Validation of the Bulgarian version of scales for outcomes in Parkinson’s disease – autonomic (SCOPA-AUT-BG)
ABSTRACT The last twenty years have witnessed a surge of interest in the autonomic symptoms in Parkinson’s disease (PD) and the possibilities to diagnose and treat them. The specialized questionnaire assessing the autonomic symptoms in Parkinson’s disease (SCOPA-AUT) has been validated and available in English, Dutch and Spanish. In this study we aim at evaluating the validity, reliability and applicability of the Bulgarian version of SCOPAAUT (SCOPA-AUT-BG ). PATIENTS AND METHODS: The study included 55 patients with idiopathic PD (mean age 64.4 ± 8.9 yrs), and 40 healthy controls (mean age 58.5 ± 9.4 yrs). Clinical severity and disease stage were assessed by United Parkinson’s disease rating scale (UPRDS) and Hoen and Yahr (H&Y). Thirty-two of the PD patients completed SCOPA-AUT-BG again after a 7-day interval. Questionnaire reliability was analyzed by determining the internal consistency, homogeneity, discriminatory and construct validity and test-retest reliability. RESULTS: Analyses showed good internal consistency of the summary evaluation of SCOPAAUT- BG (coefficient alpha of Cronbach = 0.79), which indicates the high reliability of the questionnaire. The lowest Cronbach’s alpha coefficient (0.53) was found for the subscale “cardiovascular functions”. A dominant role belongs to the subscales for gastrointestinal and urinary functions (Cronbach’s Alpha > 0.7), where a significantly high correlation of PD with the UPDRS scale was observed. We found high test-retest reliability based on the responses associated with dysfunction of the gastrointestinal, urinary, thermoregulatory and pupillary autonomic systems. The correlation of the results of SCOPA-AUT-BG with UPDRS is higher than that with H&Y, and the construct validity is high except for the cardiovascular and pupillomotor functions subscales. CONCLUSION: The results of this study show that SCOPA-AUT-BG is a valid and reliable specialized questionnaire to evaluate autonomic function in patients with Parkinson’s disease. Using it allows for more detailed clinical evaluation of these patients and justifies the need to refer them to specialized examination of autonomic functions.