Validity and Reliability of SCOPA Sleep Scale Turkish Version in Parkinson's Disease

The aim of this study was to form the Turkish adaptation of the SCOPA-SleepScale to be used in evaluating sleep quality in individuals with Parkinson's disease and to test its psychometric properties.

Data for this methodological study was collected between May and December 2017 in the neurology outpatient clinic of a hospital through face to face interviews with patients with a diagnosis of Parkinson's disease. The sample of the study consisted of 105 patients of 18 years of age and above with no additional neurological diseases who volunteered for the study. The SCOPA Sleep Scale was translated into Turkish through translation and back translation, and expert views were taken to test content validity. The reliability analyses of the scale were performed using item- total score correlations, test-retest correlations, and internal consistency. Exploratory factor analyses were conducted for construct validity and the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) were applied for criterion validity. The appropriateness of data for factor analysis was examined using the Kaiser-Meyer-Olkin (KMO) and Bartlett's tests.

The factor loads of the SCOPA Sleep Scale varied between 0.743 and 0.901, and the Turkish version of the scale exhibited a two factor structure in compliance with the original scale. The Cronbach`s alpha coefficient was found 0.907 for the nighttime sleep sub-dimension and 0.906 for the daytime sleepiness sub-dimension. In the test-retest evaluation, a correlation of 0.948 was obtained in the nighttime sleep sub-dimension of the scale and a correlation of 0.956 was obtainedin the daytime sleepiness sub-dimension of the scale. The nighttime sleep sub-dimension of the scale showed a positive correlation with PSQI, while the daytime sleepiness sub-dimension showed a positive correlation with ESS.

The Turkish form of the SCOPA Sleep Scale is a valid and reliable tool to evaluate the sleep quality of individuals with Parkinson's disease.