title: Tremor and clinical fluctuation are related to sleep disorders in Chinese patients with Parkinson's disease.
abstract: OBJECTIVE
  To study the relationship between sleep disturbances and symptoms in patients with Parkinson's disease (PD).
  
  
  METHODS
  The Parkinson's Disease Sleep Scale-Chinese Version (PDSS-CV) was used to evaluate the sleep disturbances of PD patients in a cross sectional study. The Unified Parkinson's Disease Rating Scale (UPDRS) parts II-IV, and the Hoehn & Yahr (H&Y) stage were used to determine the level of motor function in PD and the severity of PD. The Spearman correlation and a multiple regression analysis were used to identify the relationship between sleep disturbances and symptoms of PD. The quantities derived from the UPDRS and the H&Y stage and disease duration were compared between groups of patients either with or without sleep disturbances identified by the PDSS. This study was conducted from December 2011 to March 2012 at the First Affiliated Hospital of Sun Yat-sen University, in Guangzhou.
  
  
  RESULTS
  A total of 136 PD patients were included in this study. The overall total PDSS score in PD patients was 107.58 ± 23.35 points (range: 30-146). There were significant differences in the disease duration, the H&Y stage, and the UPDRS section subscores between groups of patients either with or without sleep disturbances (Kruskal-Wallis Test, p <0.05). There were significant negative correlations between PDSS scores and the UPDRS subscores, the H&Y stage and the disease duration (Spearman correlation, p < 0.05). The multiple regression analysis indicated that sleep disturbances identified by the PDSS were only associated with daily life activity, tremor intensity and clinical fluctuation (R(2) = 0.22, F(3,132) = 12.4, p < 0.001). The correlations were also significant when the contribution of the other two factors was excluded using partial correlations.
  
  
  CONCLUSIONS
  The level of daily life activity and the occurrences of tremor and clinical fluctuation are likely to be important factors that lead to PD patients' sleep disturbances. This study may elucidate an important clue for the relationship between sleep disturbances and PD symptoms.
authors.affiliation: Department of Neurological Intensive Care Unit, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Department of Neurological Intensive Care Unit, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, China.
authors.forename: Cunzhou
authors.initials: C
authors.lastname: Shen
authors.affiliation: Department of Internal Medicine, Nansha central Hospital, Guangzhou 511457, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Neurology, The Second Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou 510300, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Qian
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Sun Yat-sen University, NO. 58 Zhongshan Road 2, Guangzhou 510080, China.
authors.forename: Yifan
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Sun Yat-sen University, NO. 58 Zhongshan Road 2, Guangzhou 510080, China.
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Sun Yat-sen University, NO. 58 Zhongshan Road 2, Guangzhou 510080, China.
authors.forename: Wenbiao
authors.initials: W
authors.lastname: Xian
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Sun Yat-sen University, NO. 58 Zhongshan Road 2, Guangzhou 510080, China.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Pei
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Sun Yat-sen University, NO. 58 Zhongshan Road 2, Guangzhou 510080, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Chen
keywords: Parkinson’s disease; Parkinson’s disease sleep scale-Chinese Version(PDSS-CV); Sleep disorders; Unified Parkinson’s Disease Rating Scale (UPDRS)