Improving accuracy in the diagnosis of Alzheimer's disease

During a longitudinal study of outpatients with early Alzheimer's disease, several patients were found to have been incorrectly diagnosed as having a progressive dementia; case histories of three such patients are presented. Certain objective tests of dementia (The Extended Scale for Dementia, Mini-Mental Status, etc.) and language functions (The Porch Index of Communicative Ability), as well as The London Psychogeriatric Rating Scale (completed by a family member), have been found useful and are described briefly. The importance of reevaluating demented patients to document the course of their illness is emphasized to improve the accuracy of diagnosis in suspected cases of Alzheimer's disease.