title: Changes in cardiac variability after REM sleep deprivation in recurrent nightmares.
abstract: OBJECTIVE
  To assess whether dysfunctional autonomic regulation during REM sleep as indexed by heart rate variability (HRV) is a pathophysiological factor in frequent nightmares (NMs).
  
  
  METHODS
  Monitoring with polysomnography (PSG) and electrocardiography (ECG) for 3 consecutive nights: Night 1 (N1), adaptation night; N2, administration of partial REM sleep deprivation; N3, recovery night. Differences between NM and control (CTL) groups assessed for ECG measures drawn from wakefulness, REM sleep, and Stage 2 sleep on both N1 and N3.
  
  
  METHODS
  Hospital-based sleep laboratory.
  
  
  METHODS
  Sixteen subjects with frequent NMs (> or = 1 NM/week; mean age = 26.1 +/- 8.7 years) but no other medical or psychiatric disorders and 11 healthy comparison subjects ( < 1 NM/month; mean age = 27.1+/- 5.6 years).
  
  
  RESULTS
  NM and CTL groups differed on 2 REM sleep measures only on N1; the NM group had longer REM latencies and REM/NREM cycle durations than did the CTL group. No differences were found on time domain and absolute frequency domain ECG measures for either N1 or N3. However, altered HRV for the NM group was suggested by significantly higher LFnu, lower HFnu, and higher LF/HF ratio than for the CTL group.
  
  
  CONCLUSIONS
  Results are consistent with a higher than normal sympathetic drive among NM subjects which is unmasked by high REM sleep propensity. Results also support a growing literature linking anxiety disorders of several types (panic disorder, posttraumatic stress disorder (PTSD), generalized anxiety disorder) to altered HR variability.
authors.affiliation: Sleep Research Center, Hôpital du Sacré-Coeur de Montréal, Québec, Canada. tore.nielsen@umontreal.ca
authors.forename: Tore
authors.initials: T
authors.lastname: Nielsen
authors.forename: Tyna
authors.initials: T
authors.lastname: Paquette
authors.forename: Elizaveta
authors.initials: E
authors.lastname: Solomonova
authors.forename: Jessica
authors.initials: J
authors.lastname: Lara-Carrasco
authors.forename: Roberto
authors.initials: R
authors.lastname: Colombo
authors.forename: Paola
authors.initials: P
authors.lastname: Lanfranchi
mesh_terms: D000293:Adolescent; D000328:Adult; D001007:Anxiety / Q000503:physiopathology / Q000523:psychology; D001143:Arousal / Q000502:physiology; D004325:Dreams / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D010555:Personality Inventory / Q000706:statistics & numerical data; D017286:Polysomnography; D011594:Psychometrics; D012008:Recurrence; D012892:Sleep Deprivation / Q000503:physiopathology* / Q000523:psychology; D012895:Sleep, REM / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000503:physiopathology; D014851:Wakefulness / Q000502:physiology; D055815:Young Adult