Chapter 4 Psychological Assessment and Intervention in Rehabilitation
Psychologists have historically played multiple vital roles in both the scientific and clinical components of the field of rehabilitation. More than 50 years ago, the specialty of rehabilitation psychology defined biopsychosocial parameters as critical parameters in the assessment and treatment of individuals with disability. This chapter is a brief explanation of the principles and practices of rehabilitation psychology. Please see the recent Handbook of Rehabilitation Psychology134 for further information on these topics and for diagnosis-specific discussions.
Rehabilitation psychologists serve multiple clients including patients, family members, and staff. They also serve community entities such as schools, employers, and vocational rehabilitation agencies. This chapter provides an overview of common activities of rehabilitation psychologists and also addresses emerging topics, such as the burgeoning needs of returning military personnel and the new roles for rehabilitation psychologists.57 The reader is also directed to excellent chapters on rehabilitation psychology in the first three editions of this text, as a considerable amount of the material covered therein remains both accurate and relevant.
The most fundamental function of rehabilitation psychologists is the assessment and treatment of emotional, cognitive, and psychological disorders—whether congenital or acquired. Rehabilitation psychologists evaluate changes in neuropsychological functions that accompany brain injury or dysfunction, and advise on the implications of these for rehabilitation therapies and postdischarge life. This includes suggesting behavioral management strategies for problems such as pain and insomnia; counseling on issues related to sexuality and disability; aiding in transition from institution to community (including return to school or work)136,137; assisting in answering questions of capacity or guardianship needs; and advocating for reduction of environmental and societal barriers to independent functioning of persons with disabilities.
Rehabilitation psychologists can work with the patient and treating team and/or family groups. Although treatment teams are now found in other areas of medicine (e.g., primary care100 and psychiatry277), no other health care endeavor brings together such a diverse collection of specialists, and perhaps no other specialty has played as many unique roles on the rehabilitation team as the psychologist.55
As Diller99 wrote, “The key to rehabilitation is the interdisciplinary team.” Diller noted even back in 1990 that fiscal pressures were working to undercut the existence of interdisciplinary teams, but they have persisted. Rehabilitation teams, however, have evolved, and their composition can differ depending on the particular rehabilitation setting. As Scherer et al.330 noted, regardless of setting or area of specialization, the rehabilitation psychologist is consistently involved in interdisciplinary teamwork.
Rehabilitation psychologists can assist other staff in interpreting, understanding, and dealing with “problem behaviors” (e.g., low motivation, denial, irritability) exhibited by patients, friends, and family members.64 They can educate the treating team about the contribution of both stable personality traits and the more transient emotional responses to disability and hospitalization, to patient (and family) behavior. Rehabilitation psychologists also participate in rehabilitation research, as investigators in the Model Systems for spinal cord injury (SCI), traumatic brain injury (TBI), and burn care, for example. Rehabilitation psychologists can also use their training in group dynamics to assist in conflict resolution among team members, patient, staff, and family.62
To promote patients’ progress toward functional goals, such as resuming school and obtaining employment, rehabilitation psychologists collaborate with community agencies such as schools and vocational rehabilitation services. For example, evaluations by pediatric rehabilitation psychologists can form the basis for accommodations offered in school settings to children with congenital or acquired disabilities. Adults benefit from assessment services by rehabilitation psychologists, because these can be used to determine eligibility for services and to inform decisions regarding the nature of services that can be provided by state vocational rehabilitation agencies. Armed with knowledge of the Americans with Disabilities Act8 and related legislation, rehabilitation psychologists can be a resource for patients and community agencies regarding rights and responsibilities related to accommodations in facilities and employment settings.
Assessment
Drawing on expertise in functional neuroanatomy, psychometric theory, psychopathology, psychosocial models of illness and disability, and psychological and neuropsychological assessment and treatment applications,284 rehabilitation psychologists can provide essential assessment services in both inpatient and outpatient settings. Recognizing the multiple determinants of patient outcomes, rehabilitation psychologists take a multifactorial, multidimensional approach to assessment of cognitive functions, emotional state, behavior, personality, family dynamics, and the environment to which the patient will ultimately return.400 These assessments have many goals (Box 4-1).
BOX 4-1 Partial List of Goals of Rehabilitation Psychologists’ Assessments
Clinical Interviews and Behavioral Observations
Rehabilitation psychologists provide assessment services across the continuum of rehabilitation settings. Although the nature of the assessment varies with the referral question(s), two commonalities apply to virtually all of these assessments. First, a comprehensive clinical interview with the patient and other informants is done whenever possible. This interview covers developmental history, medical history, prior psychiatric and psychological treatment, behavioral health issues (e.g., substance abuse), educational and vocational achievements, psychosocial factors (e.g., information about family of origin, current family system, and other potential social supports), and historical style of coping with stress (see Chapter 3 in Strauss et al.353 and Part II in Frank et al.134). The focus is on the effects of psychological factors and cognitive abilities on daily functional abilities.
Neuropsychological Assessment
Overview
Neuropsychological assessment has become increasingly important in inpatient settings since the expansion of brain injury rehabilitation programs in the 1980s.84,309 Patients with brain injury or other neurologic conditions (e.g., stroke, multiple sclerosis) now comprise a large segment of the rehabilitation population, as do older adults with nonneurologic impairments who also show cognitive effects of normal aging that should be considered in rehabilitation planning.219 Inpatient screening by the rehabilitation psychologist is a standard and important component of the care of these individuals, consistent with best practices guidelines advanced by the U.S. Department of Veterans Affairs378 and endorsed by the American Academy of Physical Medicine and Rehabilitation.3 Outpatient assessments of neuropsychological functioning are also critical for continuing treatment planning, making educational/vocational recommendations, and tracking outcome.336
Inpatient Neuropsychological Assessment
Early rehabilitation neuropsychology assessments can take different forms, depending on the patient’s mental status. For patients at a low level of consciousness, initial (and serial) assessment with brief screening measures (e.g., Coma/Near Coma scale,300 Orientation Log180) can identify subtle changes in cognitive functioning that are not apparent from casual observation. Such early information regarding recovery of orientation can also help predict functional outcomes at discharge.412
For individuals at Rancho Los Amigos Scale VI and above, neuropsychological testing early in acute rehabilitation provides a baseline against which changes in functioning over time can be documented. Testing during this phase also provides an early indication of patients’ potential for improvement over time. Early cognitive screening can predict later need for supervision162 and functional outcomes.98,337 It should also be noted that performance on neuropsychological testing after the resolution of posttraumatic amnesia has been associated with return to productivity (employment or attending school) at 1-year postinjury.32,73,178,320 Neuropsychological assessment results during this period more directly predict functional outcomes among individuals with TBI than does injury severity.51,271 Information from baseline testing can also be incorporated into education for family members to help them understand the sources of certain troubling behaviors (e.g., neglect, impulsivity), and to begin to envision the range of possible outcomes and start to cope with potential long-term sequelae.
Neuropsychological testing of the fully oriented patient can be a vital component of rehabilitation planning and treatment. The resulting data document cognitive strengths and weaknesses that enable the rehabilitation psychologist to suggest useful strategies for promoting learning and fostering participation in rehabilitation, and to call attention to potential barriers to progress.344 Neuropsychological assessments involve the evaluation of fundamental skills (e.g., attention, information encoding), which underlie more complex behaviors that are the goals of other therapies (e.g., learning to use adaptive equipment). Armed with a map of the patient’s “cognitive landscape,” the rehabilitation psychologist can work with the team to develop intervention strategies for maximizing the patient’s success in acquiring the skills that are the goals of therapy.
In inpatient settings, rehabilitation psychologists identify neurobehavioral problems (e.g., depression, irritability, fatigue, restlessness) that are frequently reported after brain injury.327 These difficulties can impede participation and gains in rehabilitation,294 and they also have long-term functional implications.48 Depression can result from neurologic changes,123 adjustment-related issues,317 and/or premorbid personality and psychiatric difficulties.294 Depression can significantly limit a patient’s ability to learn new skills in rehabilitation.294 Those experiencing significant depression often evidence greater functional limitations than cognitive test scores alone would predict. When such a discrepancy is uncovered, rehabilitation psychologists can highlight the interplay between psychological issues and functional performance, and assist the team in developing behavioral strategies to minimize this impediment to progress.
For individuals nearing discharge from acute rehabilitation, neuropsychological testing can inform recommendations about important postdischarge issues and complex activities such as the ability to live independently,358 to return to work or school,38 and to resume driving.229
Many patients for whom brain-related insults are not the primary admission diagnosis might also benefit from neuropsychological testing. For example, approximately half of individuals with SCI have evidence of TBI,87 a comorbidity that is seen as a particularly challenging one in rehabilitation,310 and one associated with more limited functional gains during rehabilitation224 and increased costs.39 Because their TBI-related impairments are typically more subtle than those of individuals with a primary TBI diagnosis, neuropsychological testing of individuals with SCI can be more sensitive to their cognitive impairments than are broader screening measures such as the FIM.39
Elderly patients admitted for nonneurologic problems can also benefit from inpatient neuropsychological testing. Research indicates that cognitive deficits occur with equal frequency among elderly individuals admitted for rehabilitation after lower limb fractures and those being treated for stroke.237 Neuropsychological testing of these individuals can raise awareness of subtle cognitive difficulties that might affect participation in rehabilitation. In addition, dementia appears to be more common in geriatric rehabilitation populations than in elderly individuals living in the community, but it often remains undetected in rehabilitation settings.218 Neuropsychological screening is recommended for uncovering cognitive deficits and for identifying priorities for intervention during rehabilitation and in the context of discharge planning.219 Assessment of cognitive functioning has also been shown to predict outcomes in elderly individuals admitted to rehabilitation for such conditions as hip fractures.170
Outpatient Neuropsychological Assessment
Even when assessments have been completed in the inpatient setting, outpatient neuropsychological testing is often a valuable component of follow-up care for rehabilitation populations with neurologic conditions.269 Although inpatient assessments provide valuable baseline data, numerous factors can affect recovery over time,396 and declines in cognitive functioning might even occur in a small portion of individuals. In these situations, follow-up outpatient neuropsychological testing can signal the need for further medical workup. In addition, when compared with inpatient testing results, outpatient neuropsychological assessments allow determination of changes in functioning over time. These are important data, given the observed variability in patients’ recovery patterns.257
Neuropsychological testing can be particularly valuable in deciding whether outpatient rehabilitation services are likely to be helpful for individuals who first present to physiatry clinics later in their recovery. The testing data can aid in decision making about interventions for cognitive deficits, such as the use of neuropharmacologic treatments.416 As with inpatient evaluations, the rehabilitation psychologist strives to differentiate the relative contributions of neurobehavioral, psychological, and cognitive issues to daily functioning, because this can have direct implications for treatment planning. For example, if poor daily memory functioning is due to emotional distress, psychotherapy for adjustment issues or psychopharmacologic treatment, or both, would be indicated rather than training in compensatory strategies.
Outpatient neuropsychological assessments also play an important role in educating the patient and family about ongoing cognitive and neurobehavioral consequences of the injury or insult, and promoting advocacy for the patient and family. While teaching the patient and family members about the patient’s condition is a primary goal in the inpatient setting and can have positive benefits on patient outcomes,285 families and patients rarely retain all information provided to them. A follow-up consultation after the patient has had real-life experiences of success and failure provides an opportunity for the rehabilitation psychologist to draw connections among the patient’s medical condition, neuropsychological functioning, and daily difficulties. The implications of neuropsychological test performance for daily functioning are discussed. This discussion also takes into account changes secondary to recovery of functioning and development of new compensatory strategies, as well as changes in situational factors. Assessment findings form the basis for specific recommendations regarding adaptation tactics that can be used in patients’ daily lives (e.g., memory notebooks), and for guidance regarding how to achieve or adjust as necessary long-term goals such as returning to work, school, or independent living.292
For many individuals with persistent cognitive limitations, outpatient neuropsychological testing provides a basis for addressing issues related to disability. In addition to being associated with concurrent levels of productivity,11 outpatient testing at 5 months postinjury predicts return to productivity at 1 year postinjury.158 While many individuals resume working or attending school, accommodations or assistance might be needed, and test results can help clarify just what special provisions are needed. Not only can neuropsychological testing document cognitive strengths and weaknesses for determinations of eligibility for state services (e.g., vocational rehabilitation), but it can also help guide the nature of the services that are provided. As detailed in subsequent sections, neuropsychological testing can drive recommendations regarding accommodations in the educational realm. For those individuals unable to work because of their neurologic condition, neuropsychological testing is often relied on in determinations of disability by government as well as private organizations.356
Domains Assessed
Primary domains assessed in neuropsychological evaluations include intelligence, academic ability, memory, attention, processing speed, language, visual-spatial skills, executive abilities, sensory-motor functions, behavioral functions, and emotional status.217 Box 4-2 shows selected neuropsychological measures grouped by primary cognitive domain. (Virtually all neuropsychological tests are multifactorial, so the groupings in Box 4-2 are based on the presumed major cognitive skill required by the test.) While a deficit in any area can have a significant impact on functional outcomes for a given patient, large-scale studies suggest that memory, attention, and executive functioning have particular relevance for rehabilitation populations, including individuals with TBI.151
BOX 4-2 Sample Neuropsychological Tests by Primary Cognitive Domain
Intellectual Functioning/Academic Abilities
Wechsler Adult Intelligence Scales (WAIS-III/WAIS-IV)386,390
Wechsler Abbreviated Scale of Intelligence (WASI)387
Stanford-Binet Intelligence Scale364
Stanford-Binet Intelligence Scales, Fifth Edition316
Shipley Institute of Living Scale, Revised411
Learning and Memory
Auditory Consonant Trigram Test260,287
Rey Auditory-Verbal Learning Test331
California Verbal Learning Test–Second Edition91
Hopkins Verbal Learning Test–Revised44
Benton Visual Retention Test24
Language Skills
Boston Diagnostic Aphasia Examination, Third Edition150
Multilingual Aphasia Examination25
Peabody Picture Vocabulary Test, Third Edition108
Visual-Spatial Skills
Judgment of Line Orientation26
Hooper Visual Organization Test176
Executive Functions
Raven’s Progressive Matrices301
Wisconsin Card Sorting Test154
Memory impairments are prevalent after acquired neurologic injuries such as TBI244 and stroke,12 and can be significantly disruptive to the rehabilitation process. Memory problems can interfere with a patients’ ability to learn and retain new skills and/or develop compensatory strategies taught by rehabilitation providers. Memory problems can significantly hamper the achievement of important functional outcomes and productivity.32,156
Attention is a multifaceted construct that underlies all other cognitive skills and is especially important for intact memory functioning, because information that is not attended to cannot be recalled at a later time. Components of attention include focused attention, sustained attention, selective attention, alternating attention, and divided attention.344 In addition to memory problems, attention deficits are among the most commonly reported difficulties in persons with TBI208 and in those with a history of stroke.215 Deficits in attention are also associated with relatively poorer long-term functional outcomes, including diminished likelihood of returning to work and independent living.47
Executive functioning is a complex cognitive domain encompassing multiple skills that pervade all aspects of daily life. Neural systems engaged in executive functioning involve interconnections of diverse neuroanatomic regions,139 but the frontal lobes are viewed as especially vital. Executive functioning deficits include difficulties with problem solving, reasoning, planning, response inhibition, judgment, and use of feedback to modify one’s performance, as well as behavioral deficits such as problems with self-awareness and poor motivation. Neuropsychological tests typically focus on evaluating cognitive manifestations of executive dysfunction. Behavioral evaluation of executive functioning relies to a great extent on observations in natural settings, but some behaviors might emerge during testing. Several questionnaires are specifically designed to detect these behavioral issues, such as the Frontal Systems Behavior Sale (FrSBe).152 Deficits in executive functioning predict important outcomes such as poor quality of life174 and functional outcomes.215
Test Considerations
Fixed Versus Flexible Batteries
Rehabilitation psychologists must balance the relative costs and benefits of fixed versus flexible assessment batteries in neuropsychological assessments. With fixed batteries, such as the expanded Halstead-Reitan battery,166 the same set of tests is administered to all patients, regardless of the referral questions, and the normative data for all tests are based on a single population. Because all tests are co-normed, proponents of this approach assert that this allows for more confidence in drawing conclusions about an individual’s strengths and weaknesses, based on variability in performances across tests. Because a wide range of domains is evaluated, the rehabilitation psychologist might also identify strengths and weaknesses that were not anticipated on the basis of the referral questions or other information such as lesion locus.191
Another variant of the fixed testing approach involves the use of a test battery that is population specific15 and is developed by the rehabilitation psychologist for use with a particular patient cohort (e.g., individuals with a particular diagnosis such as multiple sclerosis).23 With this type of fixed battery, rehabilitation psychologists can amass their own clinically based normative data sets against which new patients can be compared. This approach also promotes research opportunities, because psychological and neuropsychological factors that influence participation in rehabilitation and outcomes after discharge can be identified and evaluated.
As a result, the generally preferred alternative is a flexible testing approach, one in which a core set of measures is supplemented with additional tests that are selected depending on the referral question.255 As the evaluation unfolds, measures can be added or subtracted according to early findings, as strengths and weaknesses become apparent. The examiner might elect to probe certain areas in more detail to clarify their therapeutic import. At the core of this approach is the notion that flexible batteries allow for personalization of an assessment based on patient needs.15 Flexible batteries seem more responsive to the constraints of inpatient rehabilitation settings and are the preferred approach of most neuropsychologists, regardless of work setting.297
Modifying Tests for Special Populations
In rehabilitation settings, perhaps more than in any other, psychologists must be aware of factors that can produce “construct-irrelevant variance”252 in the assessment of persons with disabilities. These influences can cause spurious elevations or depressions in test scores and result in misleading inferences about the patient’s abilities and deficits. Given that most neuropsychological measures were developed for assessment of physically healthy people, the norms might not apply to those with certain disabilities. Scores on most neuropsychological tests can also be skewed by such influences as pain, fatigue, visual difficulties, and motor impairments, problems that are quite common among rehabilitation populations. These effects should be eliminated, or at least minimized, so as not to obscure assessment of the neuropsychological phenomena of interest.
A related sort of distortion can occur with instruments intended to assess personality or emotional status, because phenomena that constitute “symptoms” for nondisabled individuals might not carry the same (or any) psychologically relevant diagnostic meaning for those having disabilities. For example, the Minnesota Multiphasic Personality Inventory–2 (MMPI-2) contains items dealing with bowel function, sensory changes, and other physical phenomena that are typical consequences of SCI. Persons with SCI (or TBI, stroke, or multiple sclerosis, among others) who answer these questions honestly can produce profiles suggesting psychological pathology where there is none.140,253,359 Related measures such as the Symptom Checklist-90-Revised (SCL-90-R) are subject to similar skewing.401
Although standardized testing is the foundation on which contemporary psychological assessment is built, there is considerable support in statements of professional organizations, test publishers, and experienced clinicians for “reasonable accommodations” in testing persons with disabilities.65 The elderly, who are a rapidly expanding segment of the population, can also require special adaptations in assessment.66 For example, the most recent edition of the Wechsler Adult Intelligence Scale (WAIS-N)390 addresses these issues in a section on “suitability and fairness.” The “fairness” issue in particular is a long overdue concept in psychology.128,144 While devoting most attention to modifications for persons with hearing impairment, the WAIS-IV manual warns evaluators against “attribut(ing) low performance on a cognitive test to low intellectual ability when, in fact, it may be related to physical, language, or sensory difficulties.”390 Alterations or accommodations in the testing procedures should be recorded and taken into account in interpreting the test data. While it is recognized that “some modifications invalidate the use of norms, such testing of limits often provides very valuable qualitative and quantitative information.”390
What else can the psychologist do in such situations to ensure fair, accurate, and informative assessment? One method involves “pruning” of those items on measures designed to assess personality or emotional state that are perceived to be irrelevant to the constructs being assessed. Gass141 identified 14 potentially confounding items that, once the presence of brain injury has been established, can be removed and the protocol rescored to yield a “purified” profile. Gass140 also identified 21 “stroke symptoms” that can be handled in the same manner. Woessner and Caplan401,402 used expert consensus to determine that 14 and 19 items, respectively, from the SCL-90-R concerned phenomena that were part of the “natural history” of TBI or stroke. They argued that scores indicating pathology in physically healthy people could hold very different diagnostic significance for persons with acute or chronic medical conditions. Failure to attend to possible scale distortions could lead to misinterpretation, erroneous diagnosis, and subsequent misguided treatment.
Some authors49,106 have argued against this method, maintaining that important information might be lost if items are deleted from standard measures, or that the psychometric properties of the instrument could be significantly altered. These authors based their position on studies of individuals in litigation, however, where validity is a pervasive concern. Stein et al.351 offer a nuanced discussion of the pros and cons of retaining or eliminating “somatic items” in assessment of stroke survivors, pointing out that while these might represent a clinical problem, their mere presence offers no clue to etiology and, therefore, to treatment. The rehabilitation psychologist must analyze these symptoms in light of all available information to determine whether a psychologically treatable problem exists.
In the case of neuropsychological measures, greater ingenuity (and caution) is required to ensure that valid information is obtained from test administration. Although one naturally wants to know the impact of the disabling condition on the individual’s functioning, one does not want to consume time and energy simply to confirm the obvious. It is poor practice to administer a 60-item test of visual processing only to discover that the patient saw only part of the stimulus display because of a neurologically based deficit in attention to and awareness of one side of space (unilateral neglect). Possible strategies range from simply allowing extra time for those with psychomotor slowing or impaired manual dexterity, to actually modifying test materials themselves. Berninger et al.28 adapted certain subtests of the Wechsler Adult Intelligence Scale–Revised for use with persons with speech or motor disabilities. They created multiple-choice alternatives for verbal measures (allowing participants to point to their chosen answer), enlarged visual stimuli, and used materials adapted with Velcro to reduce the impact of motor impairment when manual manipulation is required. Caplan60 created a “midline” version of the Raven Coloured Progressive Matrices, a multiple-choice, “fill-in-the-blank” test of visual analysis and reasoning. Response alternatives are arrayed in a single column instead of rows, eliminating the lateral scanning component that limits the performance of patients with unilateral neglect. Patients with neglect performed significantly better on “midline” items than the standard ones, while those without neglect performed equally well on both types of item.
Not all authors support this approach. Lee et al.214 cautioned that even minor deviations from standard procedures can produce “significant alterations” in performance. We view this as part of the challenge in practicing what is still the “art” of assessment, an endeavor with a substantial scientific base but one that does not mandate robotic behavior on the part of the examiner.
Test Interpretation
Population normative data provide a benchmark for the average level of ability on a certain task for a given population. Some data sets include corrections for factors that can affect test performance, such as gender, age, and education.166,220 The Heaton et al.166 database designates particular T-score ranges as “above average” (T = 55+), “average” (T = 45 to 54), or “below average” (T = 40 to 44), and these encompass roughly 85% of all scores. “Impaired” scores of increasing severity (e.g., “mild” or “moderate to severe”) are associated with progressively lower T-score ranges of 5 points, with the exception of “severe impairment” (T = 0 to 19). Increasing attention is also being paid to the influence of cultural factors,124,126 although the development of truly “culture-free” or “culture-fair” neuropsychological assessment tools is in its infancy. Although understanding an individual’s functioning compared with population norms can be a helpful starting point, it is also necessary to determine whether a decline from the “average level” reflects a loss of functioning for a particular individual. This requires a consideration of a patient’s likely premorbid abilities.
In the absence of premorbid neuropsychological data (i.e., from testing before insult), estimates of premorbid functioning allow for intraindividual comparisons by identifying a probable baseline against which current test scores can be compared. Techniques for inferring premorbid abilities include the following:
An understudied problem is the variability with which certain terms are used in describing test performance. While adherence to a system such as that of Heaton et al.166 described above ensures consistency in the use of “impairment descriptors,” the process of drawing intraindividual comparisons by using premorbid estimates can lead to meaningful differences across clinicians in the application of such terms as “moderately impaired,” “within expectation,” or “within normal limits.” One can argue that mixing within a single report of “normative descriptors” (e.g., “high average,” “borderline”), “impairment descriptors” (e.g., “mildly impaired,” “defective”), and “expectation descriptors” (e.g., “within expectation,” “below expectation”) is both semantically inconsistent and conceptually confusing.61,159 A “high average” score for an exceptionally well-educated individual might still reflect “mild impairment,” while a “borderline” score could still be “within expectation” for one with far less schooling. Clear communication between the rehabilitation psychologist and the consumers of neuropsychological assessments (e.g., patient, family members, physiatrists, and other health care providers) is required to ensure that test findings are explained in a manner that clarifies the conclusions regarding an individual patient’s relative strengths and deficits.
Factors Affecting Validity
Interpretation of serial neuropsychological assessments, conducted to monitor functioning over time or determine the efficacy of interventions, can be clouded by practice effects—that is, improvements in test scores resulting from familiarity with the test (or even with the process of testing) rather than real gains in cognitive functioning. Research has indicated that some tests are more susceptible to practice effects, such as those evaluating memory.242 Rehabilitation psychologists take several steps to minimize the impact of practice effects. First, comprehensive retesting evaluations are generally scheduled at sufficiently lengthy intervals (e.g., at least 6 months) to reduce the likelihood that patients can remember the test content. Alternative test forms with different test stimuli can also be used. This is especially important when the retest interval is brief. For example, comparable sets of words can be used for list-learning tasks (e.g., Hopkins Verbal Learning Test–Revised).44 There is also growing documentation of the utility of statistical corrections, such as the Reliable Change Index181 and regression-based models360 to determine whether genuine and clinically relevant change has occurred on repeat testing.167
Although the importance of assessment of patient effort has been recognized for some time,282 there has been an avalanche of reports on “symptom validity” testing during the past decade, in large part because of the increased use of neuropsychological findings in forensic settings.37,212 Although poor patient effort has been estimated to occur in 15% to 30% of forensic evaluations, the likely frequency in clinical settings remains relatively low at 8%.260,313 Current standards of practice propose that assessment of symptom validity is a necessary part of all evaluations, although the procedures can vary in different settings.51 Several aspects of patients’ presentations can be examined for indications of poor or variable effort, including variability of performances across tests measuring similar abilities, and consistency between presenting medical factors (e.g., lesion locus) and test performance. One can ask whether the data exhibit “neuropsychological coherence.” Indices of effort are embedded in some tests that are often standard components of neuropsychological evaluations.254 Measures that rely on normative comparisons or use a forced choice paradigm have also been specifically developed as tests of “motivational impairment.”29,37,212
