Methodological problems with diagnosis of dementia in community surveys: the choice of items to study higher functions.

The 'global' character of dementia distinguishes it from other organic syndromes but in community surveys memory impairment is the predominant early symptom and the aphasia, apraxia and agnosia triad characteristic of dementia of Alzheimer type disease (DAT) may be hard to demonstrate. Both the Mini-Mental State (MMS) and CAMDEX contain appropriate items but information about how elderly persons in general perform on these tests is limited. This paper examines the relative difficulty of the items in a general practice sample and compares their sensitivity and specificity taking AGECAT organic diagnosis as criterion.