title: Short-term stability of sleep and heart rate variability in good sleepers and patients with insomnia: for some measures, one night is enough.
abstract: OBJECTIVE
  Quantify the short-term stability of multiple indices of sleep and nocturnal physiology in good sleeper controls and primary insomnia patients.
  
  
  METHODS
  Intra-class correlation coefficients (ICC) were used to quantify the short-term stability of study outcomes.
  
  
  METHODS
  Sleep laboratory.
  
  
  METHODS
  Fifty-four adults with primary insomnia (PI) and 22 good sleeper controls (GSC).
  
  
  METHODS
  Visually scored sleep outcomes included indices of sleep duration, continuity, and architecture. Quantitative EEG outcomes included power in the delta, theta, alpha, sigma, and beta bands during NREM sleep. Power spectral analysis was used to estimate high-frequency heart rate variability (HRV) and the ratio of low- to high-frequency HRV power during NREM and REM sleep.
  
  
  RESULTS
  With the exception of percent stage 3+4 sleep; visually scored sleep outcomes did not exhibit short-term stability across study nights. Most QEEG outcomes demonstrated short-term stability in both groups. Although power in the beta band was stable in the PI group (ICC = 0.75), it tended to be less stable in GSCs (ICC = 0.55). Both measures of cardiac autonomic tone exhibited short-term stability in GSCs and PIs during NREM and REM sleep.
  
  
  CONCLUSIONS
  Most QEEG bandwidths and HRV during sleep show high short-term stability in good sleepers and patients with insomnia alike. One night of data is, thus, sufficient to derive reliable estimates of these outcomes in studies focused on group differences or correlates of QEEG and/or HRV. In contrast, one night of data is unlikely to generate reliable estimates of PSG-assessed sleep duration, continuity or architecture, with the exception of slow wave sleep.
authors.affiliation: Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Israel
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Buysse
authors.forename: Robert T
authors.initials: RT
authors.lastname: Krafty
authors.forename: Amy
authors.initials: A
authors.lastname: Begley
authors.forename: Jean
authors.initials: J
authors.lastname: Miewald
authors.forename: Martica
authors.initials: M
authors.lastname: Hall
mesh_terms: D000328:Adult; D004569:Electroencephalography / Q000379:methods; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D017286:Polysomnography / Q000379:methods; D012890:Sleep; D007319:Sleep Initiation and Maintenance Disorders / Q000503:physiopathology*; D012894:Sleep Stages