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Diagnostic tools for dementia
Maturitas 63 (2009) 181–185
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Review
Diagnostic tools for dementia Catherine F. Hatfield, Robert B. Dudas, Tom Dening ∗ Cambridgeshire & Peterborough NHS Foundation Trust, Box 311, Fulbourn Hospital, Cambridge, CB21 5EF, UK
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Article history: Received 5 March 2009 Accepted 11 March 2009 Keywords: Dementia Alzheimer’s disease Diagnosis Assessment Rating scales Cognitive testing
a b s t r a c t As population ageing means that dementia is becoming more prevalent, it is increasingly important that clinicians from all types of practice are familiar with assessing patients who have possible cognitive impairment. The diagnosis of the syndrome of dementia remains a clinical process, supplemented by relevant investigations including cognitive testing. This paper reviews some of the more commonly used tools for assessing cognition, behaviour and overall functioning in patients with possible or established dementia. Several categories of instruments are considered, including brief screening tests, neuropsychological test batteries, scales for behavioural and psychiatric symptoms, and functional and global assessments. It is recommended that clinicians familiarise themselves with a small number of scales that can be readily employed in everyday practice. © 2009 Elsevier Ireland Ltd. All rights reserved.
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Diagnostic criteria for dementia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Screening tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1. Abbreviated Mental Test Score (AMTS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2. Six Item Cognitive Impairment Test (6CIT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3. Clock drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4. Mini-Mental State Examination (MMSE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neuropsychological test batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1. The Addenbrooke’s Cognitive Examination-Revised (ACE-R) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Behavioural and psychiatric symptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1. BEHAVE-AD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2. Neuropsychiatric Inventory (NPI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Functional and Global Assessments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1. Blessed Dementia Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2. Global Deterioration Scale (GDS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3. Clinical Dementia Rating (CDR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4. Clinicians’ Global Impression of Change (CGI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Disclosure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dementia is a syndrome due to disease of the brain of a chronic and progressive nature in which there is disturbance of multiple higher cortical functions such as memory, thinking, orientation, comprehension, calculation, language and judgement without clouding of consciousness. These cognitive impairments
∗ Corresponding author. Tel.: +44 01223 218890; fax: +44 01223 218992. E-mail address: [email protected] (T. Dening). 0378-5122/$ – see front matter © 2009 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.maturitas.2009.03.005
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are commonly accompanied by deterioration in emotional control, social behaviour, or motivation. The commonest causes of dementia in older people are Alzheimer’s disease (AD) and vascular dementia (VaD), with mixed pathology being fairly common too, especially in people aged 80 or above. The diagnosis of dementia remains primarily clinical. It is essential to gather an accurate history both from the patient and from an informant. Blood and radiological investigations are routinely ordered to screen for reversible causes and exclude other conditions. Some formal testing of cognitive function is essential and a
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wide variety of different tests are available to measure different aspects of cognition, function and behaviour. This review discusses some of the most commonly used tests, including simple screening tests, more complex systems for cognitive examination, and tools for assessing neuropsychiatric symptoms, functional ability and overall severity of dementia. We suggest which might be most appropriate for a given clinical situation and we also briefly discuss criteria using for making the diagnosis of dementia.
dated [8]. The main advantage is that the items are extremely simple (three orientation items, count backwards from 20, months of the year in reverse order, and learn an address) and the scale is culturally unbiased. However, the scoring involves weighting of the items to produce a score out of 28, with a cut-off of 7/8 having high sensitivity and specificity even in mild dementia.
2.3. Clock drawing 1. Diagnostic criteria for dementia The two standard systems in use for the diagnosis of dementia are DSM-IV and ICD-10, which are basically similar. Both define the dementia syndrome and then present operational criteria for diagnosing types of dementia, such as Alzheimer’s disease, vascular dementia and so on. Although they contain criteria for dementia due to Parkinson’s disease, they do not include criteria for some important forms of dementia, such as dementia with Lewy bodies (DLB) or frontotemporal dementia (FTD), or less common forms such as corticobasal degeneration or progressive supranuclear palsy. These disorders have diagnostic criteria developed by expert groups [1,2]. As the diagnostic criteria of DSM-IV and ICD-10 have been found wanting for research purposes, other, more precise diagnostic systems are commonly used to diagnose Alzheimer’s disease (NINCDS-ADRDA [3]) and vascular dementia (NINDS-AIREN [4]). 2. Screening tests In general practice or the medical out-patient clinic when a patient complains of memory problems a brief screening test is needed to establish whether there is cause for concern prompting further investigation or referral or whether the patient may be reassured. A number of brief cognitive tests exist for this purpose. 2.1. Abbreviated Mental Test Score (AMTS) The AMTS [5] is a clinician-rated 10 item scale. The questions are age, time of day, recall of an address, year, place, recognition of two people, date of birth, dates of world war I, name of the monarch and counting backwards from 20 to 1. It was developed as a screening test for medical inpatients and is frequently used in acute hospital settings although its use has also been extended to screening for cognitive impairment in the community. Its main advantages are its brevity and the fact that there are no tasks involving reading, writing or drawing meaning that problems with visual impairment or physical frailty are avoided. However, some of the items are not necessarily culturally fair, e.g. the date of world war 1 may be less imprinted on the minds of younger people. The AMTS shows high correlations with other cognitive tests such as the MMSE (0.87) and CAMCOG (0.72) [6]. With a cut-off score of 7 out of 10 in a population of medical inpatients it has a sensitivity of 81% and specificity of 84% against the DSM-III R diagnosis of dementia. The negative predictive value in this population was 99% and positive predictive value 25% [7]. The AMTS is therefore a useful screening test as a score > 7 reliably rules out cognitive impairment. A low score should prompt further investigation but is not diagnostic. The AMTS score cannot distinguish between delirium and dementia unless serial tests are performed. 2.2. Six Item Cognitive Impairment Test (6CIT) Among other very brief tests, the 6CIT is suitable for general use. The items have been derived from a regression analysis of a larger dementia scale, and the original version has been updated and vali-
The patient is asked to draw a clock face marking the hours and then draws the hands to indicate a time (e.g. 10 min past 11). The advantages are that this test is quick and easy to administer for the clinician and non-threatening for the patient as it avoids didactic questioning. It also largely avoids problems with language although there is an effect of education. Probably the simplest scoring method is that of Shulman et al. [9] which employs a 6 point system rating the drawing 0 = no attempt, 1 = severely disorganised, 2 = wrong number placement, 3 = wrong time, 4 = minor visuospatial error or 5 = no errors. More complex 10 point scoring systems have been devised with detailed instructions in an attempt to reduce the element of subjective judgement [10,11] but the simpler system still achieves an acceptable inter-rater reliability of 0.89 [12]. In a number of studies the clock drawing test has been shown to achieve a mean of 85% for both sensitivity and specificity and to have a good correlation (0.61) with the MMSE [13]. This is despite the test having no real memory component. In addition to the obvious visuospatial elements, the task also requires planning and to some extent tests frontal executive functions.
2.4. Mini-Mental State Examination (MMSE) The MMSE [14] is probably the most widely used test of cognitive function. It was originally intended to differentiate functional from organic illness. It has been used as a screening tool, in the diagnosis of dementia, to assess severity and change over time and to evaluate response to treatment. MMSE scores have even been enshrined in the NICE guidance on acetylcholinesterase inhibitor treatment. The MMSE has a maximum score of 30 points. The test items are orientation to time and place (10 points), registration of 3 words (3), attention and calculation (5), recall of 3 words (3), language (8) and visual construction (1). A score of 24 or less is regarded as abnormal but this should be taken in the context of the patient’s age, educational background and language. At this cut-off it has a specificity of 82% and sensitivity of 87% [15]. Over the years, various adaptations have been suggested to the original test. For instance, Molloy et al. [16] produced a standardised version in an attempt to improve the objectivity and inter-rater reliability of the test. Essentially, the SMMSE provides more detailed instructions on how the scale should be administered and suggests that spelling ‘world’ backwards should be used instead of serial subtraction. The MMSE tests a broader range of cognitive functions than the brief screening tests described above whilst still being short and uncomplicated enough for use by non-specialists. It also has the major advantage of being very widely understood and its properties have been studied extensively in a number of different populations [17,18]. The MMSE does however have several shortcomings. It dates from an era when dementia was considered to be a unitary syndrome of global deterioration of intellect and so it is less concerned with the subtypes of dementia. It does not examine frontal executive functions and includes only very crude measures of episodic and semantic memory, and visuospatial skills. Therefore, it is insensitive to the earliest stages of dementia, especially of certain types, notably FTD or DLB.
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Table 1 The content and clinical application of the ACE-R. ACE task/domain
Cognitive function
Modification to ACE
Diagnostic usefulness
Name and address
Anterograde episodic memory
3 versions to avoid recall effect, recognition added
Naming Verbal fluency Language
Confrontation naming and semantic memory Frontal lobe function, semantic memory, speed Confrontational naming
Visuospatial skills
Visuomotor skills, praxis, vision
Lower frequency items to avoid ceiling effects Scaled scoring revised to increase sensitivity Semantic comprehension questions added → differentiate semantic impairment and nominal dysphasia Dot counting and fragmented letters → differentiates visuospatial impairment and motor symptoms; clock drawing scored 0–5 to increase sensitivity
Poor learning and delayed recall in AD, relatively good recognition for learnt items in depression AD, APS, FTD PD, APS, depression FTD
DLB, APS, AD
AD; Alzheimer’s disease, APS: atypical Parkinsonian syndromes, PD: Parkinson’s disease, FTD, frontotemporal dementia, and DLB: dementia with Lewy bodies.
3. Neuropsychological test batteries These differ from screening tests in that they are more detailed and cover a wider range of cognitive domains. The MMSE is in fact a minimalist test battery as it has single items that test areas of language and visuospatial functioning. Most test batteries are however quite time consuming to administer and are therefore perhaps of more use for research than routine clinical practice. Examples include the ADAS-COG [19], the Dementia Rating Scale [20], CAMCOG [21] and the computerised CANTAB system [22]. This review concentrates on one example, which is relatively short and can be readily used in ordinary clinical practice. 3.1. The Addenbrooke’s Cognitive Examination-Revised (ACE-R) The ACE-R, an extended version of the MMSE, was developed with the intention of creating a simple cognitive test for the early detection of progressive degenerative dementing illnesses and to help differentiate between the most common aetiologies [23]. The ACE-R is brief and easy to administer by any health care professional. With most patients, it takes about 12–20 min and there is a user’s manual which explains how to administer the individual tasks and interpret the scores. It can be used in any setting; in- or out-patient, GP or neurological, psychiatric, or other specialist setting. The ACE-R has excellent sensitivity and specificity to dementia (at a cut-off of 82 points: 0.84 and 1.00, respectively). Following initial screening and diagnosis, monitoring of disease progression is possible because there are A, B and C versions available, thus eliminating possible practice effects. Norms are available for different age groups. A total of 100 points is made up from five domain scores: attention/orientation (18 points), memory (26 points), verbal fluency (14 points), language (26 points), and visuospatial functions (16 points). The original version of the test battery (Addenbrooke’s Cognitive Examination, ACE) detected dementia with greater sensitivity and better predictive values than did the MMSE and successfully differentiated Alzheimer’s disease from frontotemporal dementia [24]. Importantly, the performance of the ACE was not affected by comorbid mood symptoms or mood disorder [25]. To improve its differential diagnostic capabilities, the ACE was modified taking into account advances in the neuropsychological description of the most important dementing conditions. Table 1 illustrates how individual tasks or whole domains of the ACE-R can help differential diagnosis. The ACE-R includes tasks of anterograde episodic memory, semantic memory and mental speed. Impairment of these cognitive functions has been shown to be the earliest marker of Alzheimer’s disease [26,27]. Anterograde memory is tested by immediate recall of recently presented information, such as learning a name and address and with a delayed recall task. Semantic memory is tested,
for example, by naming famous people from description (e.g. the US president who was assassinated in the 1960s) and naming of line drawings of less common and rare concepts (e.g. penguin or harmonica). A true semantic deficit is distinguished from an isolated naming problem by identifying items from a picture (e.g. ‘Point to the one which is found in the Antarctic.’). Tests of mental speed include timed verbal fluency tasks testing letter and category fluencies. Impairment on letter fluency and other language tasks with relatively spared orientation and delayed recall on the name and address task predict FTD as opposed to AD. Other relatively common causes of dementia such as atypical Parkinsonian syndromes (progressive supranuclear palsy, corticobasal degeneration, multiple system atrophy, and DLB) can also be successfully differentiated with the ACE-R, even when the MMSE scores of many of these patients may still be in the normal range [28]. 4. Behavioural and psychiatric symptoms With the emphasis on cognitive testing, it should not be forgotten that non-cognitive symptoms are an important component of the syndrome of dementia and contribute greatly to care-giver burden. Scales are also available to assess the severity of behavioural and psychiatric symptoms and functional ability. 4.1. BEHAVE-AD The BEHAVE-AD [29] is the original behaviour rating scale in Alzheimer’s disease. It was designed by reviewing the case notes of a sample of patients with severe AD and picking out commonly reported difficult behaviours. It is a clinician-rated scale derived from interviewing the caregiver. It covers the following areas of symptomatology: delusional ideas, hallucinations, activity disturbance (wandering, purposeless and inappropriate activity), aggression, rhythm disturbance (sleep–wake cycle), affective disturbance and anxiety. Inter-rater reliability ranged from 0.65 to 0.91 [30]. 4.2. Neuropsychiatric Inventory (NPI) The NPI [31] differs from BEHAVE-AD in that it assesses more affective symptoms such as apathy and elation rather than simply behaviours and also covers symptoms associated with forms of dementia other than AD such as disinhibition. The score is based on a clinician interview with the carer. The severity and frequency of symptoms in 12 domains are rated separately. There are screening questions for each domain designed to minimise assessment time by concentrating only on those areas where problems are revealed. The domains covered are delusions, hallucinations, dysphoria, anxiety, agitation, euphoria, disinhibition, irritability, apathy, aberrant motor behaviour, sleep disorders and eating
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disorders. In the original study it achieved test–retest reliability of 0.79–0.86 and 90–100% agreement between raters. 5. Functional and Global Assessments Scales which rate solely cognitive function or specific symptoms fail to capture the impact of dementia on the lives of sufferers and carers. Global assessment scales aim to make an objective assessment of the overall severity of dementia taking into account both cognition and functional status. These can be most useful when assessing the impact of treatments or interventions or in service evaluation. 5.1. Blessed Dementia Scale This was one of the earliest scales developed for the assessment of dementia [32]. It combines cognitive and functional assessments incorporating tests of orientation and memory (autobiographical, semantic and short term recall) with questions relating to performance of ADLS and changes in personality and habits. The test is scored from 0 to 28 with higher scores indicating a greater degree of impairment. It is less commonly used now as it requires interview of the patient and an informant but the scores have been shown to correlate with plaque count at post mortem. 5.2. Global Deterioration Scale (GDS) The scale comprises seven detailed clinical descriptions of stages ranging from normal cognition to very severe dementia [33]. The clinician chooses the description which most closely matches the clinical state of the patient. Concurrent validity is demonstrated by highly significant correlations with the MMSE. Inter-rater and test–retest reliability has consistently been found to be greater than 0.90 [30]. 5.3. Clinical Dementia Rating (CDR) The clinical dementia rating [34,35] is frequently used in trials. Six domains are assessed: memory, orientation, judgement (problem solving and financial affairs), community affairs (function at work, volunteer and social groups), home (function within home, hobbies) and personal care. Each is rated from 0 (unimpaired) to 3 (severe impairment). Inter-rater reliability is 0.89. It has been validated against neuropathological information. 5.4. Clinicians’ Global Impression of Change (CGI) This scale provides only minimal instructions and depends on the clinician’s ability to detect changes in the clinical condition of a patient from a specified baseline. The clinician’s assessment is not specified but may include patient and informant interviews and cognitive test scores. It is rated from 1 = very much improved to 7 = very much worse with 4 being no change. However, there are several variants (see Burns et al. [36] for examples), with other names, including the clinicians’ interview-based impression of change (CIBIC; or CIBIC-plus if an informant interview is included), so different versions may not be comparable. Nonetheless, this approach is quite popular in drug trials for dementia, since the face validity of clinician-perceived change is thought to be high. 6. Conclusion With longer life expectancy, more people will live into old age and experience cognitive impairment of some aetiology. Dementia becomes much more common with increasing age, and for AD the prevalence rates are about 24% for 85–89 year olds, increasing to 45% at age 95 and above [37].
Certain types of dementia can already be ameliorated by medication (e.g. AD by acetyl cholinesterase inhibitors) and several lines of pharmacological and other treatments are in various stages of development, offering the hope of treatment that will be able permanently to halt or reverse the underlying pathology. Early and accurate diagnosis can not only expedite the initiation of suitable treatment but also helps to avoid serious side effects from inappropriate treatment (e.g. the use of antipsychotic drugs in DLB). There is a range of instruments available for from the clinical assessment of possible dementia (many more are described by Burns et al. [36]) and most of the more recent scales offer good sensitivity and specificity, certainly comparable to many diagnostic techniques used elsewhere in medicine. The accurate diagnosis and management of dementia, especially that of more complex and atypical cases, still requires a specialist opinion. However, the detection of dementia through focussed but careful history taking and straightforward cognitive testing is now within the reach of every clinician. In routine clinical practice, we suggest the use of a simple screening instrument or the use of ACE-R, which is comprehensive but simple to use, with consideration of other scales as required for neuropsychiatric symptoms or the assessment of overall functioning. Disclosure The authors have no financial interest in the use of any of the instruments described. RBD has contributed to the development of the ACE-R. TD leads the old age theme for the NIHR CLAHRC for Cambridgeshire & Peterborough. Acknowledgements RBD has contributed to the development of the ACE-R. TD leads the old age theme for the NIHR CLAHRC for Cambridgeshire & Peterborough. References [1] McKeith IG, Dickson DW, Lowe J, et al. Diagnosis and management of dementia with Lewy bodies: third report of the DLB consortium. Neurology 2005;65:1863–72. [2] Neary D, Snowden JS, Gustafson L, et al. Frontotemporal lobar degeneration: a consensus on clinical diagnostic criteria. Neurology 1998;51:1546–54. [3] McKhann G, Drachman D, Folstein M, et al. Clinical diagnosis of Alzheimer’s disease: report of the NINCDS-ADRDA Work Group under the auspices of Department of Health and Human Services Task Force on Alzheimer’s Disease. Neurology 1984;34:939–44. [4] Roman GC, Tatemichi TK, Erknjuntti T, et al. Vascular dementia: diagnostic criteria for research studies. Report of the NINDS-AIREN International Workshop. Neurology 1993;43:250–60. [5] Qureshi K, Hodkinson M. Evaluation of a 10 question mental test of the institutionalised elderly. Age Ageing 1974;3:152–7. [6] MacKenzie D, Copp P, Shaw RJ, Goodwin GM. Brief cognitive screening of the elderly: a comparison of the Mini-Mental State Examination (MMSE), Abbreviated Mental Test (AMT) and Mental Status Questionnaire (MSQ). Psychol Med 1996;26:427–30. [7] Antonelli Incalzi R, Cesari M, Pedone C, Carosella L, Carbonin P. Construct validity of the Abbreviated Mental Test in older medical inpatients. Dement Geriatr Cogn Dis 2003;15:199–206. [8] Brooke P, Bullock R. Validation of a 6-item cognitive impairment test with a view to primary care usage. Int J Geriatr Psychiatry 1999;14:936–40. [9] Shulman K, Shedletsky R, Silver I. The challenge of time: clock drawing and cognitive function in the elderly. Int J Geriatr Psychiatry 1986;1:135–40. [10] Wolf-Klein, Silverstone FA, Levy AP, Brod MS, Bruer J. Screening for Alzheimer’s disease by clock drawing. J Am Geriatr Soc 1989;37:730–4. [11] Brodaty H, Moore CM. The clock drawing test for dementia of the Azheimer’s type: a comparison of three scoring methods in a memory disorders clinic. Int J Geriatr Psychiatry 1997;12:619–27. [12] Schramm U, Berger G, Müller R, Kratzsch T, Peters J, Frölich L. Psychometric properties of the clock drawing test and MMSE or short performance test (SKT) in dementia screening in a memory clinic population. Int J Geriatr Psychiatry 2002;17:254–60. [13] Shulman K. Clock drawing: is it the ideal cognitive screening test? Int J Geriatr Psychiatry 2000;15:548–61.
C.F. Hatfield et al. / Maturitas 63 (2009) 181–185 [14] Folstein MF, Folstein SE, McHugh PR. “Mini-Mental State”: a practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res 1975;12:189–98. [15] Tombaugh TN, McIntyre NJ. The Mini-Mental State Examination: a comprehensive review. J Am Geriatr Soc 1992;40:922–35. [16] Molloy DW, Alemayehu E, Roberts R. Reliability of a standardized Mini-Mental State Examination compared with the traditional Mini-Mental State Examination. Am J Psychiatry 1991;148:102–5. [17] O’Connor DW, Pollitt PA, Hyde JB. The reliability and validity of the MiniMental State Examination in a British community survey. J Psychiatr Res 1989;23:87–96. [18] Crum RM, Anthony JC, Bassett SS, Folstein MF. Population based norms for the Mini-Mental State Examination by age and educational level. JAMA 1993;269:2386–91. [19] Rosen WG, Mohs RC, Davis KL. A new rating scale for Alzheimer’s disease. Am J Psychiatry 1984;141:1356–64. [20] Mattis S. Dementia Rating Scale. Odessa, FL: Psychological Assessment Resources Inc.; 1998. [21] Roth M, Tym E, Mountjoy CQ, et al. CAMDEX. A standardised instrument for the diagnosis of mental disorder in the elderly with special reference to the early detection of dementia. Br J Psychiatry 1986;149:698–770. [22] Cambridge Cognition (2009) CANTAB Tests—Overview. Retrieved 24/2/2009, from http://www.cantab.com/science/cantab-tests-all.asp. [23] Mioshi E, Dawson K, Mitchell J, Arnold R, Hodges JR. The Addenbrooke’s Cognitive Examination Revised (ACE-R): a brief cognitive test battery for dementia screening. Int J Geriatr Psychiatry 2006;21:1078–85. [24] Mathuranath PS, Nestor PJ, Berrios GE, et al. A brief cognitive test battery to differentiate Alzheimer’s disease and frontotemporal dementia. Neurology 2000;55:1613–20. [25] Dudas RB, Berrios GE, Hodges JR. The Addenbrooke’s Cognitive Examination (ACE) in the differential diagnosis of early dementias versus affective disorder. Am J Geriatr Psychiatry 2005;13:218–26.
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[26] Swainson R, Hodges JR, Galton CJ, et al. Early detection and differential diagnosis of Alzheimer’s disease and depression with neuropsychological tasks. Dement Geriatr Cogn Disord 2001;12:265–80. [27] Nestor PJ, Scheltens P, Hodges JR. Advances in the early detection of Alzheimer’s disease. Nat Med 2004;10 Suppl.:S34–41. [28] Bak T, Mioshi E. A cognitive bedside assessment beyond the MMSE: the Addenbrooke’s Cognitive Examination. Pract Neurol 2007;7:245–9. [29] Reisberg B, Borenstein J, Salob SP, et al. Behavioral symptoms in Alzheimer’s disease: phenomenology and treatment. J Clin Psychiatry 1987;48(Suppl. 5):9– 15. [30] Sclan S, Saillon A, Franssen E, et al. The behavior pathology in Alzheimer’s disease rating scale (BEHAVE-AD): reliability and analysis of symptom category scores. Int J Geriatr Psychiatry 1996;11:819–30. [31] Cummings JL, Mega M, Gray K, et al. The neuropsychiatric inventory: comprehensive assessment of psychopathology in dementia. Neurology 1994;44:2308–14. [32] Blessed G, Tomlinson BE, Roth M. The association between quantitative measures of dementia and of senile change in the cerebral grey matter of elderly subjects. Br J Psychiatry 1968;114:797–811. [33] Reisberg B, Ferris SH, de Leon MJ, Crook T. The global deterioration scale (GDS) for assessment of primary degenerative dementia. Am J Psychiatry 1982;139:1136–9. [34] Hughes CP, Berg L, Danziger WL, et al. A new clinical scale for the staging of dementia. Br J Psychiatry 1982;140:566–72. [35] Morris J. The CDR: current version and scoring rules. Neurology 1993;43:2412–3. [36] Burns A, Lawlor, Craig S. Assessment scales in old age psychiatry. 2nd edn. London: Informa Healthcare; 2004. [37] Fratiglioni L, von Strauss E, Qiu CX. Epidemiology of the dementias of old age. In: Jacoby R, Oppenheimer C, Dening T, Thomas A, editors. Oxford textbook of old age psychiatry. Oxford: Oxford University Press; 2008. p. 391– 406.
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Review
Diagnostic tools for dementia Catherine F. Hatfield, Robert B. Dudas, Tom Dening ∗ Cambridgeshire & Peterborough NHS Foundation Trust, Box 311, Fulbourn Hospital, Cambridge, CB21 5EF, UK
a r t i c l e
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Article history: Received 5 March 2009 Accepted 11 March 2009 Keywords: Dementia Alzheimer’s disease Diagnosis Assessment Rating scales Cognitive testing
a b s t r a c t As population ageing means that dementia is becoming more prevalent, it is increasingly important that clinicians from all types of practice are familiar with assessing patients who have possible cognitive impairment. The diagnosis of the syndrome of dementia remains a clinical process, supplemented by relevant investigations including cognitive testing. This paper reviews some of the more commonly used tools for assessing cognition, behaviour and overall functioning in patients with possible or established dementia. Several categories of instruments are considered, including brief screening tests, neuropsychological test batteries, scales for behavioural and psychiatric symptoms, and functional and global assessments. It is recommended that clinicians familiarise themselves with a small number of scales that can be readily employed in everyday practice. © 2009 Elsevier Ireland Ltd. All rights reserved.
Contents 1. 2.
3. 4.
5.
6.
Diagnostic criteria for dementia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Screening tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1. Abbreviated Mental Test Score (AMTS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2. Six Item Cognitive Impairment Test (6CIT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3. Clock drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4. Mini-Mental State Examination (MMSE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neuropsychological test batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1. The Addenbrooke’s Cognitive Examination-Revised (ACE-R) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Behavioural and psychiatric symptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1. BEHAVE-AD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2. Neuropsychiatric Inventory (NPI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Functional and Global Assessments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1. Blessed Dementia Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2. Global Deterioration Scale (GDS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3. Clinical Dementia Rating (CDR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4. Clinicians’ Global Impression of Change (CGI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Disclosure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dementia is a syndrome due to disease of the brain of a chronic and progressive nature in which there is disturbance of multiple higher cortical functions such as memory, thinking, orientation, comprehension, calculation, language and judgement without clouding of consciousness. These cognitive impairments
∗ Corresponding author. Tel.: +44 01223 218890; fax: +44 01223 218992. E-mail address: [email protected] (T. Dening). 0378-5122/$ – see front matter © 2009 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.maturitas.2009.03.005
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are commonly accompanied by deterioration in emotional control, social behaviour, or motivation. The commonest causes of dementia in older people are Alzheimer’s disease (AD) and vascular dementia (VaD), with mixed pathology being fairly common too, especially in people aged 80 or above. The diagnosis of dementia remains primarily clinical. It is essential to gather an accurate history both from the patient and from an informant. Blood and radiological investigations are routinely ordered to screen for reversible causes and exclude other conditions. Some formal testing of cognitive function is essential and a
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wide variety of different tests are available to measure different aspects of cognition, function and behaviour. This review discusses some of the most commonly used tests, including simple screening tests, more complex systems for cognitive examination, and tools for assessing neuropsychiatric symptoms, functional ability and overall severity of dementia. We suggest which might be most appropriate for a given clinical situation and we also briefly discuss criteria using for making the diagnosis of dementia.
dated [8]. The main advantage is that the items are extremely simple (three orientation items, count backwards from 20, months of the year in reverse order, and learn an address) and the scale is culturally unbiased. However, the scoring involves weighting of the items to produce a score out of 28, with a cut-off of 7/8 having high sensitivity and specificity even in mild dementia.
2.3. Clock drawing 1. Diagnostic criteria for dementia The two standard systems in use for the diagnosis of dementia are DSM-IV and ICD-10, which are basically similar. Both define the dementia syndrome and then present operational criteria for diagnosing types of dementia, such as Alzheimer’s disease, vascular dementia and so on. Although they contain criteria for dementia due to Parkinson’s disease, they do not include criteria for some important forms of dementia, such as dementia with Lewy bodies (DLB) or frontotemporal dementia (FTD), or less common forms such as corticobasal degeneration or progressive supranuclear palsy. These disorders have diagnostic criteria developed by expert groups [1,2]. As the diagnostic criteria of DSM-IV and ICD-10 have been found wanting for research purposes, other, more precise diagnostic systems are commonly used to diagnose Alzheimer’s disease (NINCDS-ADRDA [3]) and vascular dementia (NINDS-AIREN [4]). 2. Screening tests In general practice or the medical out-patient clinic when a patient complains of memory problems a brief screening test is needed to establish whether there is cause for concern prompting further investigation or referral or whether the patient may be reassured. A number of brief cognitive tests exist for this purpose. 2.1. Abbreviated Mental Test Score (AMTS) The AMTS [5] is a clinician-rated 10 item scale. The questions are age, time of day, recall of an address, year, place, recognition of two people, date of birth, dates of world war I, name of the monarch and counting backwards from 20 to 1. It was developed as a screening test for medical inpatients and is frequently used in acute hospital settings although its use has also been extended to screening for cognitive impairment in the community. Its main advantages are its brevity and the fact that there are no tasks involving reading, writing or drawing meaning that problems with visual impairment or physical frailty are avoided. However, some of the items are not necessarily culturally fair, e.g. the date of world war 1 may be less imprinted on the minds of younger people. The AMTS shows high correlations with other cognitive tests such as the MMSE (0.87) and CAMCOG (0.72) [6]. With a cut-off score of 7 out of 10 in a population of medical inpatients it has a sensitivity of 81% and specificity of 84% against the DSM-III R diagnosis of dementia. The negative predictive value in this population was 99% and positive predictive value 25% [7]. The AMTS is therefore a useful screening test as a score > 7 reliably rules out cognitive impairment. A low score should prompt further investigation but is not diagnostic. The AMTS score cannot distinguish between delirium and dementia unless serial tests are performed. 2.2. Six Item Cognitive Impairment Test (6CIT) Among other very brief tests, the 6CIT is suitable for general use. The items have been derived from a regression analysis of a larger dementia scale, and the original version has been updated and vali-
The patient is asked to draw a clock face marking the hours and then draws the hands to indicate a time (e.g. 10 min past 11). The advantages are that this test is quick and easy to administer for the clinician and non-threatening for the patient as it avoids didactic questioning. It also largely avoids problems with language although there is an effect of education. Probably the simplest scoring method is that of Shulman et al. [9] which employs a 6 point system rating the drawing 0 = no attempt, 1 = severely disorganised, 2 = wrong number placement, 3 = wrong time, 4 = minor visuospatial error or 5 = no errors. More complex 10 point scoring systems have been devised with detailed instructions in an attempt to reduce the element of subjective judgement [10,11] but the simpler system still achieves an acceptable inter-rater reliability of 0.89 [12]. In a number of studies the clock drawing test has been shown to achieve a mean of 85% for both sensitivity and specificity and to have a good correlation (0.61) with the MMSE [13]. This is despite the test having no real memory component. In addition to the obvious visuospatial elements, the task also requires planning and to some extent tests frontal executive functions.
2.4. Mini-Mental State Examination (MMSE) The MMSE [14] is probably the most widely used test of cognitive function. It was originally intended to differentiate functional from organic illness. It has been used as a screening tool, in the diagnosis of dementia, to assess severity and change over time and to evaluate response to treatment. MMSE scores have even been enshrined in the NICE guidance on acetylcholinesterase inhibitor treatment. The MMSE has a maximum score of 30 points. The test items are orientation to time and place (10 points), registration of 3 words (3), attention and calculation (5), recall of 3 words (3), language (8) and visual construction (1). A score of 24 or less is regarded as abnormal but this should be taken in the context of the patient’s age, educational background and language. At this cut-off it has a specificity of 82% and sensitivity of 87% [15]. Over the years, various adaptations have been suggested to the original test. For instance, Molloy et al. [16] produced a standardised version in an attempt to improve the objectivity and inter-rater reliability of the test. Essentially, the SMMSE provides more detailed instructions on how the scale should be administered and suggests that spelling ‘world’ backwards should be used instead of serial subtraction. The MMSE tests a broader range of cognitive functions than the brief screening tests described above whilst still being short and uncomplicated enough for use by non-specialists. It also has the major advantage of being very widely understood and its properties have been studied extensively in a number of different populations [17,18]. The MMSE does however have several shortcomings. It dates from an era when dementia was considered to be a unitary syndrome of global deterioration of intellect and so it is less concerned with the subtypes of dementia. It does not examine frontal executive functions and includes only very crude measures of episodic and semantic memory, and visuospatial skills. Therefore, it is insensitive to the earliest stages of dementia, especially of certain types, notably FTD or DLB.
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Table 1 The content and clinical application of the ACE-R. ACE task/domain
Cognitive function
Modification to ACE
Diagnostic usefulness
Name and address
Anterograde episodic memory
3 versions to avoid recall effect, recognition added
Naming Verbal fluency Language
Confrontation naming and semantic memory Frontal lobe function, semantic memory, speed Confrontational naming
Visuospatial skills
Visuomotor skills, praxis, vision
Lower frequency items to avoid ceiling effects Scaled scoring revised to increase sensitivity Semantic comprehension questions added → differentiate semantic impairment and nominal dysphasia Dot counting and fragmented letters → differentiates visuospatial impairment and motor symptoms; clock drawing scored 0–5 to increase sensitivity
Poor learning and delayed recall in AD, relatively good recognition for learnt items in depression AD, APS, FTD PD, APS, depression FTD
DLB, APS, AD
AD; Alzheimer’s disease, APS: atypical Parkinsonian syndromes, PD: Parkinson’s disease, FTD, frontotemporal dementia, and DLB: dementia with Lewy bodies.
3. Neuropsychological test batteries These differ from screening tests in that they are more detailed and cover a wider range of cognitive domains. The MMSE is in fact a minimalist test battery as it has single items that test areas of language and visuospatial functioning. Most test batteries are however quite time consuming to administer and are therefore perhaps of more use for research than routine clinical practice. Examples include the ADAS-COG [19], the Dementia Rating Scale [20], CAMCOG [21] and the computerised CANTAB system [22]. This review concentrates on one example, which is relatively short and can be readily used in ordinary clinical practice. 3.1. The Addenbrooke’s Cognitive Examination-Revised (ACE-R) The ACE-R, an extended version of the MMSE, was developed with the intention of creating a simple cognitive test for the early detection of progressive degenerative dementing illnesses and to help differentiate between the most common aetiologies [23]. The ACE-R is brief and easy to administer by any health care professional. With most patients, it takes about 12–20 min and there is a user’s manual which explains how to administer the individual tasks and interpret the scores. It can be used in any setting; in- or out-patient, GP or neurological, psychiatric, or other specialist setting. The ACE-R has excellent sensitivity and specificity to dementia (at a cut-off of 82 points: 0.84 and 1.00, respectively). Following initial screening and diagnosis, monitoring of disease progression is possible because there are A, B and C versions available, thus eliminating possible practice effects. Norms are available for different age groups. A total of 100 points is made up from five domain scores: attention/orientation (18 points), memory (26 points), verbal fluency (14 points), language (26 points), and visuospatial functions (16 points). The original version of the test battery (Addenbrooke’s Cognitive Examination, ACE) detected dementia with greater sensitivity and better predictive values than did the MMSE and successfully differentiated Alzheimer’s disease from frontotemporal dementia [24]. Importantly, the performance of the ACE was not affected by comorbid mood symptoms or mood disorder [25]. To improve its differential diagnostic capabilities, the ACE was modified taking into account advances in the neuropsychological description of the most important dementing conditions. Table 1 illustrates how individual tasks or whole domains of the ACE-R can help differential diagnosis. The ACE-R includes tasks of anterograde episodic memory, semantic memory and mental speed. Impairment of these cognitive functions has been shown to be the earliest marker of Alzheimer’s disease [26,27]. Anterograde memory is tested by immediate recall of recently presented information, such as learning a name and address and with a delayed recall task. Semantic memory is tested,
for example, by naming famous people from description (e.g. the US president who was assassinated in the 1960s) and naming of line drawings of less common and rare concepts (e.g. penguin or harmonica). A true semantic deficit is distinguished from an isolated naming problem by identifying items from a picture (e.g. ‘Point to the one which is found in the Antarctic.’). Tests of mental speed include timed verbal fluency tasks testing letter and category fluencies. Impairment on letter fluency and other language tasks with relatively spared orientation and delayed recall on the name and address task predict FTD as opposed to AD. Other relatively common causes of dementia such as atypical Parkinsonian syndromes (progressive supranuclear palsy, corticobasal degeneration, multiple system atrophy, and DLB) can also be successfully differentiated with the ACE-R, even when the MMSE scores of many of these patients may still be in the normal range [28]. 4. Behavioural and psychiatric symptoms With the emphasis on cognitive testing, it should not be forgotten that non-cognitive symptoms are an important component of the syndrome of dementia and contribute greatly to care-giver burden. Scales are also available to assess the severity of behavioural and psychiatric symptoms and functional ability. 4.1. BEHAVE-AD The BEHAVE-AD [29] is the original behaviour rating scale in Alzheimer’s disease. It was designed by reviewing the case notes of a sample of patients with severe AD and picking out commonly reported difficult behaviours. It is a clinician-rated scale derived from interviewing the caregiver. It covers the following areas of symptomatology: delusional ideas, hallucinations, activity disturbance (wandering, purposeless and inappropriate activity), aggression, rhythm disturbance (sleep–wake cycle), affective disturbance and anxiety. Inter-rater reliability ranged from 0.65 to 0.91 [30]. 4.2. Neuropsychiatric Inventory (NPI) The NPI [31] differs from BEHAVE-AD in that it assesses more affective symptoms such as apathy and elation rather than simply behaviours and also covers symptoms associated with forms of dementia other than AD such as disinhibition. The score is based on a clinician interview with the carer. The severity and frequency of symptoms in 12 domains are rated separately. There are screening questions for each domain designed to minimise assessment time by concentrating only on those areas where problems are revealed. The domains covered are delusions, hallucinations, dysphoria, anxiety, agitation, euphoria, disinhibition, irritability, apathy, aberrant motor behaviour, sleep disorders and eating
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disorders. In the original study it achieved test–retest reliability of 0.79–0.86 and 90–100% agreement between raters. 5. Functional and Global Assessments Scales which rate solely cognitive function or specific symptoms fail to capture the impact of dementia on the lives of sufferers and carers. Global assessment scales aim to make an objective assessment of the overall severity of dementia taking into account both cognition and functional status. These can be most useful when assessing the impact of treatments or interventions or in service evaluation. 5.1. Blessed Dementia Scale This was one of the earliest scales developed for the assessment of dementia [32]. It combines cognitive and functional assessments incorporating tests of orientation and memory (autobiographical, semantic and short term recall) with questions relating to performance of ADLS and changes in personality and habits. The test is scored from 0 to 28 with higher scores indicating a greater degree of impairment. It is less commonly used now as it requires interview of the patient and an informant but the scores have been shown to correlate with plaque count at post mortem. 5.2. Global Deterioration Scale (GDS) The scale comprises seven detailed clinical descriptions of stages ranging from normal cognition to very severe dementia [33]. The clinician chooses the description which most closely matches the clinical state of the patient. Concurrent validity is demonstrated by highly significant correlations with the MMSE. Inter-rater and test–retest reliability has consistently been found to be greater than 0.90 [30]. 5.3. Clinical Dementia Rating (CDR) The clinical dementia rating [34,35] is frequently used in trials. Six domains are assessed: memory, orientation, judgement (problem solving and financial affairs), community affairs (function at work, volunteer and social groups), home (function within home, hobbies) and personal care. Each is rated from 0 (unimpaired) to 3 (severe impairment). Inter-rater reliability is 0.89. It has been validated against neuropathological information. 5.4. Clinicians’ Global Impression of Change (CGI) This scale provides only minimal instructions and depends on the clinician’s ability to detect changes in the clinical condition of a patient from a specified baseline. The clinician’s assessment is not specified but may include patient and informant interviews and cognitive test scores. It is rated from 1 = very much improved to 7 = very much worse with 4 being no change. However, there are several variants (see Burns et al. [36] for examples), with other names, including the clinicians’ interview-based impression of change (CIBIC; or CIBIC-plus if an informant interview is included), so different versions may not be comparable. Nonetheless, this approach is quite popular in drug trials for dementia, since the face validity of clinician-perceived change is thought to be high. 6. Conclusion With longer life expectancy, more people will live into old age and experience cognitive impairment of some aetiology. Dementia becomes much more common with increasing age, and for AD the prevalence rates are about 24% for 85–89 year olds, increasing to 45% at age 95 and above [37].
Certain types of dementia can already be ameliorated by medication (e.g. AD by acetyl cholinesterase inhibitors) and several lines of pharmacological and other treatments are in various stages of development, offering the hope of treatment that will be able permanently to halt or reverse the underlying pathology. Early and accurate diagnosis can not only expedite the initiation of suitable treatment but also helps to avoid serious side effects from inappropriate treatment (e.g. the use of antipsychotic drugs in DLB). There is a range of instruments available for from the clinical assessment of possible dementia (many more are described by Burns et al. [36]) and most of the more recent scales offer good sensitivity and specificity, certainly comparable to many diagnostic techniques used elsewhere in medicine. The accurate diagnosis and management of dementia, especially that of more complex and atypical cases, still requires a specialist opinion. However, the detection of dementia through focussed but careful history taking and straightforward cognitive testing is now within the reach of every clinician. In routine clinical practice, we suggest the use of a simple screening instrument or the use of ACE-R, which is comprehensive but simple to use, with consideration of other scales as required for neuropsychiatric symptoms or the assessment of overall functioning. Disclosure The authors have no financial interest in the use of any of the instruments described. RBD has contributed to the development of the ACE-R. TD leads the old age theme for the NIHR CLAHRC for Cambridgeshire & Peterborough. Acknowledgements RBD has contributed to the development of the ACE-R. TD leads the old age theme for the NIHR CLAHRC for Cambridgeshire & Peterborough. References [1] McKeith IG, Dickson DW, Lowe J, et al. Diagnosis and management of dementia with Lewy bodies: third report of the DLB consortium. Neurology 2005;65:1863–72. [2] Neary D, Snowden JS, Gustafson L, et al. Frontotemporal lobar degeneration: a consensus on clinical diagnostic criteria. Neurology 1998;51:1546–54. [3] McKhann G, Drachman D, Folstein M, et al. Clinical diagnosis of Alzheimer’s disease: report of the NINCDS-ADRDA Work Group under the auspices of Department of Health and Human Services Task Force on Alzheimer’s Disease. Neurology 1984;34:939–44. [4] Roman GC, Tatemichi TK, Erknjuntti T, et al. Vascular dementia: diagnostic criteria for research studies. Report of the NINDS-AIREN International Workshop. Neurology 1993;43:250–60. [5] Qureshi K, Hodkinson M. Evaluation of a 10 question mental test of the institutionalised elderly. Age Ageing 1974;3:152–7. [6] MacKenzie D, Copp P, Shaw RJ, Goodwin GM. Brief cognitive screening of the elderly: a comparison of the Mini-Mental State Examination (MMSE), Abbreviated Mental Test (AMT) and Mental Status Questionnaire (MSQ). Psychol Med 1996;26:427–30. [7] Antonelli Incalzi R, Cesari M, Pedone C, Carosella L, Carbonin P. Construct validity of the Abbreviated Mental Test in older medical inpatients. Dement Geriatr Cogn Dis 2003;15:199–206. [8] Brooke P, Bullock R. Validation of a 6-item cognitive impairment test with a view to primary care usage. Int J Geriatr Psychiatry 1999;14:936–40. [9] Shulman K, Shedletsky R, Silver I. The challenge of time: clock drawing and cognitive function in the elderly. Int J Geriatr Psychiatry 1986;1:135–40. [10] Wolf-Klein, Silverstone FA, Levy AP, Brod MS, Bruer J. Screening for Alzheimer’s disease by clock drawing. J Am Geriatr Soc 1989;37:730–4. [11] Brodaty H, Moore CM. The clock drawing test for dementia of the Azheimer’s type: a comparison of three scoring methods in a memory disorders clinic. Int J Geriatr Psychiatry 1997;12:619–27. [12] Schramm U, Berger G, Müller R, Kratzsch T, Peters J, Frölich L. Psychometric properties of the clock drawing test and MMSE or short performance test (SKT) in dementia screening in a memory clinic population. Int J Geriatr Psychiatry 2002;17:254–60. [13] Shulman K. Clock drawing: is it the ideal cognitive screening test? Int J Geriatr Psychiatry 2000;15:548–61.
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