Assessing health-related quality of life with the SCOPA-PS in French individuals with Parkinson's disease having undergone DBS-STN: A validation study.

Abstract Introduction The aims of this study were to validate the French version of the SCales for Outcomes in Parkinson's Disease-PsychoSocial (SCOPA-PS) in individuals with Parkinson's disease (PD) who underwent deep brain stimulation of the subthalamic nucleus (DBS-STN), to confirm the unifactorial structure of this questionnaire, and to establish its psychometric properties. Methods Routinely used psychological questionnaires (BDI-II, STAI-Y, PDQ-39, UPDRS III) and the SCOPA-PS were used for a cross-sectional observational study of 154 PD patients. SCOPA-PS acceptability, scaling assumption, reliability, ordinal confirmatory factor analysis and validity were assessed. Results The ICC for two-week test-retest reliability was 0.88. SEM was 8.42. In confirmatory factor analysis, the one-factor model showed an acceptable fit to the data (Chi 2 /df = 2.130; CFI = 0.976; RMSEA = 0.086). No floor or ceiling effects were observed. Skewness was 0.33. Item-total correlation coefficients ranged from 0.47 to 0.71. Cronbach's alpha was 0.86. SCOPA-PS SI correlated with PDQ-39 SI ( r s  = 0.83) and with state-anxiety and depression ( r s  = 0.56 and 0.69 respectively). The SCOPA-PS SI was higher in more depressed patients and in those with the most severe PD motor symptoms. Conclusion and discussion SCOPA-PS French version is a one-factor scale with satisfactory psychometric properties consistent with other language versions. This short scale can be used to evaluate the psychosocial component of QoL in PD patients treated with DBS-STN.