Submitted to: Sleep
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/28/2003
Publication Date: 11/15/2002
Citation: HARMAN, K., PIVIK, T., D'EON, J.L., WILSON, K.G., SWENSON, J.R., MATSUNAGA, L. SLEEP IN DEPRESSED AND NON-DEPRESSED PARTICIPANTS WITH CHRONIC LOW BACK PAIN: EEG AND BEHAVIORAL FINDINGS. SLEEP. 2002. v. 25. p. 775-783.
Interpretive Summary: Complaints of reduced sleep quality and depression are common among subjects with chronic low back pain (CLBP). Measures of sleep (recordings for four consecutive nights) and depression were obtained in healthy subjects and in subjects with CLBP to study the interactions among these variables. Study groups did not differ in sleep amounts or patterns, but detailed analyses of brain wave frequencies showed differences consistent with reduced sleep quality in CLBP subjects--particularly those with signs of depression.
Technical Abstract: Study Objectives: To study the nature of sleep disturbance in depressed and non-depressed chronic low back pain (CLBP) patients. Design: A controlled, consecutive four-night polysomnographic study. Patients: Participants were screened (psychological, psychiatric and physical) to determine their study group, and twenty-one [CLBP: 4 depressed (D), 6 non-depressed (ND); 11 Controls (C)] participants were studied. Measurements and Results: On all nights, standard polysomnographic sleep measures as well as midline occipital and frontal EEG and respiration were recorded on a Grass Model 7 polygraph. Pain, sleep quality and depression were also measured. CLBP participants reported significant levels of pain and sleep disturbance as compared to C, but all groups had equivalent amounts of sleep and comparable sleep architecture. EEG power spectral analyses revealed significant differences with C having: more sigma across sites; more low beta activity occipitally and frontally than ND; and more occipital sigma and less high beta activity than D participants. Between pain sub-groups, D showed more occipital delta, more occipital and central alpha and more high beta activity across all sites than ND participants. Conclusions: Lower sigma power in CLBP participants suggests less effective sensorimotor gating that may contribute to poor sleep quality. Pain subgroup differences underscore the need to consider the influence of depression in the evaluation of sleep in clinical populations. This study controlled for many factors other than pain which may contribute to the sleep complaints in this population. Consequently, the absence of signs of major sleep disturbance must not be interpreted as evidence of a lack of a true sleep problem in CLBP, but more likely reflect control of these factors as well as the difficulty in measuring sleep quality. Supported by: The Ontario Mental Health Foundation and the Research Development Fund, Faculty of Health Sciences, University of Ottawa.