CONSISTENCY OF CLINICAL-DIAGNOSIS IN A COMMUNITY-BASED LONGITUDINAL-STUDY OF DEMENTIA AND ALZHEIMERS-DISEASE

We evaluated the consistency of the diagnosis of dementia in a multicu ltural, longitudinal community-based study of cognitive impairment and dementia. We diagnosed dementia using a fixed neuropsychological para digm; the diagnosis also required historical evidence of functional im pairment, In a sample of 656 subjects with at least one annual follow- up examination, dementia was confirmed at 1 year in 89% of the 304 sub jects initially demented, and in 90% of the 136 subjects with the init ial diagnosis of probable Alzheimer's disease (AD). The 34 initially d emented subjects who failed to meet criteria for dementia at follow-up included 13 with an initial diagnosis of probable AD. All 34 still ha d evidence of cognitive impairment; this group was more likely to have a history of pulmonary disease, multiple medication use, or chronic a lcohol use than other demented patients. Consistency of dementia diagn osis did not vary according to educational attainment or ethnic backgr ound. The use of a neuropsychological paradigm such as ours in large l ongitudinal studies of dementia may minimize interobserver diagnostic variability or diagnostic drift over time while contributing the benef its of a comprehensive cognitive evaluation to the diagnostic process.