Psychophysiological responses in patients with fibromyalgia syndrome

Aberrances in autonomic cardiovascular regulation in fibromyalgia syndrome and their relevance for clinical pain reports

OBJECTIVE

To investigate autonomic cardiovascular regulation in fibromyalgia syndrome (FMS).

METHODS

In 35 patients and 29 healthy controls, electrocardiography, impedance cardiography, and finger continuous blood pressure measurements were conducted. Assessed parameters comprised blood pressure, R-R interval (RRI), heart rate variability, baroreflex sensitivity (BRS), stroke volume, and left ventricular ejection time (LVET). To evaluate cardiovascular autonomic reactivity to mental stress, parameters were obtained at rest and during an arithmetic task. As an estimate of clinical pain severity, participants completed the McGill Pain Inventory.

RESULTS

Patients exhibited lower power in all heart rate variability frequency bands (p < .05), lower BRS (7.13 +/- 3.45 versus 10.73 +/- 5.72 ms/mmHg), as well as reduced stroke volume, LVET, and RRI (p < .05). Stress-induced modulations were less pronounced in BRS, LVET, blood pressure, and RRI (all p < .05). Across the whole sample and in both subgroups, BRS (r = -.40) and blood pressure (r = -.39) correlated negatively with pain severity.

CONCLUSIONS

The data suggest that autonomic cardiovascular regulation in FMS is impaired in terms of reduced sympathetic and parasympathetic influences, as well as baroreflex malfunctioning. Furthermore, autonomic cardiovascular adjustment to acute stress is blunted. The inverse association between BRS and pain severity reflects the well-documented pain inhibition through the baroreceptor system. On account of this and the reduced baroreflex function in FMS, one may assume deficient ascending pain inhibition arising from the cardiovascular system, which may contribute to hyperalgesia that is characteristic of the disorder.

Deviations in the endocrine system and brain of patients with fibromyalgia: cause or consequence of pain and associated features?

The brain and endocrine system are crucial interfaces responding to pathological and psychological processes. This review discusses whether endocrine deviations and structural and functional changes in the brain are a cause or consequence of fibromyalgia. Studies in patients with fibromyalgia virtually uniformly observed subtle alterations in hypothalamic pituitary adrenal functioning, hyporeactive autonomic nervous system responsiveness to stressors, and structural and functional changes in the brain. Our model proposes that predisposing factors, such as genetic vulnerability and trauma, have led to an alteration of the nociceptive system including several neuroendocrine changes. The resulting pain and associated symptoms, such as sleep disturbance, low fitness, fatigue, stress, and distress, are a cause of new neuroendocrine changes. The model predicts that favorable neuroendocrine changes are to be expected after successful pharmacological or non-pharmacological interventions that target pain and associated symptoms.

Physiological responses to low-force work and psychosocial stress in women with chronic trapezius myalgia

Background

Repetitive and stressful work tasks have been linked to the development of pain in the trapezius muscle, although the underlying mechanisms still remain unclear. In earlier studies, it has been hypothesized that chronic muscle pain conditions are associated with imbalance in the autonomic nervous system, predominantly expressed as an increased sympathetic activity. This study investigates whether women with chronic trapezius myalgia show higher muscle activity and increased sympathetic tone at baseline and during repetitive low-force work and psychosocial stress, compared with pain-free controls.

Methods

Eighteen women with chronic trapezius myalgia (MYA) and 30 healthy female controls (CON) were studied during baseline rest, 100 min of repetitive low-force work, 20 min of psychosocial stress (Trier Social Stress Test, TSST), and 80 min recovery. The subjects rated their pain intensity, stress and energy level every 20 min throughout the experiment. Muscle activity was measured by surface electromyography in the trapezius muscle (EMGtrap) and deltoid muscle (EMGdelt). Autonomic reactivity was measured through heart rate (HR), skin conductance (SCL), blood pressure (MAP) and respiration rate (Resp).

Results

At baseline, EMGtrap, stress ratings, and HR were higher in MYA than in CON. Energy ratings, EMGdelt, SCL, MAP and Resp were, however, similar in the two groups. Significant main group effects were found for pain intensity, stress ratings and EMGtrap. Deltoid muscle activity and autonomic responses were almost identical in MYA and CON during work, stress and recovery. In MYA only, pain intensity and stress ratings increased towards the end of the repetitive work.

Conclusion

We found increased muscle activity during uninstructed rest in the painful muscle of a group of women with trapezius myalgia. The present study could not confirm the hypothesis that chronic trapezius myalgia is associated with increased sympathetic activity. The suggestion of autonomic imbalance in patients with chronic local or regional musculoskeletal pain needs to be further investigated.

Mindfulness meditation for symptom reduction in fibromyalgia: psychophysiological correlates

OBJECTIVES

Fibromyalgia, a chronic pain syndrome, is often accompanied by psychological distress and increased basal sympathetic tone. In a previous report it was shown that mindfulness-based stress-reduction (MBSR) reduced depressive symptoms in patients with fibromyalgia with gains maintained at two months follow-up (Sephton et al., Arthr Rheum 57:77-85, 2007). This second study explores the effects of MBSR on basal sympathetic (SNS) activation among women with fibromyalgia.

METHODS

Participants (n = 24) responded to a television news appearance, newspaper, and radio advertisements. Effects on anxiety, depressive symptoms, and SNS activation measures were tested before and after MBSR using a within-subjects design.

RESULTS

The MBSR treatment significantly reduced basal electrodermal (skin conductance level; SCL) activity (t = 3.298, p = .005) and SCL activity during meditation (t = 4.389, p = .001), consistent with reduced SNS activation.

CONCLUSIONS

In this small sample, basal SNS activity was reduced following MBSR treatment. Future studies should assess how MBSR may help reduce negative psychological symptoms and attenuate SNS activation in fibromyalgia. Further clarification of psychological and physiological responses associated with fibromyalgia may lead to more beneficial treatment.

Treatment options and patient perspectives in the management of fibromyalgia: future trends

Fibromyalgia (FM) is a common, complex, and difficult to treat chronic widespread pain disorder, which usually requires a multidisciplinary approach using both pharmacological and non-pharmacological (education and exercise) interventions. It is a condition of heightened generalized sensitization to sensory input presenting as a complex of symptoms including pain, sleep dysfunction, and fatigue, where the pathophysiology could include dysfunction of the central nervous system pain modulatory systems, dysfunction of the neuroendocrine system, and dysautonomia. A cyclic model of the pathophysiological processes is compatible with the interrelationship of primary symptoms and the array of postulated triggers associated with FM. Many of the molecular targets of current and emerging drugs used to treat FM have been focused to the management of discrete symptoms rather than the condition. Recently, drugs (eg, pregabalin, duloxetine, milnacipran, sodium oxybate) have been identified that demonstrate a multidimensional efficacy in this condition. Although the complexity of FM suggests that monotherapy, non-pharmacological or pharmacological, will not adequately address the condition, the outcomes from recent clinical trials are providing important clues for treatment guidelines, improved diagnosis, and condition-focused therapies.

Dysfunctional beliefs, stress and sleep disturbance in fibromyalgia

OBJECTIVE

To explore sleep-related dysfunctional beliefs, stress levels and sleep quality in patients with fibromyalgia in comparison to healthy controls.

METHODS

One hundred sixty-six participants (83 patients with fibromyalgia and 83 healthy controls) completed self-report measures exploring beliefs and attitudes about sleep, perceived stress, sleep quality and levels of pain and fatigue.

RESULTS

Relative to healthy controls, patients with fibromyalgia revealed significantly higher levels of dysfunctional beliefs and attitudes about sleep and perceived stress. High dysfunctional beliefs were significantly associated with poorer sleep quality and high perceived stress was significantly related to higher sleep disturbances and daytime dysfunction.

CONCLUSIONS

Beliefs about sleep and perceived stress play a significant role in the sleep quality of patients with fibromyalgia. Interventions to improve sleep quality for people with fibromyalgia need to identify and address dysfunctional beliefs about sleep and incorporate stress management approaches.

Pain, disability and coping reflected in the diurnal cortisol variability in patients scheduled for lumbar disc surgery

BACKGROUND

Symptoms of lumbar disc herniation can be induced by both mechanical compression of the nerve roots and by biochemical irritants from the disc tissues. Proinflammatory cytokines, as well as stress are potent stimulators of the hypothalamic-pituitary-adrenal axis, reflected in enhanced release of cortisol from the adrenal cortex. Altered cortisol production is also associated to behaviour and coping patterns. The aim of the present study was to explore the relation between pain, physical function, psychosocial factors and quality of life to the diurnal cortisol variability, in patients with lumbar disc herniation.

METHOD

This study had a cross-sectional design. Forty-two patients with lumbar disc herniation, verified by magnetic resonance imaging and a clinical examination by an orthopaedic surgeon, were included in the study. All patients were scheduled for disc surgery. The diurnal cortisol variability was examined before surgery. The patients were dichotomised into two groups based on low or high diurnal cortisol variability. Pain, disability, work related stress, quality of life, coping and fear avoidance beliefs, were estimated by standardised questionnaires.

RESULTS

The low diurnal cortisol variability group was distinguished by a higher median score regarding leg pain at activity and significantly more disability (p<0.05). The patients with a low diurnal cortisol variability had significantly lower coping self-statement scores, but higher pain coping catastrophising scores (p<0.05).

CONCLUSION

Patients with lumbar disc herniation and a low diurnal cortisol variability had lower physical function, perceived lower possibilities of influencing their pain, and were more prone to catastrophise than patients with lumbar disc herniation and a high diurnal cortisol variability.

Heterogeneity of psychophysiological stress responses in fibromyalgia syndrome patients

Dysregulated psychophysiological responses have been observed in patients with fibromyalgia syndrome (FMS), although the results are inconsistent. Surface electromyographic (EMG), systolic and diastolic blood pressure, heart rate (HR), and skin conductance levels (SCLs) were continuously recorded at baseline, and during a series of stress and relaxation tasks in 90 FMS patients and 30 age and sex matched healthy controls (HCs). The patient sample demonstrated lower baseline EMG levels compared to the HCs on all tasks. In contrast, the patients displayed elevated HR and SCL (sympathetic vasomotor and sudomotor indices, respectively) during both stress tasks. A cluster analysis identified four psychophysiological response patterns: 63.3% of HCs showed increased muscle tension and stable cardiovascular responses; 34.8% of FMS patients showed a pattern of increased sympathetic vasomotor reactivity with stable sudomotor and reduced muscular response; 12.2% of FMS patients showed a pattern of increased sympathetic sudomotor reactivity connected with increased sympathetic vasomotor response and reduced muscular response; and, in contrast, 46.7% of FMS patients showed a pattern of parasympathetic vasomotor reactivity and reduced sudomotor as well as muscular response. The identification of low baseline muscle tension in FMS is discrepant with other chronic pain syndromes and suggests that unique psychophysiological features may be associated with FMS. The different psychophysiological response patterns within the patient sample support the heterogeneity of FMS.