title: Chronic fatigue, unrefreshing sleep and nocturnal polysomnography.
abstract: OBJECTIVE
  To investigate the complaint of unrefreshing sleep with study of sleep electroencephalogram (EEG) in patients with chronic fatigue.
  
  
  METHODS
  Fourteen successively seen patients (mean age: 41.1 9.8) who complained of chronic fatigue but denied sleepiness and agreed to participate were compared to 14 controls (33.6+/-10.2 years) who were monitored during sleep recorded in parallel. After performing conventional sleep scoring we applied Fast Fourier Transformation (FFT) for the delta 1, delta 2, theta, alpha, sigma 1, sigma 2, beta EEG frequency bands. The presence of non-rapid eye movement (NREM) sleep instability was studied with calculation of cyclic alternating pattern (CAP) rate. Two-way analysis of variance (ANOVA) was performed to analyze FFT results and Mann-Whitney U-test to compare CAP rate in both groups of subjects.
  
  
  RESULTS
  Slow wave sleep (SWS) percentage and sleep efficiency were lower, but there was a significant increase in delta 1 (slow delta) relative power in the chronic fatigue group when compared to normals (P<0.01). All the other frequency bands were proportionally and significantly decreased compared to controls. CAP rate was also significantly greater in subjects with chronic fatigue than in normals (P=0.04). An increase in respiratory effort and nasal flow limitation were noted with chronic fatigue.
  
  
  CONCLUSIONS
  The complaints of chronic fatigue and unrefreshing sleep were associated with an abnormal CAP rate, with increase in slow delta power spectrum, affirming the presence of an abnormal sleep progression and NREM sleep instability. These specific patterns were related to subtle, undiagnosed sleep-disordered breathing.
authors.affiliation: Stanford University Sleep Disorders Clinic, 401 Quarry road, suite 3301, Stanford, CA 94305, USA. cguil@stanford.edu
authors.forename: Christian
authors.initials: C
authors.lastname: Guilleminault
authors.forename: Dalva
authors.initials: D
authors.lastname: Poyares
authors.forename: Agostinho da
authors.initials: Ad
authors.lastname: Rosa
authors.forename: Ceyda
authors.initials: C
authors.lastname: Kirisoglu
authors.forename: Tatiana
authors.initials: T
authors.lastname: Almeida
authors.forename: Maria Cecilia
authors.initials: MC
authors.lastname: Lopes
mesh_terms: D000328:Adult; D001921:Brain / Q000503:physiopathology; D003700:Delta Rhythm; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D004569:Electroencephalography; D015673:Fatigue Syndrome, Chronic / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology*; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D017286:Polysomnography; D012720:Severity of Illness Index; D012890:Sleep / Q000502:physiology*; D012891:Sleep Apnea Syndromes / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D020178:Sleep Disorders, Circadian Rhythm / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology*; D012894:Sleep Stages / Q000502:physiology