Reliability and validity of the Japanese version of the Agitated Behaviour in Dementia Scale in Alzheimer's disease: three dimensions of agitated behaviour in dementia

Background: Agitation in dementia seriously affects not only patients’ quality of life (QOL), but also caregivers’ QOL. Thus, an appropriate assessment of agitated behaviour in dementia is needed for clinical management. We developed the Japanese version of the Agitated Behaviour in Dementia scale (ABID), examined its reliability and validity, and carried out its factor analysis to elucidate its factor structure. Methods: The Japanese version of the ABID was given caregivers of 149 Japanese patients with Alzheimer’s disease (AD). The internal-consistency, test–retest reliability and concurrent validity of the Japanese version of the ABID were then examined. A factor analysis was used to examine the agitated behavioural dimensions underlying ABID. Results: The Japanese version of the ABID showed an excellent internal reliability for both frequency ratings (Cronbach’s a= 0.89) and reaction ratings (Cronbach’s a= 0.92), and an excellent test–retest reliability for both frequency ratings and reaction ratings. The total score for the frequency ratings of the ABID was significantly associated with the Cohen-Mansfield Agitation Inventory (CMAI), and the total score for the reaction ratings of the ABID was significantly associated with the Zarit Burden Interview. The factor analysis showed three subtypes: physically agitated behaviour, verbally agitated behaviour and psychosis symptoms. Conclusions: The Japanese version of the ABID promises to be useful for assessing agitated behaviour in patients with AD. Importantly, understanding these subtypes of agitated behaviour might have implications for individualized treatment plans.