How to assess the merits of psychological and neuropsychological test evaluations

Psychological and neuropsychologi­cal test evaluations, like all consulta­tive diagnostic services, can vary in quality and clinical utility. Many of these examinations provide valuable insights and helpful recommendations; regretta­bly, some assessments are only marginally beneficial and can contribute to diagnostic confusion and uncertainty.

When weighing the pros and cons of evaluations, consider these best practices.

Gold-standard tests ought to be in-cluded in the assessment. These include (but are not limited to) the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV); Wechsler Memory Scale-Fourth Edition (WMS-IV); Delis-Kaplan Executive Function System (D-KEFS); Wechsler Individual Achievement Test-Third Edition (WIAT-III); and the Minnesota Multiphasic Personality Inventory-2 (MMPI-2). These tests have a strong evidence base that:
• demonstrates good reliability (ie, pro­duce consistent and accurate scores across examiners and time intervals and are rela­tively free of measurement error)
• demonstrates good validity (ie, have been shown to measure aspects of psycho­logical and neuropsychological functioning that they claim to measure).

Many gold-standard tests are normed on national samples and are stratified by age, sex, ethnicity or race, educational level, and geographic region. They also include normative data based on the performance of patients who have neuropsychiatric syndromes often seen by psychiatrists in practice.¹

The test battery ought to comprise cognitive and neuropsychological mea­sures as well as affective and behav­ioral measures. When feasible, these tests should be supplemented by informant-based measures of neuropsychiatric functioning to obtain a comprehensive assessment of the patient’s capacities and skills.

An estimated premorbid baseline should be established. This is done by taking a relevant history and adminis­tering tests, such as the National Adult Reading Test (NART), that can be used to compare against current test perfor­mance. This testing-in-context approach helps differentiate long-term limitations in information processing, which might be attributed to a DSM-5 intellectual dis­ability, specific learning disorder, or other neurodevelopmental disorder, from a known or suspected recent neurobehav­ioral change.

Tests in the assessment should tap a broad set of neurobehavioral functions. Doing so ensures that, when a patient is referred with a change in cognition or other aspects of mental status, it will be easier to determine whether clinically significant score discrepancies exist across different ability and skill domains. Such dissocia­tions in performance can have important implications for the differential diagnosis and everyday functioning.

Tests that are sensitive to a patient’s over-reporting of symptoms should be used as part of the evaluation in cases of suspected malingering—especially subtle simulation that might elude identifica­tion with brief screening-level measures.² These tests can include the Test of Memory Malingering (TOMM) and the Structured Interview of Reported Symptoms, 2nd edition (SIRS-2).

Test recommendations ought to be grounded in findings; practical; and relatively easy to implement. They also should be consistent with the treatment set­ting and the patient’s lifestyle, values, and treatment preferences.³

Disclosure
Dr. Pollak reports no financial relationships with any company whose products are mentioned in this article or with manufacturers of competing products.