title: Heart rate variability in patients with idiopathic Parkinson's disease with and without obstructive sleep apnea syndrome.
abstract: BACKGROUND
  Obstructive sleep apnea syndrome (OSAS) is associated with repeated apnea-induced sympathetic surges leading to specific alterations of the power spectrum of heart rate variability (HRV). Sympathetic dysfunction evolves early in idiopathic Parkinson's disease (PD), but the consequences on cardiac autonomic response to OSAS have not been studied so far in PD patients.
  
  
  METHODS
  Sixty-two patients with PD (35 without OSAS (PD-wo), 27 with OSAS (PD-OSAS)) and 62 age-matched control subjects (25 without OSAS (Co-wo), 37 with OSAS (Co-OSAS)) were included. HRV variables - including mean R-R interval, standard deviation of all normal-to-normal R-R intervals (SDNN), both low frequency (LF) and high frequency (HF) power bands, and the LF/HF ratio - were computed automatically from full-night polysomnography and calculated separately for each sleep stage.
  
  
  RESULTS
  HRV variables were similar in PD-wo and PD-OSAS. In contrast, Co-OSAS showed significantly higher LF power in NREM1 and NREM2 sleep and higher LF/HF ratio in NREM1, NREM2 and slow wave sleep than Co-wo. Similarly, correlations between HRV variables and parameters of OSAS severity were found only in controls but not in PD patients.
  
  
  CONCLUSIONS
  Our results suggest that the sympathetic response to OSAS is blunted in PD, giving further clinical evidence of the sympathetic denervation commonly observed in this neurodegenerative disorder.
authors.affiliation: Department of Neurology, University Hospital of Zurich, Switzerland. phvalko@gmx.ch
authors.forename: Philipp O
authors.initials: PO
authors.lastname: Valko
authors.forename: Sabrina
authors.initials: S
authors.lastname: Hauser
authors.forename: Esther
authors.initials: E
authors.lastname: Werth
authors.forename: Daniel
authors.initials: D
authors.lastname: Waldvogel
authors.forename: Christian R
authors.initials: CR
authors.lastname: Baumann
mesh_terms: D000368:Aged; D015992:Body Mass Index; D004562:Electrocardiography; D005260:Female; D007839:Functional Laterality; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications*; D017286:Polysomnography; D012189:Retrospective Studies; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000209:etiology*; D013223:Statistics as Topic; D018709:Statistics, Nonparametric