Researchers reported a significant relationship between sleep disturbances in Parkinson’s disease (PD) patients and their disease-related disability, including tremors, impaired posture, and slowed movement. Also, excessive daytime sleepiness and REM sleep behavior disorder were more common in PD patients than control subjects.
The study, “Impact of sleep-related symptoms on clinical motor subtypes and disability in Parkinson’s disease: a multicentre cross-sectional study,” was published in the Journal of Neurology, Neurosurgery & Psychiatry.
Different PD motor subtypes have been described through clinical observation. However, there’s not a lot of research done about the effect of PD non-motor symptoms on the clinical motor subtypes. So, whether the presence of different non-motor symptoms predicts a specific clinical motor subtype remains an open question.
To address this, the team performed a multicenter study to assess non-motor symptoms of 436 PD patients. In addition, 401 age and sex-matched control subjects without any neurological or psychiatric diseases were recruited.
Participants completed questionnaires regarding their habits, education, and sleep status. They also were submitted to a series of tests, including motor experiences of daily living and motor examination. Clinical motor subtypes were defined as tremor dominant (TD), intermediate, and postural instability and gait disturbances (PIGDs).
Regarding the sleep aspect of the study, scientists evaluated PD-related sleep problems (PD-SP), excessive daytime sleepiness (EDS) and probable REM sleep behavior disorder (pRBD).
Results show that, compared to controls, PD patients were more likely to have PD-related sleep problems (35.1% vs 7%), excessive daytime sleepiness (37.8% vs 15.5%), and probable REM sleep behavior disorder (35.1% vs 7.7%).
In addition, the PIGD group had higher PDSS-2 and ESS adjusted scores than the TD group. PDSS-2 and ESS are short for Parkinson’s Disease Sleep Scale 2 and Epworth Sleepiness Scale, respectively. The first characterizes and quantifies the various aspects of nocturnal sleep problems in PD; the latter measures daytime sleepiness.
Additionally, the number of sleep-related symptoms (PD-SP, EDS and pRBD), followed by disease duration, PIGD subtype, and depression, were all predictors of disease-related disability, assessed through the Movement Disorder Society-Unified PD Rating Scale part II score.
The “cross-sectional survey results indicate a possible relationship between the clinical motor subtypes of PD and sleep-related symptoms and demonstrate the importance of the clinical assessment and management of sleep-related symptoms (PD-SP, EDS and pRBD), which have a significant impact on disease-related disability compared with motor symptoms in patients with PD,” the team concluded.