Validation of the dimensional apathy scale and predictors of apathy in stroke survivors

The study aimed to: (i) translate and culturally adapt the DAS into Persian; (ii) examine the psychometric properties of both the DAS-S and DAS-I; (iii) analyze the three components of both the DAS-S and DAS-I to assess apathy dimensionally; (iv) determine the optimal cut-off points using ROC analysis for the DAS-S, DAS-I, and their subscales; and (v) identify predictors of initiation, emotional, and executive apathy in stroke survivors. This study included 115 stroke survivors and 38 healthy controls. Both DAS versions were evaluated for acceptability, reliability, and validity. Exploratory factor analysis was conducted to assess construct validity. Receiver Operating Characteristic curve analysis was used to determine optimal cut-off points. Multiple regression analyses were performed to identify predictors of apathy. Cronbach's alpha was 0.88 for DAS-S and 0.85 for DAS-I. ICC2,1 was > 0.93 for both versions. Total and subscale scores of both DAS versions showed weak to moderate correlations with the Neuropsychiatric Inventory-Apathy subscale (r = 0.39-0.69). Principal component analysis showed three components (executive, emotional, and initiation) for DAS-S and DAS-I, explaining 49.26% and 53.02% of the variance, respectively. The optimal cut-off was 31 for DAS-S (88.89% sensitivity, 86.36% specificity) and 29 for DAS-I (92.52% sensitivity, 86.36% specificity). Depression was the strongest predictor of executive subscale scores of both DAS versions, as well as the initiation subscale of the DAS-S, explaining 33.90-48.90% of the variance. However, for the emotional subscale of both DAS versions, the strongest predictor was the level of daily activity. The two versions of DAS effectively identify apathy subtypes and are reliable and valid for assessing apathy in stroke survivors. They effectively discriminate between apathetic and non-apathetic stroke survivors. Depression is the strongest predictor of executive and initiation apathy, whereas functional indicators-particularly independence in activities of daily living-predict emotional apathy.