Neuropsychological assessment in dementia

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REFERENCES Blessed G, Tomlinson B E, Roth M. The association between quantitative measures of dementia and of senile changes in the cerebral grey matter of elderly patients. Br J Psychiatryy 1968; 114: 797–811. Clarfield A M. The reversible dementias: do they reverse? Ann Intern Med 1988; 109: 476–86. Dubois B, Slachevsky, Litvan I, Pillon B. The FAB: a Frontal Assessment Battery at bedside. Neurologyy 2000; 55: 1621–6. Folstein M F, Folstein S E, McHugh P R. ‘Mini-Mental State’. A practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res 1975; 12: 189–98. Massoud F, Devi G, Moroney J T et al. The role of routine laboratory studies and neuroimaging in the diagnosis of dementia: a clinicopathological study. J Am Geriatr Socc 2000; 48: 1204–10. Monsch A U, Bondi M W, Salmon D P et al. Clinical validity of the Mattis Dementia Rating Scale in detecting dementia of the Alzheimer type. A double cross-validation and application to a community-dwelling sample. Arch Neurol 1995; 52: 899–904. Roth M, Tym E, Mountjoy C Q 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: 698–709. Shulman K I. Clock-drawing: is it the ideal cognitive screening test? Int J Geriatr Psychiatry 2000; 15: 548–61. Walstra G J M, Teunisse S, van Gool W A, van Crevel H. Reversible dementia in elderly patients referred to a memory clinic. J Neurol 1997; 244: 17–22. FURTHER READING Burns A, Dening T, Lawlor B. Clinical Guidelines in Old Age Psychiatry. London: Martin Dunitz, 2002. (A comprehensive overview of guidelines for diagnosis, treatment and management.) Burns A, Downs W, Kampers W. Current Dementia. London: Science Press, 2003. (A readable pocket book that highlights the main current issues in dementia.) Cummings J L. Neuroimaging in the dementia assessment: is it necessary? J Am Geriatr Soc 2000; 48: 1345–6. (An interesting discussion on the merits of neuroimaging in the assessment of dementia.) Hodges J R. Cognitive Assessment for Clinicians. Oxford: Oxford University Press, 2003. (An excellent practical guide to cognitive tests that can be conducted in clinic or at the bedside.)

Neuropsychological assessment in dementia David J Gracey Robin G Morris

The term ‘dementia’ encompasses a wide range of neurological conditions that give rise to global decline in cognitive functioning. Diagnostic criteria vary, but perhaps the most commonly used are based on DSM-IV (American Psychiatric Association, 1994), which specifies memory deficit as a primary diagnostic feature, along with at least one other type of cognitive impairment. Hence, the main criteria that define dementia are primarily neuropsychological, and place a premium on accurate neuropsychological investigation. Standardized test procedures can be used for diagnostic purposes, and also for progressive monitoring of the disease state and evaluation of psychopharmacological treatment and cognitive/behavioural intervention programmes. Any meaningful approach to assessment has to consider the contribution of several conceptually distinct, but interconnecting, domains of cognitive function. This contribution highlights the most pertinent areas that should be investigated.

Principles of assessment in older adults: some special considerations The general principles of neuropsychological assessment (Lezak, 1997) should apply regardless of the population under scrutiny. However, additional care and consideration may be required to ensure that those principles are upheld when working with older adults (particularly when it comes to investigations of suspected dementia). Many older people have heightened reservations about the prospect of formalized testing, which could well be due to cohort differences about the meaning and circumstances around having to undergo psychological testing procedures. Extra time may be required to explain the purpose of the assessment, nullify undue concerns and establish rapport. Certainly in some cases the degree of understanding and willingness to engage can be complicated further by reduced insight (as is often the case in late-onset

Practice points David J Gracey y is a Clinical Psychologist in Older Adult Mental Health Services for Oxleas NHS Trust, Bexleyheath, UK. He qualified from Queen’s University, Belfast, and trained in clinical psychology at the Institute of Psychiatry, London.His research interests include cognitive– behavioural therapy for older adults, the neuropsychology of ageing and psychopharmacology.

• Always consider the possibility that a patient presenting with cognitive problems may have a delirium or depression • Obtain as much background information as possible before seeing the patient • A detailed collateral history from a family member or carer is essential • Investigate other cognitive symptoms, not just the presenting complaint • Assessment should include other members of the multidisciplinary team, e.g. functional assessment of activities of daily living by the occupational therapist

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Robin G Morris is Professor of Neuropsychology at the Institute of Psychiatry, London, UK, and Head of the Clinical Neuropsychology Department at King’s College Hospital, London. His research interests include the neuropsychology of Alzheimer’s disease, specializing in investigating memory function and awareness of cognitive impairment.

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Alzheimer’s disease). The willingness of the clinician to adopt a more relaxed and unhurried style can be of immense benefit, both in terms of improving test conditions and, ultimately, confidence in drawing conclusions from the assessment. There are other ways that ageing may have an impact on the outcome of neuropsychological assessment. Given that the sensory decline occurs more frequently among older adults, the influence that vision and/or hearing loss has on psychometric testing cannot be understated. The use of test material that relies primarily on a single modality (either visual or auditory) is one good way of overcoming any interpretative obstacles. Alternatively, some tests have versions that are specifically designed for people with sensory loss (e.g. the booklet version of the National Adult Reading Test (see below) for people with reduced vision). More straightforward measures include slowing down the rate of delivery of verbal instructions or test material and increasing the volume (but not the pitch) at which information is presented. Finally, checking whether or not the patient normally uses glasses or a hearing aid (and encouraging them to bring such equipment with them on the day of assessment) is a crucial, albeit obvious, practice point.

sensitive for detecting cognitive impairment within several domains (Figure 1 shows some examples of patient drawings). As standalone clinical measures, however, these tests are open to criticism; clinicians should avoid being over-reliant on a single screening score for diagnostic purposes. Screening tools should probably be viewed as providing pointers for more detailed clinical or neuropsychological assessment. Test batteries such as the Middlesex Elderly Assessment of Mental State (MEAMS; Golding, 1989) offer a more comprehensive approach to screening assessment. Premorbid and current intellectual functioning While there is an intuitive notion that with increasing severity of dementia comes greater cognitive impairment, this belies the fact that different domains of cognitive functioning may decline at different rates. Premorbid tests of intelligence are a useful way to establish a point of comparison for how patients are performing on various tests of cognition. With the possible exception of assessment for those individuals who are considered at high risk of developing the disorder (e.g. where there are familial cases of early-onset dementia), the opportunity to conduct premorbid testing on patients with dementia is rare. Gaining estimates from educational and occupational history is one crude way of circumventing this problem. A more viable approach has been to draw inferences about premorbid intelligence in areas of cognitive functioning that are more resistant to deterioration in dementia, such as an individual’s reading ability. The National Adult Reading Test (NART; Nelson and Willison, 1991) requires a prior knowledge of irregular words that violate common principles of phoneme production (e.g. cellist, gauche). The NART has enjoyed widespread clinical usage, but has to some extent been superseded by the Wechsler Test of Adult Reading (WTAR; Holdnack, 2001), which is standardized alongside the Wechsler Adult Intelligence Scale – III (WAIS-III; Wechsler, 1997). Specialist tests such as the Cambridge Contextual Reading Test (Beardsall, 1997) can also be considered. Comparing current intellectual functioning with estimates of premorbid ability can also provide important information about rates of decline or act as a baseline to monitor change. The most comprehensive and well-standardized measure of current intellectual ability is the WAIS-III. Despite its widespread usage, administering a full WAIS-III battery in an older adult population may be contraindicated because the overall length can prove unacceptable (there are 14 subtests with a likely administration time of 90 minutes). A four-item version, the Wechsler Abbreviated Scale of Intelligence (WASI; Wechsler, 1999) is available, and its brevity is likely to enhance its usefulness.

Modes of assessment Screening assessments The need for accurate cognitive screening tools to aid prompt, efficient detection and diagnosis is now more than ever a priority and such tools make up the bulk of neuropsychological assessments. Treatment protocols for dementia have most benefit if pharmacological intervention begins as early as possible. Brief tests of mental status are commonly used in clinical practice (see also page 16), the most popular being the Mini-Mental State Examination (MMSE; Folstein et al., 1975). A useful supplement to this is the Clock Drawing Test (Freedman et al., 1994), which is

Severely distorted clock-drawing in two patients with probable Alzheimer’s disease

Memory Although dementia typically leads to deficits in several cognitive domains, the main feature of memory impairment is perhaps the most debilitating. One should, however, be mindful that the popular conception of a ‘memory problem’ tends to be something of a catch-all phrase describing a range of difficulties with other possible origins (e.g. language or sensory impairment). Furthermore, there is a lack of clear distinction between the various types of memory impairments that might arise in clinical practice (e.g. normal age-related versus age-inappropriate memory loss). More confusing still is a lack of consensus about the point at which mild memory impairment constitutes a transitional phase into a later

1 In the clock-drawing test, patients are asked to draw and number a clock face, and then place the hands in the correct position for a given time. This tests a wide range of cognitive skills including comprehension, visual memory, visuospatial abilities, numerical thinking and executive functioning.

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older adults. The Kendrick Object Learning Test (KOLT; Kendrick, 1985) is a visual memory task that is testable for more severe levels of impairment. More ecologically valid tests (i.e. approximating real-life experiences) include the Doors and People Test (Baddeley et al., 1994) and the Rivermead Behavioural Memory Test (Wilson et al., 1999).

Outline of the stages of memory impairment in dementia Mild memory impairment • Lapses in memory are noticed, for example, by failure to carry out errands or in conversations with other people; forgetting the details of recent events • These problems may be attributed to other factors, such as the effects of stress or depression, or ‘age-appropriate’ cognitive ageing • The memory disorder may represent a prodromal period before the onset of dementia

Executive functioning Particularly during the early stages of dementia, high levels of competency and independence in carrying out routine and familiar tasks may be observed, although these abilities tend to break down when novel or complex problems are encountered. The term ‘executive function’ subsumes a number of interrelated cognitive skills relating to the sequencing and organization of cognition and behaviour. Given what is understood to be the neuroanatomical underpinning of such skills, tests that have been developed are particularly sensitive to frontal lobe damage. Brief tests of executive function include the Stroop Test (Trennery et al., 1989) and the abbreviated version of the Wisconsin Card Sorting Test (Grant and Berg, 1993), both of which have norms for the older adult population. The Hayling and Brixton Tests (Burgess and Shallice, 1997), although relatively brief, are a particularly useful assessment tool. A more comprehensive test battery, the Behavioural Assessment of Dysexecutive Syndrome (BADS; Wilson et al., 1996), is a well-standardized and ecologically valid approach to assessing executive function. Its use in advanced stages of dementia with more widespread dysfunction is, however, not advised, as consistent scoring below threshold on these tests is unlikely to reveal much clinically and may only serve to increase agitation and a perceived sense of failure.

Mild or moderate impairment • The memory impairment becomes more pronounced and more easily noticed by friends and relatives • The errors include consistently forgetting important pieces of information, forgetting reasonably familiar people and getting disorientated, even in relatively familiar surroundings. The patient becomes unable to keep track of daily events and shows temporal and spatial disorientation • The memory impairment may force reliance on a carer, and the person may seek medical help, often prompted by the carer • Insight is variable, and frequently the patient may not recognize the true extent of their memory difficulties Severe impairment • The patient is substantially disorientated, and memory impairment can cause safety problems; for example, associated with wandering • Severe memory impairment includes forgetting close relatives • Marked signs of memory disorder may include paramnesia and confabulation

Breakdown of language functioning as Alzheimer’s disease progresses

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Early phase • Impaired word retrieval manifests as word-finding and confrontation-naming difficulties • In conversation, the pattern of language is circumlocutory • Comprehension of complex verbal material is impaired

stage of dementia. Figure 2 outlines the typical stages of memory impairment in dementia. Neuropsychological assessment of memory impairment in dementia should, at the very least, aim to cover verbal and nonverbal memory, immediate and delayed recall, as well as the influence of multi-trial learning on memory. Most test batteries include assessment for these areas, but it is also important to check if norms for older adults are available. The most recent version of the Wechsler Memory Scale (WMS-III; Wechsler, 1997) has updated norms to age 89, although it may be impractical to administer such an extensive battery on an older population. Using selective WMSIII subtests (such as Logical Memory and Visual Reproduction) is one viable alternative, and separate normative data are available. The Adult Memory and Information Processing Battery (AMIPB; Coughlan and Hollows, 1985) offers a good compromise between brevity and comprehensiveness. The AMIPB has four subtests (Story Recall, Figure Recall, List Learning and Design Learning), although it has been standardized on a relatively small sample and norms are available only up to age 75. A number of memory tests have been specifically developed for

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Middle phase • Word-finding difficulties are more pronounced • The content of language can become vague and meaningless • The syntax of language output is simplified • Impaired language comprehension is exacerbated by the breakdown of reasoning ability • ‘Positive’ signs of language disorder arise, such as paraphasia and verbal perseveration Late phase • Mutism can occur • Any language produced may be limited to the meaningless repetition of words or nonsense sounds

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Case study non-verbal memory, with impairment in both immediate and delayed (30 minutes) recall. Furthermore, repeated presentation of stimuli did not appear to aid recall

Referral: A 70-year-old woman was referred for assessment following concerns expressed by family members regarding ongoing memory problems

Executive functioning: On the Trail Making Test, she was unable to complete Trial B (which requires alternating between letter/number stimuli), indicating impairment in mental flexibility. She was also assessed using the Hayling (response inhibition: poor) and Brixton (spatial anticipation: impaired) tests

Neuropsychological screening: Mini-Mental State Examination score was 27/30, with points lost for recall Premorbid estimate: National Adult Reading Test estimated a fullscale IQ of 123 (within the ‘superior’ range) Current intellectual functioning: Performance on the Wechsler Abbreviated Scale of Intelligence was within the ‘low average’ range. Verbal skills: vocabulary=55, similarities=23, verbal IQ=84; performance skills: block design=42, matrix reasoning=34, performance IQ=82; full-scale IQ=81

Conclusions: This lady’s presentation indicated a clinically significant decline in overall intellectual functioning when compared with available age-related normative data and her own premorbid level of functioning. Although there may be a general slowing down of cognitive processes, memory and executive difficulties were still quite marked. This pattern is consistent with early dementia, and recommendations were made for repeated assessment of functioning at a later date, as well as the need for in-depth neurological investigation

Memory: In the Kendrick Object Learning Task, her score was below the cut-off which defines the range of scores obtained by people with dementia. Scores on items of the Adult Information Processing and Memory battery showed deficits in both verbal and

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Language Deficits in other cognitive domains tend to become more prominent as dementia progresses. Impairments in language functioning may be expected as neuronal loss becomes increasingly extensive. Broadly speaking, deficits in terms of speech, naming and auditory comprehension might be expected (Figure 3 outlines the way these sort of deficits are likely to present as dementia due to Alzheimer’s disease progresses). Several standardized language test batteries are available, such as the popular Boston Diagnostic Aphasia Examination (Goodglass and Kaplan, 1983). Tests that look specifically at naming ability include the Boston Naming Test (Goodglass and Kaplan, 2001) and the Graded Naming Test (McKenna and Warrington, 1983), both of which have norms for an older adult population. Finally, auditory comprehension can be examined using the Tokens Test (Benton et al., 1994).

clinical questions. This typically involves using a preliminary set of tests that later forms the basis for selecting more specific tests where there is indication of a particular area (or areas) of deficit (see Figure 4). Crucially, however, this ability to ‘mix and match’ should be tempered by the need to select tests that are sufficently sensitive to the overall level of an individual’s impairment and do not undermine the discriminative power of any particular test battery. ‹

REFERENCES American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th edition (DSM-IV). Washington, DC: American Psychiatric Association, 1994. Baddeley A D, Emslie H, Nimmo-Smith I. Doors and People. Bury St Edmunds: Thames Valley Test Co, 1994. Benton A L, de Hamsher K S, Siven A B. Multilingual Aphasia Examination. Iowa City, IA: AJA Associates, 1994. Burgess P W, Shallice T. The Hayling and Brixton Tests. Bury St Edmunds: Thames Valley Test Co, 1997. Coughlan A K, Hollows S E. The Adult Memory and Information Processing Batteryy (AMIPB). Leeds: Psychology Department, St James’s University Hospital, 1985. Folstein M F, Folstein S E, McHugh P R. ‘Mini-Mental State’. A practical method of grading the cognitive state of patients for the clinician. J Psychiatr Res 1975; 12: 189–98. Freedman M, Leach L, Kaplan E, Winocur G, Shullman K, Delis D C. Clock Drawing: A Neuropsychological Analysis. New York: Oxford University Press, 1994. Golding E. Middlesex Elderly Assessment of Mental State. Bury St Edmunds: Thames Valley Test Co, 1989. Goodglass H, Kaplan E. Boston Diagnostic Aphasia Examination. Philadelphia: Lea and Febiger, 1983. Goodglass H, Kaplan E. The Boston Naming Test. Baltimore, MD: Lippincott, Williams & Wilkins, 2001.

Visuospatial functioning Occasionally, patients with otherwise intact intellectual ability and visual acuity will present with poor constructional skills (e.g. copying a diagram) or inability to orientate themselves within familiar surroundings. Failure on relevant items of the MEAMS (see above) may indicate the need for further investigation of visuospatial functioning, as can impaired performance on subtests that might form part of a preliminary assessment (e.g. Block Design or Matrix Reasoning, both of which are included in the WAIS-III and the WASI). Probably the most in-depth test battery is the Visual Object and Space Perception battery (VOSP; Warrington and James, 1991), although norms are available up to 69 years only.

What tests should be used? As clinicians become increasingly familiar with the wide range of test material available, they should feel more competent and capable of selecting the appropriate tests to address the prevailing

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Grant D A, Berg E A. The Wisconsin Card Sorting Test. Windsor: NFER, 1993. Holdnack J A. The Weschler Test of Adult Reading. San Antonio: Psychological Corporation, 2001. Kendrick D C. Kendrick Cognitive Tests for the Elderly. Windsor: NFERNelson, 1985. Lezak M D. Neuropsychological Assessment. New York: Oxford University Press, 1997. McKenna P, Warrington E K. The Graded Naming Test. Cambridge: Cambridge Cognition, 1983. Nelson H, Willison J R. National Adult Reading Test (NART): Test Manual. 2nd edition. Windsor: NFER-Nelson, 1991. Trennery M R, Crossen B, De Boe J. Stroop Neuropsychological Screening Test. Windsor: NFER-Nelson, 1989. Warrington E K, James M. The Visual Object and Space Perception Battery. Bury St Edmunds: Thames Valley Test Co, 1991. Wechsler D. Wechsler Abbreviated Scale of Intelligence (WASI). San Antonio: Psychological Corporation, 1999. Wechsler D. Wechsler Adult Intelligence Scale – III (WAIS-III). San Antonio: Psychological Corporation, 1997. Wechsler D. Wechsler Memory Scale – Third Edition (WMS-III). San Antonio: Psychological Corporation, 1997. Wilson B A, Alderman N, Burgess P W, Emslie H, Evans J J, eds. Behavioural Assessment of the Dysexecutive Syndrome. Bury St Edmunds: Thames Valley Test Co, 1996. Wilson B A, Cockburn J, Baddeley A D. The Rivermead Behavioural Memory Test (RBMT): Extended Version. Bury St Edmunds: Thames Valley Test Co, 1999.

Structural imaging in the dementias Jonathan M Schott Nick C Fox

Dementia is defined as an acquired, usually progressive impairment of multiple domains of cognition, including memory, in the presence of normal consciousness, sufficient to impact on the activities of normal life (American Psychiatric Association, 1994). Differentiating between the many causes of dementia is increasingly important, especially as new specific treatments become available. This contribution discusses the role of structural neuroimaging in the diagnosis of dementia.

Neuroimaging modalities Several imaging modalities may be used in the assessment of a patient with dementia. These may be conveniently divided into structural and functional imaging. Structural imaging comprises computed tomography (CT) and magnetic resonance imaging (MRI). CT scanning g is based on the fact that different tissues attenuate X-rays according to their density. If an X-ray beam is rotated around a subject’s head, the degree of attenuation (Hounsfield unit) can then be measured by an array of detectors; this information can be reconstructed to provide an image of the brain. CT scans are widely available, cheap and relatively rapid; disadvantages include the exposure to ionizing radiation and the relatively poor resolution and tissue contrast compared with MRI. MRII utilizes the fact that hydrogen ions in a magnetic field emit a radio signal following excitation by a radiofrequency pulse. Different tissues have different MR properties; by altering acquisition parameters, these different properties can be used to generate an image highlighting a particular tissue type. Tissues with a large amount of freely mobile water appear dark in T1-weighted images, but bright in T2-weighted or fluid attenuation inversion recovery (FLAIR) sequences. MRI avoids X-ray irradiation, but MR scanners

Practice points • Neuropsychological assessment involves the application of scientific knowledge through standardized test procedures, thus allowing changes in cognitive functioning to be more effectively identified, monitored and managed • Dementia can affect a broad range of interconnecting cognitive domains; however, the pattern of deterioration can be highly variable • Assessments conducted as part of a screening measure, while useful, are not a substitute for more precise and detailed neuropsychological investigation • Clinicians should be alert to the possibility that mild cognitive impairment may be part of a natural, age-appropriate decline; however, this usually warrants at least further longitudinal testing

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Jonathan M Schottt is Alzheimer’s Society Research Fellow at the Dementia Research Centre, Institute of Neurology, London, UK. He is a neurologist whose research interests include the use of MRI as a diagnostic and progression marker in dementia. Nick C Foxx is Senior Lecturer in Neurology and MRC Senior Clinical Fellow at the Institute of Neurology, London, UK. He qualified from Cambridge University and St Thomas’ Hospital, London. His research in MRI use in Alzheimer’s disease and related disorders resulted in the now widely used technique of registration-based atrophy measurement from serial MRI, with applications for a range of neurological conditions.

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