Predictors of decline in Alzheimer's disease.

Age of onset and aphasia are frequently proposed as predictors of decline in Alzheimer's disease (AD). We compared longitudinally the neuropsychological test performance of AD patients classified as Fast Decliners (FD, N = 18) based on the rate of change of their scores on the Mini-Mental State Examination (MMS) and a group classified as Slow Decliners (SD, N = 15). There was no statistical difference in the age of onset of AD or in severity of dementia at first visit. Performance on verbal tests was the best predictor of rapid cognitive decline, even after the influence of the overall degree of dementia had been accounted for. Among the language tasks, performance on a naming test was the best predictor. The results of this study do not support age of onset as a predictor of the course of AD. On the other hand, poor performance on language tests does predict a more rapid rate of decline in AD.