Special Article Neurology 1996;47:592599

Assessment: Neuropsychological Testing of Adults.

Considerations for neurologists

Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology

This report considers the use of neuropsychological assessment of adults for neurologists, including the appropriate application and limitations of neuropsychological testing, specific disorders where evaluation is pertinent, and issues surrounding neuropsychological consultation to neurologists. The report excludes neuropsychological testing in developmental disorders. The report was assembled from a review of the pertinent literature, opinions, and information from experts in the fields of Neurology and Neuropsychology and input from the Academy at large.

Diseases of the brain commonly produce changes in behavior, including impairment of cognitive abilities and production of neuropsychiatric symptoms. Knowledge of the presence and characteristics of these behavioral changes can aid in the diagnosis, management, and longitudinal care of patients with neurologic disease. Neuropsychological evaluation is one means of garnering quantitative information about behavioral changes in patients with known neurologic diseases or who are considered to be at risk for brain dysfunction.

Technical issues in neuropsychologic assessment.

 Neuropsychological. evaluation can characterize cognitive and behavioral disturbances and may be helpful to the clinician in the course of diagnostic assessment, rehabilitation planning, or development of a management plan. Like other tests, neuropsychological assessments are of limited usefulness by themselves and must be interpreted in conjunction with other clinical, imaging, and laboratory information. Neuropsychological evaluations have the advantage of being objective, safe, portable, and relevant to the functional integrity of the brain.

Results of neuropsychological assessment must be considered in the context of the patient's age, education, socioeconomic status, and cultural background. These factors can affect test performance and condition the conclusions that can be inferred from the evaluation. In addition, issues involved in test contruction such as the reliability, validity, and sensitivity of the assessment procedures have an impact on the conclusions that can be drawn from neuropsychological evaluations.

Neuropsychologic tests and neurologic function.

Many widely used psychological tests were constructed before the emergence of much of the currently available information relating altered behavior to brain dysfunction. Commonly used instruments such as the Wechsler Adult Intelligence Scale (WAIS and its revised form WAIS-R)and the Wechsler Memory Scale (WMS and its revised form WMS-3) were constructed without the specific intention of using them as instruments to assess brain function and detect brain disorders, but extensive experience with these instruments provides a basis for interpreting the tests in neurologic terms. The Halstead-Reitan Battery was developed specifically to detect "organic" dysfunction and differentiate between patients with and without brain damage (e.g., to distinguish "organic" from "functional" disorders). Differential diagnosis of neurologic disorders or precise delineation of the underlying neuronal systems affected was not intended. Newer tests designed in concert with evolving information regarding the mediation of behavior by specific structures or circuits provide greater insight into the integrity or disintegration of neurologic function. Most current neuropsychological assessment approaches use several of the traditional tests in combination with newer techniques developed specifically to evaluate neurocognitive activities and provide insight into brain function in different disease states.

Clinicians must be cognizant of the fact that there is great variability in the training of individuals providing neuropsychological consultation. Those with training, experience, and demonstrated competence are best qualified. For example, individuals can be certified by the American Board of Clinical Neuropsychology or the American Board of Professional Neuropsychology, hold a doctoral degree in Psychology from an accredited institution, complete postdoctoral training in a neuropsychology training program, or hold a professional license.

Direct experience with whether the assessments are useful and well informed provide the basis for judging the individual's competence and usefulness as a consultant. Administration of test batteries that are too long or too short to answer the specified questions, failure to recognize the limitations of neuropsychological tests (especially with regard to localization and diagnosis), administration of inappropriate tests or tests without proper standardization, and preparation of unhelpful reports are indications of inadequate preparation. In addition, in some cases, neuropsychological tests are administered by a technician for later interpretation by a neuropsychologist. Technicians may be less likely to identify spurious data or to modify their procedures to optimize information collection, and this may lead to interpretive errors.

Executive Summary. Most current neuropsychological tests have established validity and reliability, and the information garnered from them can be regarded with confidence when the tests are administered using the prescribed method and interpreted by an individual with competence and experience. Neuropsychological evaluation is usually able to distinguish between normal and abnormal but cannot determine the cause of neurologic diseases. Neuropsychological testing is critical in patients undergoing epilepsy surgery and can be useful in management planning in patients with suspected dementia, MS, Parkinson's disease, TBI, stroke, and HIV encephalopathy. Neuropsychological referrals should be specific and guided by preliminary mental status assessment by the clinician. Neuropsychological consultation should focus on the referring question and should not provide specific medical recommendations.

Rating. Established. Neuropsychological assessment is accepted as appropriate by the practicing medical community for the indications and under the conditions described here. There is class II evidence for these specific conditions, and a type A recommendation is made with the restrictions noted above.