title: EEG power during waking and NREM sleep in primary insomnia.
abstract: OBJECTIVE
  Pathophysiological models of insomnia invoke the concept of 24-hour hyperarousal, which could lead to symptoms and physiological findings during waking and sleep. We hypothesized that this arousal could be seen in the waking electroencephalogram (EEG) of individuals with primary insomnia (PI), and that waking EEG power would correlate with non-REM (NREM) EEG.
  
  
  METHODS
  Subjects included 50 PI and 32 good sleeper controls (GSC). Five minutes of eyes closed waking EEG were collected at subjects' usual bedtimes, followed by polysomnography (PSG) at habitual sleep times. An automated algorithm and visual editing were used to remove artifacts from waking and sleep EEGs, followed by power spectral analysis to estimate power from 0.5-32 Hz.
  
  
  RESULTS
  We did not find significant differences in waking or NREM EEG spectral power of PI and GSC. Significant correlations between waking and NREM sleep power were observed across all frequency bands in the PI group and in most frequency bands in the GSC group.
  
  
  CONCLUSIONS
  The absence of significant differences between groups in waking or NREM EEG power suggests that our sample was not characterized by a high degree of cortical arousal. The consistent correlations between waking and NREM EEG power suggest that, in samples with elevated NREM EEG beta activity, waking EEG power may show a similar pattern.
authors.affiliation: Sleep Medicine Institute and Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, PA ; Kaiser Permanente Department of Internal Medicine, Oakland, CA.
authors.forename: You Meme
authors.initials: YM
authors.lastname: Wu
authors.forename: Regina
authors.initials: R
authors.lastname: Pietrone
authors.forename: J David
authors.initials: JD
authors.lastname: Cashmere
authors.forename: Amy
authors.initials: A
authors.lastname: Begley
authors.forename: Jean M
authors.initials: JM
authors.lastname: Miewald
authors.forename: Anne
authors.initials: A
authors.lastname: Germain
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Buysse
mesh_terms: D000328:Adult; D001143:Arousal / Q000502:physiology*; D016022:Case-Control Studies; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D017286:Polysomnography / Q000379:methods; D012016:Reference Values; D018570:Risk Assessment; D012720:Severity of Illness Index; D007319:Sleep Initiation and Maintenance Disorders / Q000175:diagnosis*; D012895:Sleep, REM / Q000502:physiology*; D013997:Time Factors; D014851:Wakefulness / Q000502:physiology*
keywords: EEG; Insomnia; NREM sleep; spectral analysis; wakefulness