The social functioning in dementia scale (SF-DEM): Exploratory factor analysis and psychometric properties in mild, moderate, and severe dementia

INTRODUCTION: The psychometric properties of the social functioning in dementia scale over different dementia severities are unknown. METHODS: We interviewed 299 family carers of people with mild, moderate, or severe dementia from two UK research sites; examined acceptability (completion rates); conducted exploratory factor analysis; and tested each factor's internal consistency and construct validity. RESULTS: Of 299, 285 (95.3%) carers completed questionnaires. Factor analysis indicated three distinct factors with acceptable internal consistency: spending time with other people, correlating with overall social function (r = 0.56, P < .001) and activities of daily living (r = −0.48, P < .001); communicating with other people correlating with activities of daily living (r = −0.66, P < .001); and sensitivity to other people correlating with quality of life (r = 0.35, P < .001) and inversely with neuropsychiatric symptoms (r = −0.45, P < .001). The three factors' correlations with other domains were similar across all dementia severities. DISCUSSION: The social functioning in dementia scale carer version measures three social functioning domains and has satisfactory psychometric properties in all severities of dementia.