Perception of noxious and innocuous heat stimulation among healthy women and women with fibromyalgia: association with mood, somatic focus, and catastrophizing

Intensity dependence of auditory-evoked cortical potentials in fibromyalgia patients: a test of the generalized hypervigilance hypothesis

On the basis of recent evidence concerning the amplification of incoming stimulation in fibromyalgia (FM) patients, it has been proposed that a generalized hypervigilance of painful and nonpainful sensations may be at the root of this disorder. So far, research into this issue has been inconclusive, possibly owing to the lack of agreement as to the operational definition of "generalized hypervigilance" and to the lack of robust objective measures characterizing the sensory style of FM patients. In this study, we recorded auditory-evoked potentials (AEPs) elicited by tones of increasing intensity (60, 70, 80, 90, and 105 dB) in 27 female FM patients and 25 healthy controls. Fibromyalgia patients presented shorter N1 and P2 latencies and a stronger intensity dependence of their AEPs. Both results suggest that FM patients may be hypervigilant to sensory stimuli, especially when very loud tones are used. The most noteworthy difference between patients and control subjects is at the highest stimulus intensity, for which far more patients maintained increased N1-P2 amplitudes in relation to the 90-dB tones. The larger AEP amplitudes to the 105-dB tones suggest that defects in an inhibitory system protecting against overstimulation may be a crucial factor in the pathophysiology of FM. Because a stronger loudness dependence of AEPs has been related to weak serotonergic transmission, it is hypothesized that for many FM patients deficient inhibition of the response to noxious and intense auditory stimuli may be due to a serotonergic deficit.

PERSPECTIVE

The study of auditory-evoked potentials in response to tones of increasing intensity in FM patients may help to clarify the pathophysiology of this disorder, especially regarding the role of inhibition deficits involving serotonergic dysfunction, and may be a useful tool to guide the pharmacologic treatment of FM patients.

[Considerations on alterations in brain activity in patients with fibromyalgia]

Fibromyalgia is a chronic musculoskeletal pain disorder of unknown etiology, characterized by widespread pain. Clinical and experimental research has demonstrated that patients with fibromyalgia may have enhanced pain sensitivity at several points of the body, together with neuroendocrine abnormalities, and abnormal activation of pain-related brain regions. Recent data have also shown that affective and cognitive processing of pain-related information could also be disturbed in fibromyalgia. In our opinion, all these findings suggest the existence of abnormal central pain processing, which could be responsible for the persistence of chronic pain in these patients.

The relationship of adult attachment to emotion, catastrophizing, control, threshold and tolerance, in experimentally-induced pain

Although insecure attachment has been associated with a range of variables linked with problematic adjustment to chronic pain, the causal direction of these relationships remains unclear. Adult attachment style is, theoretically, developmentally antecedent to cognitions, emotions and behaviours (and might therefore be expected to contribute to maladjustment). It can also be argued, however, that the experience of chronic pain increases attachment insecurity. This project examined this issue by determining associations between adult attachment characteristics, collected prior to an acute (coldpressor) pain experience, and a range of emotional, cognitive, pain tolerance, intensity and threshold variables collected during and after the coldpressor task. A convenience sample of 58 participants with no history of chronic pain was recruited. Results demonstrated that attachment anxiety was associated with lower pain thresholds; more stress, depression, and catastrophizing; diminished perceptions of control over pain; and diminished ability to decrease pain. Conversely, secure attachment was linked with lower levels of depression and catastrophizing, and more control over pain. Of particular interest were findings that attachment style moderated the effects of pain intensity on the tendency to catastrophize, such that insecurely attached individuals were more likely to catastrophize when reporting high pain intensity. This is the first study to link attachment with perceptions of pain in a pain-free sample. These findings cast anxious attachment as a vulnerability factor for chronic pain following acute episodes of pain, while secure attachment may provide more resilience.

Catastrophizing and pain in arthritis, fibromyalgia, and other rheumatic diseases

OBJECTIVE

Pain is among the most frequently reported, bothersome, and disabling symptoms described by patients with osteoarthritis, rheumatoid arthritis, fibromyalgia, and other musculoskeletal conditions. This review describes a growing body of literature relating catastrophizing, a set of cognitive and emotional processes encompassing magnification of pain-related stimuli, feelings of helplessness, and a generally pessimistic orientation, to the experience of pain and pain-related sequelae across several rheumatic diseases.

METHODS

We reviewed published articles in which pain-related catastrophizing was assessed in the context of one or more rheumatic conditions. Because much of the available information on catastrophizing is derived from the more general chronic pain literature, seminal studies in other disease states were also considered.

RESULTS

Catastrophizing is positively related, in both cross-sectional and prospective studies across different musculoskeletal conditions, to the reported severity of pain, affective distress, muscle and joint tenderness, pain-related disability, poor outcomes of pain treatment, and, potentially, to inflammatory disease activity. Moreover, these associations generally persist after controlling for symptoms of depression. There appear to be multiple mechanisms by which catastrophizing exerts its harmful effects, from maladaptive influences on the social environment to direct amplification of the central nervous system's processing of pain.

CONCLUSION

Catastrophizing is a critically important variable in understanding the experience of pain in rheumatologic disorders as well as other chronic pain conditions. Pain-related catastrophizing may be an important target for both psychosocial and pharmacologic treatment of pain.

Abnormal affective modulation of somatosensory brain processing among patients with fibromyalgia

OBJECTIVE

It is well established that subjective pain perception can be modulated by negative mood states and that patients with chronic pain are characterized by high levels of depression and anxiety. Nevertheless, very little is known about the effects of negative mood induction on brain processing of somatosensory information in fibromyalgia. The objective of the present study was to examine the influence of two emotional states (pleasant and unpleasant) on brain activity of patients with fibromyalgia (FM; n = 27) and with musculoskeletal (MSK) pain resulting from identifiable somatic lesions (n = 16).

METHODS

For this purpose, somatosensory-evoked potentials (SEPs) elicited by nonpainful pneumatic stimuli, delivered to the right and left hand following an oddball paradigm, were recorded when patients were viewing affective slides.

RESULTS

As compared with patients with MSK pain, patients with FM displayed overall larger P50 amplitude to tactile stimuli. In addition, significantly larger P50 and smaller N80 amplitudes were found within patients with FM when they were viewing the unpleasant rather than the pleasant slides.

CONCLUSION

Our data suggest an abnormal processing of nonpainful somatosensory information in FM, especially when somatic signals are arising from the body within an aversive stimulus context. These findings provide further support for the use of biopsychosocial models for understanding FM and other chronic pain states.

Differences in unpleasantness induced by experimental pressure pain between patients with fibromyalgia and healthy controls

Pain possesses both sensory and affective dimensions, which are highly correlated yet distinct. Comparison of these dimensions within experimental pain settings has resulted in the construct of relative unpleasantness. Relative unpleasantness is defined as the amount of affective unpleasantness elicited for a given sensory magnitude. The aim of this study was to determine the relationship between affective and sensory components of evoked pain in subjects with fibromyalgia (FM) and healthy controls. Here we show that patients with FM unexpectedly display less relative unpleasantness than healthy controls in response to random noxious pressure stimuli. Relative unpleasantness was not correlated with distress, anxiety, or depression, which were pronounced in the FM group. Clinical pain in patients with FM was perceived to be more unpleasant than the evoked pain stimuli. These results are consistent with the concept that chronic pain may reduce the relative unpleasantness of evoked pain sensations.

Urinary electrophoretic profiles from chronic fatigue syndrome and chronic fatigue syndrome/fibromyalgia patients: a pilot study for achieving their normalization

Aim of our study was to determine if there were distinct, disease-related patterns of urinary analytes in chronic fatigue syndrome (CFS) and chronic fatigue syndrome/fibromyalgia (CFS/FM) compared to normal controls (NC). Urine was collected from these subjects for two consecutive 24 h periods and aliquots were submitted to micellar electrokinetic chromatography (MEKC). To compensate for the differences in peak migration times, these were normalized from the 35 min duration of run to a 100-point scale, and each peak was assigned its normalized time measure. Peak heights were also normalized by dividing the mAU by that of the internal standard (creatinine) and multiplying by 100. MEKC with normalization for peak height and migration time generated comparable results within each of the patient groups. CFS/FM and CFS had significant differences in peaks compared to NC that may be of significance as biomarkers of illnesses.

Positive affect as a source of resilience for women in chronic pain

A sample of 124 women with osteoarthritis or fibromyalgia, or both, completed initial assessments for demographic data, health status, and personality traits and 10-12 weekly interviews regarding pain, stress, negative affect, and positive affect. Multilevel modeling analyses indicated that weekly elevations of pain and stress predicted increases in negative affect. Both higher weekly positive affect as well as greater positive affect on average resulted in lower negative affect both directly and in interaction with pain and stress. Finally, increases in weekly negative affect and higher average negative affect related to greater levels of pain in subsequent weeks. In contrast, higher levels of overall positive affect predicted lower levels of pain in subsequent weeks.

Effects of chronic widespread pain on the health status and quality of life of women after breast cancer surgery

Background

Most research and treatment of post-breast cancer chronic pain has focused on local or regional pain problems in the operated area. The purpose of this pilot study was to compare and contrast the pain characteristics, symptom impact, health status, and quality of life of post-breast cancer surgery women with regional chronic pain versus those with widespread chronic pain.

Methods

A cross-sectional, descriptive design compared two groups of women with chronic pain that began after surgery: regional pain (n = 11) and widespread pain (n = 12). Demographics, characteristics of the surgery, as well as standardized questionnaires that measured pain (Brief Pain Inventory (BPI), Short Form McGill Pain Questionnaire (MPQ-SF)), disease impact (Fibromyalgia Impact Questionnaire (FIQ), Functional Assessment of Cancer Therapy-Breast (FACT-B)), health status (Medical Outcomes Short Form (SF-36)) and quality of life (Quality of Life Scale (QOLS)) were gathered.

Results

There were no significant differences between the groups on any demographic or type of surgery variable. A majority of both groups described their pain as aching, tender, and sharp on the MPQ-SF. On the BPI, intensity of pain and pain interference were significantly higher in the widespread pain group. Differences between the two groups reached statistical significance on the FIQ total score as well as the FACT-B physical well-being, emotional well-being and breast concerns subscales. The SF-36 physical function, physical role, and body pain subscales were significantly lower in the widespread pain group. QOLS scores were lower in the widespread pain group, but did not reach statistical significance.

Conclusion

This preliminary work suggests that the women in this study who experienced widespread pain after breast cancer surgery had significantly more severity of pain, pain impact and lower physical health status than those with regional pain.

Influence of social support and emotional context on pain processing and magnetic brain responses in fibromyalgia

OBJECTIVE

To examine the effects of social support provided by the presence of patient's significant other on pain ratings, pain thresholds, and brain activity associated with tactile stimulation in 18 fibromyalgia (FM) patients and 18 migraine patients (controls), and to assess the influence of emotional context on thermal pain perception and processing of non-pain-related information.

METHODS

Thermal pain thresholds and somatosensory brain magnetic responses elicited by tactile stimulation at the elbow (a painful tender point in the FM group) and at the finger (nonpainful site) were evaluated under 2 experimental conditions of social support: patient alone and patient's significant other present. Brain activity was recorded using a 151-channel whole-head magnetoencephalography system. Additionally, the emotional context during presentation of tactile stimuli was manipulated by presenting aversive, pain-related pictures and neutral pictures and asking the patients to imagine that they were experiencing the situations depicted.

RESULTS

Thermal pain thresholds indicated greater sensitivity in FM patients than in migraine patients, as well as enhanced sensitivity at the elbow than at the fingers. Specifically, in FM patients, there were significant reductions in pain sensitivity and subjective pain ratings when patients were stimulated at the painful tender point in the presence of their significant others as compared with the ratings when the patients were alone. Brain activity elicited by elbow stimulation was also significantly reduced in FM patients when a significant other was present as compared with the activity when the patient was alone. These effects were not observed in the migraine patients.

CONCLUSION

When the significant other was present, FM patients reported less pain and thermal pain sensitivity and showed diminished brain activity elicited upon tactile stimulation of a tender point compared with these levels when the patients were alone. These findings are consistent with the hypothesis that social support through the presence of a significant other can influence pain processing at the subjective-behavioral level as well as the central nervous system level.

Relationship between changes in coping and treatment outcome in patients with Fibromyalgia Syndrome

The present study utilized a sample of 198 individuals with Fibromyalgia Syndrome (FMS) to examine the association between treatment process variables (beliefs, coping strategies) and treatment outcomes (pain severity, activity level, emotional distress and life interference) related to a 4-week multidisciplinary fibromyalgia treatment program. Multiple regression analyses were utilized to evaluate these relationships pretreatment to posttreatment as well as from pretreatment to 3- and 6-month follow-ups. The results indicated that outcomes were most closely related to: (1) an increased sense of control over pain, (2) a belief that one is not necessarily disabled by FM, (3) a belief that pain is not necessarily a sign of damage, (4) decreased guarding, (5) increased use of exercise, (6) seeking support from others, (7) activity pacing and (8) use of coping self-statements. These findings are consistent with a cognitive-behavioural model of fibromyalgia, and suggest targets for therapeutic change.