Adaptation of the Caregiver Version of the Starkstein Apathy Scale (SAS) into Turkish and Investigation of Its Reliability and Validity in Parkinson's Disease.

OBJECTIVE

Our study aimed to adapt the caregiver version of the Starkstein Apathy Scale (SAS) to Turkish culture and examine its validity and reliability.

METHOD: 45 patients were diagnosed with Parkinson's Disease (PD), and 40 healthy individuals and their relatives participated in the study. The questions were changed from first-person to third-person statements without any changes. Confirmatory factor analysis was performed for construct validity in the validity analysis. Discriminant validity was performed with a healthy control group. The relationship with the Neuropsychiatric Inventory (NPI) apathy subtest was examined for criterion-dependent validity analysis. In the reliability analysis of the scale, Cronbach's alpha internal consistency analysis was performed. A Receiver Operating Characteristic (ROC) analysis was conducted to determine the cut-off value of the scale.

RESULTS

During the validity and reliability studies, it was observed that items 3 and 13 were incompatible with other factors, reduced the model fit, and were removed from the scale due to low internal consistency. In the analysis with 12 items, a three-factor structure was obtained as 'motivation', 'behavioral', and 'cognitive'. In confirmatory factor analysis, the fit values of the scale were Comparative Fit Index (CFI) =1.000, Normed Fit Index (NFI) = 0.963, and Root Mean Square Error Approximation (RMSEA)= 0.000. Consequently, the study, the Cronbach's alpha coefficient of the scale was found to be 0.84. The discriminant validity analysis found a difference between the clinical and control groups. A positive correlation was found with the NPI Apathy subscale used for criterion-dependent validity. A cut-off value of 11 points with a sensitivity of 71.15% and specificity of 95% was recommended for 12 items.

CONCLUSION

Our study showed that the SAS Caregiver is a valid and reliable scale for PD patients and can be utilized in clinical and scientific studies.