Internal Consistency, Construct Validity and Incremental Explanatory Power of the Action Observation Sheet-B (AOS-B) for Dementia Caregiver Burden and Clinical Severity.

BACKGROUND

Although the behavioral Action Observation Sheet-B (AOS-B) addresses the clinical limitations, patient anxiety and caregiver biases of traditional dementia assessments, evidence regarding its incremental explanatory power remains insufficient. Using real-world clinical data, this study evaluated the 47-item AOS-B's internal consistency, validity and independent contribution to explaining caregiver burden.

METHODS

We retrospectively analysed data from 107 patients with different dementia subtypes. Internal consistency was assessed using Cronbach's α. Validity was examined using Pearson's correlations between scores on the AOS-B and established scales (the Mini-Mental State Examination-Japanese, Hasegawa Dementia Rating Scale-Revised, Clinical Dementia Rating and the 8-item Zarit Caregiver Burden Interview-Japanese version). Hierarchical multiple regression was used to evaluate the AOS-B's independent association with caregiver burden beyond cognitive scores; receiver operating characteristic analysis was used to determine the optimal AOS-B cutoff for identifying high-risk caregiver burden (Zarit Caregiver Burden Interview score ≥ 13).

RESULTS

The AOS-B showed excellent internal consistency (α = 0.904). While global cognitive function (Mini-Mental State Examination-Japanese) was associated with caregiver burden, hierarchical regression analysis indicated that adding AOS-B scores significantly increased the model's explanatory power (ΔR2 = 0.208, p < 0.001). Receiver operating characteristic analysis yielded an area under the curve of 0.750 and 65.0 as a potential cutoff (sensitivity: 77.8%, specificity: 67.6%) for identifying high-risk caregiver burden. AOS-B scores did not differ significantly among dementia subtypes, though statistical power was limited by the subgroup sizes.

CONCLUSIONS

The AOS-B demonstrated high internal consistency and construct validity as a non-invasive tool that complements standardised cognitive tests by capturing practical caregiving challenges. Using the 65.0-point threshold with existing caregiver burden scales may help clinicians better identify specific intervention targets and optimise resource allocation in routine practice.