Diagnosis of Alzheimer Disease

Diagnosis plays a critical role in the development of improved therapies. Diagnosis is a particularly important issue in therapeutic trials for disorders such as Alzheimer’s disease, which are defined primarily by clinical and pathological criteria rather than by laboratory tests. It is routine practice at the present time to establish strict inclusion and exclusion criteria for participation in a therapeutic trial before the study is begun. These criteria derive from the diagnostic formulations in use at the time the study is designed. Specific “diseases” such as Alzheimer’s disease are, from this viewpoint, convenient abstractions for describing groups of clinical phenomena and for focusing research on particular clinical problems. The choice of appropriate diagnostic inclusion and exclusion criteria for therapeutic trials in Alzheimer’s disease, as in other diseases, will continue to require judgement.