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Excessive daytime sleepiness and its risk factors in incident Parkinson's disease
  1. David P Breen1,
  2. Caroline H Williams-Gray1,
  3. Sarah L Mason1,
  4. Tom Foltynie2,
  5. Roger A Barker1
  1. 1Centre for Brain Repair, University of Cambridge, Cambridge, UK
  2. 2Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, London, UK
  1. Correspondence to Dr David P Breen, Centre for Brain Repair, University of Cambridge, ED Adrian Building, Forvie Site, Robinson Way, Cambridge CB2 0PY, UK; dpbreen1{at}

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Excessive daytime sleepiness (EDS) can be a feature of various neurodegenerative diseases including Parkinson's disease (PD). EDS puts patients at increased risk of accidents while driving and it is important to identify such patients in order to advise them and others about their individual level of risk and the potential therapeutic options available to them.

The most commonly used method for assessing EDS in the clinic is the Epworth Sleepiness Scale (ESS)—a self-completed questionnaire which scores the tendency to fall asleep during eight everyday situations. The final score ranges from 0–24, with scores greater than 10 generally considered pathological. This questionnaire has been widely used in unselected PD cohorts, with the prevalence of EDS ranging from 3–50%.1 Although there is a general consensus that dopaminergic medications contribute to EDS in PD,2 there is less agreement about other risk factors. One possible explanation for these disparities is that heterogeneous PD cohorts were studied at different points in their disease course. Some studies have also suggested that the Catechol O-methyltransferase (COMT) val158met polymorphism (which is known to significantly alter enzyme activity) may be associated with EDS.

In this study, we report on the prevalence of EDS and its risk factors in a population-representative incident PD cohort.

Patients and methods

This cohort was recruited between December 2000 and December 2002, when we attempted to collect all newly diagnosed cases of parkinsonism in the country …

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  • Contributors DPB carried out the analysis and interpretation of the data, and prepared the manuscript. CHWG, SLM and TF carried out patient assessments and edited the manuscript. RAB conceived the study and edited the manuscript. All authors gave final approval for the manuscript to be published.

  • Funding This work was supported by a NIHR Biomedical Research Award to Addenbrooke's Hospital/University of Cambridge, as well as grants from Parkinson's UK/Big Lottery Fund, Wellcome Trust and Patrick Berthoud Charitable Trust. DPB and CHWG have each been recipient of a Raymond and Beverly Sackler Studentship.

  • Competing interests None.

  • Patient consent Obtained.

  • Ethics approval Cambridgeshire Research Ethics Committee.

  • Provenance and peer review Not commissioned; externally peer reviewed.