Test and Answers – 106 References – 108
4.1 Background
4.1.4 Neuropsychological Assessment Procedures
Interview
The neuropsychological interview allows the clinician to obtain pertinent background information that is often not in medical charts. Data gathered includes demographics, important developmental, educational and psychosocial his- tory, as well as information pertaining to current concerns or complaints [10]. Establishing rapport and engaging the patient in the assessment process at the start of the interview is essential to ensure that valid and reliable assessment data is gathered. Older adults may be worried about the implica- tions of the testing as it relates to their independence. They are also more likely to be anxious due to unfamiliarity with standardized or computerized testing. Taking time to orient the patient to the assessment process, use of technology (if any), reviewing the purpose and goals of the assessment, and allowing sufficient time for the patient to ask questions is imperative with respect to reducing uncertainty and anxiety to ensure more valid test results.
Teaching Point
Begin the interview by explaining the assessment procedure and the cognitive skills to be assessed using lay terms. Review limits to confidentiality. Ask the patient to describe their understanding of why they have been asked to participate in such an assessment. This will provide information as to the patient’s level of insight into any cognitive or functional changes. Other qualita- tive information obtained during the interview that might not be observed in a more structured testing Neuropsychology in Late Life
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session includes observations of the patient’s behaviors, mannerisms, and spontaneous speech. For example, is the patient socially inappropriate, making sexually charged comments, or relating to the examiner in a much more familiar way than expected? All of these are suggestive of frontal lobe behavioral dysfunction.
Attending to qualities of speech and language may identify word-finding problems or paraphasias.
Establishing Premorbid Level of Functioning The interview should elicit information that is relevant for establishing an individualized premorbid baseline ability, as it will be against this baseline that the patient’s performance on age-normative neuropsychological test data will be com- pared. Premorbid general intellectual ability may be esti- mated using history of educational and occupational attainment. Establishing educational history should include probing for learning or academic difficulties as most older adults would not have been formally diagnosed with learning disability or intellectual impairment in childhood. As such, the clinician may need to ask probing questions about educa- tional attainment or barriers to education (see .Table 4.1).
In the absence of a history of familial upheaval or childhood trauma, a patient who describes a history of delayed acquisi- tion of basic academic skills, grade repetitions, and failure to complete high school is likely to have had an undiagnosed intellectual or learning disability. This is important to iden- tify because, in such a case, cognitive difficulties on standard- ized testing may not actually reflect a decline. It is equally important to consider baseline functioning among those patients who excelled in their youth and younger adulthood.
For example, it would be expected that patients who described themselves as “top of the class,” who had completed univer- sity education, and/or held a successful professional career to have been above average premorbidly. Within this context, the patient may perform within normal limits on standard- ized age-matched testing, but this in fact may represent a decline from their higher than average baseline.
Subjective Cognitive and Physical Changes
Asking the patient to explain their understanding of why they have been referred for neuropsychological assessment may reveal specific subjective cognitive concerns, particu- larly in the case of patients who do not have NCD or who have mild NCD and retain insight. The most common cogni- tive concern among older adults is memory [11]. Regardless of whether patients spontaneously report concerns or not, it is important to ask probing questions (see .Table 4.1) about common memory and other cognitive changes associated with the major classes of NCDs, as many patients may not be aware of or able to spontaneously generate a full description of changes. Moreover, memory complaints may actually be due to other cognitive difficulties, most frequently, poor
attention or concentration. Physical problems such as bal- ance or motor problems, sensory loss (visual, auditory, tac- tile), and pain should also be queried as should medication use and adherence and sleep quality and daytime fatigue.
Emotional functioning, including mood, anxiety, and frus- tration, should also be queried as symptoms of depression are often difficult to distinguish from a dementing process in the absence of formal testing and anxiety can lead to inattention and associated memory difficulties. When patients endorse difficulties, it is important to verify whether this is a change from their baseline or a worsening or reemergence of a long- standing difficulty.
.Table 4.1 Examples of interview questions Domain Examples of questions Premorbid
ability
What was your childhood like?
Did you struggle to learn to read or write?
Was math more difficult for you?
How far did you go in school?
Were you ever held back a year?
What kind of a student were you?
Did you fail any classes/courses?
What did you do for work?
What was your longest held job?
Cognitive difficulties
Do you have any difficulty remembering appointments? Conversations? To relay messages? Items when shopping?
Any difficulty coming up with people’s names? Names of everyday items?
Do you find yourself unable to think of the word you want to use?
Do the wrong words ever come out when you are speaking?
Any difficulty following other people in conversation?
Any difficulty finding your way around?
Getting lost?
Any difficulty making decisions or choices?
Any difficulty doing things with your hands, such as small buttons?
Course When did you first notice your (cognitive) problem?
Did it start all of a sudden?
Did it creep up gradually?
What was happening in your life when you first noticed your problem?
Has it gotten worse over time or stayed the same?
Functioning Have you noticed any difficulties getting things done around the house?
Any trouble paying bills on time?
Difficulty preparing meals?
Have you accidentally left the stove on?
Have there been any mix-ups with your medication?
Do you need help with any activities?
Have you stopped or modified your work as a result of these difficulties?
Teaching Point (Continued) H.E. McNeely and J.P. King
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Establishing Nature and Course of Decline
When cognitive, motor, sensory, or emotional changes or concerns are endorsed, it is critical to determine the nature of onset and progression of these changes over time. Sudden or insidious? Progressive or static? Changes associated with cer- tain forms of NCDs such as Alzheimer disease are more likely to begin insidiously and worsen gradually over a num- ber of years. In contrast, cognitive difficulties associated with medical conditions such as myocardial infarction or stroke would have a more abrupt onset and static course. A sudden onset and stepwise course may also be associated with NCD due to vascular disease secondary to accumulation of cere- bral damage associated with numerous small vessel and/or transient ischemic events. Cognitive difficulties associated with depressive or anxiety disorders may wax and wane over time in accordance with the mood or anxiety state but may also persist during periods of euthymia and worsen with age.
Teaching Point
Determining the nature of onset and course of changes will allow the examiner to generate hypotheses regard- ing differential diagnosis and guide in the selection of specific neuropsychological assessment tools to aid in this differential process.
Daily Functioning
It is important to characterize changes to daily functioning including basic activities of daily living and instrumental activities of daily living. Basic activities of daily living include self-care tasks, while instrumental activities of daily living involve more complex tasks such as managing finances and preparing meals. In order for a patient with documented cognitive changes to meet criteria for a diagnosis of major NCD, a substantial change or decline in daily functioning is required. This can often only be obtained from a collateral interview, as patients with most forms of major NCD will often lack insight into functional changes. For example, when Mr. S. is asked about his typical daily activities, he reports that he reads the paper from front to back each morning, plays bridge several times a week, and participates in volunteering at the YMCA. However, Mrs. S. reports that Mr. S. has not been able to do any of those activities for sev- eral years.
Collateral Interview
Speaking with a collateral informant very familiar with the patient prior to the onset of any suspected changes is crucial either because the patient lacks insight into changes or they may deliberately minimize or conceal difficulties due to con- cerns of how this might impact their independence. For older adults with a history of neuropsychiatric illness that impacts cognition, such as depressive disorder, the collateral infor- mant might clarify whether the current presentation is con- sistent with previous episodes of depression or represents a
change. For example, in the case of a moderate to advanced NCD due to Alzheimer disease pathology, the patient may be disoriented to time and describe their abilities and daily activities according to a younger version of themselves. As well, with certain types of NCD, such as the behavioral vari- ant of frontotemporal NCD, subtle personality and/or behav- ioral changes are the first signs of the disorder and are often accompanied by a loss of insight due to degeneration of fron- tal brain regions. Thus, patient self-report regarding the type and time-course of any cognitive or functional changes should be validated with the collateral informant.
Additionally, the collateral informant might be able to pro- vide further information to help determine premorbid base- line level.
Teaching Point
Speaking with a collateral informant separately, with the patient’s consent, is preferred, especially in situations where the patient may lack insight into cognitive difficulties, so that the informant can speak more openly about their concerns. Most patients will readily agree to have their collateral informant interviewed separately.
Occasionally, some patients will not authorize a separate collateral interview, and in such cases where objective cognitive deficits are absent or minimal, the lack of collateral can make it impossible to determine if the patient meets criteria for minor NCD. In such cases, repeat neuropsychological assessment would be recommended to monitor for further declines over time.
Cognitive Screening
Cognitive screening with tools such as the Mini Mental State Exam (MMSE) [12] or the Montreal Cognitive Assessment (MoCA) [13] is the recommended first step when older adults present with subjective cognitive complaints in both acute and tertiary care settings because they are brief and can inform the need for lengthier cognitive testing. The MoCA is recommended, as it is copyrighted but freely available for use by most healthcare professionals and has been translated into 56 different languages, and there are three alternate versions of the English MoCA for use in serial assessment. When using a screening tool, it is important to review administra- tion instructions prior to beginning in order to ensure the data gathered is valid. An administration manual for the MoCA is available online (7www.mocatest.org). Other con- siderations when using screening measures include complet- ing the testing in a quiet, distraction-free setting, when the patient is alert, comfortable, and wearing corrective lenses or hearing aids (if required), and completing the testing in the patient’s native language or most commonly used current language. The MoCA screens most aspects of cognition, including attention/concentration, executive functions, memory, language, visual spatial skills, and orientation. This can be useful for screening normal age-related concerns,
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concerns of the “worried well,” or identifying individuals whose performance is suggestive of a decline. Cognitive screening measures are also useful for monitoring cognition over time in patients at risk for decline.
A score above the cutoff on cognitive screening may belie cognitive changes. This is often the case early in the course of NCD where cognitive changes may be too subtle to be detected by a screening measure. In such cases, more exten- sive neuropsychological assessment will be required.
Teaching Point
While cognitive screens can be useful for identifying suspected NCD and monitoring patients over time, it is important to refer patients for comprehensive neuropsy- chological assessment before the total score on the screen drops much below the cutoff. Once a sufficient level of cognitive impairment is reached, differential diagnosis becomes more complicated and is often not possible with neuropsychological testing. It is preferable to err on the side of caution at the earlier signs of cognitive change rather than wait until NCD is strongly indicated before seeking full neuropsychological assessment.
Comprehensive Neuropsychological Assessment
There are three main goals to completing a comprehensive neuropsychological assessment with older adults: first, to aid in differential diagnosis of cognitive changes due to normal aging from major or mild NCD or a primary psychiatric dis- order; second, to characterize the cognitive profile of spared and impaired functions to provide input into differential diagnosis of a specific etiology of the identified deficits; and, third, to use the cognitive profile to generate individualized recommendations regarding treatments and supports.
Format of Assessment
Information gathered from the clinical interview, collateral informant, referral source, and medical history/chart review together guide test selection for a full assessment. Most neu- ropsychologists follow a “flexible battery” approach whereby routine test batteries are informed by patient groups, while supplemental measures and procedures may be integrated to evaluate specific concerns. A basic neuropsychological test battery with older adults will include measures to assess the major domains of cognition: intellectual ability, attention/
concentration, memory, language, visual spatial and con- structional skills, social-emotional function, and praxis.
Within the usual tests allocated to assess these domains, additional measures may be added to further assess particu- lar concerns. For example, to query behavior-variant fronto- temporal NCD, the clinician may administer the Frontal Behavior Inventory [14] to obtain an objective measure of behavioral disturbance in addition to standard cognitive executive function performance.
Intellectual Ability
Assessment of intellectual ability includes both estimation of premorbid general ability and current objective ability.
Premorbid intellectual ability is measured most often using a single word reading test, such as the Test of Premorbid Function (TOPF) [15] or the North American Adult Reading Test (NAART) [16]. Scores are transformed using an algo- rithm into estimated premorbid IQ. Current general intellec- tual ability is most often assessed using a version of the Wechsler Adult Intelligence Scale (WAIS). The full WAIS is currently in its fourth revision (WAIS-IV) [17], and the com- mercially available short form, the Wechsler Adult Scale of Intelligence, is in its second revision (WASI-II) [18]. The advantage of using the full WAIS-IV is that in addition to the traditional Full-Scale Intellectual Quotient (FSIQ), the results generate four index scores: a verbal intellectual ability index (VIQ), a performance-based or nonverbal intellectual index (PIQ), a working memory index (WMI), and a measure of information processing speed (PSI), as well as the General Ability Index (GAI)—a new addition to the WAIS-IV which represents a full-scale IQ factoring out the negative impact of slowed processing speed and working memory difficulties.
The GAI is important to consider with psychiatric popula- tions who often present with slowed processing speed and working memory impairments secondary to mood or anxi- ety issues which may “pull down” the FSIQ. The WMI and PSI scores can be helpful in interpreting results of memory and executive functioning tests, especially with younger patients (see 7Sect. 4.2.1). However, the full WAIS-IV can take two or more hours to administer in its entirety, and so it is often onerous for use with very old individuals and with those patients who are strongly suspected of having a NCD. The WASI-II is a good alternative, with both a four- subtest and a two-subtest option, generating an estimated FSIQ, VIQ, and PIQ in a fraction of the time. Comparison of estimated premorbid and current FSIQ will reveal if there has been a generalized decline. A difference of 1.5 or more stan- dard deviations between scores is considered reflective of a significant decline.
Teaching Point
Given that the majority, if not all, objective measures of premorbid intelligence are based on measures of single word reading, it is important to note that the score may not be valid for an individual with a history of a reading or verbal learning disability or for someone whose first language is other than that being assessed. In such a case, broader level of educational and occupational attainment may be better qualitative estimates of premorbid ability.
Attention/Executive Function
Attention and concentration are typically assessed using both auditory verbal and visual stimuli. Simple auditory attention span is most frequently assessed using the digit span test,
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whereby strings of single digit numerals of increasing length are read aloud and the patient repeats them back. The simple auditory attention span is resistant to most forms of NCD and remains relatively intact until later in the illness progres- sion. Normal span is seven plus or minus two digits. More complex auditory attention, involving working memory, is assessed with the backward version of the digit span test, whereby strings of digits are read aloud and the patient is asked to repeat them in a backward sequence. Standardized forms of the digit span test, along with age-corrected norma- tive data, are included within the WAIS-IV as well as the Wechsler Memory Scales. Visual attention is often assessed with the Trail Making Test, which is also comprised of a simple version (Trails A) whereby the patient is instructed to connect a series of numerals scattered across a page using a single pencil line as quickly as possible. The more complex version (Trails B) is considered by many a measure of execu- tive function as it involves holding in mind and alternating between two sets of material. Patients are shown a paper with numbers and letters scattered across and are asked to alternately sequence the numbers and letters, in numerical and alphabetical orders, as quickly as possible. There is evi- dence for the use of Trails B as a screening measure for driv- ing ability [19]. Trails B time of over 3 minutes, and/or three or more errors, is useful for screening of cognitive impair- ment that might negatively impact driving. Other measures of executive function involve simple problem-solving and set shifting measures such as the reasoning and conceptual shift- ing subtest of the Kaplan-Baycrest Neurocognitive Assessment (KBNA) [20], while subtle difficulties in higher functioning patients may be detected using complex mea- sures of abstract reasoning or problem-solving such as the Category Test [21] or Wisconsin Card Sorting Test [22].
Verbal fluency may also be considered a measure of executive function, as frontal lobe integrity is required to perform the strategic semantic memory search needed to generate words that match the given cue. The Controlled Oral Word Association Test (COWA) [23] is a measure of phonemic flu- ency that involves quickly generating words to match a given letter cue. Semantic verbal fluency involves asking the patient to name as many items belonging to a given category in 1 minute. Commonly used semantic categories include ani- mal names or fruits and vegetables.
Teaching Point
When completing verbal fluency testing, it is again important to consider the native language of the patient, as this may negatively impact performance even if the conversational speech is very fluent. In addition, the impact of slowing due to normal aging and the effects of formal education must be taken into account. Therefore, the raw verbal fluency score is not as relevant as a norm corrected score. Various normative data sets are available that correct scores for age and education [24].
Memory
Assessment of memory utilizes both verbal and visually based content and measures of immediate and delayed recall and recognition. Memory difficulties represent the most common subjective cognitive complaint among older adults.
However, memory is not a unitary construct. It is composed of a learning or encoding phase, a consolidation phase, and a retrieval phase. Thus, it is very important that formal mem- ory assessment involves assessment of all three stages of the memory process, and that it is completed with measures that correct for normal aging. Verbal learning and memory is assessed using list learning tasks, such as the California Verbal Learning Task-2 (CVLT-2) [7], the Rey Auditory Verbal Learning Task (RAVLT) [25], or the Hopkins Verbal Learning Task-Revised (HVLT-R) [6]. List learning tasks are composed of a list of words that is read aloud to the patient over several learning trials. Immediate recall of the list is pro- vided by the patient after each trial, and a learning curve is generated that indicates whether the patient is able to acquire more information and benefit from repetition. After a delay, the patient is asked to spontaneously recall all the words from the list, assessing free recall. Poor free recall does not neces- sarily mean that all the words learned during acquisition were not consolidated or have been forgotten. In this regard, providing recognition cues after free recall typically assists with memory retrieval for both healthy older adults and those with depression indicating that difficulties during free recall are retrieval based rather than reflective of rapid forget- ting or reduced retention.
Teaching Point
Intact recognition in the face of poor recall indicates that memory storage is intact but that frontally mediated strategic memory retrieval is impaired. If the patient also demonstrates impairment on executive measures, this pattern will suggest that executive impairment is likely contributing to poor memory in daily life.
Verbal memory is also assessed using story memory tasks, such as the logical memory subtest of the Wechsler Memory Scale-IV (WMS-IV) [26] or the story subtest of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) [27]. Story memory tasks involve the presentation of a larger volume of auditory verbal information in a more meaningful context compared to list-learning tasks. This allows the examiner to determine whether a patient’s memory can benefit from the provision of greater context and meaningfulness. Qualitatively, the clinician might also assess if the patient is able to recall the
“gist” of the story, but forgets the details, suggestive of left frontal impairment. Poor story recall compared to better list memory performance also provides useful clinical information to help with treatment planning. This type of memory profile indicates that the patient will have better retention and recall if new information is provided in small
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