Use of the Visual Analogue Parkinson’s Disease Sleep Scale in Nigeria.

Background. Sleep disturbances are common in persons with Parkinson’s disease (PD) but often go undetected by attending physicians. Due to its simplicity, the visual analogue PD Sleep Scale (PDSS) could be valuable in the detection and management of sleep disturbances in contexts such as Nigeria where text heavy self-report assessments are difficult to implement due to limited formal education. We aim to test the utility of the PDSS in identifying nocturnal sleep problems in Nigerians with PD. Methods. We evaluated a dataset comprising information collected as part of a two-centre prevalence and case control study of behavioural disturbances among persons with PD in southwestern Nigeria. Nocturnal sleep problems in PD were assessed using the PDSS. We also independently administered the Neuropsychiatric Inventory Questionnaire (NPI-Q). We examined indicators of construct validity by comparing the PDSS with the NPI-Q nighttime behavioural subscale, known group validity by comparing with Hoehn and Yahrs stages of PD, and discriminant validity by comparing PDSS scores in cases and controls. We generated Spearman correlation coefficients, Games-Howell post hoc adjustments in ANOVA, and step-down Bonferroni corrections for multiple comparisons. Results. Among 150 persons with PD and 150 matched neurologically healthy controls, PDSS scores were discriminated in 13 out of the 15 items (step-down Bonferroni corrected p<0.003). Ten items demonstrated statistical correlations with the NPI-Q (r=0.45 to 0.49 for overall sleep quality, sleep onset insomnia, sleep maintenance insomnia, and sleep related hallucinations). PDSS scores worsened as motor severity increased (Games-Howell post hoc adjusted p<0.05 for Early to Severe PD). Conclusion. The PDSS was useful in identifying a variety of nocturnal sleep problems in people living with PD. These results provide support for the utility of the tool in Nigeria and similar contexts where many patients have limited or no formal education.