Functional decline in the early stages of Alzheimer's disease.

At present most reports of functional decline in patients with Alzheimer's Disease (AD) are anecdotal, and few studies have objectively documented the course of the disease. This is a report of a 2-year follow-up of 15 AD patients characterized by mild functional impairment, and 22 age-, sex-, and education-matched control subjects. In a previous cross-sectional study of these 37 subjects and 16 AD patients with moderate functional impairment, we found that measures of memory and attention deficits accounted for much of the impairment observed in functional competence. The current longitudinal study found that these same initial assessments could be used to predict functional decline in the 15 mildly impaired patients. These patients were observed to decline to levels similar to those of the 16 moderate patients. In contrast, the control subjects exhibited little decline during the same period. These results both affirm that it is possible to diagnose AD in its mild form and demonstrate the validity of the initial diagnosis.