THE STAGES OF ALZHEIMERS-DISEASE - A REAPPRAISAL

'Stages', as used in clinical practice and research, are defined, thei r value described, and criteria are proposed for their evaluation. The specific interest is in staging Alzheimer's disease (AD). Two staging systems, one based on the Global Deterioration Scale (GDS) and one ba sed on the Mini-Mental State Exam (MMSE), are compared in terms of the se criteria, as an illustration of the process involved. We propose th at there is not one unique staging system, that different staging crit eria might be appropriate to different research or clinical needs, dep ending on which part of the temporal course of the disease is of prima ry interest, and on whether the focus is on cognitive, functional, neu rological, behavioral, economic, or other issues. GDS staging seems a better choice for the later stages of AD when the focus is on function al change. MMSE staging seems a better choice for tracking the earlier stages of AD when the focus is on cognitive change.