Neuropsychological prediction of dementia and the absence of dementia in healthy elderly persons

Identification of elderly individuals with low and high risk for future dementia has emerged as an important clinical and public health issue. To address this issue, we assessed neuropsychological performance in 317 initially nondemented elderly persons between 75 and 85 years of age and followed them for at least 4 years as part of the Bronx Aging Study. Four measures of cognitive function from the baseline assessment (delayed recall from the Buschke Selective Reminding Test, recall from the Fuld Object Memory Evaluation, the Digit Symbol subtest from the Wechsler Adult Intelligence Scale, and a verbal fluency score) can identify one subgroup with an 85% probability of developing dementia over 4 years and another with a 95% probability of remaining free of dementia. The model achieved an overall positive predictive value of 68%, or three times the base rate, for prediction of the development of dementia in our sample. The overall negative predictive value for prediction of absence of dementia was 88%. Baseline measures of cognitive function, often performed many years before the actual diagnosis of dementia, can provide important information about dementia risk. The group likely to develop dementia becomes a target for preventive or early therapeutic interventions, and the group unlikely to develop dementia can be reassured.