Reduced rapid eye movement density in Parkinson disease: A polysomnography-based case-control study

Lynn A. Schroeder, Olivier Rufra, Nicolas Sauvageot, François Fays, Vannina Pieri, Nico J. Diederich*

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

22 Citations (Scopus)


Study Objectives: To explore rapid eye movement density (RD) in patients with idiopathic Parkinson disease (IPD) and to investigate its usefulness as surrogate marker of excessive daytime sleepiness, a frequent complaint in IPD patients. Methods: Retrospective polysomnography study on 81 subjects without dementia: 29 patients with early stage IPD (disease duration . 3 y), 21 patients with middle- stage IPD (disease duration > 3 and < 8 y) and 31 healthy controls (HC). Rapid eye movement (REM) sleep was defined as any REM episode with > 3 min of continuous REM sleep. RD was defined as number of ocular movements per minute of REM sleep. Patients with early stage IPD and HC fulfilled the PDspecific sleepiness questionnaires Parkinson'fs Disease Sleep Scale (PDSS) and the Nonmotor Symptoms Questionnaire for Parkinson'fs disease (NMSQuest). Results: RD was lower in patients with IPD than in HC. The difference was most significant between patients with middle stage IPD and HC (P = 0.001), and most prominent for the third REM episode, again when comparing patients with middle stage IPD and HC (P = 0.03). RD was independent from sex, age, and other sleep parameters. In early stage IPD, RD correlated with the PDSS score (r = .0.63, P = 0.001) and the sleep-related questions of the NMSQuest score (r = 0.48, P = 0.017). Conclusions: REM density is reduced in patients with IPD and correlates with subjective scores on sleep impairment. As an indicator of persistent high sleep pressure, reduced RD in IPD is eligible as a biomarker of excessive daytime sleepiness in IPD. It possibly reflects direct involvement of the brainstem REM generation sites by the disease process. RD is a promising new tool for sleep research in IPD.

Original languageEnglish
Pages (from-to)2133-2139
Number of pages7
Issue number12
Publication statusPublished - 1 Dec 2016


  • Excessive daytime sleepiness
  • Parkinson disease
  • REM density
  • REM sleep


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