Functional disability in Alzheimer's disease.

Functional impairment is a core symptom of Alzheimer's disease. The most accurate indicator of functional impairment is the decline in performance of Activities of Daily Living (ADL). Several scales have been used to measure ADL in geriatric and Alzheimer's disease (AD) populations including the Disability Assessment for Dementia (DAD). The key to making a correct differential diagnosis between benign cognitive impairment and dementia is the detection of a decline in functioning. The instrumental ADL (IADL) relevant items of the DAD could provide crucial guidance in the diagnosis of early stage AD for primary care physicians. It is anticipated that the role of primary care physicians, already essential for the management of the AD patient, will expand to include the diagnosis of earlier cases and the prescription of cholinergic drugs as treatment. ADL assessment tools such as the DAD may help their tasks.