Date Published: March 11, 2019
Publisher: Public Library of Science
Author(s): Zhong Rui, Chen Qingling, Zhang Xinyue, Zhang Xin, Lin Weihong, Federica Provini.
Sleep benefit (SB) refers to the poorly understood phenomenon in Parkinson’s disease (PD) in which patients wake up in the morning with improved motor function. Although previous studies have suggested that several related factors are associated with SB, this relationship remains controversial.
This systematic review and meta-analysis aimed to identify the possible related factors of SB in PD.
We searched PubMed, EMBASE and WanFang databases to collect eligible articles. We calculated pooled estimates of odds ratios (ORs) or the mean deviation (MD) with 95% confidence intervals.
We found 3 related factors associated with SB: the duration of PD (MD 1.22, 95% CI: 0.21–2.23), sleep efficiency (MD -4.48,95% CI: -7.24- -2.44), and on-state MDS-UPDRS-Ⅲ total score (MD 3.05, 95% CI: 0.53–5.57).
PD patients with SB are more likely to have a long duration of PD, a low sleep efficiency and a high MDS-UPDRS-Ⅲ total score. Our work helps obtain a better understanding of sleep SB in PD and its underlying mechanisms. More studies need to be conducted to evaluate the associations between clinical factors in PD and the SB phenomenon.
Parkinson’s disease (PD) is a chronic, progressive, disabling neurodegenerative disorder that begins in mid to late life and is characterized by motor impairment, autonomic dysfunction, and, in many patients, psychological and cognitive changes[1, 2]. Sleep disorders are common among Parkinson’s disease(PD) patients and included insomnia, excessive sleeping, and restless legs syndrome, which can reduce the quality of life in PD patients[3, 4]. Furthermore, limited treatment options are available . However, there are also reports of PD patients experiencing a beneficial effect of sleep. Upon waking in the morning, some patients describe a good mobility, as if they are in an ‘on’ state induced by medication, contrary to what would be expected after a night without medication. PD patients with sleep benefit(SB) even feel “this is my best time, as if I had no disease or it were much milder”, when they wake up in the morning before taking any medication. Some patients are even able to delay or decrease the dose of morning medication due to sleep benefit(SB). Therefore, sleep benefit is the experience of a temporary decrease in PD symptoms upon awakening after a period of sleep (night or daytime) and before drug intake; the patient is feeling as good as “on” (or better); thus, it is a subjective measure. Sleep is believed to improve the extrapyramidal motor functions of these patients. However, the subjective versus objective SB in PD is controversial, and several previous studies revealed a significant discrepancy between subjective functional and objective motor improvement. A study by Lee et al concluded that most PD patients experience subjective SB with no measurable motor improvement.
This systematic review and meta-analysis included 7 clinical observational studies that assessed the associations of related risk factors with SB in PD patients. We showed that PD duration, sleep efficiency and on-state MDS-UPDRS-Ⅲ total score were significantly associated with SB in PD. In other words, PD patients with SB are more likely to have a long duration of PD, a low sleep efficiency and a high MDS-UPDRS-Ⅲ total score.