Development of an instrument to assess social functioning in dementia: The Social Functioning in Dementia scale (SF-DEM).

INTRODUCTION: Social functioning is a core domain in the life of people with dementia, but there is no accepted instrument to measure it. We aimed to develop the Social Functioning in Dementia (SF-DEM) scale and test its psychometric properties for assessing social function in people with dementia.

METHODS: We interviewed people with mild dementia and family caregivers to develop patient and caregiver-rated SF-DEM versions and refined them through interviews with health care professionals. We tested its psychometric properties in 30 dyads of people with dementia and family caregivers.

RESULTS: Both SF-DEM versions had content validity and demonstrated concurrent validity against a single item rating overall social functioning (patient rated r  = 0.42, 95% CI [0.07-0.68]; caregiver rated r  = 0.59, 95% CI [0.29-0.78]). All participants found it acceptable. Analyses showed reliability (test-retest, inter-rater, internal consistency) and indications of responsiveness to change.

DISCUSSION: SF-DEM shows promise as a valid, reliable, acceptable measure of social functioning in dementia.