When patients present with memory or other cognitive complaints, objective verification of the nature and extent of these problems and the determination of their functional impact are goals of the neuropsychological evaluation. To ascertain this, the evaluation will assess eight major areas of cognitive function along with aspects of mood and personality. The basic areas assessed or ‘cognitive domains’ include: (i) general orientation and alertness, (ii) attention/concentration, (iii) intellect, (iv) memory, (v) language, (vi) executive functions, (vii) visuoperception/spatial judgement, and (viii) sensorimotor control. A brief discussion of each of these domains and the tests commonly used to measure each are described in the sections that follow. More detailed discussion of the range of instruments available to clinicians can be found in other sources³.

General Orientation

Orientation is a particularly important function that can be disrupted by a number of medical (e.g. delirium), psychiatric (e.g. depression) and neurological disorders⁴. In assessing general personal awareness, the neuropsychologist will establish the patient’s ability to orient to time (e.g. year, date, time of day), place (e.g. current location), personal information (e.g. name, age) and situation (e.g. why they are having a doctor’s appointment). Commonly, the examining clin-ician may use mental status tests in which orientation screening is included, such as the Mini-Mental State Examination (MMSE)⁵ or more detailed batteries, such as the Mattis Dementia Rating Scale⁶ and the comprehensive memory battery of the Wechsler Memory Scale⁷. Targeted, well-validated measures of orientation, such as the Temporal Orientation Test (TOT)⁸, are often selected and preferred by neuropsychologists over mental status screening tests, in order to streamline the evaluation and allow comprehensive evaluation of domains only cursorily measured in a screening metric.

Attentional Functions

The components of attention tapped within the neuropsychological examination include visual and auditory: (i) simple attention span, (ii) selective attention, (iii) vigilance or sustained attention, (iv) divided attention and (v) alternating attention⁹. There are a number of well-validated tests from which to choose when assessing attention and concentration, some of which are now computerized.

Simple attention span, the number of units held in immediate mem-ory, is commonly assessed by tests such as the Digit Span subtest from the Wechsler Adult Intelligence Scale III (WAIS-III)¹⁰ or the Spatial Span test of the Wechsler Memory Scale III⁷. Selectiveatten-tionrequires the ability to respond to relevant stimuli while simul-taneously inhibiting response to irrelevant, distracting stimuli, such as in speeded target identification tasks (e.g. Symbol Search of the WAIS-III) or the Ruff 2 and 7 Selective Attention Test^10,11). Vigilancerequires that stimuli be attended to over a period of time, commonly assessed by computerized continuous performance tests (CPTs), such as the Test of Variables of Attention (T.O.V.A.)¹². Dividedattentionrequires response to multiple competing tasks that occur simulta-neously, such as tasks involving the simultaneous performance of both verbal repetition and visual search tasks. Alternatingattentionrequires an individual to shift between tasks, such as the Trails B task, which requires switching between number and letters. It should be noted that tests of attention are easily influenced by a number of factors.

Failure on any single attentional test, or any neuropsychological test for that matter, can occur for a myriad of reasons. Consequently, it is important to consider confounds (e.g. sensory or motor limi-tations) and factors that may modify performance (e.g. educational experience) before drawing conclusions regarding impairments. Typ-ically a neuropsychologist will look for consistency of performance across at least two tests measuring the same cognitive function before drawing an inference of compromised function.

Intelligence

Intelligence is a multifaceted construct that examines capacities of reasoning, problem solving, creative thought and abstraction, measured both verbally and non-verbally. Significant impairments in this domain result in compromised function, a defining feature of dementia. The tests most commonly used for the purpose of assess-ing intelligence are those of the Wechsler Adult Intelligence Scale IV (WAIS-IV)¹³ (and its predecessors, WAIS-III and the WAIS-R), due to the well-established psychometric properties (reliability, validity and clinical utility) and extensive normative information for a broad age range (age 16–89). The WAIS tests also afford a comprehensive survey of a number of complex cognitive processes, including calculation, verbal and non-verbal abstraction, fund of knowledge, comprehension, reasoning and problem solving, spatial judgement, and sensorimotor integration. In situations where administration of an entire intelligence battery may be impractical, shorter versions are available (e.g. Wechsler Abbreviated Scale of Intelligence, WASI¹⁴). Alternatively, the neuropsychologist may sample specific areas of concern. Subtests of the WAIS, such as Block Design and Similarities, are sensitive indicators of brain disease and are often selected to quickly assess non-verbal and verbal abstraction, respectively.

Learning and Memory