Monozygotic twins discordant for chronic fatigue syndrome - Objective
measures of sleep

Journal of Psychosomatic Research, Volume 56, Issue 2 , February
2004, Pages 207-212

Nigel Ball [a], Dedra S. Buchwald [b,*],  Douglas Schmidt [a],
Jack Goldberg [c], Suzanne Ashton [b] and Roseanne Armitage [d]

a Virginia Mason Sleep Disorders Center, University of Washington,
Seattle, WA, USA
b Department of Medicine, University of Washington, Seattle, WA, USA
cDepartment of Epidemiology, University of Washington, Seattle, WA, USA
d Department of Psychiatry, University of Texas Southwestern Medical
Center, Dallas, TX, USA

[*] Corresponding author. Harborview Medical Center, 325 9th Avenue, Box
359772, , Seattle, WA, , USA. Tel.: +1-206-341-4439; fax: +1-206-731-8247
E-mail: mailto:dedra@u.washington.edu

Received 2 November 2001;  accepted 15 April 2002.  Available online 4
March 2004.


Abstract
Purpose: Chronic fatigue syndrome (CFS) is characterized by profound
fatigue accompanied by disturbances of sleep, cognition, mood, and other
symptoms. Our objective was to describe sleep architecture in
CFS-discordant twin pairs.

Methods: We conducted a co-twin control study of 22 pairs of monozygotic
twins where one twin met criteria for CFS and the co-twin was healthy.
Twins underwent two nights of polysomnography.

Results: The percentage of Stage 3 and REM sleep was greater among the
CFS twins than their healthy co-twins (P.05 for both), but no other
differences in sleep architecture including sleep latency, REM latency,
and total sleep time were observed. Compared to their co-twins, CFS twins
had higher values for the apnea-hypopnea index and apnea-hypopnea arousal
index (P.05 for both).

Conclusion: These results do not provide strong evidence for a major role
for abnormalities in sleep architecture in CFS. Respiration appears
impaired in CFS, but these clinical abnormalities cannot alone account
for the prominence of sleep complaints in this illness. The co-twin
control methodology highlights the importance of selecting well-matched
control subjects.

Author Keywords: Chronic fatigue syndrome;
Polysomnography; Sleep; Twins


Copyright © 2004 Elsevier Inc. All rights reserved.