Chronic fatigue syndrome (CFS) has been associated with altered amounts of slow wave sleep, which could reflect reduced electroencephalograph (EEG) activity and impaired sleep regulation. A study published in the journal SLEEP finds that CFS is also associated with a blunted slow wave activity (SWA) response to sleep challenge, suggesting an impairment of the basic sleep drive and homeostatic response.
The study, authored by Roseanna Armitage, PhD, and colleagues at the University of Michigan, focused on 13 pairs of identical twins discordant for CFS. Analyses, which were restricted to the first four non-REM periods each night in order to show comparability, revealed that SWA, or other sleep EEG measures, did not differ between the CFS and healthy twins during a regular night's sleep. According to Armitage, it was only after a "challenge" to sleep regulation was introduced (keeping them awake an extra four hours) that the CFS twins exhibited significantly less SWA power in the first non-REM period of recovery sleep and accumulated a smaller percentage of SWA in the first non-REM period than their twin counterparts.
"CFS shares symptoms with depression, and some experts have suggested that it is not a distinctly different disorder," said Armitage. "We have also conducted studies of SWA response to sleep challenge in depression, and the results are very different. Depressed women did not show a blunted SWA response to sleep challenge. The present CFS study included only women, and none had current depression. Therefore, our results cannot be explained on the basis of depression."
Experts recommend that adults get between seven and eight hours of sleep each night to maintain good health and optimum performance. Persons who think they might have a sleep disorder are urged to consult with their primary care physician, who will refer them to a sleep specialist.
Article: "The Impact of a Four-Hour Sleep Delay on Slow Wave Activity in Twins Discordant for Chronic Fatigue Syndrome", Sleep, May 1, 2007.
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