Validation of the Arabic version of Parkinson's Disease Sleep Scale-Revised Version (PDSS-2)

Objectives: Parkinson's disease sleep scale (PDSS) was recommended by the Movement Disorder Society task force for screening and grading the severity of sleep problems in Parkinson's disease (PD). This work aimed to examine the validity and reliability of an Arabic version of PDSS-2.

Methods: This cross-sectional study was carried out on 133 patients fulfilling diagnostic criteria for PD. The patients were clinically assessed using the following scales: Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), modified Hoehn and Yahr Scale (H&Y), non-motor symptoms scale (NMSS), Beck Depression Inventory (BDI), and Pittsburgh Sleep Quality Index (PSQI). PDSS-2 scale was translated according to approved translation standards into Arabic and back-translated into English. Patients were asked to respond based on their experience in the last week.

Results: The mean PDSS2 score for the included PD patients was 17±10. Cronbach's α coefficient value was 0.89, indicating good internal consistency. Most items showed high item-total correlation; the lowest was 0.375, considered higher than the conventional cut-off of 0.3. Test-retest reliability showed good agreement (ICC: 0.848). The exploratory factor analysis showed that items had been loaded over four factors. Total PDSS-2 score was positively correlated to age, disease duration, modified H&Y scale, MDS-UPDRS, NMSS, BDI, and global PSQI score. A cut-off point of 13 could differentiate poor sleepers from good sleepers with 91% sensitivity and 70% specificity (AUC 0.893, P<0.001).

Conclusion: The Arabic version of PDSS-2 has appropriate validity and can be reliably used for assessing sleep-related problems in Arabic-speaking patients with PD.