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Mild Traumatic Brain Injury in the Occupational Setting
Concussion Supplement
Mild Traumatic Brain Injury in the Occupational Setting Victor H. Chang, MD, Lisa A. Lombard, MD, Michael R. Greher, PhD Abstract: The evaluation and management of mild traumatic brain injury (mTBI) in the occupational setting may pose significant challenges for even the most-seasoned practitioner. Providers must simultaneously address the clinical management of mTBI and be familiar with the systematic and administrative requirements related to the management of injured workers with mTBI who are covered by workers’ compensation insurance, including causation, return to work, and the potential of permanent impairment. Given the primarily subjective nature of many mTBI symptoms, an injured worker with a delayed recovery may raise the question, if not suspicion, of symptom magnification and secondary gain. This review discusses the evaluation and treatment of the injured worker with mTBI, and focuses on the medicolegal issues that are present in the workers’ compensation system, especially the role of neuropsychological evaluations. Although significant differences exist regarding classification schema, for the purposes of this discussion, mTBI is used to encompass the terms concussion, postconcussive syndrome, and persistent postconcussive syndrome. PM R 2011;3:S387-S395
INTRODUCTION Perhaps the most famous person to sustain a work-related traumatic brain injury (TBI) was Phineas Gage, a 25-year-old railway worker. In 1848, while setting explosives, a 13-pound iron tamping rod pierced his left eye and frontal lobe, and exited through his skull. Amazingly, he survived this insult, but, due to severe behavioral and personality changes, he was reportedly unable to successfully return to employment [1]. This brief but graphic anecdote informs us of several points: the brain is incredibly complex, resilient, and vulnerable at the same time; the residual effects of a severe TBI can be overestimated, and, by corollary, the effects of mild traumatic brain injury (mTBI) can be underestimated; and, finally, even 163 years since Gage’s storied injury, we are only beginning to unravel the evidence that underlies mTBI. During Phineas Gage’s era, injured workers bore the cost of medical treatment but had the right to sue an employer for negligence or an act of omission. It was not until the early 1900s that the first workers’ compensation (WC) law was passed in the United States and not until 1949 that all states had enacted some kind of WC system. Each state governs its own WC policies and procedures, and certain employees are covered under a federal system. However, common themes exist for both the injured worker and the employer. Typically, once causation has been established, the injured worker is entitled to (1) medical treatment for the work-related injury or disease, (2) lost wages, and (3) financial remuneration in the event of permanent impairment or disability. Also, an injured worker does not need to prove that the employer is at fault to be able to seek medical care. As a trade-off, the injured worker gives up the right to sue an employer for a work-related injury, and the employer is not liable for pain and suffering. Delayed recovery after mTBI is perhaps one of the most challenging situations encountered in the WC system, with controversy being more the rule than the exception. Independent of any work-related issues, the clinical aspects of mTBI, including diagnosis, management, and outcomes can be difficult. When factoring in the medicolegal aspects of the WC system, the complexity of care can seem overwhelming. PM&R 1934-1482/11/$36.00 Printed in U.S.A.
V.H.C. Department of Physical Medicine and Rehabilitation, University of Colorado School of Medicine, Mailstop F-493, 12631 East 17th Ave, Rm 2513, Aurora, CO 80045. Address correspondence to: V.H.C.; e-mail: [email protected] Disclosure: 5B, as requested by attorneys or insurers L.A.L. Department of Physical Medicine and Rehabilitation, Indiana University School of Medicine, Indianapolis, IN Disclosure: nothing to disclose M.R.G. Department of Neurosurgery, University of Colorado School of Medicine, Aurora, CO Disclosure: 5B, engage in some forensic consultation, including cases of TBI Disclosure Key can be found on the Table of Contents and at www.pmrjournal.org
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The multiplicity of symptoms after mTBI includes cognitive, emotional, and physical symptoms, and commonly requires multiple providers across different specialties. There is no specific specialty that takes “ownership” of TBI, and neurologists, neurosurgeons, physiatrists, internists, family practitioners, and occupational medicine physicians are often the primary physicians. Furthermore, specialists, including psychiatrists, neuropsychologists, otolaryngologists, and ophthalmologists, may address specific symptoms of mTBI. Allied health care professionals are usually consulted, including physical and occupational therapists, speech-language pathologists, vestibular therapists, and chiropractors. Lastly, employers, insurance case managers and adjustors, forensic medical experts, and attorneys may be involved. Consensus is often difficult within one specialty alone and can be extremely difficult among multiple providers, which necessitates a skillful approach to the overall management of the injured worker with mTBI and an appreciation of the controversies that exist related to this diagnosis.
EPIDEMIOLOGY Similar to the general population, a diagnosis of work-related mTBI is prone to both under- and overdiagnosis, because many injuries may go unreported, whereas, at other times, symptoms unrelated to mTBI may be errantly diagnosed as such, especially in delayed recovery situations. There is limited information available regarding the epidemiology of mTBI in the workplace. Kristman et al [2] reported that approximately 6 of 1000 lost-time claims were associated with mTBI. Kraus and Fife [3] reported a higher incidence of work-related mTBI, noting an occurrence of 17 of 1000 lost-time claims. The majority of these injuries (54%) resulted from a fall. TBI is most common in manual laborers, most often in men younger than 40 years old. Detailed information about mTBI in the workplace is difficult to estimate, although the majority of all TBIs (60%-80%) in the United States are classified as mild [4]. Etiology of work-related mTBI varies with the type of job performed, but falls are the most common cause overall, particularly in the construction, manufacturing, sales, and service sectors, and account for 40%-60% of all work-related TBIs. Motor vehicle accidents and bluntforce trauma (either struck by or against an object) are the next most common causes of work-related mTBI, each accounting for about 20% of all work-related TBIs [5-7].
PREDICTIVE FACTORS OF OUTCOME Germaine to the outcome of work-related mTBI is the ability of the injured worker to return to work and whether or not there is a permanent impairment or disability. These issues have significant financial implications to the injured worker, employer, and insurer. Predictors for mTBI outcomes are
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difficult in any setting and even more so in the occupational setting, because financial implications are involved at every stage. Carroll et al [8] critically reviewed 428 studies related to prognosis after mTBI and accepted 120 after critical review, noting that cognitive deficits and symptoms were common in the acute stage, but the majority of studies reported recovery over 3-12 months. The researchers also concluded that when symptoms persisted, compensation and litigation were factors, but there was little consistent evidence for other predictors. Similar findings have been noted in other studies [9]. In addition, various meta-analyses suggest that the vast majority of patients with uncomplicated mTBI (ie, those without evidence in injury-related intracranial lesion) experience a rapid cognitive recovery that ranges anywhere from a few days to 3 months [10-15].
NONSPECIFICITY OF mTBI SYMPTOMS AND RESPONSE BIAS The majority of mTBI symptoms are subjective in nature, and it is critical that the initial provider not just evaluate the postinjury symptoms but also query the injured worker about any preinjury symptoms at the first visit and continue to investigate any preinjury symptoms at subsequent visits. In general, patients tend to underestimate past problems (ie, “good old days” bias), which can impact their perceived level of current problems and recovery [16]. With the passing of time, an injured worker with mTBI may often see numerous providers and retell the history multiple times. The injured worker’s recounting of the injury and subsequent symptoms may become less accurate over time, with misattribution of symptoms in relation to the injury. As a result of interactions with multiple providers, injured workers may introduce additional symptoms to their history based on these interactions, even though the symptoms may not have actually occurred or may have occurred in a different fashion than reported. Response bias is defined as a class of behaviors that reflects less than a fully truthful, accurate, or valid symptom report and presentation. Response bias does not assume that the injured worker is consciously attempting to feign symptoms but is rather a ubiquitous phenomenon that affects almost any domain of human self-report. It is also important to recognize the potential for provider bias. Martelli et al [17] reported that 25% of surveyed professionals who evaluate and treat injured workers suspected exaggeration or malingering. In addition, the majority of these professionals believed that they would personally be treated unfairly in the WC system if they were injured. Response bias does not imply that the provider must doubt the veracity of the injured worker’s reported symptoms but rather that the provider must recognize that the reported cognitive, emotional, and physical symptoms that are attributed to a work-related mTBI may have been present
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before the injury or may be related to factors other than the mTBI. There are numerous reports in the medical literature that note the nonspecificity of cognitive, emotional, and physical symptoms that are commonly reported after mTBI. These symptoms are not unique to mTBI, are present in the normal population [18,19], are highly correlated with chronic pain [20-22] or depressive symptoms [23], and have been found to occur at similar rates in both claimants who report mTBI and claimants who report bodily injuries without mTBI [24]. It also is important to note that there often is a discrepancy between self-reported cognitive complaints and actual cognitive deficits as identified via neuropsychological testing [25,26]. In injured workers with protracted symptoms after mTBI, especially those individuals in whom symptoms fail to improve or to worsen over time and symptom magnification is suspected, the provider must thoroughly investigate factors other than the mTBI, including emotional factors (eg, depression, anxiety), pain issues, poor sleep, medication effects, and secondary gain.
CONTROVERSY REGARDING mTBI OUTCOMES Although it is generally accepted that mTBI symptoms are organically based in the first few weeks (and perhaps the first few months) after mTBI, the delineation between physiological and psychological etiology becomes blurred when symptoms persist over time. Controversy exists regarding the outcomes of mTBI. Although the neuropsychological literature has consistently demonstrated that uncomplicated mTBI typically results in a full and rapid cognitive recovery, increased public awareness of mTBI over the past several years, especially in professional athletes and military combatants, has resulted in debate about this issue in public forums and popular media. Similar controversy exists in injured workers with mTBI and with persistent symptoms. The WC system requires the practitioner to address the causation of symptoms and return to work at all stages of treatment. In addition, at the time of case closure (eg, maximum medical improvement), an opinion must be rendered regarding permanent impairment and disability, with significant financial implications as a result. With these factors in mind, there has been particular interest in identifying which injured workers are likely to have a protracted clinical course. Estimates of persistent symptoms and disability after mTBI vary between 5% and 10%, with conflicting reports in the medical literature regarding the etiology of ongoing symptoms. A growing consensus suggests that previous estimates of nonrecovery in the 15%-20% range were likely inflated [9,10] and attributes protracted symptoms to psychological and other noninjury-related factors more so than neurologic factors. Classification of mTBI also is not uniform, which makes interpretation of peer-reviewed literature diffi-
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cult. Although the American Congress of Rehabilitation Medicine definition of mTBI is one of the most commonly referenced criteria, given the broad inclusion criteria that range from “any alteration of mental status” to “a maximum of 24 hours of posttraumatic amnesia,” it is difficult to draw any generalized conclusions regarding outcome from the diagnosis of mTBI alone. Also, studies often do not distinguish between “simple” or “uncomplicated” mTBI (eg, normal computed tomography or magnetic resonance imaging of the brain) versus “complicated” mTBI (eg, clinical symptoms that meet mTBI criteria in the presence of an abnormal computed tomography or magnetic resonance imaging of the brain). As such, the mTBI cohort is more of a heterogeneous than a homogeneous population. Prognostication of persistent symptoms based on classification of mTBI alone is ill advised, because the diagnosis of mTBI itself is not predictive of chronic symptomatology [17]. In work-related and civil litigation mTBI literature, there is increased recognition of the influence of financial incentives. Bias also is a confounder, including the injured worker, provider, employer, and insurer. Although consensus may be more uniform in moderate or severe TBI regarding causation, reasonableness, and relatedness of treatment, severity of impairment and disability, and feasibility of return to work, these issues often are highly contentious in injured workers with mTBI. Forensic evaluations, particularly neuropsychological assessment, are common when injured workers with mTBI have persistent symptoms. However, these forensic evaluations often provide little in the way of ongoing management of these individuals, particularly because they rarely occur in the early stages of treatment. Although it is beyond the scope of this review to detail the specifics of neuropsychological evaluation, it is imperative that providers attain a basic understanding of the key issues and controversies that involve mTBI and that are assessed in neuropsychological evaluations. Because comprehensive neuropsychological testing is typically reserved for patients with persistent symptoms (eg, 3 months or more after injury), it is critical that the providers involved in the acute phase (eg, first month after injury) recognize the factors that are typically seen in delayed recovery after mTBI. More importantly, beyond recognizing these negative predictors, providers must be able to adjust treatment to mitigate the chances of a poor outcome.
ASSESSMENT OF mTBI Physical A variety of physical symptoms may be present after mTBI, with headaches, dizziness, and visual disturbances being the commonly reported symptoms. These symptoms may be interrelated or may be independent of each other. Within the scope of this discussion, these symptoms are only briefly reviewed.
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Headaches that occur within 1 week of head trauma are referred to as posttraumatic headaches (PTH). Although the majority of patients with PTH have resolution within several months of injury, approximately 18%-33% of patients with PTH have persistent symptoms beyond 1 year. Lew et al [27] reported that 37% of all PTH had clinical presentations similar to tension-type headache, and 29% had clinical presentations similar to migraine. Evaluation of the patient with PTH should include a detailed examination of the cranial nerves and musculoskeletal assessment of the face (including the jaw), head, and cervical regions. Abnormal findings, such as cranial neuropathies (eg, visual neglect, saccadic pursuits, facial weakness), should prompt further diagnostic testing or imaging of the brain, skull, and/or cervical spine. Psychological factors also should also be investigated as a contributor to chronic PTH. Dizziness is often reported after mTBI and may or may not correlate with headache or other symptoms. The differential diagnosis is broad but includes central mechanisms (eg, brainstem dysfunction), peripheral etiology (eg, benign paroxysmal positional vertigo), and psychological factors (eg, anxiety). Initial evaluation may include a Dix-Hallpike maneuver to diagnosis benign paroxysmal positional vertigo. Otolaryngology evaluation and testing may be necessary to rule out other conditions, such as a perilymph fistula or hydrops. Cervical imaging, including vertebrobasilar system assessment, should be pursued if dissection is suspected. The presence of hearing loss should prompt further evaluation of the tympanic membrane or consideration of a computed tomography to rule out a temporal skull fracture. Various visual symptoms may be reported after mTBI and may be secondary to cranial neuropathies, orbital involvement, headaches, or emotional factors. Ocular motor or visual field deficits should prompt further evaluation, such as brain magnetic resonance imaging or referral to ophthalmology. Posttrauma vision syndrome and visual midline shift syndrome have been described, and vision therapy or prism glasses may be recommended to treat these conditions, but these remain controversial topics, with little in the way of peer-reviewed publications. Patients with ongoing visual symptoms typically require further assessment with ophthalmology.
Cognitive and/or Emotional Brief Cognitive Screening (“in office”). Initial “in office” cognitive assessment after mTBI should include evaluation of arousal, attention span, orientation, memory, fund of knowledge, and executive function. Informal cognitive assessment also is imperative, including the injured worker’s ability to provide a history, and the manner in which the injured worker provides a history and responds to questions (eg, linear and/or direct thought processes, tangentiality, distractibility, comportment). The Mini-Mental State Exam-
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ination is commonly used but is of limited utility in evaluating mTBI given its focus on orientation and short-term memory. By comparison, the Montreal Cognitive Assessment may be a reasonable choice given its test-retest reliability, internal consistency, content validity, and ease of administration (10 minutes) [28]. However, there is no criterion standard cognitive screening tool for mTBI, and deficits may still exist in the presence of normal scores. As such, further in-depth testing may be necessary for persistent or subtle symptoms. Whether or not a cognitive screening tool is used, it is essential that ongoing assessments involve more than basic orientation and attention, and should include some measure of executive function. Emotional factors also may be present and superimposed on true cognitive deficits or may be the cause of cognitive dysfunction. The initial history must distinguish emotional conditions, such as acute stress reactions in the initial moments at the scene (eg, feelings of “panic,” “fear,” or being “stunned”) from the symptoms of true mTBI (eg, disorientation, confusion). These symptoms often mimic one another and can be challenging to distinguish in the absence of supportive first responder or emergency department records. The differentiation between an acute stress reaction and mTBI, therefore, may present as a diagnostic dilemma, and, in these situations, if the provider is unsure, then early referral to another provider who specializes in brain injury is advisable. Neuropsychological Evaluation. Consultation with a neuropsychologist is often recommended for any patient with mTBI but should be considered early on in the occupational setting. Although providers tend to think of neuropsychological consultation in a fairly uniform fashion that involves comprehensive neuropsychological testing 3 months or more after injury, neuropsychologists can provide a variety of services early or late in the treatment process. These services can take several forms, depending upon the clinical need and the recommendations of the referring provider but, for the purposes of this article, are divided into 3 options, which can be completed individually or in combination: (1) early neuropsychological consultation and/or intervention, (2) screening neuropsychological evaluation, and (3) comprehensive neuropsychological evaluation. After clearance from initial providers, which may include neuroimaging and other treatment, initial neuropsychological consultation is recommended for the purposes of (1) acquiring a detailed history from the injured worker about the events of the injury itself; (2) obtaining a differential diagnosis of mTBI based on this history and/or psychological symptoms, such as depression, anxiety, or somatic focus; (3) providing education and reassurance to the injured worker with regard to the natural course of recovery from mTBI and the role of complicating psychological and physical factors; and (4) providing recommendations to address these latter issues early in the treatment process. Early, brief intervention
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that emphasizes education and reassurance has substantial empirical support for reducing the probability of persistent cognitive symptoms after mTBI [29-32]. Mittenberg [33] discusses the phenomenon of “expectation as etiology” and the significant benefits of providing patients with mTBI with positive expectations regarding outcome from injury. The detrimental impact of negative prognostication by providers also is well known and frequently is discussed in the context of iatrogenic complaints, and concepts known as “diagnosis threat,” or the “nocebo effect” [34,35]. Within the first few weeks after mTBI, providers may opt to refer patients for a screening neuropsychological evaluation, which, in essence, is more extensive than a mental status examination such as the Montreal Cognitive Assessment but more abbreviated than a comprehensive neuropsychological evaluation. As with the early neuropsychological interventions described above, these screening evaluations are intended to be completed in the early stages of recovery (ie, first 3 months after injury). The purpose is to briefly evaluate primary areas of cognition with the goal of determining current status, especially if there are concerns regarding the ability to return to work. Screening evaluations also can be used to establish a baseline of cognitive functioning for comparison should additional testing be warranted in the future and may help to determine if further intervention is needed. A comprehensive neuropsychological evaluation is typically completed at a minimum of 3 months after injury. Numerous factors are involved with this time frame, including clinical, practical, and economic reasons. Clinically, because the vast majority of patients with mTBI have spontaneous recovery within the first 3 months of injury, comprehensive neuropsychological testing may not be indicated and greater emphasis on education and reassurance is the most likely way to positively impact the outcome during this time frame. From a practical standpoint, formal testing usually requires a full day of testing. It is time consuming, impractical, and cost prohibitive to do repeated testing on a routine basis, and, therefore, it is recommended that providers only make referrals for a comprehensive neuropsychological evaluation when indicated by the case and appropriate with regard to time. A similar clinical management model was proposed by Kirkwood et al [36] for pediatric mTBI. In addition to acquiring a detailed history and assisting with a differential diagnosis of mTBI based on the acute symptoms at the time of injury, a comprehensive neuropsychological evaluation provides a detailed assessment of current cognitive and emotional functioning. Critical to the evaluation is that TBI does not globally affect all neurocognitive domains, and reported symptoms that are atypical or inconsistent with mTBI should raise suspicion of non-TBI factors. In particular, well-rehearsed information, such as a patient’s fund of factual knowledge and long-term memories of salient life events, should remain unaffected by the early
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cognitive impact of a mTBI. The neuropsychological evaluation can be particularly helpful in determining the role of additional, non-TBI factors, such as other neurologic disorders, psychological dysfunction, chronic pain, poor sleep, insufficient effort, and symptom magnification with regard to persisting cognitive symptoms beyond the typical window of recovery. Such determinations often guide treatment and are of importance to injured workers, employers, and insurers. In addition, if injured workers have undergone a screening evaluation within the first 3 months after injury, a comprehensive neuropsychological evaluation can be completed for comparative purposes to objectively track the course of cognitive symptoms over time and provide further recommendations for treatment. In cases in which symptoms persist despite the passage of time, a vicious cycle may evolve. The injured worker may question the competency of his or her providers and perceive the employer and insurer as unsupportive. Providers, employers, and insurers may suspect symptom magnification and secondary gain, which causes additional strain among all parties involved. Employers and insurers may question the necessity of work removal or modified duty and may pressure the provider and employee to return to regular duty. This combination of factors can lead to an adversarial system of care, increasing the complexity of the clinical issues. Amelioration of this situation is difficult once it has occurred, and early education and recognition of intrinsic personality traits and social factors may help to prevent this outcome. The neuropsychologist, whether completing early neuropsychological consultation and/or intervention, neuropsychological screening, or comprehensive neuropsychological evaluation, may be in the best position to address this issue. Neuropsychological Testing: The Mechanics of Assessment and Interpretation. Comprehensive neuropsychological testing is commonly used to evaluate the neurobehavioral effects of mTBI and to quantify a patient’s relative cognitive strengths and weaknesses. There are several test approaches, although the popularity of a flexible battery approach has increased significantly over the years and is currently used by approximately 78% of practitioners versus the fixed and/or standardized battery approach at only 5% [37]. Several cognitive domains are assessed, including attention and/or concentration, processing speed, executive functioning, language functioning, visuospatial functioning, learning and memory, overall intellectual abilities, and sensory and/or motor functioning. Measures of psychological functioning (eg, depression, anxiety) are frequently administered, given the impact of psychological factors on quality of life, and the potential impact of such factors on cognitive performance, perceptions of cognitive function, and overall recovery. Interpretation of neuropsychological test data is a complex process that involves quantitative comparisons with normative data as well as qualitative analysis. Neuropsycho-
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logical reports may be difficult for non-neuropsychologists to interpret, especially test results that include percentiles compared with normative data. For those unfamiliar with this type of data presentation, the 50th percentile may be interpreted as a negative result, and both patients and providers may hold expectations of 80th or 90th percentiles. However, this often is unrealistic and fails to account for the range of normal scores and normal variability in cognitive performance across an extended cognitive assessment. In fact, neuropsychological test scores at the 50th percentile are entirely normal, and normal values extend down to the 16th percentile. The majority of healthy individuals will demonstrate at least one performance below the 16th percentile on a comprehensive assessment [38], and average scores among high intelligence quotient individuals still typically indicate normal functioning [39]. In the case of mTBI, cognitive deficits that may occur as a function of injury in the very early period of recovery tend to be mild in both scope and severity. It also should be emphasized that the neuropsychologist’s ability to diagnose mTBI is based on a careful history of the acute symptoms at the time of the event, not the neuropsychological test results. In actuality, neuropsychological test results are nonspecific indicators of impairment that can be impacted by a multitude of factors besides mTBI, including many already noted (eg, emotional status, sleep and/or fatigue, pain, effort and/or motivation). To infer an association between mTBI and impaired test scores, the neuropsychologist must consider the patient’s clinical history, diagnostic test results, and psychosocial history, as well as the neuropsychological literature with regard to outcome from mTBI. Differences of opinion may exist between neuropsychologists with regard to mTBI diagnosis and symptoms, and providers (other than neuropsychologists) are not expected to understand all of the complexities involved related to neuropsychological evaluations. Nevertheless, they should recognize the potential clinical utility of the early neuropsychological referral, independent of its use in cases that involve delayed recovery and forensic evaluations. Providers often struggle with the clinical management of the injured worker with mTBI after a comprehensive neuropsychological evaluation. It is common that neuropsychological test results yield minimal, if any, findings that would suggest ongoing cognitive symptoms are related to the mTBI itself. It also is common that psychological factors such as depression and anxiety may be significant contributors to both cognitive and physical symptoms. Although it would seemingly be a relief to the injured worker that his or her cognitive symptoms are not related to brain damage and instead are secondary to a potentially treatable condition, such as depression or anxiety, the injured worker may react negatively to this conclusion. This type of response may relate to the negative social stigma associated with depression and anxiety, as well as the lack of financial remuneration if symptoms are not a consequence of the mTBI. As such,
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injured workers may misunderstand, misinterpret, or minimize findings that do not support mTBI and reject conclusions that suggest psychological or motivational etiology of their ongoing symptoms. They may view these results as a threat to the authenticity of their complaints, which may increase their mistrust of their providers and the WC system. In these situations, in which the clinical relationship has become strained, remediation may be difficult or impossible, especially because the injured worker’s belief in TBI may be firmly entrenched, or other psychological or motivational factors may be present. Prevention of this downward spiral is the mainstay of treatment, and early education may be helpful in avoiding this adversarial outcome, with a strong focus on the high likelihood of spontaneous recovery, especially in the presence of increased media reporting and social awareness of TBI. Also, the interrelationship of cognitive, emotional, and physical symptoms should be discussed. Lastly, the high occurrence of cognitive, emotional, and physical symptoms in everyday life should be discussed, with the emphasis that not all symptoms after mTBI are a result of the injury, especially with the passage of time. Assessment of Effort. Assessment of effort is imperative for all providers but is particularly important in neuropsychological evaluations. Increased recognition of the role of effort, particularly in cases with the potential for secondary gain, has resulted in the development of various symptom validity tests (SVT), which systematically assess effort on cognitive testing. Contemporary publications, including various position papers by national neuropsychology associations, have emphasized the importance of SVTs in such cases. The majority of SVTs rely on probabilistic analysis of scores (ie, relative to chance) on forced choice tests and comparison with other SVT scores [40]. Multiple SVTs are included within the typical neuropsychological evaluation so that the examinee perceives these tests as another measure of neurocognitive functioning. SVTs appear to be more difficult than they actually are, and most SVTs provide cutoffs that indicate a minimum score that can be achieved by patients with established neurocognitive disorders. Therefore, performances that fall below established cutoffs are indicative of inconsistent or suboptimal effort rather than frank cognitive dysfunction. Providers should be careful not to warn patients about the use of SVTs during neuropsychological evaluation because this may result in more-sophisticated methods of symptom magnification [39]. Although SVTs are sometimes colloquially referred to as “malingering tests,” this terminology is often misleading and inflammatory. Like other psychological constructs, effort on cognitive testing likely exists on a continuum that ranges from good to very poor, the latter of which can occur for a variety of reasons. Poor effort may be under the conscious control of the patient but, in many cases, may be related to unconscious, psychological factors, such as a somatoform
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conditions. In its most extreme form, poor effort can occur due to malingering, and the Slick et al [41] diagnostic criteria for “possible,” “probable,” or “definite” malingering of cognitive dysfunction are common reference points for neuropsychologists in the context of failed SVTs. These criteria are multifactorial and take into account negative response bias on testing as well as discrepancies with test data and (1) known patterns of brain functioning, (2) observed behavior, (3) collateral reports, and (4) documented background history. However, there is debate about the validity and utility of the diagnosis of malingering and whether the symptoms of malingering are objectively distinguishable from somatoform disorder [42].
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Clinical treatment of mTBI in the context of a WC injury is theoretically no different than in any other situation in which mTBI exists. However, in addition to managing the clinical symptoms associated with mTBI, in the WC system, providers must also address issues of causation, apportionment, relatedness and reasonableness of treatment as related to the work injury, and work capacity. When the injured worker is deemed to be at maximum medical improvement, providers must also determine if a permanent impairment and permanent work restrictions are required. Because each state governs its own WC policies and because certain occupations are addressed in a federal WC system, providers must be familiar with the rules and regulations that exist for different work populations. Medical treatment guidelines may exist and form the basis of the expected assessment and treatment algorithms for work-related injuries. Providers must be familiar with these guidelines (when applicable) and are typically expected to adhere to them. Medical treatment guidelines for mTBI may require documentable improvements in function to continue treatment, which may be difficult given the subjective nature and variability of many symptoms. In mTBI, continuation of treatment for “maintenance” of a condition or prevention of clinical deterioration may be difficult for the provider to justify. Justification in these situations typically requires a detailed narrative regarding the nature of the condition and the clinical necessity of the proposed treatment, and even then may be subject to additional review or deferred to the legal system.
through the employer. Headaches, dizziness, and visual disturbances may prevent the injured worker from being able to perform the essential functions of a job and may also limit driving. There is no simple solution for these situations, and it is common to have multiple specialists involved in the treatment plan. Psychological assessment is also highly suggested in these situations to assess psychological and motivational factors, and to consider cognitive behavioral therapy or other behavioral strategies. Work-hardening programs may be considered, and when the injured worker is near maximum medical improvement, functional capacity evaluations may be considered. However, functional capacity evaluations may be of limited utility, especially with the variability noted in injured workers with headaches or dizziness, especially when high-level balance or working from heights is required. Cognitive factors after mTBI may present as even more of a significant challenge for return to work than physical symptoms. These problems include incorporation of neuropsychological test results into on-the-job activities, interfacing with the employer, and setting appropriate work restrictions during the recovery process. Restrictions should be commensurate with the worker’s cognitive status, if present in the initial stages of recovery. During the early recovery period, injured workers with mTBI may require modified duty for cognitive symptoms, such as cognitive fatigue, attention and/or concentration difficulties, memory impairments, or executive dysfunction. Modified duty may be very difficult to assign, particularly in situations in which real-time supervision or evaluation of the injured worker’s job performance is not possible. Job descriptions may not provide enough detailed information for the provider to assign specific work restrictions, and it is impossible for the provider to know the nuances of every job type. In these situations, field-case management and community-based occupational therapy may be beneficial, as well as close collaboration with the employer to gain further understanding of the injured worker’s occupation, prior performance, and postinjury performance. Permanent job restrictions that involve reduced hours should be thoroughly considered before being instituted, because this may severely limit the injured worker’s employability, and may have negative financial implications for employers and insurers. Permanent restrictions also have high potential for reinforcing negative self-appraisals with regard to the patient’s cognitive status and long-term prognosis for recovery.
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CONCLUSION
In the WC system, return to work must be addressed on a routine basis, and, for mTBI issues, typically include cognitive, emotional, and physical symptoms. Physical symptoms after mTBI often pose a significant challenge in return to work, particularly for the manual laborer who may not have transferrable skills, or when modified duty is not available
The clinical management of mTBI can be challenging enough without the additional complexities of medicolegal issues frequently encountered in the WC system. Increased public awareness of mTBI will likely fuel the ongoing controversies that exist regarding the diagnosis and management of all patients with mTBI, and the WC system will not be immune
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to these effects. Providers who treat injured workers with mTBI are seemingly destined for failure if the injured worker’s symptoms do not spontaneously resolve. However, early recognition of poor predictors of outcome and appreciation of resources that usually are readily available in the WC system may help prevent delayed recovery in work-related mTBI. Returning to our most famous work-related patient with TBI, Phineas Gage, it seems that dismal reports of his poor vocational outcome that have been routinely described may be overstated. A recent review of records indicates that, after a brief recovery period, he was able to rejoin the workforce successfully as a farm worker, a travelling “exhibitor,” and a stagecoach driver in Chile. It was only after he developed epilepsy that he had trouble maintaining employment [1]. At a time when clinical management of TBI and administrative support were essentially nonexistent, Mr Gage’s ability to return to work was nothing short of remarkable. Keeping this in mind, whereas the needs of the injured worker with mTBI and the complexities of the WC system seem overwhelming at times, Mr Gage’s outcome should be of encouragement to providers who are treating patients with less-severe TBI injury, including facilitation of return to work.
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1. Macmillan M, Lea ML. Rehabilitating Phineas Gage. Neuropsychol Rehabil 2010;20:641-658. 2. Kristman VL, Cote P, Van Eerd D, et al. Prevalence of lost-time claims for mild traumatic brain injury in the working population: Improving estimates using workers compensation databases. Brain Inj 2008;22: 51-59. 3. Kraus JF, Fife D. Incidence, external causes and outcomes of workrelated brain injury in males. J Occup Med 1985;27:757-760. 4. Rutland-Brown W, Langlois JA, Thomas KE, Xi YL. Incidence of traumatic brain injury in the United States, 2003. J Head Trauma Rehabil 2006;21:544-548. 5. Kim H, Colantonio A, Chipman M. Traumatic brain injury occurring at work. NeuroRehabilitation 2006;21:269-278. 6. Wrona RM. The use of state workers’ compensation administrative data to identify injury scenarios and quantify costs of work-related traumatic brain injuries. J Safety Res 2006;37:75-81. 7. Colantonio A, McVittie D, Lewko J, Yin J. Traumatic brain injuries in the construction industry. Brain Inj 2009;23:873-878. 8. Carroll LJ, Cassidy JD, Peloso PM, et al. Prognosis for mild traumatic brain injury: Results of the WHO Collaborating Centre Task Force on Mild Traumatic Brain Injury. J Rehabil Med 2004;43(Suppl):84-105. 9. Binder L, Rohling M. Money matters: A meta-analytic review of the effects of financial incentives on recovery after closed-head injury. Am J Psychiatry 1996;153:7-10. 10. McCrea M, Iverson GL, McAllister TW, et al. An integrated review of recovery after mild traumatic brain injury (MTBI): Implications for clinical management. Clin Neuropsychol 2009;23:1368-1390. 11. Iverson GL. Outcome from mild traumatic brain injury. Curr Opin Psychiatry 2005;18:301-317. 12. Binder LM, Rohling ML, Larrabee GJ. A review of mild head trauma. Part I: Meta-analytic review of neuropsychological studies. Clin Neuropsychol 1997;19:421-431. 13. Rohling ML, Binder LM, Demakis GJ, Larrabee GJ, Ploetz DM, Langhinrichsen-Rohling J. A meta-analysis of neuropsychological outcome
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after mild traumatic brain injury: Re-analyses and reconsiderations of Binder et al. (1997), Frenchman et al. (2005), and Pertab et al. (2009). Clin Neuropsychol 2011;25:608-623. Frenchman KAR, Fox AM, Mayberry MT. Neuropsychological studies of mild traumatic brain injury: A meta-analytic review of research since 1995. J Clin Exp Neuropsychol 2005;27:334-351. Schretlen DJ, Shapiro AM. A quantitative review of the effects of traumatic brain injury on cognitive functioning. Int Rev Psychiatry 2003;15:341-349. Iverson GL, Lange RT, Brooks BL, Rennison VL. Good old days bias following mild traumatic brain injury. Clin Neuropsychol 2010;24: 17-37. Martelli MF, Nicholson K, Zasler ND, Bender MC. Assessment of response bias in clinical and forensic evaluations of impairment following TBI. In: Zasler ND, Katz DI, Zafonte RD, eds. Brain Injury Medicine Principles and Practice. New York: Demos; 2007, 1183-1203. Iverson GL, Lange RT. Examination of “postconcussion-like” symptoms in a healthy sample. Appl Neuropsychol 2003;10:137-144. Powell GE. Mild traumatic brain injury and postconcussion syndrome: The importance of base rates in diagnosis and clinical formulation. J Neurol Neurosurg Psychiatry 2008;79:237. Iverson GL, McCracken LM. “Postconcussive” symptoms in persons with chronic pain. Brain Inj 1997;11:783-790. Smith-Seemiller L, Fow NR, Kant R, Franzen MD. Presence of postconcussion syndrome symptoms in patients with chronic pain vs mild traumatic brain injury. Brain Inj 2003;17:199-206. Meares S, Shores EA, Taylor AJ, et al. Mild traumatic brain injury does not predict acute postconcussion syndrome. J Neurol Neurosurg Psychiatry 2008;79:300-306. Iverson GL. Misdiagnosis of the persistent postconcussion syndrome in patients with depression. Arch Clin Neuropsychol 2006;21:303-310. Lees-Haley PR, Fox DD, Courtney JC. A comparison of complaints by mild brain injury claimants and other claimants describing subjective experiences immediately following their injury. Arch Clin Neuropsychol 2001;16:689-695. Wang Y, Chan RC, Deng Y. Examination of postconcussion-like symptoms in healthy university students: Relationships to subjective and objective neuropsychological function performance. Arch Clin Neuropsychol 2006;21:339-347. Spencer RJ, Drag LL, Walker SJ, Bieliauskas LA. Self-reported cognitive symptoms following mild traumatic brain injury are poorly associated with neuropsychological performance in OIF/OEF veterans. J Rehabil Res Dev 2010;47:521-530. Lew HL, Lin PH, Fuh JL, Wang SJ, Clark DJ, Walker WC. Characteristics and treatment of headache after traumatic brain injury: A focused review. Am J Phys Med Rehabil 2006;85:619-627. Ismail Z, Rajji TK, Shulman KI. Brief cognitive screening instruments: An update. J Geriatr Psychiatry 2010;25:111-120. Mittenberg W, Canyock EM, Condit D, Patton C. Treatment of postconcussion syndrome following mild head injury. J Clin Exp Neuropsychol 2001;23:829-836. Borg J, Holm L, Cassidy JD, et al. Diagnostic procedures in mild traumatic brain injury: Results of the WHO Collaborating Centre Task Force on Mild Traumatic Brain Injury, J Rehab Med 2004;43(Suppl): 61-75. Comper P, Bisschop SM, Carnide N, Tricco A. A systematic review of treatments for mild traumatic brain injury. Brain Inj 2005;19:863-880. Ponsford, J. Rehabilitation interventions after mild head injury. Curr Opin Neurol 2005;18:692-697. Mittenberg W, Diguilio DV, Perrin S, Bass AE. Symptoms following mild head injury: Expectation as aetiology. J Neurol Neurosurg Psychiatry 1992;55:200-204. Iverson GL, Brooks BL, Ashton VL, Lange RT. Interview versus questionnaire symptom reporting in people with the postconcussion syndrome. J Head Trauma Rehabil 2010;25:23-30.
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35. Suhr JA, Gunstad J. “Diagnosis Threat”: The effect of negative expectations on cognitive performance in head injury. J Clin Exp Neuropsychol 2002;24:448-457. 36. Kirkwood MW, Yeates KO, Taylor HG, Randolph C, McCrea M, Anderson VA. Management of pediatric mild traumatic brain injury: A neuropsychological review from injury through recovery. Clin Neuropsychol 2008;22:769-800. 37. Sweet J, Giuffre Meyer D, Nelson NW, Moberg PJ. The TCN/AACN 2010 “Salary Survey”: Professional practices, beliefs, and incomes of U.S. neuropsychologists. Clin Neuropsychol 2011;25:12-61. 38. Binder LM, Iverson GL, Brooks BL. To err is human: “Abnormal” neuropsychological scores and variability are common in healthy adults. Arch Clin Neuropsychol 2009;24:31-46.
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39. Greiffenstein MF. Clinical myths of forensic neuropsychology. Clin Neuropsychol 2009;23:286-296. 40. Richards PM, Kirk JW. Traumatic brain injury across the lifespan: A neuropsychological tutorial for attorneys. Psychol Inj Law 2010;3: 3-24. 41. Slick DJ, Sherman EMS, Iverson GL. Diagnostic criteria or malingered neurocognitive dysfunction: Proposed standards for clinical practice and research. Clin Neuropsychol 1999;13:545-561. 42. Boone KB. A reconsideration of the Slick et al. (1999) Criteria for Malingered Neurocognitive Dysfunction. In: Boone KB, ed. Assessment of Feigned Cognitive Impairment: A Neuropsychological Perspective. New York: Guilford; 2007, 29-49.
Mild Traumatic Brain Injury in the Occupational Setting Victor H. Chang, MD, Lisa A. Lombard, MD, Michael R. Greher, PhD Abstract: The evaluation and management of mild traumatic brain injury (mTBI) in the occupational setting may pose significant challenges for even the most-seasoned practitioner. Providers must simultaneously address the clinical management of mTBI and be familiar with the systematic and administrative requirements related to the management of injured workers with mTBI who are covered by workers’ compensation insurance, including causation, return to work, and the potential of permanent impairment. Given the primarily subjective nature of many mTBI symptoms, an injured worker with a delayed recovery may raise the question, if not suspicion, of symptom magnification and secondary gain. This review discusses the evaluation and treatment of the injured worker with mTBI, and focuses on the medicolegal issues that are present in the workers’ compensation system, especially the role of neuropsychological evaluations. Although significant differences exist regarding classification schema, for the purposes of this discussion, mTBI is used to encompass the terms concussion, postconcussive syndrome, and persistent postconcussive syndrome. PM R 2011;3:S387-S395
INTRODUCTION Perhaps the most famous person to sustain a work-related traumatic brain injury (TBI) was Phineas Gage, a 25-year-old railway worker. In 1848, while setting explosives, a 13-pound iron tamping rod pierced his left eye and frontal lobe, and exited through his skull. Amazingly, he survived this insult, but, due to severe behavioral and personality changes, he was reportedly unable to successfully return to employment [1]. This brief but graphic anecdote informs us of several points: the brain is incredibly complex, resilient, and vulnerable at the same time; the residual effects of a severe TBI can be overestimated, and, by corollary, the effects of mild traumatic brain injury (mTBI) can be underestimated; and, finally, even 163 years since Gage’s storied injury, we are only beginning to unravel the evidence that underlies mTBI. During Phineas Gage’s era, injured workers bore the cost of medical treatment but had the right to sue an employer for negligence or an act of omission. It was not until the early 1900s that the first workers’ compensation (WC) law was passed in the United States and not until 1949 that all states had enacted some kind of WC system. Each state governs its own WC policies and procedures, and certain employees are covered under a federal system. However, common themes exist for both the injured worker and the employer. Typically, once causation has been established, the injured worker is entitled to (1) medical treatment for the work-related injury or disease, (2) lost wages, and (3) financial remuneration in the event of permanent impairment or disability. Also, an injured worker does not need to prove that the employer is at fault to be able to seek medical care. As a trade-off, the injured worker gives up the right to sue an employer for a work-related injury, and the employer is not liable for pain and suffering. Delayed recovery after mTBI is perhaps one of the most challenging situations encountered in the WC system, with controversy being more the rule than the exception. Independent of any work-related issues, the clinical aspects of mTBI, including diagnosis, management, and outcomes can be difficult. When factoring in the medicolegal aspects of the WC system, the complexity of care can seem overwhelming. PM&R 1934-1482/11/$36.00 Printed in U.S.A.
V.H.C. Department of Physical Medicine and Rehabilitation, University of Colorado School of Medicine, Mailstop F-493, 12631 East 17th Ave, Rm 2513, Aurora, CO 80045. Address correspondence to: V.H.C.; e-mail: [email protected] Disclosure: 5B, as requested by attorneys or insurers L.A.L. Department of Physical Medicine and Rehabilitation, Indiana University School of Medicine, Indianapolis, IN Disclosure: nothing to disclose M.R.G. Department of Neurosurgery, University of Colorado School of Medicine, Aurora, CO Disclosure: 5B, engage in some forensic consultation, including cases of TBI Disclosure Key can be found on the Table of Contents and at www.pmrjournal.org
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The multiplicity of symptoms after mTBI includes cognitive, emotional, and physical symptoms, and commonly requires multiple providers across different specialties. There is no specific specialty that takes “ownership” of TBI, and neurologists, neurosurgeons, physiatrists, internists, family practitioners, and occupational medicine physicians are often the primary physicians. Furthermore, specialists, including psychiatrists, neuropsychologists, otolaryngologists, and ophthalmologists, may address specific symptoms of mTBI. Allied health care professionals are usually consulted, including physical and occupational therapists, speech-language pathologists, vestibular therapists, and chiropractors. Lastly, employers, insurance case managers and adjustors, forensic medical experts, and attorneys may be involved. Consensus is often difficult within one specialty alone and can be extremely difficult among multiple providers, which necessitates a skillful approach to the overall management of the injured worker with mTBI and an appreciation of the controversies that exist related to this diagnosis.
EPIDEMIOLOGY Similar to the general population, a diagnosis of work-related mTBI is prone to both under- and overdiagnosis, because many injuries may go unreported, whereas, at other times, symptoms unrelated to mTBI may be errantly diagnosed as such, especially in delayed recovery situations. There is limited information available regarding the epidemiology of mTBI in the workplace. Kristman et al [2] reported that approximately 6 of 1000 lost-time claims were associated with mTBI. Kraus and Fife [3] reported a higher incidence of work-related mTBI, noting an occurrence of 17 of 1000 lost-time claims. The majority of these injuries (54%) resulted from a fall. TBI is most common in manual laborers, most often in men younger than 40 years old. Detailed information about mTBI in the workplace is difficult to estimate, although the majority of all TBIs (60%-80%) in the United States are classified as mild [4]. Etiology of work-related mTBI varies with the type of job performed, but falls are the most common cause overall, particularly in the construction, manufacturing, sales, and service sectors, and account for 40%-60% of all work-related TBIs. Motor vehicle accidents and bluntforce trauma (either struck by or against an object) are the next most common causes of work-related mTBI, each accounting for about 20% of all work-related TBIs [5-7].
PREDICTIVE FACTORS OF OUTCOME Germaine to the outcome of work-related mTBI is the ability of the injured worker to return to work and whether or not there is a permanent impairment or disability. These issues have significant financial implications to the injured worker, employer, and insurer. Predictors for mTBI outcomes are
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difficult in any setting and even more so in the occupational setting, because financial implications are involved at every stage. Carroll et al [8] critically reviewed 428 studies related to prognosis after mTBI and accepted 120 after critical review, noting that cognitive deficits and symptoms were common in the acute stage, but the majority of studies reported recovery over 3-12 months. The researchers also concluded that when symptoms persisted, compensation and litigation were factors, but there was little consistent evidence for other predictors. Similar findings have been noted in other studies [9]. In addition, various meta-analyses suggest that the vast majority of patients with uncomplicated mTBI (ie, those without evidence in injury-related intracranial lesion) experience a rapid cognitive recovery that ranges anywhere from a few days to 3 months [10-15].
NONSPECIFICITY OF mTBI SYMPTOMS AND RESPONSE BIAS The majority of mTBI symptoms are subjective in nature, and it is critical that the initial provider not just evaluate the postinjury symptoms but also query the injured worker about any preinjury symptoms at the first visit and continue to investigate any preinjury symptoms at subsequent visits. In general, patients tend to underestimate past problems (ie, “good old days” bias), which can impact their perceived level of current problems and recovery [16]. With the passing of time, an injured worker with mTBI may often see numerous providers and retell the history multiple times. The injured worker’s recounting of the injury and subsequent symptoms may become less accurate over time, with misattribution of symptoms in relation to the injury. As a result of interactions with multiple providers, injured workers may introduce additional symptoms to their history based on these interactions, even though the symptoms may not have actually occurred or may have occurred in a different fashion than reported. Response bias is defined as a class of behaviors that reflects less than a fully truthful, accurate, or valid symptom report and presentation. Response bias does not assume that the injured worker is consciously attempting to feign symptoms but is rather a ubiquitous phenomenon that affects almost any domain of human self-report. It is also important to recognize the potential for provider bias. Martelli et al [17] reported that 25% of surveyed professionals who evaluate and treat injured workers suspected exaggeration or malingering. In addition, the majority of these professionals believed that they would personally be treated unfairly in the WC system if they were injured. Response bias does not imply that the provider must doubt the veracity of the injured worker’s reported symptoms but rather that the provider must recognize that the reported cognitive, emotional, and physical symptoms that are attributed to a work-related mTBI may have been present
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before the injury or may be related to factors other than the mTBI. There are numerous reports in the medical literature that note the nonspecificity of cognitive, emotional, and physical symptoms that are commonly reported after mTBI. These symptoms are not unique to mTBI, are present in the normal population [18,19], are highly correlated with chronic pain [20-22] or depressive symptoms [23], and have been found to occur at similar rates in both claimants who report mTBI and claimants who report bodily injuries without mTBI [24]. It also is important to note that there often is a discrepancy between self-reported cognitive complaints and actual cognitive deficits as identified via neuropsychological testing [25,26]. In injured workers with protracted symptoms after mTBI, especially those individuals in whom symptoms fail to improve or to worsen over time and symptom magnification is suspected, the provider must thoroughly investigate factors other than the mTBI, including emotional factors (eg, depression, anxiety), pain issues, poor sleep, medication effects, and secondary gain.
CONTROVERSY REGARDING mTBI OUTCOMES Although it is generally accepted that mTBI symptoms are organically based in the first few weeks (and perhaps the first few months) after mTBI, the delineation between physiological and psychological etiology becomes blurred when symptoms persist over time. Controversy exists regarding the outcomes of mTBI. Although the neuropsychological literature has consistently demonstrated that uncomplicated mTBI typically results in a full and rapid cognitive recovery, increased public awareness of mTBI over the past several years, especially in professional athletes and military combatants, has resulted in debate about this issue in public forums and popular media. Similar controversy exists in injured workers with mTBI and with persistent symptoms. The WC system requires the practitioner to address the causation of symptoms and return to work at all stages of treatment. In addition, at the time of case closure (eg, maximum medical improvement), an opinion must be rendered regarding permanent impairment and disability, with significant financial implications as a result. With these factors in mind, there has been particular interest in identifying which injured workers are likely to have a protracted clinical course. Estimates of persistent symptoms and disability after mTBI vary between 5% and 10%, with conflicting reports in the medical literature regarding the etiology of ongoing symptoms. A growing consensus suggests that previous estimates of nonrecovery in the 15%-20% range were likely inflated [9,10] and attributes protracted symptoms to psychological and other noninjury-related factors more so than neurologic factors. Classification of mTBI also is not uniform, which makes interpretation of peer-reviewed literature diffi-
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cult. Although the American Congress of Rehabilitation Medicine definition of mTBI is one of the most commonly referenced criteria, given the broad inclusion criteria that range from “any alteration of mental status” to “a maximum of 24 hours of posttraumatic amnesia,” it is difficult to draw any generalized conclusions regarding outcome from the diagnosis of mTBI alone. Also, studies often do not distinguish between “simple” or “uncomplicated” mTBI (eg, normal computed tomography or magnetic resonance imaging of the brain) versus “complicated” mTBI (eg, clinical symptoms that meet mTBI criteria in the presence of an abnormal computed tomography or magnetic resonance imaging of the brain). As such, the mTBI cohort is more of a heterogeneous than a homogeneous population. Prognostication of persistent symptoms based on classification of mTBI alone is ill advised, because the diagnosis of mTBI itself is not predictive of chronic symptomatology [17]. In work-related and civil litigation mTBI literature, there is increased recognition of the influence of financial incentives. Bias also is a confounder, including the injured worker, provider, employer, and insurer. Although consensus may be more uniform in moderate or severe TBI regarding causation, reasonableness, and relatedness of treatment, severity of impairment and disability, and feasibility of return to work, these issues often are highly contentious in injured workers with mTBI. Forensic evaluations, particularly neuropsychological assessment, are common when injured workers with mTBI have persistent symptoms. However, these forensic evaluations often provide little in the way of ongoing management of these individuals, particularly because they rarely occur in the early stages of treatment. Although it is beyond the scope of this review to detail the specifics of neuropsychological evaluation, it is imperative that providers attain a basic understanding of the key issues and controversies that involve mTBI and that are assessed in neuropsychological evaluations. Because comprehensive neuropsychological testing is typically reserved for patients with persistent symptoms (eg, 3 months or more after injury), it is critical that the providers involved in the acute phase (eg, first month after injury) recognize the factors that are typically seen in delayed recovery after mTBI. More importantly, beyond recognizing these negative predictors, providers must be able to adjust treatment to mitigate the chances of a poor outcome.
ASSESSMENT OF mTBI Physical A variety of physical symptoms may be present after mTBI, with headaches, dizziness, and visual disturbances being the commonly reported symptoms. These symptoms may be interrelated or may be independent of each other. Within the scope of this discussion, these symptoms are only briefly reviewed.
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Headaches that occur within 1 week of head trauma are referred to as posttraumatic headaches (PTH). Although the majority of patients with PTH have resolution within several months of injury, approximately 18%-33% of patients with PTH have persistent symptoms beyond 1 year. Lew et al [27] reported that 37% of all PTH had clinical presentations similar to tension-type headache, and 29% had clinical presentations similar to migraine. Evaluation of the patient with PTH should include a detailed examination of the cranial nerves and musculoskeletal assessment of the face (including the jaw), head, and cervical regions. Abnormal findings, such as cranial neuropathies (eg, visual neglect, saccadic pursuits, facial weakness), should prompt further diagnostic testing or imaging of the brain, skull, and/or cervical spine. Psychological factors also should also be investigated as a contributor to chronic PTH. Dizziness is often reported after mTBI and may or may not correlate with headache or other symptoms. The differential diagnosis is broad but includes central mechanisms (eg, brainstem dysfunction), peripheral etiology (eg, benign paroxysmal positional vertigo), and psychological factors (eg, anxiety). Initial evaluation may include a Dix-Hallpike maneuver to diagnosis benign paroxysmal positional vertigo. Otolaryngology evaluation and testing may be necessary to rule out other conditions, such as a perilymph fistula or hydrops. Cervical imaging, including vertebrobasilar system assessment, should be pursued if dissection is suspected. The presence of hearing loss should prompt further evaluation of the tympanic membrane or consideration of a computed tomography to rule out a temporal skull fracture. Various visual symptoms may be reported after mTBI and may be secondary to cranial neuropathies, orbital involvement, headaches, or emotional factors. Ocular motor or visual field deficits should prompt further evaluation, such as brain magnetic resonance imaging or referral to ophthalmology. Posttrauma vision syndrome and visual midline shift syndrome have been described, and vision therapy or prism glasses may be recommended to treat these conditions, but these remain controversial topics, with little in the way of peer-reviewed publications. Patients with ongoing visual symptoms typically require further assessment with ophthalmology.
Cognitive and/or Emotional Brief Cognitive Screening (“in office”). Initial “in office” cognitive assessment after mTBI should include evaluation of arousal, attention span, orientation, memory, fund of knowledge, and executive function. Informal cognitive assessment also is imperative, including the injured worker’s ability to provide a history, and the manner in which the injured worker provides a history and responds to questions (eg, linear and/or direct thought processes, tangentiality, distractibility, comportment). The Mini-Mental State Exam-
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ination is commonly used but is of limited utility in evaluating mTBI given its focus on orientation and short-term memory. By comparison, the Montreal Cognitive Assessment may be a reasonable choice given its test-retest reliability, internal consistency, content validity, and ease of administration (10 minutes) [28]. However, there is no criterion standard cognitive screening tool for mTBI, and deficits may still exist in the presence of normal scores. As such, further in-depth testing may be necessary for persistent or subtle symptoms. Whether or not a cognitive screening tool is used, it is essential that ongoing assessments involve more than basic orientation and attention, and should include some measure of executive function. Emotional factors also may be present and superimposed on true cognitive deficits or may be the cause of cognitive dysfunction. The initial history must distinguish emotional conditions, such as acute stress reactions in the initial moments at the scene (eg, feelings of “panic,” “fear,” or being “stunned”) from the symptoms of true mTBI (eg, disorientation, confusion). These symptoms often mimic one another and can be challenging to distinguish in the absence of supportive first responder or emergency department records. The differentiation between an acute stress reaction and mTBI, therefore, may present as a diagnostic dilemma, and, in these situations, if the provider is unsure, then early referral to another provider who specializes in brain injury is advisable. Neuropsychological Evaluation. Consultation with a neuropsychologist is often recommended for any patient with mTBI but should be considered early on in the occupational setting. Although providers tend to think of neuropsychological consultation in a fairly uniform fashion that involves comprehensive neuropsychological testing 3 months or more after injury, neuropsychologists can provide a variety of services early or late in the treatment process. These services can take several forms, depending upon the clinical need and the recommendations of the referring provider but, for the purposes of this article, are divided into 3 options, which can be completed individually or in combination: (1) early neuropsychological consultation and/or intervention, (2) screening neuropsychological evaluation, and (3) comprehensive neuropsychological evaluation. After clearance from initial providers, which may include neuroimaging and other treatment, initial neuropsychological consultation is recommended for the purposes of (1) acquiring a detailed history from the injured worker about the events of the injury itself; (2) obtaining a differential diagnosis of mTBI based on this history and/or psychological symptoms, such as depression, anxiety, or somatic focus; (3) providing education and reassurance to the injured worker with regard to the natural course of recovery from mTBI and the role of complicating psychological and physical factors; and (4) providing recommendations to address these latter issues early in the treatment process. Early, brief intervention
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that emphasizes education and reassurance has substantial empirical support for reducing the probability of persistent cognitive symptoms after mTBI [29-32]. Mittenberg [33] discusses the phenomenon of “expectation as etiology” and the significant benefits of providing patients with mTBI with positive expectations regarding outcome from injury. The detrimental impact of negative prognostication by providers also is well known and frequently is discussed in the context of iatrogenic complaints, and concepts known as “diagnosis threat,” or the “nocebo effect” [34,35]. Within the first few weeks after mTBI, providers may opt to refer patients for a screening neuropsychological evaluation, which, in essence, is more extensive than a mental status examination such as the Montreal Cognitive Assessment but more abbreviated than a comprehensive neuropsychological evaluation. As with the early neuropsychological interventions described above, these screening evaluations are intended to be completed in the early stages of recovery (ie, first 3 months after injury). The purpose is to briefly evaluate primary areas of cognition with the goal of determining current status, especially if there are concerns regarding the ability to return to work. Screening evaluations also can be used to establish a baseline of cognitive functioning for comparison should additional testing be warranted in the future and may help to determine if further intervention is needed. A comprehensive neuropsychological evaluation is typically completed at a minimum of 3 months after injury. Numerous factors are involved with this time frame, including clinical, practical, and economic reasons. Clinically, because the vast majority of patients with mTBI have spontaneous recovery within the first 3 months of injury, comprehensive neuropsychological testing may not be indicated and greater emphasis on education and reassurance is the most likely way to positively impact the outcome during this time frame. From a practical standpoint, formal testing usually requires a full day of testing. It is time consuming, impractical, and cost prohibitive to do repeated testing on a routine basis, and, therefore, it is recommended that providers only make referrals for a comprehensive neuropsychological evaluation when indicated by the case and appropriate with regard to time. A similar clinical management model was proposed by Kirkwood et al [36] for pediatric mTBI. In addition to acquiring a detailed history and assisting with a differential diagnosis of mTBI based on the acute symptoms at the time of injury, a comprehensive neuropsychological evaluation provides a detailed assessment of current cognitive and emotional functioning. Critical to the evaluation is that TBI does not globally affect all neurocognitive domains, and reported symptoms that are atypical or inconsistent with mTBI should raise suspicion of non-TBI factors. In particular, well-rehearsed information, such as a patient’s fund of factual knowledge and long-term memories of salient life events, should remain unaffected by the early
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cognitive impact of a mTBI. The neuropsychological evaluation can be particularly helpful in determining the role of additional, non-TBI factors, such as other neurologic disorders, psychological dysfunction, chronic pain, poor sleep, insufficient effort, and symptom magnification with regard to persisting cognitive symptoms beyond the typical window of recovery. Such determinations often guide treatment and are of importance to injured workers, employers, and insurers. In addition, if injured workers have undergone a screening evaluation within the first 3 months after injury, a comprehensive neuropsychological evaluation can be completed for comparative purposes to objectively track the course of cognitive symptoms over time and provide further recommendations for treatment. In cases in which symptoms persist despite the passage of time, a vicious cycle may evolve. The injured worker may question the competency of his or her providers and perceive the employer and insurer as unsupportive. Providers, employers, and insurers may suspect symptom magnification and secondary gain, which causes additional strain among all parties involved. Employers and insurers may question the necessity of work removal or modified duty and may pressure the provider and employee to return to regular duty. This combination of factors can lead to an adversarial system of care, increasing the complexity of the clinical issues. Amelioration of this situation is difficult once it has occurred, and early education and recognition of intrinsic personality traits and social factors may help to prevent this outcome. The neuropsychologist, whether completing early neuropsychological consultation and/or intervention, neuropsychological screening, or comprehensive neuropsychological evaluation, may be in the best position to address this issue. Neuropsychological Testing: The Mechanics of Assessment and Interpretation. Comprehensive neuropsychological testing is commonly used to evaluate the neurobehavioral effects of mTBI and to quantify a patient’s relative cognitive strengths and weaknesses. There are several test approaches, although the popularity of a flexible battery approach has increased significantly over the years and is currently used by approximately 78% of practitioners versus the fixed and/or standardized battery approach at only 5% [37]. Several cognitive domains are assessed, including attention and/or concentration, processing speed, executive functioning, language functioning, visuospatial functioning, learning and memory, overall intellectual abilities, and sensory and/or motor functioning. Measures of psychological functioning (eg, depression, anxiety) are frequently administered, given the impact of psychological factors on quality of life, and the potential impact of such factors on cognitive performance, perceptions of cognitive function, and overall recovery. Interpretation of neuropsychological test data is a complex process that involves quantitative comparisons with normative data as well as qualitative analysis. Neuropsycho-
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logical reports may be difficult for non-neuropsychologists to interpret, especially test results that include percentiles compared with normative data. For those unfamiliar with this type of data presentation, the 50th percentile may be interpreted as a negative result, and both patients and providers may hold expectations of 80th or 90th percentiles. However, this often is unrealistic and fails to account for the range of normal scores and normal variability in cognitive performance across an extended cognitive assessment. In fact, neuropsychological test scores at the 50th percentile are entirely normal, and normal values extend down to the 16th percentile. The majority of healthy individuals will demonstrate at least one performance below the 16th percentile on a comprehensive assessment [38], and average scores among high intelligence quotient individuals still typically indicate normal functioning [39]. In the case of mTBI, cognitive deficits that may occur as a function of injury in the very early period of recovery tend to be mild in both scope and severity. It also should be emphasized that the neuropsychologist’s ability to diagnose mTBI is based on a careful history of the acute symptoms at the time of the event, not the neuropsychological test results. In actuality, neuropsychological test results are nonspecific indicators of impairment that can be impacted by a multitude of factors besides mTBI, including many already noted (eg, emotional status, sleep and/or fatigue, pain, effort and/or motivation). To infer an association between mTBI and impaired test scores, the neuropsychologist must consider the patient’s clinical history, diagnostic test results, and psychosocial history, as well as the neuropsychological literature with regard to outcome from mTBI. Differences of opinion may exist between neuropsychologists with regard to mTBI diagnosis and symptoms, and providers (other than neuropsychologists) are not expected to understand all of the complexities involved related to neuropsychological evaluations. Nevertheless, they should recognize the potential clinical utility of the early neuropsychological referral, independent of its use in cases that involve delayed recovery and forensic evaluations. Providers often struggle with the clinical management of the injured worker with mTBI after a comprehensive neuropsychological evaluation. It is common that neuropsychological test results yield minimal, if any, findings that would suggest ongoing cognitive symptoms are related to the mTBI itself. It also is common that psychological factors such as depression and anxiety may be significant contributors to both cognitive and physical symptoms. Although it would seemingly be a relief to the injured worker that his or her cognitive symptoms are not related to brain damage and instead are secondary to a potentially treatable condition, such as depression or anxiety, the injured worker may react negatively to this conclusion. This type of response may relate to the negative social stigma associated with depression and anxiety, as well as the lack of financial remuneration if symptoms are not a consequence of the mTBI. As such,
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injured workers may misunderstand, misinterpret, or minimize findings that do not support mTBI and reject conclusions that suggest psychological or motivational etiology of their ongoing symptoms. They may view these results as a threat to the authenticity of their complaints, which may increase their mistrust of their providers and the WC system. In these situations, in which the clinical relationship has become strained, remediation may be difficult or impossible, especially because the injured worker’s belief in TBI may be firmly entrenched, or other psychological or motivational factors may be present. Prevention of this downward spiral is the mainstay of treatment, and early education may be helpful in avoiding this adversarial outcome, with a strong focus on the high likelihood of spontaneous recovery, especially in the presence of increased media reporting and social awareness of TBI. Also, the interrelationship of cognitive, emotional, and physical symptoms should be discussed. Lastly, the high occurrence of cognitive, emotional, and physical symptoms in everyday life should be discussed, with the emphasis that not all symptoms after mTBI are a result of the injury, especially with the passage of time. Assessment of Effort. Assessment of effort is imperative for all providers but is particularly important in neuropsychological evaluations. Increased recognition of the role of effort, particularly in cases with the potential for secondary gain, has resulted in the development of various symptom validity tests (SVT), which systematically assess effort on cognitive testing. Contemporary publications, including various position papers by national neuropsychology associations, have emphasized the importance of SVTs in such cases. The majority of SVTs rely on probabilistic analysis of scores (ie, relative to chance) on forced choice tests and comparison with other SVT scores [40]. Multiple SVTs are included within the typical neuropsychological evaluation so that the examinee perceives these tests as another measure of neurocognitive functioning. SVTs appear to be more difficult than they actually are, and most SVTs provide cutoffs that indicate a minimum score that can be achieved by patients with established neurocognitive disorders. Therefore, performances that fall below established cutoffs are indicative of inconsistent or suboptimal effort rather than frank cognitive dysfunction. Providers should be careful not to warn patients about the use of SVTs during neuropsychological evaluation because this may result in more-sophisticated methods of symptom magnification [39]. Although SVTs are sometimes colloquially referred to as “malingering tests,” this terminology is often misleading and inflammatory. Like other psychological constructs, effort on cognitive testing likely exists on a continuum that ranges from good to very poor, the latter of which can occur for a variety of reasons. Poor effort may be under the conscious control of the patient but, in many cases, may be related to unconscious, psychological factors, such as a somatoform
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conditions. In its most extreme form, poor effort can occur due to malingering, and the Slick et al [41] diagnostic criteria for “possible,” “probable,” or “definite” malingering of cognitive dysfunction are common reference points for neuropsychologists in the context of failed SVTs. These criteria are multifactorial and take into account negative response bias on testing as well as discrepancies with test data and (1) known patterns of brain functioning, (2) observed behavior, (3) collateral reports, and (4) documented background history. However, there is debate about the validity and utility of the diagnosis of malingering and whether the symptoms of malingering are objectively distinguishable from somatoform disorder [42].
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Clinical treatment of mTBI in the context of a WC injury is theoretically no different than in any other situation in which mTBI exists. However, in addition to managing the clinical symptoms associated with mTBI, in the WC system, providers must also address issues of causation, apportionment, relatedness and reasonableness of treatment as related to the work injury, and work capacity. When the injured worker is deemed to be at maximum medical improvement, providers must also determine if a permanent impairment and permanent work restrictions are required. Because each state governs its own WC policies and because certain occupations are addressed in a federal WC system, providers must be familiar with the rules and regulations that exist for different work populations. Medical treatment guidelines may exist and form the basis of the expected assessment and treatment algorithms for work-related injuries. Providers must be familiar with these guidelines (when applicable) and are typically expected to adhere to them. Medical treatment guidelines for mTBI may require documentable improvements in function to continue treatment, which may be difficult given the subjective nature and variability of many symptoms. In mTBI, continuation of treatment for “maintenance” of a condition or prevention of clinical deterioration may be difficult for the provider to justify. Justification in these situations typically requires a detailed narrative regarding the nature of the condition and the clinical necessity of the proposed treatment, and even then may be subject to additional review or deferred to the legal system.
through the employer. Headaches, dizziness, and visual disturbances may prevent the injured worker from being able to perform the essential functions of a job and may also limit driving. There is no simple solution for these situations, and it is common to have multiple specialists involved in the treatment plan. Psychological assessment is also highly suggested in these situations to assess psychological and motivational factors, and to consider cognitive behavioral therapy or other behavioral strategies. Work-hardening programs may be considered, and when the injured worker is near maximum medical improvement, functional capacity evaluations may be considered. However, functional capacity evaluations may be of limited utility, especially with the variability noted in injured workers with headaches or dizziness, especially when high-level balance or working from heights is required. Cognitive factors after mTBI may present as even more of a significant challenge for return to work than physical symptoms. These problems include incorporation of neuropsychological test results into on-the-job activities, interfacing with the employer, and setting appropriate work restrictions during the recovery process. Restrictions should be commensurate with the worker’s cognitive status, if present in the initial stages of recovery. During the early recovery period, injured workers with mTBI may require modified duty for cognitive symptoms, such as cognitive fatigue, attention and/or concentration difficulties, memory impairments, or executive dysfunction. Modified duty may be very difficult to assign, particularly in situations in which real-time supervision or evaluation of the injured worker’s job performance is not possible. Job descriptions may not provide enough detailed information for the provider to assign specific work restrictions, and it is impossible for the provider to know the nuances of every job type. In these situations, field-case management and community-based occupational therapy may be beneficial, as well as close collaboration with the employer to gain further understanding of the injured worker’s occupation, prior performance, and postinjury performance. Permanent job restrictions that involve reduced hours should be thoroughly considered before being instituted, because this may severely limit the injured worker’s employability, and may have negative financial implications for employers and insurers. Permanent restrictions also have high potential for reinforcing negative self-appraisals with regard to the patient’s cognitive status and long-term prognosis for recovery.
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CONCLUSION
In the WC system, return to work must be addressed on a routine basis, and, for mTBI issues, typically include cognitive, emotional, and physical symptoms. Physical symptoms after mTBI often pose a significant challenge in return to work, particularly for the manual laborer who may not have transferrable skills, or when modified duty is not available
The clinical management of mTBI can be challenging enough without the additional complexities of medicolegal issues frequently encountered in the WC system. Increased public awareness of mTBI will likely fuel the ongoing controversies that exist regarding the diagnosis and management of all patients with mTBI, and the WC system will not be immune
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to these effects. Providers who treat injured workers with mTBI are seemingly destined for failure if the injured worker’s symptoms do not spontaneously resolve. However, early recognition of poor predictors of outcome and appreciation of resources that usually are readily available in the WC system may help prevent delayed recovery in work-related mTBI. Returning to our most famous work-related patient with TBI, Phineas Gage, it seems that dismal reports of his poor vocational outcome that have been routinely described may be overstated. A recent review of records indicates that, after a brief recovery period, he was able to rejoin the workforce successfully as a farm worker, a travelling “exhibitor,” and a stagecoach driver in Chile. It was only after he developed epilepsy that he had trouble maintaining employment [1]. At a time when clinical management of TBI and administrative support were essentially nonexistent, Mr Gage’s ability to return to work was nothing short of remarkable. Keeping this in mind, whereas the needs of the injured worker with mTBI and the complexities of the WC system seem overwhelming at times, Mr Gage’s outcome should be of encouragement to providers who are treating patients with less-severe TBI injury, including facilitation of return to work.
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