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Keywords

actigraphy in fibromyalgia, fatigue, sleep quality

 

Authors

  1. Landis, Carol A.
  2. Frey, Christine A.
  3. Lentz, Martha J.
  4. Rothermel, James
  5. Buchwald, Dedra
  6. Shaver, Joan L.F.

Abstract

Background: Limited data are available on the relationship between self-reported sleep quality, fatigue, and behavioral sleep patterns in women with fibromyalgia (FM).

 

Objectives: To compare self-reported sleep quality, fatigue, and behavioral sleep indicators obtained by actigraphy between women with FM and sedentary women without pain, and to examine relationships among these variables.

 

Methods: Twenty-three women with FM (M = 47.3, +/- 6.7 years) and 22 control women (M = 43.5, +/- 8.2 years) wore an actigraph on the nondominant wrist for 3 consecutive days at home. Each day women reported bedtimes, rise times, and ratings of sleep quality and fatigue in a diary. Self-reported sleep quality, fatigue, and indicators of sleep quality obtained from actigraphy (e.g., total sleep time, sleep efficiency, sleep latency, wake after sleep onset, and fragmentation index) were averaged. The Mann Whitney U test was used to assess group differences. Pearson Product Moment Correlation was used to evaluate relationships between sleep quality and fatigue, and among sleep quality, fatigue, and actigraphy sleep indicators.

 

Results: Women with FM reported poorer sleep quality and more fatigue compared to controls (both p < .001). Actigraphy sleep indicators were not different between groups. In women with FM but not in controls, self-reported sleep quality was directly related to actigraphy indicators of total sleep time (r = .635, p < .01) and inversely related to sleep fragmentation (r = - .46, p < .05). Fatigue in women with FM was directly related to actigraphy indicators of wake after sleep onset (r = .57, p < .01), and inversely related to sleep efficiency (r = - .545, p < .01).

 

Discussion: Self-reported sleep quality and fatigue are associated with behavioral indicators of sleep quality at home in women with FM. Actigraphy is a useful objective measure of improved sleep outcomes in intervention studies.

 

Fibromyalgia (FM) is a common chronic pain condition, increasingly encountered in primary care settings. The prevalence of FM in the general population in the United States is estimated at 2-4% (Wolfe, Ross, Anderson, Russell, & Hebert, 1995). Fibromyalgia is nine times more common among women than men and the prevalence increases with age, affecting nearly 7% of women over 60 years of age (Wolfe et al., 1995). The case definition of FM is widespread pain in four body quadrants for at least 3 months' duration with tenderness found at 11 out of 18 discrete musculoskeletal areas with palpation (Wolfe et al., 1990). Although fatigue and disturbed sleep are not included in these standard FM criteria, over 75% of patients with FM report poor sleep quality and enduring fatigue (White, Speechley, Harth, & Ostbye, 2000;Wolfe, Hawley, & Wilson, 1996). Poor sleep quality likely contributes to greater fatigue and impaired daytime functioning in FM (Cote & Moldofsky, 1997;Jennum, Drewes, Andreasan, & Nielsen, 1993;Menefee et al., 2000). Self-reported sleep disturbance correlates with fatigue in FM (Wolfe et al., 1996) but relationships between objective measures of poor sleep quality and fatigue have not been well documented, particularly in studies conducted at home. Fatigue severely affects the ability of FM patients to carry out routine daily activities, to exercise, and to think clearly (Bennett, Cook, Clark, Burckhardt, & Campbell, 1997;Cote et al., 1997).

 

Sleep patterns obtained by polysomnography (PSG) in FM show modest increased amounts of nonrapid-eye-movement (NREM) stage 1 (transitional sleep) and wakefulness after sleep onset at night, such that sleep efficiency as an indicator of sleep quality is reduced (Drewes, Svendsen, Nielson, Taagholt, & Bjerregard 1994;Jennum et al., 1993). Women with FM symptoms also show more sleep fragmentation/hour as an indicator of sleep continuity, especially during the first half of the night (Shaver et al., 1997). Nonetheless, when women with FM who are free of current psychiatric disorders are compared to those of a similar age, their subjective perceptions of poor sleep are often out of proportion to and do not match modest changes in PSG sleep quality and continuity indicators. The polysonogram, which is based on the simultaneous physiologic recordings of brain wave activity, eye movements, and chin muscle tone, is considered the most valid objective method for measuring sleep stages. However, recent PSG studies in healthy women have shown that indicators of reduced sleep continuity and quality were more closely related to self-reported sleep quality compared to sleep stages (Akerstedt, Hume, Minors, & Waterhouse, 1994). Controversy surrounds the clinical significance and diagnostic value of PSG in FM, in part, because of the mismatch between self-reported and PSG sleep stages and quality indicators.

 

Disturbed sleep patterns have been observed with the use of actigraphy, an objective behavioral indicator of sleep, in FM and in chronic pain. Patients with FM showed increased levels of activity at night compared to healthy controls (Korszun et al., 2002). Relationships between self-report measures of sleep quality and actigraphy also have been assessed. In patients with chronic rheumatological pain, reduced sleep efficiency by actigraphy did not correlate with self-reported sleep quality (Lavie et al., 1992;Wilson, Watson, & Currie, 1998). However, other actigraphy sleep indicators (i.e., sleep latency and amount of wakefulness after sleep onset) have been correlated with diary reports of sleep quality (Wilson et al., 1998).

 

Increasingly in sleep research, data derived from self-report sleep diaries and from actigraphy are used to validate sleep patterns in subjects prior to sleep laboratory assessment. Compared to PSG, actigraphy is a less resource-intensive method to monitor sleep quality and continuity, especially in the home environment and over extended time periods. If relationships among actigraphy sleep indicators, self-reported sleep quality, and daytime fatigue can be shown, then actigraphy could be a useful objective measure to evaluate the extent of abnormal sleep and the effectiveness of interventions to improve sleep and daytime functioning in FM. Thus, the purpose of this study was (a) to compare indicators of sleep quality and continuity obtained from actigraphy (e.g., total sleep time, sleep efficiency, wakefulness after sleep onset, and fragmentation index) at home in a group of FM patients and a sedentary group of pain-free women of similar age; and (b) to examine whether self-reported sleep quality and fatigue were related to these actigraphy indicators of sleep quality.