Predictors of Mucosal and Muscle Pain in Vulvodynia: A Cross-Sectional Analysis From the National Vulvodynia Registry

Diagnostic criteria for provoked vestibulodynia (PVD) rely on mucosal pain in the vulvar vestibule, with less emphasis on pain from pelvic floor muscles. It is unknown how psychosocial variables associated with PVD are differentially associated with mucosal versus muscle pain. Analysis of data from the National Vulvodynia Registry (n = 202) revealed several factors associated with increased mucosal pain: pain duration (P = .043), the McGill sensory subscore (P = .0086) and the Gracely pain scale (P< .001). Increased mucosal pain was also associated with decreased arousal (P = .036). On the other hand, factors significantly associated with greater muscle pain included number of comorbid pain conditions (P = .001), decreased intercourse frequency post PVD onset (P = .02) and higher scores on the McGill sensory (P = .0001) and affective (P = .0002) subscores, the Gracely pain scale (P = .0012), and state anxiety (P < .001). Sexual function was also significantly impacted by high pelvic floor muscular pain, with lower scores for arousal (P = .046), orgasm (P = .0014) and satisfaction (P = .013), and higher pain (P = .01). Significant differences in the relationship between muscle and mucosal pain for pain duration (P = .005), McGill affective score (P = .001), orgasm (P = .049), change in intercourse frequency (P = .027), and state anxiety (P = .030) suggest the possibility of mucosal or muscle pain predominant PVD subtypes. PERSPECTIVE: Patients with higher pelvic floor muscle pain scores than mucosal pain scores may represent different subgroups or characteristics of patients with provoked vestibulodynia. This research highlights the importance of assessment of the pelvic floor muscles in addition to the cotton swab test of the vestibule.

Chronic Pregabalin Treatment Ameliorates Pain, but not Depressive-Like Behaviors, in a Reserpine-Induced Myalgia Model in Rats

BACKGROUND

Anticonvulsants are often prescribed as coanalgesics for pathologies presenting chronic pain, such as chronic neuropathic pain and fibromyalgia. These pathologies are associated with a wide range of comorbidities: chronic fatigue, cognitive impairment, sleep disturbances, and mood disorders. Pregabalin, an anticonvulsant used to treat fibromyalgia syndrome, has been proven to improve pain and fatigue symptoms. However, most studies have not considered the analytic effect of this drug on comorbid depressive-like symptoms in this syndrome.

OBJECTIVES

The main study objective was to examine the role of pregabalin in depressive symptomatology comorbid to chronic widespread pain using a reserpine-induced myalgia model.

STUDY DESIGN

A randomized, controlled, animal study.

SETTING

Research and data analyses were performed at the GESADA laboratory, Department of Human Anatomy and Embryology, University of Valencia, Spain.

METHODS

Forty-six Sprague-Dawley male rats were used. Acute chronic pregabalin administration was tested for depressive-like behaviors (Forced Swimming and Novelty-Suppressed Feeding Tests) and for alteration of pain thresholds (tactile allodynia, Electronic Von Frey test; and mechanical hyperalgesia, Randall and Selitto test). The same procedures were followed with duloxetine as a positive control.

RESULTS

Pregabalin significantly improved depressive-like behaviors in acute, but not chronic treatment, and significantly ameliorated pain thresholds.

LIMITATIONS

Lack of histological and electrophysiological tests.

CONCLUSIONS

Pregabalin is not effective in depressive-like symptoms associated with chronic pain but might play an acute antidepressive-like role given its antinociceptive effect.

Thermal Infrared Imaging Can Differentiate Skin Temperature Changes Associated With Intense Single Leg Exercise, But Not With Delayed Onset of Muscle Soreness

Muscle damage and soreness associated with increased exercise training loads or unaccustomed activity can be debilitating and impact the quality of subsequent activity/performance. Current techniques to assess muscle soreness are either time consuming, invasive or subjective. Infrared thermography has been identified as a quick, non-invasive, portable and athlete friendly method of assessing skin temperature. This study assessed the capability of thermal infrared imaging to detect skin temperature changes that may accompany the inflammatory response associated with delayed onset muscular soreness (DOMS). Eight recreationally trained participants (age 25 ± 3 years, mass 74.9 ± 13.6 kg, training minutes 296 ± 175 min·wk^-1) completed 6 sets of 25 maximal concentric/eccentric contractions of the right knee flexors/extensors on a dynamometer to induce muscle damage and DOMS. The left knee extensors acted as a non-exercise control. Neuromuscular performance, subjective pain assessment and infrared thermography were undertaken at baseline, 24 and 48 hr post the DOMS-inducing exercise protocol. Data were analysed using Bayesian hierarchical regression and Cohen's d was also calculated. Maximal voluntary contraction torque was statistically lower at 24 hr (d = -0.70) and 48 hr (d = -0.52) compared to baseline, after the DOMS-inducing exercise protocol. These neuromuscular impairments coincided with statistically higher ratings of muscle soreness at 24 hr (d = 0.96) and 48 hr (d = 0.48). After adjusting for ambient temperature, anterior thigh skin temperature was statistically elevated at 24 hr, but not 48 hr, compared with baseline, in both the exercised and non-exercised leg. Thigh temperature was not different statistically between legs at these time points. Infrared imaging was able to detect elevations in skin temperature, at 24 hrs after the DOMS inducing exercise protocol, in both the exercised and non-exercised thigh. Elevations in the skin temperature of both thighs, potentially identifies a systemic inflammatory response occurring at 24 hr after the DOMS-inducing exercise protocol.

No Influence of Prematch Subjective Wellness Ratings on External Load During Elite Australian Football Match Play

PURPOSE

To determine whether there is an association between external match load and contextual factors on subjective wellness in the days before and after Australian Rules football match play.

METHODS

A total of 34 elite male Australian football players completed a subjective wellness questionnaire in the days leading into the match (-3, -2, and -1 d), the day of (match day), and the days after each match (+3, +2, and +1 d). Players subjectively rated each item (mood, energy, stress, leg heaviness, muscle soreness, sleep quality, hours slept, and total wellness [a sum of the total response score]) on a visual analog scale ranging from 1 to 10, with 1 representing the negative end of the continuum. External load during competitive matches was quantified using accelerometer-derived PlayerLoad, and running activity was quantified using global positioning system technology across 2 competitive seasons. The relationships between perceptions of wellness (within-individual z score), external match load, and contextual factors (match result, match location, and between-matches recovery duration) were analyzed using linear mixed models.

RESULTS

Mixed-effect linear models revealed trivial effects of match-day wellness z score on subsequent external match load metrics. Match result (win) and PlayerLoad in the anteroposterior vector (au·min-1) were associated with an increased (estimate ± SE: 0.30 ± 0.13 z score) and reduced subjective wellness (-0.15 ± 0.06 z score), respectively.

CONCLUSION

The results of this study suggest that prematch perceived wellness does not relate to external match load in elite Australian football players. The between-matches microcycle length appears to be sufficient to restore perceived wellness to values that do not affect the subsequent external match loads.

Associations between the injustice experience questionnaire and treatment term in patients with acute Whiplash-associated disorder in Japan: Comparison with Canadian data

Introduction

This study aimed to investigate the differences in the Injustice Experience Questionnaire (IEQ) scores during the early period after the diagnosis of Whiplash-associated disorder (WAD) between Japanese and Canadian samples, and the associations between the IEQ scores and treatment terms in Japanese patients with acute WAD.

Methods

We used secondary data for the IEQ scores of Canadian patients with acute WAD. In Japan, we collected data from 85 consecutively enrolled patients with acute WAD, and their treatment terms were collected; these referred to the number of days between the date of injury and the closure date of the insurance claim and the number of treatment visits. Before treatment, the Numeric Rating Scale, Neck Disability Index, Hospital Anxiety and Depression Scale, IEQ, and Euro Quality of Life five-dimensional questionnaire were administered. The variables were subjected to multivariate analysis with each treatment term.

Results

The IEQ scores were higher in Japan than in Canada. Through multiple regression analysis, IEQ scores were independently correlated with treatment terms. The optimal cutoff point of the IEQ scores for a prolonged treatment term was 21 and 22 points, respectively.

Conclusions

The IEQ scores were associated with treatment terms in patients with acute WAD in Japan.

The effectiveness of stabilization appliance therapy among patients with myalgia

BACKGROUND

The efficacy of stabilization appliance therapy for masticatory muscle pain is debated. Therefore, there are currently no clear usage standards. We analyzed patient factors influencing its efficacy and characterized masticatory muscle pain subtypes to determine appropriate therapy candidates.

METHODS

This case series study recruited patients diagnosed with local myalgia or myofascial pain and used variables related to temporomandibular disorders in the analysis. We used temporary appliance to screen patients for sleep bruxism for 2 weeks. Afterwards, we initiated therapy with stabilization appliances. Efficacy was evaluated via tenderness intensity during muscle palpation and the treatment satisfaction score after 2 months of treatment.

RESULTS

We analyzed 62 (91%) patients. Tenderness upon muscle palpation was mitigated in 27 patients. Mitigated tenderness odds ratios were 0.035 for myofascial pain, 0.804 for 15-item Patient Health Questionnaire scores, and 1.915 for facet length. Thirty-nine patients expressed satisfaction; satisfaction odds ratios were 0.855 for 9-item Patient Health Questionnaire scores, 1.606 for facet length, and 4.023 for awake bruxism awareness.

CONCLUSIONS

Stabilization appliance therapy is most effective for patients with awake bruxism awareness, local myalgia, long facets, and no psychosocial risk factors.

The cardinal exercise stopper: Muscle fatigue, muscle pain or perception of effort?

The capacity to sustain high-intensity aerobic exercise is essential for endurance performance. Therefore, it is important to understand what is the factor limiting time to exhaustion (TTE) in healthy and fit adults. In Study 1, maximal voluntary cycling power (MVCP) was measured in 11 volunteers before and immediately after a high-intensity TTE test on cycle ergometer. Cadence was 60 rpm in both the MVCP and TTE tests. Despite a 35% loss in MVCP, power produced during the final MVCP test (mean ± SD 469 ± 111 W) was significantly higher than the power required by the TTE test (269 ± 55 W) (P < 0.001). In Study 2, 12 participants performed a cold pressor test (CPT) to the limit of tolerance followed by a high-intensity TTE test on cycle ergometer. Ratings of pain unpleasantness (RPU) during the TTE test were anchored to the unpleasantness of pain experienced during the CPT. On average, the RPU was 9.7 ± 0.4 at completion of the CPT and 5.0 ± 0.9 at exhaustion during the TTE test. The difference between these two ratings of pain unpleasantness was statistically significant (P < 0.001). In both Studies 1 and 2, the slope of the rating of perceived exertion (RPE) during the TTE test correlated significantly with TTE (r = -0.75 and -0.83, P < 0.01). Results of this two-part investigation suggest that perception of effort, rather than severe locomotor muscle fatigue or intolerably unpleasant muscle pain, is the cardinal exercise stopper during high-intensity aerobic exercise.

Reorganization of motor unit activity at different sites within the human masseter muscle during experimental masseter pain

The aims were to test the hypotheses that experimental masseter muscle pain leads to recruitment and/or derecruitment of motor units at different sites within the masseter and that the patterns of change in motor unit activity differ between sites. Single motor unit (SMU) activity was recorded at two sites within the right masseter [superior/anterior, inferior/posterior (IP)] during isometric biting tasks (ramp, step level) on an intraoral force transducer in 17 participants during three experimental blocks comprising no infusion (baseline), 5% hypertonic saline infusion (pain), or isotonic saline infusion (control). A visual analog scale (VAS) was used to score pain intensity. The VAS scores were statistically significantly greater during infusion of hypertonic saline than during infusion of isotonic saline. No significant differences in force levels and rates of force change were found between experimental blocks. In comparison with isotonic saline infusion, SMUs could be recruited and derecruited at both sites during hypertonic saline infusion. The frequency of recruitment or derecruitment, in comparison with no change, was statistically significantly greater at the IP site than at the superior/anterior site. Experimental noxious masseter stimulation results in a reorganization of motor unit activity throughout the muscle, and the pattern of reorganization may be different in different regions of the muscle.

Influence of Baseline Psychological Health on Muscle Pain During Atorvastatin Treatment

BACKGROUND

3-hydroxy-3-methylglutaryl coenzyme A reductase reductase inhibitors (statins) are generally well tolerated, with statin-associated muscle symptoms (SAMS) the most common side effect (~10%) seen in statin users. However, studies and clinical observations indicate that many of the self-reported SAMS appear to be nonspecific (ie, potentially not attributable to statins).

OBJECTIVE

Mental health and well-being influence self-perception of pain, so we sought to assess the effect of baseline well-being and depression on the development of muscle pain with 6 months of atorvastatin 80 mg/d (ATORVA) or placebo in healthy, statin-naive adults.

METHODS

The Psychological General Well-being Index (n = 83) and Beck Depression Inventory (n = 55) questionnaires were administered at baseline in participants (aged 59.5 ± 1.2 years) from the effect of Statins on Skeletal Muscle Function and Performance (STOMP) trial (NCT00609063). Muscle pain (Short-Form McGill Pain Questionnaire [SF-MPQ]), pain that interferes with daily life (Brief Pain Inventory [BPI]), and pain severity (BPI) were then measured before, throughout, and after treatment.

RESULTS

At baseline, there were no differences in well-being (Psychological General Well-being Index), depression (Beck Depression Inventory), or pain measures (SF-MPQ and BPI) (P values ≥ .05) between the placebo and ATORVA groups. Baseline well-being correlated negatively with baseline BPI pain severity (r = -0.290, P = .008). Baseline depression correlated with baseline pain (SF-MPQ; r = 0.314, P = .020). Baseline well-being and depression did not predict the change in pain severity or interference after 6 months among the total sample or between groups (P values ≥ .05).

CONCLUSION

Baseline well-being and depression were not significant predictors of pain after 6 months of ATORVA (P values ≥ .05). Thus, they do not appear to increase the risk of SAMS in otherwise healthy adults.

[Chronic pain : Perception, reward and neural processing]

Many chronic pain syndromes are characterized by enhanced perception of painful stimuli as well as alterations in cortical processing in sensory and motor regions. In this review article the alterations in muscle pain and neuropathic pain are described. Alterations in patients with fibromyalgia and chronic back pain are described as examples for musculoskeletal pain and also in patients with phantom limb pain after amputation and complex regional pain syndrome as examples for neuropathic pain. In addition to altered pain perception, cumulative evidence on alterations in the processing of reward and the underlying mechanisms in chronic pain has been described. A description is given of what is known on how pain and reward interact and affect each other. The relevance of such interactions for chronic pain is discussed. The implications of these findings for therapeutic approaches are delineated with respect to sensorimotor training and behavioral therapy, focusing on the effectiveness of these approaches, mechanisms and future developments. In particular, we discuss operant behavioral therapy in patients with chronic back pain and fibromyalgia as well as prosthesis training in patients with phantom limb pain and discrimination, mirror and imaginary training in patients with phantom limb pain and complex regional pain syndrome. With respect to the processing of reward, the focus of the discussion is on the role of reward and associated learning in pain therapy.

Satisfaction with Life in Orofacial Pain Disorders: Associations and Theoretical Implications

AIMS

To test if patients with masticatory myofascial pain, local myalgia, centrally mediated myalgia, disc displacement, capsulitis/synovitis, or continuous neuropathic pain differed in self-reported satisfaction with life. The study also tested if satisfaction with life was similarly predicted by measures of physical, emotional, and social functioning across disorders.

METHODS

Satisfaction with life, fatigue, affective distress, social support, and pain data were extracted from the medical records of 343 patients seeking treatment for chronic orofacial pain. Patients were grouped by primary diagnosis assigned following their initial appointment. Satisfaction with life was compared between disorders, with and without pain intensity entered as a covariate. Disorder-specific linear regression models using physical, emotional, and social predictors of satisfaction with life were computed.

RESULTS

Patients with centrally mediated myalgia reported significantly lower satisfaction with life than did patients with any of the other five disorders. Inclusion of pain intensity as a covariate weakened but did not eliminate the effect. Satisfaction with life was predicted by measures of physical, emotional, and social functioning, but these associations were not consistent across disorders.

CONCLUSIONS

Results suggest that reduced satisfaction with life in patients with centrally mediated myalgia is not due only to pain intensity. There may be other factors that predispose people to both reduced satisfaction with life and centrally mediated myalgia. Furthermore, the results suggest that satisfaction with life is differentially influenced by physical, emotional, and social functioning in different orofacial pain disorders.

A survey of joint and muscle aches, pain, and stiffness comparing women with and without breast cancer

CONTEXT

Joint and muscle aches, pain, and stiffness have been reported to be a problem for some women after adjuvant breast cancer treatment; however, the extent and impact of this problem are unknown.

OBJECTIVES

The purpose of this study was to determine the prevalence of this problem in comparison with women of a similar age without breast cancer.

METHODS

Two hundred forty-seven women attending breast cancer follow-up clinics were invited to complete pain and quality-of-life measures. A comparison group of 274 women of similar age was drawn from women attending breast screening and benign breast clinics. Prevalence and severity of pain were compared between the two groups.

RESULTS

The mean age of all women in the study was 59 years (range 30-86 years). The median time since diagnosis of cancer was 28 months (range 2-184 months). Adjuvant treatments included radiotherapy (79%), chemotherapy (45%), and hormone therapy (81%). Sixty-two percent of women with breast cancer reported pain "today" compared with 53% of women without breast cancer (P = 0.023). Significant predictors of pain in both patient groups were cancer, age, and arthritis. For the cancer cases, significant predictors of pain were age, arthritis, taxane chemotherapy, aromatase inhibitors, and tamoxifen. Quality of life (measured by the Short Form-36) was significantly worse for women with breast cancer compared with controls and was significantly worse in the breast cancer cases with pain.

CONCLUSION

Treatment with tamoxifen, taxane chemotherapy, and aromatase inhibitors for breast cancer is predictive of joint pain, which may have an impact on women's lives for some years after breast cancer.