Long-term cognitive and functional decline in late onset Alzheimer's disease: therapeutic implications.

BACKGROUND: National Institute of Clinical Excellence guidelines advocate the use of the Mini-Mental Test Examination and a functional assessment as a means of measuring treatment response. However, there is little knowledge of the change expected in those with Alzheimer's disease in clinical practice. OBJECTIVE: to describe the long-term variability of the Mini-Mental Test Examination and Blessed Dementia Rating Scale. METHOD: 374 Alzheimer's disease patients referred to psychiatric services in southeast London were followed annually over a 3-year period. RESULTS: the mean Mini-Mental Test Examination score for the total group at baseline was 9.9 points. Individual variability in the rate of cognitive and functional decline is large and around 40% of patients after 1 year, and up to one-quarter of patients after 3 years who survived, show no change or an improvement in scores compared with baseline measures. CONCLUSIONS: in the evaluation of individual treatment response the rate of change, as measured by the Mini-Mental Test Examination and Blessed Dementia Rating Scale, is of limited value.