Sleep and other symptoms in primary fibromyalgia and in healthy controls

To evaluate sleep architecture and self-reported complaints in patients with fibromyalgia (FS). Forty patients and 10 age standardized healthy controls were included. All participants were women.

All patients and controls underwent a clinical examination and gave answers to a questionnaire. Polysomnography was done in 20 patients and in all controls.

The percent arousal time and arousal index were higher (p < 0.05 and < 0.01, respectively) among FS compared to controls, but no other differences were found in sleep architecture. Ten of the patients with FS and 2 controls showed an apnea-hypoapnea index above 5/h (NS). The arousal time and arousal index were higher in patients with apnea-hypoapnea index > or = 5 compared to controls with apnea-hypoapnea index < 5 [mean (SD)] [arousal time: 4.5 (3.2) vs 0.7 (0.7), p < 0.001, arousal index: 14.9 (10.8) vs 2.4 (3.7), p < 0.001]. In patients with FS with apnea-hypoapnea index < 5 the arousal time was higher (2.0 (1.2), p < 0.05) and arousal index marginally higher (5.6 (3.2), p = 0.07) compared to the controls. No other differences were found in sleep structure. Insomnia (difficulties falling asleep, maintaining sleep, early morning awakening), tiredness, mood, cognitive disturbances and muscular pain were all reported more commonly by patients with FS than controls. A subdivision of the patients with FS into those with apnea-hypoapnea index < 5 and apnea-hypoapnea index > or = 5 did not change these findings.

We conclude, that patients with FS show minor polysomnographic findings, with a higher occurrence of arousals. The arousals were in part explained by respiratory abnormalities. Patients with FS have several complaints, including insomnia. Some of these may relate to sleep fragmentation. Controlled studies are a requirement in investigations of sleep disorders in fibromyalgia.