Problems and conceptual issues in neuropsychological research in aging and dementia.

Neuropsychological investigation of old age and dementia faces all the problems associated with more general gerontological study. In addition, some specific difficulties in attempting to infer cerebral status from behavioral observation arise. These include uncertainty about the nature and course of normal aging, about the influence of disease and affective disturbance on performance, and about the significance of diverse interactive effects. Further, the concept of dementia requires clarification. These issues are addressed and their clinical implications discussed.