The Social Functioning Scale for Alzheimer's Disease: A Short Informant-based Measure of Functional Status in Patients with Alzheimer's Disease in Taiwan.

Objective: Evaluating social-functioning impairments in patients with Alzheimer's disease (AD) objectively is essential for clinical service. However, the existing instruments lack representative content, consensus on purposes of use, and adequate scoring systems and samples. This study was thus to develop a social functioning scale for patients: the Social Functioning Scale for Alzheimer's Disease (SFSAD).

Method: Questionnaires were analyzed from 142 AD patients, 30 patients with amnestic mild cognitive impairment (aMCI), and 50 normal controls.

Results: Based on the literature review and experts' opinions, the final scale includes 20 items in four subscales. The SFSAD showed high internal consistency coefficients (Cronbach's α = .97) and test-retest reliability (r = .99) coefficients. The content validity was desirable, and the criterion-related validity was demonstrated by a significant association with the MMSE, the IADL, and the Barthel ADL. The discriminant validity of the scale was also demonstrated as the level of social-functioning impairment was significantly related to the degree of dementia, and for construct validity, our findings supported the structure of the four-factor hypothesized model.

Conclusions: The SFSAD is thus a practical, psychometrically sound, and easy-to-administer measure to evaluate social functioning of AD and aMCI in brisk clinical settings.