective serotonin reuptake inhibitors or serotoninspecific reuptake inhibitor are a class of compounds typically used as antidepressants in the treatment of depression, anxiety disorders, and some personality disorders. Common side effects include changes in sleep pattern (insomnia or sedation), headaches, anxiety, and restlessness. Studies have shown that at high levels of the drug and drug-drug interactions there was noted mental status changes, autonomic hyperactivity, and neuromuscular side effects. Antiemetics

Antiemetic is a group of drugs typically used to prevent and control severe nausea, vomiting, and motion

sickness. Drugs in this class include antihistamines, antipsychotics, cannabinoids, benzodiazepines, 5-hydroxytryptamine antagonists, ondansetron, metoclopramide, domperidone, and glucocorticoids used for their antiemetic effects. General side effects of antiemetics that may impair driving performance include sedation, dizziness, drowsiness, blurred vision, headache, confusion, and dystonias. Significant driving impairment may be present even in the absence of subjective symptoms. Antihistamines

First generation antihistamines such as diphenhydramine and chlorpheniramine have pronounced CNS effects. Sedating antihistamines have been shown to impair psychomotor performance, simulated driving, and open-road driving. Individuals may experience impairment even in the absence of subjective symptoms of impairment. Therefore, individuals taking sedating antihistamines should be advised not to drive while on the medication. In contrast, nonsedating antihistamines do not produce this type of impairment if taken as per the recommended dosage. However, higher-than-recommended doses may impair driving performance. Antihypertensives

The common side effects of antihypertensives, such as lightheadedness, dizziness, and fatigue, coupled with the properties of hypotension, may impair driving performance. In addition, antihypertensives with a prominent CNS effect, including beta-blockers and sympatholytic drugs, such as clonidine, guanfacine, and methyldopa, may cause sedation, confusion, insomnia, and nervousness. Individuals taking antihypertensives should be advised on the potential risk of impair driving performance. Antiparkinsonians

There are several classes of medication to treat PD, including levodopa, antimuscarinics, amantadine, and dopamine agonists. Common side effects of these drugs that may impair driving include excessive daytime sleeping, lightheadedness, dizziness, blurred vision, and confusion. Sudden irresistible attacks of sleep have been shown as a side effect with the dopamine agonist drugs pramipexole and ropinirole. Although levodopa improves memory and verbal fluency, it worsens simultaneous visual and auditory reaction times Trihexyphenidyl, another popular medication for PD, impairs attention, learning, and free recall. Based on the extent of the disease, the physician may order the patient to undergo formal psychomotor testing or driving evaluation performed by a DRS. Antipsychotics

The antipsychotics most commonly used are: butyrophenones, clozapine, dibenzoxazepines, diphenylbutyl piperidines, dihydroindolones, phenothiazines, and

Road Traffic: Determination of Fitness to Drive – General

thioxanthenes. The acute administration of antipsychotics in normal individuals does induce sedation and performance decrements in visual-motor coordination and specific attentional behaviors, which have a deleterious effect on driving behavior. Antipsychotic drugs have the capacity to potentiate the effects of alcohol, sedative hypnotics, narcotics and antihistamines; therefore, the combination of antipsychotics with these substances increases the impairment of driving behavior. Most, if not all, antipsychotic medications have a strong potential to impair driving performance through various CNS effects. The ‘classic’ antipsychotics are heavily sedating, and all produce extrapyramidal side effects (EPS). Modern drugs have a lower tendency to cause EPS; they too are sedating. Patients should be counseled on such side effects and advised not to drive if they experience side effects that are severe enough to impair driving performance. In addition, the physician should consider referring the patient for formal psychomotor testing and or for on-road assessment performed by a driver rehabilitation specialist. Benzodiazepines (sedatives/anxiolytics)

Benzodiazepines are a group of medications used to treat medical conditions, such as insomnia and anxiety. They belong to a larger class of drugs known as sedative hypnotics; there actions include a reduction in agitation and irritability (i.e., sedation) and stimulate sleepinducing (hypnotic) characteristics. Benzodiazepines produce their action by increasing the influence of a chemical in the CNS called gamma-aminobutyric acid (GABA), which inhibits the rate of communication between individual neurons in the brain and thereby depress the overall rate of activity in the CNS. In addition, benzodiazepines impair nervous system functions in the peripheral nervous system. Common benzodiazepines prescribed by doctors in the United States include diazepam (Valium), alprazolam (Xanax), lorazepam (Ativan), clonazepam (Klonopin), triazolam (Halcion), and chlordiazepoxide (Librium). Another well-known benzodiazepine, the ‘club drug’ or ‘date rape’ drug flunitrazepam (Rohypnol), is banned in the United States. Some benzodiazepines take effect quite quickly and only remain in the body for a short period of time. Other benzodiazepines take effect relatively slowly and remain in the body for relatively long period of time. Benzodiazepine-like hypnotics, such as zolpidem and zaleplon have a rapid rate of elimination; therefore, psychomotor functions and skills to safely operate a motor vehicle have been shown 5 h after taking zalepon and 9 h after taking zolpidem. Individuals taking long-acting drugs or those during the daytime should be advised on the potential for impairment, even in the absence of subjective symptoms. Individuals should also be advised to avoid driving, particularly during the initial phase of dosage adjustment.

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Benzodiazepine use has demonstrated impairment to vision, attention, motor coordination, and driving performance. Evening dosage of long-acting benzodiazepines has been shown to markedly impair psychomotor function the following day. People under the influence of benzodiazepines typically experience significant impairments in their driving ability, even if they take only a single dose of the medication. The degree of benzodiazepine-related impairment increases considerably when these drugs are used recreationally in multiple doses or combined with the use of alcohol. A NHTSA study examining the effects of diazepam (Valium) reported that diazepam can degrade basic task performance skills by reducing normal alertness and attention span, create poor visual reaction times, create poor auditory (sound-related) reaction times, reduce basic judgment and decision-making skills, increase feelings of tiredness and lethargy, reduce the effectiveness of hand-eye coordination, decrease the ability to recall and use situation-specific information, and reduce the normal integration between thought and action. The standard single dosages ranging of diazepam of between 5 and 20 mg, can damage performance-related skills for a minimum of three hours; in some cases, the effects of a single dose can last as long as 10 h. Among the users, who take their prescriptions according to a doctor’s guidelines, the skill-related effects of diazepam are most noticeable in the elderly. Physicians should, if possible, prescribe doses of the shortest acting hypnotics. Patients that require the longer acting compounds or daytime doses should be advised of the potential for impairment, even in the absence of subjective symptoms. These patients should be advised to avoid driving, especially during the initial phase of dosage adjustment. Muscle Relaxants

Most skeletal muscle relaxants (carisoprodol, cyclobenzaprine, chlorzoxazone, diazepam, methocardamol, and orphenadrine) function by significantly depressing the CNS. The effects of these compounds include sedation, relaxation, euphoria, and mood alteration. Side effects associated with muscle relaxants include agitation, depression, dizziness, drowsiness, fainting, sleep disturbance, loss of coordination, and vertigo. These drugs carry warnings specifically regarding their potential effects on complex tasks, such as driving or operating hazardous machinery. Drivers should be advised on the side effects and recommended not to drive during the initial phase of dosage adjustment. A number of studies have reported that toxicological analysis of drivers arrested for impaired driving have tested positive for meprobamate and carisoprodol. However, many toxicological labs investigating DUI cases and traffic deaths routinely do not test for these compounds. Therefore, due to depressive nature of these

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compounds, likelihood of abuse, and significant level of impairment these compounds should be routinely tested in all MVA. Stimulants

The common side effects of stimulants (amphetamines and methylphenidates) that may affect driving performance include euphoria, overconfidence, nervousness, irritability, anxiety, insomnia, headache, and rebound effects as the stimulants wear off. Drivers should be advised regarding the side effects and recommended not to drive during the initial phase of dosage adjustment.

Standardized Tests for Driving Performance There are a number of methods used to assess driving performance and these methods range from cognitive testing to real-life on-road driving assessments. Cognitive measures such as the clinical dementia rating (CDR) scale, Sternberg memory search test, visual tracking and the UFOV examination, the Boston naming test (BNT) (del Toro et al., 2010), and the MMSE can all be used to assess cognitive function and level of driving impairment. The CDR is a 5-point scale used to characterize six domains of cognitive and functional performance applicable to AD and related dementias. The six domains are – memory, orientation, judgment, and problem solving, community affairs, home and hobbies, and personal care. The level of impairment/dementia score ranges from 0 to 3: 0 ¼normal, 0.5¼ very mild dementia, 1 ¼mild dementia, 2¼ moderate dementia, 3 ¼severe dementia. The American Academy of Neurology recommended using the CDR to assess individuals with DAT (Wang et al., 2010). The MMSE is a tool used in mental status examination in a systematic manner. The test consists of 11questions that assess five areas of cognitive function: orientation, registration, attention, and calculation, recall, and language. The maximum score is 30. A score of 23 or below is an indicator of cognitive impairment. The MMSE was found to be a significant predictor of final on-road driving performance results, but not of crashes and traffic violations. The BNT has been shown to be a predictor of driving ability. Physicians who have concerns that their patients may be unsafe to drive should refer these individuals to a DRS. The BNT, is a neuropsychological assessment tool to measure confrontational word retrieval in individuals with aphasia or other language disturbance caused by stroke, AD, or other dementing disorder. The BNT contains 60 line drawings graded in difficulty. The patient is told to tell the examiner the name of each picture and is given about 20 s to respond for each trial. The examiner writes down the patient’s responses in detail, using codes. If the patient fails to give the correct

response, the examiner at her or his discretion may give the patient a phonemic cue, which is the initial sound of the target word. After the patient completes the test, the examiner scores each item þ or – according to the response coding and scoring procedures. Patients with anomia often have greater difficulties with the naming of not only difficult and low frequency objects but also easy and high frequency objects. Naming difficulties may be rank ordered along a continuum. Items are rank ordered in terms of their ability to be named, which is correlated with their frequency. This type of picture-naming test is also useful in the evaluation of brain-injured adults (Kaplan and Weintraub, 1983; del Toro et al., 2010; Nicholas et al., 1988). A standardized road test may be the only appropriate means of determining driving competence in people diagnosed with neurological and physical impairment. The DRS conducts closed course, off road, and on-road performance testing. Closed course test allows assessment of a person’s ability to track, steer, and brake a car, but yields limited information on actual driving behavior. Testing in stationary training cars is not adequate for persons with central neurological disorders. It is useful in drivers recovering from a stroke or traumatic brain injury, as a prelude to formal on-road examinations. A popular standardized on-road measure is the Washington University Road Test (WURT) of driving performance, which is commonly used in driving research among the elderly and a wide range of cognitively impaired population. The WURT is a 45-min in-traffic road test done along a predetermined route. The open course test is conducted in traffic and assesses several typical driving skills, such as maintaining speed, obeying traffic signs, signaling, turning, changing lanes, and negotiating intersections. The road test provides an accurate and reliable functional assessment of driving ability and the test–retest reliability is high. The methods developed and employed in the United States for testing drivers’ performance and the presence of illicit drugs have been adapted by countries in Europe and Australia. In the UK, two drug recognition systems are used, drug recognition training (DRT) and field impairment testing (FIT). The DRT combined with the FIT system is used to identify the signs and symptoms associated with the effects of drugs and the assessment of the driver’s drug impairment. Aversion of the American field sobriety test of drivers, FIT was introduced with minor differences in Scotland, England, and Wales in 2000. The main difference between the United States and UK and European field sobriety tests is that horizontal and vertical gaze nystagmus is replaced by an examination of the pupils (Wang et al., 2010). Government Regulation

In the United States, driver’s licenses are issued by each individual state and the territories (including

Road Traffic: Determination of Fitness to Drive – General

Washington, DC). Drivers are required to obtain a license from their state of residence. The driver’s licensing regulation is specific for each state. The ultimate decision to remove and reinstate driving privileges rests in the hands of the local driver’s licensing authority. In 1991, 46 states had restrictions regarding individuals with seizures; 26 states limited drivers who have episodic loss of consciousness from other medical causes; and eight states had laws regarding individuals with known cardiac arrhythmias. Each state has certain requirements for physicians to report unsafe drivers or drivers with specific medical conditions to the states driver licensing agencies. Therefore, physicians should become familiar with the state specific regulations where they practise. State specific licensing criteria, reporting producers, medical advisory board information and contact information are available at http://www.ama-assn.org/go/olderdrivers. In addition, physicians must understand their legal responsibilities and their role to protect society from unsafe drivers (Physician’s Guide to Assessing and Counseling Older Drivers, 2010).

The Role of the Postmortem Examination All individuals involved in fatal MVAs undergo investigation by law enforcement and by either the medical examiner or the Coroner’s Office. The forensic investigation includes examination of the crash scene, the vehicle, postmortem examination of the body, toxicological analysis of body fluids, and a review of the driver’s past medical history including the prescription medication. The postmortem examination of a driver involved in a fatal motor vehicle crash allows for a final assessment of the performance and behavior of the driver and the role of their physician. The forensic pathologist is able to review the driver’s medical records and the results of the postmortem examination of the Table 1

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internal organs and the results of toxicological analysis to determine the cause of the accident.

Americans: Age 65 and Over Population

In 1990, the population of individuals aged 65 and over represented 31.2 million, 12.6% of the total US population. The most recent data from the CDC reported the elderly population at over 40 million (13%). Table 1 delays the US population by age for the years 1990, 2000, and 2010. Based on projections, by the year 2025, more than 18% of the US population will be 65 and older, and by 2040, the elderly will represent 20% (68 million) of the US population. The percentage of individuals aged 85 and older is increasing at a faster rate than ever before (U.S. Census Bureau, Census, 2000). Mortality

The three leading causes of natural death among persons aged 65 and over 65 are – heart disease, cancer, and chronic lower respiratory disease (Older Persons Health). Among unintentional injuries resulting in death, the leading causes are falls followed by MVAs. The CDC reports that over 21 700 people age 65 and older died of fall-related injuries in 2010. In 2008, data from the CDC reported that more than 5500 older adults were killed and more than 183 000 were injured in motor vehicle crashes (Raedt and Krisoffersen, 2001). The Insurance Institute for Highway Safety estimates that, by the year 2030, 25% of all fatal traffic crashes will involve drivers 65 and older (Older Driver). Number of Licensed Drivers

Currently, older drivers represent only a fraction of the total driving public. However, they represent the fastest

US population of those ages 65 and over

Age

1990 Number

65 years and over 65–74 years 65–69 years 70–74 years 75–84 years 75–79 years 80–84 years 85–94 years 85–89 years 90–94 years 95 years and over

2000 Percent

31 241 831 100.0 18 106 558 58.0 10 111 735 32.4 7 994 823 25.6 10 055 108 32.2 6 121 369 19.6 3 933 739 12.6 2 829 728 9.1 2 060 247 6.6 769 481 2.5 250 437 0.8

Number 34 991 753 18 390 986 9 533 545 8 857 441 12 361 180 7 415 813 4 945 367 3 902 349 2 789 818 1 112 531 337 238

2010 Percent 100.0 52.6 27.2 25.3 35.3 21.2 14.1 11.2 8.0 3.2 1.0

Number 40 267 984 21 713 429 12 435 263 9 278 166 13 061 122 7 317 795 5 743 327 5 068 825 3 620 459 1 448 366 424 608

Percent of US total Percent 100.0 53.9 30.9 23.0 32.4 18.2 14.3 12.6 9.0 3.6 1.1

1990 12.6 7.3 4.1 3.2 4.0 2.5 1.6 1.1 0.8 0.3 0.1

2000 12.4 6.5 3.4 3.1 4.4 2.6 1.8 1.4 1.0 0.4 0.1

2010 13.0 7.0 4.0 3.0 4.2 2.4 1.9 1.6 1.2 0.5 0.1

Percent change, 1990–2000

Percent change, 2000–2010

12.0 1.6 –5.7 10.8 22.9 21.1 25.7 37.9 35.4 44.6 34.7

15.1 18.1 30.4 4.7 5.7 –1.3 16.1 29.9 29.8 30.2 25.9

Source: Reproduced from U.S. Census Bureau, Census, 2000. 1990 Census of population, general population characteristics, United States (1990 CP-1-1); 2010 census brief: The older population. Available at: www.census.gov (accessed 14.02.14).

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growing segment of the driving population. In 1991, there were 21.8 million elderly drivers, representing 13%, with 6.6 million (4%) drivers over 85 years old. By 1999, there were 33 million licensed older drivers, representing 23% of all drivers in the US. The Federal Highway Administration reported that in 1996 there were 15 648 000 licensed drivers aged 65–74 years, and 9 522 000, aged 75 and over. It is estimated that, by the year 2020, more than 15% of drivers will be over 65 years old. The National Institute on Aging estimates that, by 2030, there will be an estimated 40 million licensed drivers, with 25% of all drivers being 65 and over, and about 9 million of these 85 and over (Older Population: Traffic Safety, 2008).

more driving errors, such as failure to yield right-ofway, incorrect lane changes, and improper turning, particularly left and turns, and turning from the wrong lane. When they crash, elderly drivers are more likely to incur injury and death. As a group, people older than 65 years nonetheless have fewer accidents than any other age group, largely because they drive fewer miles. Those older than 75 years are twice as likely as the average driver, per mile driven, to crash their cars, while those older than 85 are 2.5 times more likely, even without adjustment for miles driven. Men are 2–4 times more likely to crash than women, even when adjusted for the increased time men spend driving, though this difference begins to disappear later in life (Cooper et al., 1993; Brayne et al., 2000; Lyman et al., 2001).

Motor Vehicle Crashes

MVAs are the second leading cause of unintentional injury death among those 65 and over. In 1999; MVAs accounted for over half of those deaths. Automobile crashes claimed the lives of 33 687 Americans in 2010. The pattern of motor vehicle crashes and fatal MVAs in the United States is U-shaped. The number of fatal MVAs is high among drivers aged 15–24 years old; gradually, accidents decrease during the age of 45–55. After the age of 55, they start increasing again, with the greatest increase occurring after the age of 60. The accident rates for drivers aged 16–19 is 28 per million miles driven, whereas in adults older than 85 years old, the rate jumps to 85 accidents per million miles driven (Older Adult Drivers: Get the Facts). Profile of Elderly Drivers

Driving is an economic, social, and recreational necessity for most Americans and plays a central role in the lives of adults, especially older adults and 88% of whom rely on the private automobile for their transportation needs. Individuals with preexisting medical conditions and/or those who develop conditions that can affect their driving performance will result in a conflict between reasonable transportation opportunities and the role of physicians, and society’s need to protect public safety. Most seniors are as capable of driving safely as their younger counterparts and when they become aware that they have a problem, they typically act in a responsible manner by limiting or modifying their driving habits. Older drivers in general drive less at night, avoid heavy traffic times and complicated roadways, and limit their geographic area. Ever growing traffic volumes, congestion, and novel highway features and vehicle technologies demand greater attention by drivers. They incur accidents in situations that require astute perception, problem-solving ability, immediate reactions, and agile decision-making. However, older drivers are overrepresented when fatalities or crashes are adjusted for vehicle miles traveled. They commit

Summary In modern society there is an increasing reliance on the automobile, therefore any limitations imposed upon the driving privilege especially among the elderly population can significantly limit their personal independence. While advancing age itself is not a predictor of individual driving ability, there are many conditions common in the elderly population, which render the older operator more susceptible to vehicular accidents. Major age-related diseases, such as stroke, PD, and dementia, particularly of the Alzheimer’s variety can seriously affect an individual’s ability to operate a vehicle safety. While, the simple diagnosis of conditions such as uncomplicated, stable dementia with memory impairment may not be sufficient cause to limit the driving privilege of an otherwise capable person. However, if complex reasoning skills are deficient, then such a driver presents a greater risk as evidenced by the fact that accidents in the older age group typically occur in complicated traffic patterns, intersections, lane changing, merging, left-hand turns, and emergencies. Unfortunately, there is no adequate predriving test, which can identify the competent driver with certainty. The road evaluation has been considered by some the ‘gold standard’ to determine operating ability, but this only assesses routine functioning and cannot predict response to novel and emergency situations. Nevertheless, a road evaluation conducted by an experienced driver license examiner remains the best available measurement to assess operating skills including freedom from distractibility. If family, friends and medical personnel question the fitness of an older driver, with or without the symptoms of dementia, then a road evaluation may be an appropriate measure either to limit the privilege for the incompetent individual or to recommend remedial training or adaptations for others so that their independence can be maintained within the bounds of public and personal safety. A physician has an obligation to provide his patients with the best medical care available. Also, the physician

Road Traffic: Determination of Fitness to Drive – General

has a duty toward the society to protect the general population from risks. Therefore, when a physician discovers that his patient can no longer operate a motor vehicle safely on account of disease, cognitive ability, or other medical health then he must be removed from the roads.

See also: Road Traffic: Determination of Fitness to Drive − Driving Offense. Road Traffic: Determination of Fitness to Drive − Sobriety Tests and Drug Recognition. Road Traffic: Global Overview of Drug and Alcohol Statistics

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