Chronic fatigue, unrefreshing sleep and nocturnal polysomnography

Guilleminault, Christian; Poyares, Dalva; Rosa, Agostinho da; Kirisoglu, Ceyda; Almeida, Tatiana; Lopes, Maria Cecilia

doi:10.1016/j.sleep.2006.03.016

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Volume 7, Issue 6 , Pages 513-520, September 2006

Chronic fatigue, unrefreshing sleep and nocturnal polysomnography

Christian Guilleminault
- Stanford University Sleep Disorders Clinic, 401 Quarry road, suite 3301, Stanford, CA 94305, USA
- Corresponding author. Tel.: +1 650 723 6601; fax: +1 650 725 89 10.
Dalva Poyares
- Stanford University Sleep Disorders Clinic, 401 Quarry road, suite 3301, Stanford, CA 94305, USA
- Department of Psychobiology, Sleep Institute, Federal University of Sao Paulo, Sao Paulo, Brazil
Agostinho da Rosa
- Department of Psychobiology, Sleep Institute, Federal University of Sao Paulo, Sao Paulo, Brazil
Ceyda Kirisoglu
- Stanford University Sleep Disorders Clinic, 401 Quarry road, suite 3301, Stanford, CA 94305, USA
Tatiana Almeida
- Department of Psychobiology, Sleep Institute, Federal University of Sao Paulo, Sao Paulo, Brazil
Maria Cecilia Lopes
- Stanford University Sleep Disorders Clinic, 401 Quarry road, suite 3301, Stanford, CA 94305, USA

Received 2 January 2006; received in revised form 28 February 2006; accepted 6 March 2006.

Abstract

Background and purpose

To investigate the complaint of unrefreshing sleep with study of sleep electroencephalogram (EEG) in patients with chronic fatigue.

Patients and 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.

Keywords: Chronic fatigue, Unrefreshing sleep, Slow wave sleep, Cyclic alternating pattern, Slow delta, Sleep-disordered breathing