Unidimensional Scale for Dementia

A cognitive test comprising 27 subscales was administered to 262 demented patients and 92 normal subjects. Principal factor analysis followed by varimax and Harris-Kaiser rotation and Guttman’s scalogram analysis was performed. The analysis yielded three factors, i.e. ‘recent memory’, ‘immediate memory or attention’ and ‘remote memory’. The relationships between the three-dimensional distribution of the scores and the DSM-IIIR grade of dementia indicated the existence of a continuum of dementia severity. Scalogram analysis showed unidimensionality in the difficulty level of the subscales as well as in the severity of the cases. Thus, the simple summary score can be used as a good measure of the severity of dementia.