Dementia of the Alzheimer type will be defined by a gradual onset with a continuing cognitive decline not due to other central nervous system conditions that cause progressive deficits in memory. The cognitive decline must include a memory impairment but must also be accompanied by at least one other cognitive disturbance such as aphasia, apraxia, agnosia, or a disturbance in executive functioning. The deficits must cause significant impairments in social or occupational performance and represent a decline in function.