Muscle activity and acute stress in fibromyalgia

Transcutaneous auricular vagus nerve stimulation modulates masseter muscle activity, pain perception, and anxiety levels in university students: a double-blind, randomized, controlled clinical trial

Introduction

Chronic anxiety is a statemarked by sustained activation of the masseter muscle, manifesting in both mental and physical strain. This prolonged tension can significantly impact mental wellbeing and cognitive abilities, posing a risk for a range of health complications. This double-blind, randomized, controlled clinical trial investigated the impact of transcutaneous auricular vagus nerve stimulation (TAVNS) on masseter muscle activity, pressure pain threshold (PPT), and anxiety levels in university students with elevated anxiety.

Methods

Forty-two participants meeting inclusion criteria were randomly assigned to either active TAVNS or sham TAVNS groups. Various parameters, including masseter muscle electromyographic (EMG) signals, PPT, and Beck Anxiety Inventory (BAI) scores, were assessed before pretreatment, immediately after the intervention week, and 2 weeks follow-up.

Results

Active TAVNS significantly reduced both left and right masseter activation during resting mandibular position, persisting for 2 weeks post-intervention. Additionally, TAVNS induced a lasting decrease in both left and right masseter PPT, indicative of altered pain perception. Notably, BAI scores showed a substantial reduction, emphasizing TAVNS as a potential intervention for anxiety, with effects maintained at the 2-week follow-up.

Discussion

This study provides comprehensive insights into the multifaceted effects of TAVNS on physiological and psychological aspects associated with anxiety in university students. The promising results underscore TAVNS as a potential neuromodulatory intervention for anxiety-related conditions, warranting further research and clinical exploration.

Clinical Trial Registration

https://ensaiosclinicos.gov.br/rg/RBR-4s4kt2r.

Machine learning identifies fatigue as a key symptom of fibromyalgia reflected in tyrosine, purine, pyrimidine, and glutaminergic metabolism

Fibromyalgia patients vary in clinical phenotype and treatment can be challenging. The pathophysiology of fibromyalgia is incompletely understood but appears to involve metabolic changes at rest or in response to stress. We enrolled 54 fibromyalgia patients and 31 healthy controls to this prospective study. Symptoms were assessed using the Fibromyalgia Impact Questionnaire (FIQ) and blood samples were collected for metabolomics analysis at baseline and after an oral glucose tolerance test and a cardiopulmonary exercise test. We identified key symptoms of fibromyalgia and related them to changes in metabolic pathways with supervised and unsupervised machine learning methods. Algorithms trained with the FIQ information assigned the fibromyalgia diagnosis in new data with balanced accuracy of 88% while fatigue alone already provided the diagnosis with 86% accuracy. Supervised analyses reduced the metabolomic information from 77 to 13 key markers. With these metabolites, fibromyalgia could be identified in new cases with 79% accuracy. In addition, 5-hydroxyindole-3-acetic acid and glutamine levels correlated with the severity of fatigue. Patients differed from controls at baseline in tyrosine and purine pathways, and in the pyrimidine pathway after the stress challenges. Several key markers are involved in glutaminergic neurotransmission. This data-driven analysis highlights fatigue as a key symptom of fibromyalgia. Fibromyalgia is associated with metabolic changes which also reflect the degree of fatigue. Responses to metabolic and physical stresses result in a metabolic pattern that allows discrimination of fibromyalgia patients from controls and narrows the focus on key pathophysiological processes in fibromyalgia as treatment targets.

Pain-sensorimotor interactions: New perspectives and a new model

How pain and sensorimotor behavior interact has been the subject of research and debate for many decades. This article reviews theories bearing on pain-sensorimotor interactions and considers their strengths and limitations in the light of findings from experimental and clinical studies of pain-sensorimotor interactions in the spinal and craniofacial sensorimotor systems. A strength of recent theories is that they have incorporated concepts and features missing from earlier theories to account for the role of the sensory-discriminative, motivational-affective, and cognitive-evaluative dimensions of pain in pain-sensorimotor interactions. Findings acquired since the formulation of these recent theories indicate that additional features need to be considered to provide a more comprehensive conceptualization of pain-sensorimotor interactions. These features include biopsychosocial influences that range from biological factors such as genetics and epigenetics to psychological factors and social factors encompassing environmental and cultural influences. Also needing consideration is a mechanistic framework that includes other biological factors reflecting nociceptive processes and glioplastic and neuroplastic changes in sensorimotor and related brain and spinal cord circuits in acute or chronic pain conditions. The literature reviewed and the limitations of previous theories bearing on pain-sensorimotor interactions have led us to provide new perspectives on these interactions, and this has prompted our development of a new concept, the Theory of Pain-Sensorimotor Interactions (TOPSMI) that we suggest gives a more comprehensive framework to consider the interactions and their complexity. This theory states that pain is associated with plastic changes in the central nervous system (CNS) that lead to an activation pattern of motor units that contributes to the individual's adaptive sensorimotor behavior. This activation pattern takes account of the biological, psychological, and social influences on the musculoskeletal tissues involved in sensorimotor behavior and on the plastic changes and the experience of pain in that individual. The pattern is normally optimized in terms of biomechanical advantage and metabolic cost related to the features of the individual's musculoskeletal tissues and aims to minimize pain and any associated sensorimotor changes, and thereby maintain homeostasis. However, adverse biopsychosocial factors and their interactions may result in plastic CNS changes leading to less optimal, even maladaptive, sensorimotor changes producing motor unit activation patterns associated with the development of further pain. This more comprehensive theory points towards customized treatment strategies, in line with the management approaches to pain proposed in the biopsychosocial model of pain.

Cardiac output and arteriovenous oxygen difference contribute to lower peak oxygen uptake in patients with fibromyalgia

BACKGROUND

Patients with fibromyalgia (FM) exhibit low peak oxygen uptake ([Formula: see text]O_2peak). We aimed to detect the contribution of cardiac output to ([Formula: see text]) and arteriovenous oxygen difference [Formula: see text] to [Formula: see text] from rest to peak exercise in patients with FM.

METHODS

Thirty-five women with FM, aged 23 to 65 years, and 23 healthy controls performed a step incremental cycle ergometer test until volitional fatigue. Alveolar gas exchange and pulmonary ventilation were measured breath-by-breath and adjusted for fat-free body mass (FFM) where appropriate. [Formula: see text] (impedance cardiography) was monitored. [Formula: see text] was calculated using Fick's equation. Linear regression slopes for oxygen cost (∆[Formula: see text]O₂/∆work rate) and [Formula: see text] to [Formula: see text]O₂ (∆[Formula: see text]/∆[Formula: see text]O₂) were calculated. Normally distributed data were reported as mean ± SD and non-normal data as median [interquartile range].

RESULTS

[Formula: see text]O_2peak was lower in FM patients than in controls (22.2 ± 5.1 vs. 31.1 ± 7.9 mL∙min^-1∙kg^-1, P < 0.001; 35.7 ± 7.1 vs. 44.0 ± 8.6 mL∙min^-1∙kg FFM^-1, P < 0.001). [Formula: see text] and C(a-v)O₂ were similar between groups at submaximal work rates, but peak [Formula: see text] (14.17 [13.34-16.03] vs. 16.06 [15.24-16.99] L∙min^-1, P = 0.005) and C(a-v)O₂ (11.6 ± 2.7 vs. 13.3 ± 3.1 mL O₂∙100 mL blood^-1, P = 0.031) were lower in the FM group. No significant group differences emerged in ∆[Formula: see text]O₂/∆work rate (11.1 vs. 10.8 mL∙min^-1∙W^-1, P = 0.248) or ∆[Formula: see text]/∆[Formula: see text]O₂ (6.58 vs. 5.75, P = 0.122) slopes.

CONCLUSIONS

Both [Formula: see text] and C(a-v)O₂ contribute to lower [Formula: see text]O_2peak in FM. The exercise responses were normal and not suggestive of a muscle metabolism pathology.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03300635. Registered 3 October 2017-Retrospectively registered. https://clinicaltrials.gov/ct2/show/NCT03300635 .

Mediation Effect of Kinesiophobia on the Relationship between Cervical Joint Position Sense and Limits of Stability in Individuals with Fibromyalgia Syndrome: A Cross-Sectional Study Using Mediation Analysis

(1) Background: Individuals with fibromyalgia syndrome (FMS) may experience proprioceptive and balance impairments. Kinesiophobia is a factor that can mediate the relationship between cervical joint position sense (JPS) and limits of stability. The objectives of this study were to (1) compare the cervical JPS and limits of stability between FMS and asymptomatic individuals, (2) assess the relationship between cervical JPS and limits of stability, and (3) assess the mediation effect of kinesiophobia on the relationship between cervical JPS and limits of stability in FMS individuals. (2) Methods: In this comparative cross-sectional study, 100 individuals with FMS and 100 asymptomatic individuals were recruited. Cervical JPS was assessed using a cervical range of motion device, limits of stability (reaction time, maximum excursion, and direction control) were assessed using dynamic posturography, and FMS individuals' kinesiophobia was assessed using the Tampa scale of kinesiophobia (TSK). Comparison, correlation, and mediation analyses were performed. (3) Results: The magnitude of the mean cervical joint position error (JPE) was significantly larger in FMS individuals (p < 0.001) compared to the asymptomatic individuals. The limits of the stability test showed that FMS individuals had a longer reaction time (F = 128.74) and reduced maximum excursion (F = 976.75) and direction control (F = 396.49) compared to the asymptomatic individuals. Cervical JPE showed statistically significant moderate-to-strong correlations with reaction time (r = 0.56 to 0.64, p < 0.001), maximum excursion (r = -0.71 to -0.74, p < 0.001), and direction control (r = -0.66 to -0.68, p < 0.001) parameters of the limits of the stability test. (4) Conclusions: Cervical JPS and limits of stability were impaired in FMS individuals, and the cervical JPS showed a strong relationship with limits of stability variables. Moreover, kinesiophobia mediated the relationship between JPS and limits of stability. These factors may be taken into consideration when evaluating and developing treatment strategies for FMS patients.

Heart rate variability responses to cognitive stress in fibromyalgia are characterised by inadequate autonomous system stress responses: a clinical trial

Fibromyalgia (FM) is associated with sympathetically dominant dysautonomia, but the connection between dysautonomia and FM symptoms is unclear. Dysautonomia can be analysed with heart rate variability (HRV) and it has been proposed that FM patients comprise subgroups with differing profiles of symptom severity. In our study, 51 female FM patients aged 18 to 65 years and 31 age-matched healthy female controls followed a 20-min protocol of alternating relaxation and cognitive stress (mental arithmetic). Heart rates and electrocardiograms were registered. The HRV measures of heart rate (HR), mean interval between heart beats (RR_mean), root mean squared interval differences of successive beats (RMSSD), and the standard deviation of intervals between normal heart beats (SDNN) were analysed with generalized linear modelling. Features in HRV reactivity which differed between FM patients and controls were used to cluster the FM patients and cluster characteristics were analysed. FM patients had higher baseline HR (72.3 [SD 12.7] vs 64.5 [7.80], p < 0.001) and lower RR_mean (0.844 [0.134] vs 0.934 [0.118], p = 0.002), compared with controls. They also reacted to repeated cognitive stress with an attenuated rise in HR (- 4.41 [95% CI - 7.88 to - 0.93], p = 0.013) and attenuated decrease of RR_mean (0.06 [95 CI 0.03 to 0.09], p < 0.001), compared with controls. Clustering of FM patients by HRV reactivity resulted in three clusters characterised by (1) normal levels of HRV and HRV reactivity with low levels of depressive mood and anxiety, (2) reduced levels of HRV and impaired HRV reactivity with increased levels of depressive mood and high levels of anxiety, and (3) lowest HRV and most impaired HRV reactivity with the highest scores for depressive mood and anxiety. Our results show that FM patients have lower HRV than healthy controls and their autonomous reactions to cognitive stress are attenuated. Dysautonomia in FM associates with mood disturbance. Trial registration ClinicalTrials.gov (NCT03300635). Registered October 3 2017-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03300635 .

Modulating factors of fibromyalgia in women during the COVID-19 pandemic: A protocol for systematic review

BACKGROUND

Fibromyalgia is a disease that affects mostly women and is related to stressors. The aim of this study was to assess how the Coronavirus disease 2019 pandemic has affected women with fibromyalgia.

METHODS

A systematic review was conducted in the PubMed, ScienceDirect, and Springer Link databases, following the recommendations of the preferred reporting items for systematic reviews and meta-analyses statement. The methodological quality was assessed using the Joanna Briggs Institute critical appraisal tools for non-randomized studies.

RESULTS

A total of 6 studies were included. Most results indicated a worsening in the mental health of women with fibromyalgia during the pandemic, and this in turn impacted on physical health.

CONCLUSION

The mental health of women with fibromyalgia was more affected during the Coronavirus disease 2019 pandemic period than that of non-fibromyalgia sufferers. This was also reflected in the worsening of symptoms and weakness in performing daily activities.

Cervical Spondylosis as a Hidden Contributing Factor to Fibromyalgia: A Case Report

The present case study describes the long-term symptomatic remission in a patient with fibromyalgia (FM) after multimodal spinal manipulation. A 44-year-old woman presented with a chronic headache, severe neck pain, shoulder pain, and back pain lasting for 2 years after experiencing domestic violence. She had sleep disorders, fatigue, and depressive mood. Her primary care physician diagnosed her with FM and comorbid depression. Despite treatment with non-steroidal anti-inflammatory drugs, muscle relaxants, anti-depressants, anti-epileptics, acupuncture, and aqua-therapy, she experienced no appreciable relief from her symptoms. The patient then sought a chiropractic evaluation and potential treatment for her symptoms. At presentation, widespread tenderness was palpable over the neck, shoulder, back, anterior chest, abdominal wall, and buttock. Radiographs showed loss of cervical lordosis, widespread degenerative spondylosis, and osteitis pubis. Surface electromyography (sEMG) revealed neck and thoracic paraspinal muscular spasms. The patient was diagnosed with FM based on the American College of Rheumatology diagnostic criteria and the associated comorbidities. Multimodal chiropractic approaches, which consisted of spinal manipulation, massage, and intermittent motorized cervical traction, were used twice weekly to relieve soft-tissues and intervertebral joints and stretch core musculatures. The patient's physical and mental complaints were mostly resolved near the end of 9 months of treatment. Her symptom alleviation was associated with corresponding change in normalized sEMG signal and cervical spine realignment at the 16th- and 26th-month follow-ups. Widespread pain in FM can lead to confused thinking and a lack of awareness of cervical spondylosis. In this example, it is assumed that the noxious cervical inputs triggered an ongoing FM process. Chiropractic treatment blocked noxious inputs coming from pain sources, corrected pain thresholds, and lowered excitability, thereby eradicating FM symptoms.

Evaluation of Physiotherapy Impact on Neuromuscular Tension in Analog Astronauts at the LunAres Habitat

The evaluation of manual Trigger Point Therapy (TrPt) on mandible abduction range of Analog Astronauts (AA) surviving isolation conditions during consecutive missions at the LunAres Habitat was performed. This physiotherapy method was applied to decrease stress-related neuromuscular tension. Abduction measurements were conducted on the two groups of five AA, who endured severe isolation conditions for 14 days in the limited space of the LunAres Research Station Habitat (Piła, Poland) during missions. The test group consisted of abduction measurements of AA who received TrPt and control group of abduction measurements of AA who did not receive TrPt. All measurements were noted in the TemporoMandibular Joint (TMJ) diagnosis aspect of the integrated dental examination card SZOPPDP©. The ischemic compression was performed on an active localized trigger point-resulting in cessation of pain. Maximum abduction measurements were made with an electronic caliper, and the abduction range was compared. The change of abduction range in AA with TrPt was bigger than in AA without TrPt. A larger increase in abduction range was observed in every case in the group receiving TrPt compared to the control group. TrPt effectively decreases the neuromuscular tension, which results in an increased mandibular abduction range of AA. Observations conducted in LunAres Research Station regarding stress-related neuromuscular tension can help identify effective therapeutic methods for circumstances of social isolation.

Elevated highly sensitive C-reactive protein in fibromyalgia associates with symptom severity

Objectives

Fibromyalgia (FM), a common pain syndrome, is thought to be a non-inflammatory, nociplastic condition, but evidence implicating neuroinflammation has been increasing. Systemic inflammation may be associated with more severe symptoms in some FM patients. We studied healthy controls and FM patients with and without systemic inflammation detectable using high-sensitivity CRP (hsCRP) measurement.

Methods

We measured hsCRP levels and gathered clinical and questionnaire data [including the Fibromyalgia Impact Questionnaire (FIQ)] from 40 female FM patients and 30 age-matched healthy women. An hsCRP level &gt;3 mg/l was considered elevated.

Results

FM patients had significantly higher mean hsCRP levels than controls, explained by overweight and lower leisure-time physical activity. Eight FM patients had elevated hsCRP levels and 29 had normal hsCRP levels. Levels of hsCRP were significantly correlated with FIQ scores. Patients with elevated hsCRP had higher FIQ scores, with worse physical functioning and greater pain and were less likely to be employed than patients with normal hsCRP. These patient groups did not differ by blood count, liver function or lipid profiles, nor by education, psychological measures, sleep disturbance, smoking or comorbidities.

Conclusion

Some FM patients have elevated hsCRP, mostly due to overweight and physical inactivity. They have worse symptoms and their ability to work is impaired. Measurement of hsCRP may help to identify FM patients in greatest need of interventions supporting working ability.

Trial registration

ClinicalTrials.gov (https://clinicaltrials.gov), NCT03300635

Effect of a Combination of Magnesium, B Vitamins, Rhodiola, and Green Tea (L-Theanine) on Chronically Stressed Healthy Individuals-A Randomized, Placebo-Controlled Study

The effect of a combination of magnesium, vitamins B6, B9, B12, rhodiola and green tea/L-theanine (Mg-Teadiola) on stress was evaluated in chronically stressed, otherwise healthy individuals. Effects on stress-related quality-of-life parameters (sleep and perception of pain) were also explored. Adults with stress for ≥1 month, scoring ≥14 points on the Depression Anxiety Stress Scale (DASS)-42 questionnaire, were randomized (1:1) to receive oral Mg-Teadiola (n = 49) or a placebo (n = 51), for 28 days, with a follow-up assessment on Day 56 (NCT04391452). The primary endpoint was the change in the DASS-42 stress score from baseline to Day 28 with Mg-Teadiola versus placebo. The DASS-42 stress scores significantly decreased from baseline to Day 28 with Mg-Teadiola versus placebo (effect size, 0.29; 95% CI [0.01, 0.57]; p = 0.04). Similar reductions were observed on Day 14 (p = 0.006) and Day 56 (p = 0.02). A significant reduction in sensitivity to cold pain (p = 0.01) and a trend for lower sensitivity to warm pain was observed (p = 0.06) on Day 28. Improvements in daytime dysfunction due to sleepiness (Pittsburgh Sleep Quality Index-7 component score) were reported on Day 28, and were significant on Day 56 (p < 0.001). Mg-Teadiola is effective in managing stress in otherwise healthy individuals. Its beneficial effects on sleep and pain perception need further investigation.

Cross-sectional evaluation of socioeconomic and clinical factors and the impact of fibromyalgia on the quality of life of patients during the COVID-19 pandemic

BACKGROUND

The fibromyalgia impact questionnaire (FIQ) relates to the functional capacity, professional situation, psychological disorders, and physical symptoms, and can identify the factors that determine the impact of the syndrome and characteristics of its carriers; the higher the score, the greater the impact of fibromyalgia on the quality of life.

OBJECTIVE

To evaluate the impact of fibromyalgia on the quality of life of individuals with fibromyalgia, who were categorized according to the FIQ during the coronavirus disease pandemic.

DESIGN AND SETTING

A cross-sectional study was conducted at an institution of higher education in Taquara, RS, Brazil.

METHODS

A quantitative study was carried out, with the application of a sociodemographic and clinical questionnaire, and the FIQ in 163 Brazilian individuals with a medical diagnosis of fibromyalgia. Data were collected using SurveyMonkey software.

RESULTS

Of the female carriers, 98.2% were living in urban areas, working, and under pharmacological and complementary treatment. The FIQ results showed that seven of the 10 items had the maximum score. The items "physical function" and "feel good" had intermediate scores, and the item "missed work" had a low score. The average total score was 79.9 points, indicating that fibromyalgia had a severe impact on the participants' lives. A severe impact of fibromyalgia was observed in 61.3% of the participants, a moderate impact in 30.7%, and a low impact in 8%.

CONCLUSION

The survey findings suggest a severe impact in the majority of the Brazilian fibromyalgic population.

Glucose tolerance in fibromyalgia

OBJECTIVES

Fibromyalgia (FM) patients have an increased risk for glucose metabolism disturbances, and impaired glucose tolerance may be associated with symptom severity. Elevated levels of plasma lactate have been detected in FM patients. Both pyruvate and lactate are produced in glucose metabolism and reflect oxidative metabolism. The objective of our study was to analyse disturbances in glucose, pyruvate, or lactate metabolism in FM patients.

METHODS

We measured plasma levels of glucose, pyruvate, and lactate during an oral glucose tolerance test in 40 non-diabetic, female FM patients and 30 age- and gender-matched healthy controls.

RESULTS

FM patients showed a higher glycaemic response to the glucose load at 1 hour (F [1,68] = 10.4, P = .006) and 2 hours (F [1,68] = 7.80, P = .02), and higher glucose area under the curve (13.8 [SD 2.92] vs 11.6 [SD 2.31], P < .01), than healthy controls. Group differences were explained by higher body mass index and percentage of smokers among the FM patients. Pyruvate and lactate levels were similar in both groups.

DISCUSSION

Impaired glucose regulation in FM patients is likely not due to FM itself, but to associated lifestyle factors. Our results highlight the importance of assessing the glucose regulation status and the lifestyle factors affecting glucose regulation in FM patients for prevention or early treatment of diabetes and associated complications.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT03300635).

The Relationship between Stress and Masticatory Muscle Activity in Female Students

The aim of the study was to analyze the relationship between stress measured by the perceived stress scale (PSS-10) questionnaire and masticatory muscle activity. Experimental design assumed the study of healthy young women without temporomandibular disorders, dividing them into three groups depending on the result of the stress level and then comparing these groups in terms of bioelectrical activity of the masticatory muscles. After the exclusion criteria were applied, 63 female students (mean age: 22.3 ± 2.4 years) from Medical University of Lublin were included in the study. The subjects were then divided into 3 groups: with low (n = 18), medium (n = 18) and high stress level (n = 27), according to PSS-10 results. Resting and functional activity of temporalis anterior (TA) and masseter (MM) muscles were measured by electromyograph BioEMG III. There were statistically significant effects of group on the absolute value of asymmetry index (AsI) of TA and MM during maximum voluntary clenching on dental cotton rollers (both p = 0.02). Post hoc analysis shows that there were statistically significant differences between medium and high stress groups in AsI TA (p = 0.01) and between low and high stress groups in AsI MM (p = 0.02). Perceived stress measured by PSS-10 questionnaire seems to be associated with changes in muscular asymmetry in functional clenching activity.