Replicated evidence on the construct validity of the SCAG (Sandoz Clinical Assessment-Geriatric) scale

Factor analysis procedures, applied to a data bank of 1165 senile patients from 21 double-blind studies, yielded 5 factors: cognitive dysfunction (4 items), interpersonal relationships (4 items), apathy (4 items), affect (3 items) and somatic function (3 items). A retrospective review of the 1165 case histories revealed that patients fell into three distinct diagnostic classes: (a) patients whose symptoms of dementia were likely associated with multiple infarcts; (b) patients with other medical disorders such as metabolic imbalances, pulmonary diseases, etc. which may have induced dementia-like symptoms; and (c) primary degenerative dementia for patients with no evidence of other intervening causes. Factor analysis applied independently to the SCAG data of each of the three groups produced similar factor constructs, thereby suggesting that results reported with this instrument are valid across different geriatric diagnostic categories.