Validation of the sleep related items of the Non-motor Symptoms Questionnaire for Parkinson's disease (NMSQuest)

Abstract

Background The Non-motor Symptoms Questionnaire (NMSQuest) is a recently developed questionnaire for the evaluation of non-motor symptoms in Parkinson's disease (PD) patients, which includes sleep disorders evaluation. The clinical validity of the questionnaire has not been explored. Objective To assess the performance of the sleep/fatigue domain of the NMSQuest against other sleep measures. Methods Seventy PD patients were instructed to wear an actigraph and to fill in a sleep log over seven consecutive days in addition to the Parkinson's Disease Sleep Scale (PDSS) and the NMSQuest. Results PD patients who reported daytime sleepiness on NMSQuest obtained a significantly worse score on the PDSS sleepiness domain than PD patients who did not (12.0 ± 4.7 vs. 14.7 ± 3.4, p < 0.009). Patients reporting difficulty getting to sleep or staying asleep at night, showed lower scores on PDSS sleep quality domain than those without difficulties (15.8 ± 5.4 vs. 22.3 ± 4.6, p < 0.001). The presence of vivid dreams, acting out dreams and restlessness on NMSQuest correlated with PDSS and sleep log scores. Increased nocturnal activity was noted in subjects reporting acting out dreams. Furthermore, the number of positive answers to the sleep-fatigue questions of the NMSQuest correlated significantly with PDSS total score, sleep log total score and nocturnal activity measured by actigraphy. Conclusion NMSQuest sleep-fatigue domain identified appropriately sleep disturbances indicating its usefulness as a screening tool for sleep disorders in PD patients.