At enrollment, each participant was evaluated for history of cerebrovascular disease, focal neurological abnormalities, and impairment of cognitive or behavioral functioning. Follow-up evaluations included a neuropsychological battery, neurological examination, medication review, and informant/subject structured interview. The latter was based on the Clinical Dementia Rating (CDR)22 scale after 1998 and the Dementia Questionnaire23 before 1998. All subjects were reviewed at a diagnostic consensus conference if their Blessed Information Memory Concentration score24 was 4 or above, if their informant or subject CDR score was 0.5 or above, or if their Dementia Questionnaire was abnormal. All neuropsychological diagnostic tests and clinical data were available for review at the diagnostic conference. Diagnosis of dementia was based on DSM-III-R criteria and diagnosis of AD was based on the National Institute of Neurological and Communication Disorders and Stroke-Alzheimer’s Disease and Related Disorders Association (NINCDS-ADRDA) criteria.25
