Psychometric features of the Online Action Control Scale (ACS) in Iranian individuals with Parkinson’s disease: Predictors of Action-State Orientation (ASO)

Background and Objectives: Action control, a critical construct for regulating emotions and goal-directed behavior, is often impaired in Parkinson’s disease (PD) patients, contributing to adherence issues and psychological difficulties. To address this, the present study examined the psychometric properties of the Persian Action Control Scale (ACS) and identified predictors of ASO among Iranian patients with idiopathic PD through an online survey. Design and methods: This cross-sectional study included 130 individuals with idiopathic PD (mean age±SD: 65.32±10.06). The test-retest reliability was evaluated in 80 patients. Acceptability, internal consistency, construct validity, criterion validity, and test-retest reliability were examined for the online ACS, which was adapted for PD individual into a shorter version called the ACS-PD- Short form (ACS-PD-S). The validity metric of cut-off values was assessed using receiver operating characteristic curve analysis. Result: Exploratory factor analysis results demonstrate the ACS-PD-S was classified into three factors with 23.13%, 16.73% and 16.07% total explained variance. The ACS-PD-S exhibited acceptableskewness (range: 0.32 to 0.45), and internal consistency (Cronbach’s alpha = 0.70–0.77). The intraclass correlation coefficients for test-retest reliability met acceptable standards across all ACS-PD-S (range= 0.80 to 0.85). Furthermore, ACS-PD-S subscales demonstrated significant correlations with the Positive and Negative Affect Schedule (PANAS), Cognitive Interference Questionnaire (CIQ), Volitional Questionnaire (VQ), General Self Efficacy Scale(GSE), Short-form Self-Regulation Questionnaire (SSRQ-20), Self-Regulating Strategy Inventory-K3 (SSI-K3), (r= -0.42 to 0.41). This finding supported criterion validity for ACS-PD-S. Anxiety and depression were the strongest predictors for ACS-PD-S subscales scores. Acceptable diagnostic accuracy was obtained using ACS-PD-S to distinguish between action and state-oriented PD patients. Conclusion: The ACS-PD-S exhibited adequate psychometric properties for assessing ASO in Iranian PD patients.