Relationships among cognitive impairment, sleep, and fatigue in Parkinson's disease using the MDS-UPDRS

Abstract

Background Non-motor complications of Parkinson’s disease (PD), specifically cognitive impairment, sleep disturbances, and fatigue, are recognized as important contributors to poor patient outcomes and quality of life. How sleep problems and fatigue interrelate and impact cognitive function, however, has not systematically been investigated across the stages of PD. The aim of our study was to investigate the relationships among cognitive impairment, night-time sleep problems, daytime sleepiness, and fatigue across all severities of PD. Methods We examined these non-motor problems using the Movement Disorder Society-Sponsored Revision of the Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) in a study of 1319 PD patients drawn from three large cohort studies: the Parkinson’s Progressive Markers Initiative, the Rush University PD Cognitive-Behavioral-Imaging study, and the Movement Disorder Society-Unified Parkinson’s Disease Rating Scale Clinimetric testing program study, which spanned the gamut of disease, from early to advanced PD. Generalized linear mixed models with logit linking functions and covariates including study cohort, age, PD duration, and presence/absence of PD medications were used to examine relationships between these three non-motor symptoms and cognitive impairment. Results Of these three frequent, and often inter-twined, non-motor complications, greater daytime sleepiness and fatigue were associated with worse cognitive impairment across the full spectrum of PD (F[16,1158]=2.40 and F[16,1158]=3.45 respectively, p’s<0.0005), but an association with night-time sleep was not detected (p=0.83). Conclusions Given this association of daytime sleepiness and fatigue with cognitive impairment, clinical monitoring for these problems should be considered across all points in the PD spectrum, from early to more advanced disease.

Fatigue in Parkinson’s disease: report from a multidisciplinary symposium

“…8 Several studies suggest that cognitive performance, frontal lobe activity, and self-reported cognitive impairment are associated with fatigue. 23,24 However, fatigability on cognitive tasks may not correlate with subjective fatigue. 25 Similar to depression, fatigue is frequently associated with daytime sleepiness and sleep disorders, but can be distinguished from them by the absence of sleep being restorative, and may occur in patients with normal sleep patterns.…”

A systematic review of the literature on disorders of sleep and wakefulness in Parkinson's disease from 2005 to 2015

“…--EDS is a significant predictor of cognitive dysfunction[138] and incident development of cognitive dysfunction over 5 years[139], although another longitudinal study found no association[84]…”

Sleep and Circadian Rhythm Disorders in Parkinson’s Disease

“…EDS in PD is associated with decreased health related quality of life (64, 65), worse cognitive impairment (66), worse motor and non-motor symptoms as well as increased medication wearing off (67, 68). In PD, depressive symptoms correlate significantly with EDS (27, 63).…”