Factor Analysis of the Brief Agitation Rating Scale in a Large Sample of Norwegian Nursing Home Patients

Abstract

Background: Agitation and aggression are prevalent in dementia and put heavy strains on caregivers. Validated assessment tools measuring these symptoms are required to evaluate patients before therapy and during the follow-up period. Given the daily routine in nursing homes, abbreviated instruments are preferable. The Brief Agitation Rating Scale (BARS) is a short form of the Cohen-Mansfield Agitation Inventory. Our aim was to examine the Norwegian version of the BARS by performing a factor analysis. Methods: The data came from 1,870 nursing home patients. The primary caregivers were interviewed by research nurses using the Clinical Dementia Rating Scale, Lawton’s Physical Self-Maintenance Scale and the BARS. Results: The exploratory factor analysis of the BARS revealed 3 dimensions: physically aggressive behavior, physically nonaggressive behavior and verbal agitation. Linear regression analysis showed that reduced functioning in activities of daily living was associated with physically aggressive behavior and verbal agitation, whereas increased severity of dementia and better functioning in activities of daily living were related to physically nonaggressive behavior. In addition, verbal agitation was positively related to a higher number of drugs being taken per day. Conclusions: The factor analyses confirmed that the Norwegian version of the BARS measures the clinically relevant dimensions of agitation in dementia.