The multiple validities of neuropsychological assessment.

This article discusses construct and criterion validity of neuropsychological tests, as well as assessment validity, which allows determination of whether an individual examinee is producing valid test results. Factor analyses identify 6 domains of abilities. Tests of learning and memory and processing speed are most sensitive to presence of brain dysfunction in both traumatic brain injury (TBI) and Alzheimer's disease (AD). Tests of processing speed, working memory, verbal symbolic functions, and visuoperceptual and visuospatial judgment and problem solving are sensitive to the severity of TBI and AD, as well as to the functional consequences of these disorders, including ability to work, financial and medical decision-making capacities, and driving ability. Unilateral hemisphere stroke allows study of impairment in sensorimotor skills and lateralized neuropsychological abilities, as well as the moderating effects of aphasia and neglect on test performance. Assessment validity is determined by performance validity tests, measuring whether an examinee is providing an accurate measure of their actual level of ability, and symptom validity tests, measuring whether an examinee is providing an accurate report of their actual symptom experience. A core neuropsychological battery is described that includes tests with established construct and criterion validity, and assessment validity, for comprehensive evidence-based evaluation.