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 (SF-DEM) 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: 285/299 (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<0.001) and activities of daily living (ADLs) (r=-0.48, p<0.001); communicating with other people correlating with ADLs (r=-0.66, p<0.001); and sensitivity to other people correlating with quality of life (r=0.35, p<0.001) and inversely with neuropsychiatric symptoms (r=-0.45, p<0.001). The three factors’ correlations with other domains were similar across all dementia severities.

Discussion: The SF-DEM carer version measures three social functioning domains and has satisfactory psychometric properties in all severities of dementia.