Are patients with chronic fatigue syndrome just ‘tired’ or also ‘sleepy’?
Version of Record online: 7 OCT 2008
© 2008 European Sleep Research Society
Journal of Sleep Research
Volume 17, Issue 4, pages 427–431, December 2008
How to Cite
NEU, D., HOFFMANN, G., MOUTRIER, R., VERBANCK, P., LINKOWSKI, P. and LE BON, O. (2008), Are patients with chronic fatigue syndrome just ‘tired’ or also ‘sleepy’?. Journal of Sleep Research, 17: 427–431. doi: 10.1111/j.1365-2869.2008.00679.x
- Issue online: 28 NOV 2008
- Version of Record online: 7 OCT 2008
- Accepted in revised form 7 May 2008; received 7 November 2007
- chronic fatigue syndrome;
- multiple sleep latency test;
- sleep apnea–hypopnea syndrome;
It is presently unclear whether chronic fatigue syndrome (CFS) patients exhibit daytime sleepiness in addition to fatigue. Both, fatigue, such as that seen in CFS patients, and excessive daytime sleepiness, such as in sleep apnea–hypopnea syndrome (SAHS), remain poorly understood. Both daytime conditions are generally related to unrefreshing sleep and show affective symptoms. This study’s objective was to contribute to the understanding of the relationship between fatigue and sleepiness in CFS patients not co-morbid for primary sleep or psychiatric disorders. We compared 16 untreated CFS patients (mean age 32.8, all females) with 13 untreated SAHS (mean age 47.7, all females) patients and 12 healthy controls (mean age 32.2, all females). Objective sleepiness was measured using multiple sleep latency tests (MSLT). Subjective sleepiness and fatigue were assessed with the Epworth Sleepiness Scale and the Fatigue Severity Scale, respectively. Mean Sleep Latency (SL) on the MSLT was significantly shorter in SAHS patients than in CFS patients and CFS patients showed significantly shorter mean SL than matched controls but within normal range. Subjective sleepiness was greatest in SAHS patients and subjective fatigue was highest in CFS patients. Affective symptoms showed highest intensities in CFS patients. While higher than the control group on all measures, compared to SAHS, the CFS group had higher subjective fatigue and lower subjective and objective sleepiness. Despite possible overlap in symptoms and signs of both daytime conditions, our data indirectly support the clinical distinction between fatigue and sleepiness.