Objective: Our study aimed to adapt the caregiver version of theStarkstein Apathy Scale (SAS) to Turkish culture and examine its validityand reliability.
Method: 45 patients were diagnosed with Parkinson’s Disease (PD), and40 healthy individuals and their relatives participated in the study. Thequestions were changed from first-person to third-person statementswithout any changes. Confirmatory factor analysis was performedfor construct validity in the validity analysis. Discriminant validity wasperformed with a healthy control group. The relationship with theNeuropsychiatric Inventory (NPI) apathy subtest was examined forcriterion-dependent validity analysis. In the reliability analysis of thescale, Cronbach’s alpha internal consistency analysis was performed.A Receiver Operating Characteristic (ROC) analysis was conducted todetermine the cut-off value of the scale.
Results: During the validity and reliability studies, it was observed thatitems 3 and 13 were incompatible with other factors, reduced the modelfit, and were removed from the scale due to low internal consistency.In the analysis with 12 items, a three-factor structure was obtainedas ‘motivation’, ‘behavioral’, and ‘cognitive’. In confirmatory factoranalysis, the fit values of the scale were Comparative Fit Index (CFI)=1.000, Normed Fit Index (NFI) = 0.963, and Root Mean Square ErrorApproximation (RMSEA)= 0.000. Consequently, the study, the Cronbach’salpha coefficient of the scale was found to be 0.84. The discriminantvalidity analysis found a difference between the clinical and controlgroups. A positive correlation was found with the NPI Apathy subscaleused for criterion-dependent validity. A cut-off value of 11 points witha sensitivity of 71.15% and specificity of 95% was recommended for 12items.
Conclusion: Our study showed that the SAS Caregiver is a valid andreliable scale for PD patients and can be utilized in clinical and scientificstudies.
Keywords: Apathy, Parkinson disease, reliability, validity