A comparison of the Cohen-Mansfield agitation inventory with the CERAD behavioral rating scale for dementia in community-dwelling persons with Alzheimer's disease

In a group of 242 community-dwelling patients with Alzheimer's disease (AD), a longitudinal comparison was made of two caregiver-administered instruments for assessment of behavioral disturbance; the Cohen-Mansfield Agitation Inventory (CMAI) and the CERAD Behavioral Rating Scale for Dementia (BRSD). We examined records of the 206 patients with baseline and 12-month follow-up data for the CMAI and the BRSD who also had tests of cognitive (Mini-mental State; MMSE) and global function (Clinical Dementia Rating; CDR and Functional Assessment Staging; FAST). Among 114 AD subjects, the correlation between total CMAI at baseline and 1 month readministration was 0.83 (p < 0.0001). In the same subjects, stratified into 5 groups by MMSE scores, the correlations between BRSD baseline and 1-month scores ranged from 0.70-0.89 (p < 0.0001). There was high correlation between total scores of both instruments at baseline and 12 months. In addition, all CMAI subscales except Verbally Aggressive correlated significantly with total BRSD score at both time points, At baseline, BRSD subscales for irritability/aggression, behavioral dysregulation and psychotic symptoms and at 12 months, irritability/aggression and behavioral dysregulation correlated with total CMAI scores. Neither scale changed significantly over 1 year, but there was wide individual variation. CMAI and BRSD scores correlated with 1-year change in the FAST, but not with MMSE or CDR (which weighs cognition heavily), suggesting that behavioral disturbance may be more strongly related to ability to manage activities or daily living (executive function) than to other aspects of cognition. The CMAI and BRSD appear to be interchangeable as measures of agitation, with the CMAI possibly more useful for patients who lack language and the BRSD more sensitive to apathy and depression.