Objective. Fibromyalgia (FM) and chronic fatigue syndrome (CFS) are associated with substantial physical disability. Determinants of self-reported physical disability are poorly understood. This investigation uses objective ambulatory activity monitoring to compare patients with FM and/or CFS with controls, and examines associations of ambulatory activity levels with both physical function and symptoms during activities of daily life.Methods. Patients with FM and/or CFS (n ‫؍‬ 38, mean ؎ SD age 41.5 ؎ 8.2 years, 74% women) completed a 5-day program of ambulatory monitoring of physical activity and symptoms (pain, fatigue, and distress) and results were compared with those in age-matched controls (n ‫؍‬ 27, mean ؎ SD age 38.0 ؎ 8.6 years, 44% women). Activity levels were assessed continuously, ambulatory symptoms were determined using electronically time-stamped recordings at 5 time points during each day, and physical function was measured with the 36-item Short Form health survey at the end of the 5-day monitoring period.Results. Patients had significantly lower peak activity levels than controls (mean ؎ SEM 8,654 ؎ 527 versus 12,913 ؎ 1,462 units; P ‫؍‬ 0.003) and spent less time in high-level activities when compared with controls (P ‫؍‬ 0.001). In contrast, patients had similar average activity levels as those of controls (mean ؎ SEM 1,525 ؎ 63 versus 1,602 ؎ 89; P ‫؍‬ 0.47). Among patients, low activity levels were associated with worse self-reported physical function over the preceding month. Activity levels were inversely related to concurrent ambulatory pain (P ‫؍‬ 0.031) and fatigue (P < 0.001). Pain and fatigue were associated with reduced subsequent ambulatory activity levels, whereas activity levels were not predictive of subsequent symptoms.Conclusion. Patients with FM and/or CFS engaged in less high-intensity physical activities than that recorded for sedentary control subjects. This reduced peak activity was correlated with measures of poor physical function. The observed associations may be relevant to the design of behavioral activation programs, because activity levels appear to be contingent on, rather than predictive of, symptoms.

Objective. To compare the momentary association between salivary cortisol levels and pain, fatigue, and stress symptoms in patients with fibromyalgia (FM), and to compare diurnal cycles of cortisol secretion in patients with FM and healthy control subjects in a naturalistic environment.Methods. Twenty-eight patients with FM and 27 healthy control subjects completed assessments on salivary cortisol levels and pain, fatigue, and stress symptoms, 5 times a day for 2 consecutive days, while engaging in usual daily activities. Only those participants who adhered to the protocol (assessed via activity monitor) were included in the final analyses.Results. Twenty FM patients and 16 healthy control subjects adhered to the protocol. There were no significant differences in cortisol levels or diurnal cortisol variation between FM patients and healthy controls. Among women with FM, a strong relationship between cortisol level and current pain symptoms was observed at the waking time point (t ‫؍‬ 3.35, P ‫؍‬ 0.008) and 1 hour after waking (t ‫؍‬ 2.97, P ‫؍‬ 0.011), but not at the later 3 time points. This association was not due to differences in age, number of symptoms of depression, or self-reported history of physical or sexual abuse. Cortisol levels alone explained 38% and 14% of the variation in pain at the waking and 1 hour time points, respectively. No relationship was observed between cortisol level and fatigue or stress symptoms at any of the 5 time points.Conclusion. Among women with FM, pain symptoms early in the day are associated with variations in function of the hypothalamic-pituitary-adrenal axis.Fibromyalgia (FM) is a common clinical syndrome defined by the presence of chronic widespread pain and tenderness (1). Recent studies have identified altered central nervous system (CNS) pain processing in individuals with FM, suggesting a neurobiologic basis for the disorder (2,3). However, the precise pathophysiologic mechanisms responsible for FM remain poorly understood.The hypothalamic-pituitary-adrenal (HPA) system is the primary endocrine stress axis in humans and has been implicated in the pathophysiologic development of FM. The function of the HPA axis in patients with FM has been extensively examined, but study findings have been inconsistent. The majority of studies have identified abnormalities consistent with chronic

Objective We examined whether a tailored activity pacing intervention was more effective at reducing pain and fatigue than a general activity pacing intervention. Method Adults with knee or hip osteoarthritis (N = 32) stratified by age and gender were randomized to receive either tailored or general pacing instruction. Participants wore an accelerometer for five days that measured physical activity and allowed for repeated symptom assessment. Tailoring involved using data from the accelerometer. Outcomes at 10 week follow-up were pain (WOMAC) and fatigue (Brief Fatigue Inventory). Results Compared to general instruction, the tailored group had less fatigue interference (p = .02) and a trend towards decreased fatigue severity (p = .10) at 10 week follow-up. No group differences were found in pain reduction. Conclusion Tailoring instruction based on recent symptoms and physical activity may be a more effective symptom management approach compared to general instruction given the positive effects on fatigue.

IntroductionAlthough people with knee and hip osteoarthritis (OA) seek treatment because of pain, many of these individuals have commonly co-occurring symptoms (for example, fatigue, sleep problems, mood disorders). The purpose of this study was to characterize adults with OA by identifying subgroups with the above comorbid symptoms along with illness burden (a composite measure of somatic symptoms) to begin to examine whether subsets may have differing underlying pain mechanisms.MethodsCommunity-living older adults with symptomatic knee and hip OA (n = 129) participated (68% with knee OA, 38% with hip OA). Hierarchical agglomerative cluster analysis was used. To determine the relative contribution of each variable in a cluster, multivariate analysis of variance was used.ResultsWe found three clusters. Cluster 1 (n = 45) had high levels of pain, fatigue, sleep problems, and mood disturbances. Cluster 2 (n = 38) had intermediate degrees of depression and fatigue, but low pain and good sleep. Cluster 3 (n = 42) had the lowest levels of pain, fatigue, and depression, but worse sleep quality than Cluster 2.ConclusionsIn adults with symptomatic OA, three distinct subgroups were identified. Although replication is needed, many individuals with OA had symptoms other than joint pain and some (such as those in Cluster 1) may have relatively stronger central nervous system (CNS) contributions to their symptoms. For such individuals, therapies may need to include centrally-acting components in addition to traditional peripheral approaches.

Previous studies have identified stress system dysregulation in fibromyalgia (FM) patients; such dysregulation may be involved in the generation and/or maintenance of pain and other symptoms. Corticotropin-releasing factor (CRF) is the principal known central nervous system mediator of the stress response; however, to date no studies have examined cerebrospinal fluid (CSF) CRF levels in patients with FM. The relationship between CSF CRF level, heart rate variability (HRV), and pain, fatigue, and depressive symptoms was examined in patients with FM. Among participants (n ¼ 26), CSF CRF levels were associated with sensory pain symptoms (r ¼ 0.574, p ¼ 0.003) and affective pain symptoms (r ¼ 0.497, p ¼ 0.011), but not fatigue symptoms. Increased HRV was also strongly associated with increased CSF CRF and FM pain. In multivariate analyses adjusting for age, sex, and depressive symptoms, the association between CSF CRF and sensory pain symptoms (t ¼ 2.54, p ¼ 0.027) persisted. Women with FM who reported a history of physical or sexual abuse had lower CSF CRF levels than women who did not report such a history. CSF CRF levels are associated with both pain symptoms and variation in autonomic function in FM. Differences in CSF CRF levels among women with and without a self-reported history of physical or sexual abuse suggest that subgroups of FM patients may exist with different neurobiological characteristics. Further studies are needed to better understand the nature of the association between CSF CRF and pain symptoms in FM.

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Objective Although pain in knee osteoarthritis (OA) commonly affects activity engagement, the daily pain experience has not been fully-characterized. Specifically, the nature and impact of pain flares is not well-understood. This study characterized pain flares, defined by participants with knee OA; pain flare occurrence and experience were measured over 7 days. Methods This was a multiple methods study; qualitative methods were dominant. Data were collected during the baseline portion of a randomized controlled trial. Participants met criteria for knee OA and had moderate to severe pain. They completed questionnaires and a 7-day home monitoring period that captured momentary symptom reports simultaneously with physical activity via accelerometry (N = 45). Participants also provided individual definitions of pain flare which were used throughout the home monitoring period to indicate whether a pain flare occurred. Results Pain flares were described most often by quality (often sharp), followed by timing (seconds-minutes), and by antecedents and consequences. When asked if their definition of a flare agreed with a supplied definition, 49% of the sample reported only “somewhat”, “a little” or “not at all”. Using individual definitions, 78% experienced at least one daily pain flare over the home monitoring period; 24% had a flare on over 50% of the monitored days. Conclusions Pain flares were common, fleeting, and often experienced in the context of activity engagement. Participants’ views on what constitutes a pain flare differ from commonly accepted definitions. Pain flares are an understudied aspect of the knee OA pain experience and require further characterization.

Objective. To investigate autonomic abnormalities in male and female fibromyalgia (FM) and Gulf War illness (GWI) patients by comparing heart rate variability (HRV) with that of age-and sex-matched healthy controls. Methods. Subjects included 26 (19 women, 7 men) with FM, 11 (6 men, 5 women) with GWI, and 36 (18 men,18 women) healthy controls. HRV was determined from Holter recordings obtained in the Clinical Research Center. Analysis of variance compared 24-hour, daytime, and nighttime HRV by sex within groups and by group within sex. Results. In women with FM or GWI, HRV was significantly lower than in men with FM or GWI. HRV was similar in male and female controls. When HRV was compared by group within sex, HRV was significantly decreased in women with FM or GWI and no significant differences were seen for men with these conditions. Conclusion. Decreased HRV in FM and GWI appears to be sex dependent. Results suggest that different mechanisms may be operative in symptom expression in men and women with this spectrum of illness.