Cerebral blood flow variability in fibromyalgia syndrome: Relationships with emotional, clinical and functional variables

Unveiling the link: exploring muscle oxygen saturation in fibromyalgia and its implications for symptomatology and therapeutic strategies

Fibromyalgia, characterized as a complex chronic pain syndrome, presents with symptoms of pervasive musculoskeletal pain, significant fatigue, and pronounced sensitivity at specific anatomical sites. Despite extensive research efforts, the origins of fibromyalgia remain enigmatic. This narrative review explores the intricate relationship between muscle oxygen saturation and fibromyalgia, positing that disruptions in the oxygenation processes within muscle tissues markedly influence the symptom profile of this disorder. Muscle oxygen saturation, crucial for muscle function, has been meticulously investigated in fibromyalgia patients through non-invasive techniques such as near-infrared spectroscopy and magnetic resonance imaging. The body of evidence consistently indicates substantial alterations in oxygen utilization within muscle fibers, manifesting as reduced efficiency in oxygen uptake during both rest and physical activity. These anomalies play a significant role in fibromyalgia's symptomatology, especially in terms of chronic pain and severe fatigue, potentially creating conditions that heighten pain sensitivity and accumulate metabolic byproducts. Hypothesized mechanisms for these findings encompass dysfunctions in microcirculation, mitochondrial irregularities, and autonomic nervous system disturbances, all meriting further research. Understanding the dynamics of muscle oxygen saturation in fibromyalgia is of paramount clinical importance, offering the potential for tailored therapeutic approaches to alleviate symptoms and improve the quality of life for sufferers. This investigation not only opens new avenues for innovative research but also fosters hope for more effective treatment strategies and improved outcomes for individuals with fibromyalgia.

Measurement of event-related potentials from electroencephalography to evaluate emotional processing in Fibromyalgia Syndrome: A systematic review and meta-analysis

OBJECTIVE

The present systematic review and meta-analysis intended to: 1) determine the extent of abnormalities in emotional processing linked to emotional event-related potentials (ERPs) in Fibromyalgia Syndrome (FMS) and 2) integrate data from similar emotional tasks into a meta-analysis to clearly demonstrate the scientific and clinical value of measuring emotional ERPs by electroencephalography (EEG) in FMS.

METHODS

A systematic review and meta-analysis of studies comparing emotional processing indicated by ERPs in FMS patients and healthy controls was conducted. Fifteen articles were included in the systematic review after applying the eligibility criteria.

RESULTS

Nine articles demonstrated disturbances in emotional processing in FMS. These emotional disturbances were distributed over the whole range of ERP latencies, mainly over central, parietal, temporal and occipital areas. Despite of this, quantitative analysis revealed only significant differences in N250 and LPP/LPC between FMS patients and healthy controls, with smaller LPP/LPC and greater N250 seen in FMS.

DISCUSSION

N250 and LPP/LPC seem to be the ERPs with the greatest potential to determine emotional alterations in FMS. These ERPs are related to complex cognitive processes such as decoding features relevant to affect recognition (N250) as well differentiation between emotions, persistent engagement, conflict resolution or evaluation of emotional intensity (LPC/LPP). However, differences in task setup had an important impact on the variation of ERP outcomes. Systematization of protocols and tasks is indispensable for future studies.

The Role of Depressive Disorders in Autonomic Cardiovascular Dysregulation in Fibromyalgia

OBJECTIVE

Previous research revealed aberrances in autonomic cardiovascular regulation in fibromyalgia, which may be relevant to symptoms genesis and the increased risk of cardiovascular disorders in individuals with fibromyalgia. This study investigated the role of comorbid depression in autonomic cardiovascular dysregulations in fibromyalgia.

METHODS

Cardiovascular recordings were obtained in 53 participants with fibromyalgia who also had depression ( n = 27), in participants with fibromyalgia without depression ( n = 26), and in 29 healthy controls, at rest and during a cold pressor test and an arithmetic task. Assessed parameters included interbeat interval, blood pressure, heart rate variability, baroreflex sensitivity, stroke volume, preejection period, left ventricular ejection time, Heather index, and total peripheral resistance.

RESULTS

Participants with both fibromyalgia and depression displayed lower tonic interbeat interval, baroreflex sensitivity, and heart rate variability compared with participants with fibromyalgia without depression and controls ( p values < .012, d values = 0.71-1.06). Participants with fibromyalgia but without depression did not differ from controls in these variables. Moreover, participants with fibromyalgia who also had depression, but not those without depression, exhibited lower Heather index, stroke volume, and left ventricular ejection time compared with controls ( p values < .013, d values = 0.62-0.78). No group differences arose for preejection period or total peripheral resistance. Stress reactivity was reduced in participants with fibromyalgia, independently of depression, for diastolic blood pressure, interbeat interval, left ventricular ejection time, and heart rate variability, than in controls.

CONCLUSIONS

The role of depression in the autonomic dysregulation in fibromyalgia involves chronotropic cardiac control rather than adrenergic influences on contractility and vascular tone. Blunted cardiovascular reactivity may be ascribable to pathological factors inherent to fibromyalgia. These results underline the importance of diagnostics and treatment of comorbid depressive disorders in the management of fibromyalgia.

Chronic Pain: Clinical Updates and Perspectives

The International Association for the Study of Pain (IASP) has defined pain as an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage, which also comprises a subjective component [...].

Evaluation of Endothelial Dysfunction and Autophagy in Fibromyalgia-Related Vascular and Cerebral Cortical Changes and the Ameliorative Effect of Fisetin

Fibromyalgia (FM) is a common chronic pain syndrome that affects 1% to 5% of the population. We aimed to investigate the role of endothelial dysfunction and autophagy in fibromyalgia-related vascular and cerebral cortical changes in a reserpine-induced rat model of fibromyalgia at the histological and molecular levels and to study the ameliorative effect of fisetin. Forty adult female albino rats were divided into four groups (10 each): two control groups, the reserpine-induced fibromyalgia group, and the fisetin-treated group. The carotid arteries and brains of the animals were dissected. Frozen tissue samples were used for total RNA extraction and qPCR analysis of eNOS, caspase-3, Bcl-2, LC-3, BECN-1, CHOP, and TNF-α expression. Histological, immunohistochemical (eNOS), and ultrastructure studies were conducted. The carotid arteries revealed excessive autophagy and endothelial, vascular, and apoptotic changes. The cerebral cortex showed similar findings apart from endoplasmic reticulum stress. Additionally, there was decreased gene expression of eNOS and Bcl-2 and increased expression of caspase-3, LC-3, BECN-1, CHOP, and TNF-α. In the fisetin-treated rats, improvements in the histological and molecular results were detected. In conclusion, oxidative stress, enhanced apoptosis, and excessive autophagy are fundamental pathophysiologic mechanisms of reserpine-induced fibromyalgia. Moreover, fisetin has an ameliorative effect against fibromyalgia.

Virtual Reality-Based Therapy Reduces the Disabling Impact of Fibromyalgia Syndrome in Women: Systematic Review with Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Virtual reality-based therapy (VRBT) is a novel therapeutic approach to be used in women with fibromyalgia syndrome (FMS). The aim of our study is to assess the effect of VRBT to reduce the impact of FMS in outcomes such as pain, dynamic balance, aerobic capacity, fatigue, quality of life (QoL), anxiety and depression.

METHODS

Systematic review with meta-analysis was conducted from a bibliographic search in PubMed, Scopus, PEDro, Web of Science and CINAHL until April 2021 in accordance with PRISMA guidelines. We included randomized controlled trials (RCTs) that compare VRBT versus others to assess the mentioned outcomes in women with FMS. Effect size was calculated with standardized mean difference (SMD) and its 95% confidence interval (95% CI).

RESULTS

Eleven RCTs involving 535 women with FMS were included. Using the PEDro scale, the mean methodological quality of the included studies was moderate (6.63 ± 0.51). Our findings showed an effect of VRBT on the impact of FMS (SMD -0.62, 95% CI -0.93 to -0.31); pain (SMD -0.45, 95% CI -0.69 to -0.21); dynamic balance (SMD -0.76, 95% CI -1.12 to -0.39); aerobic capacity (SMD 0.32, 95% CI 0.004 to 0.63); fatigue (SMD -0.58, 95% CI -1.02 to -0.14); QoL (SMD 0.55, 95% CI 0.3 to 0.81); anxiety (SMD -0.47, 95% CI -0.91 to -0.03) and depression (SMD -0.46, 95% CI -0.76 to -0.16).

CONCLUSIONS

VRBT is an effective therapy that reduces the impact of FMS, pain, fatigue, anxiety and depression and increases dynamic balance, aerobic capacity and quality of life in women with FMS. In addition, VRBT in combination with CTBTE showed a large effect in reducing the impact of FMS and fatigue and increasing QoL in these women.

Short-term cerebral blood flow variability in major depressive disorder

BACKGROUND

Previous research has documented reduced heart rate and blood pressure variability in major depressive disorder (MDD), suggesting a limited capacity for cardiovascular regulation and diminished homeostatic resources in the disorder. This study aimed to complement this knowledge by investigating short-term cerebral blood flow (CBF) variability in MDD.

METHODS

Using transcranial Doppler sonography, blood flow velocities in the middle cerebral arteries of both hemispheres were recorded in 35 MDD patients and 35 healthy controls, at rest and during serial subtraction task-induced mental stress. CBF variability was represented by the root mean square of successive differences (RMSSD) in the beat-to-beat mean, systolic and diastolic flow velocity.

RESULTS

Patients, as compared to controls, exhibited smaller mean and diastolic blood flow variability in MCA both at rest and during mental stress. Mean, systolic and diastolic blood flow variability were greater during the task than at rest. CBF variability did not differ between patient subgroups composed according to medication use.

LIMITATIONS

Potential effects of blood pressure and respiration on CBF variability could not be investigated.

CONCLUSIONS

The study revealed evidence of reduced short-term CBF variability in MDD. The task-induced CBF variability increase may be ascribed to neural activity associated with arithmetic processing. Lower blood pressure variability and deficient autonomic cardiovascular control may contribute to the reduction of short-term CBF variability seen in MDD. Short-term CBF variability reflects preserved interplay of regulatory mechanisms ensuring optimal blood and energy supply to the brain. Therefore, the results suggest impaired cerebroprotective mechanisms, associated with suboptimal cerebral performance.

The cardiac, vasomotor, and myocardial branches of the baroreflex in fibromyalgia: Associations with pain, affective impairments, sleep problems, and fatigue

This study investigated the cardiac, vasomotor, and myocardial branches of the baroreflex in fibromyalgia using the spontaneous sequence method. Systolic blood pressure (SBP), interbeat interval (IBI), stroke volume (SV), pre-ejection period (PEP), and total peripheral resistance (TPR) were continuously recorded in 40 fibromyalgia patients and 30 healthy individuals during a cold pressor test and a mental arithmetic task. Sequences of covariation between SBP and IBI (cardiac branch), SV and PEP (myocardial branch), and TPR (vasomotor branch) were identified. Baroreflex sensitivity (BRS) was represented by the slope of the regression line between values in the sequences; baroreflex effectiveness (BEI) was indexed by the proportion of progressive SBP changes that elicited reflex responses. Patients exhibited lower BRS in the three branches, lower BEI in the cardiac and vasomotor branches, and reduced reactivity in cardiac BRS and BEI, SBP, IBI, SV, and PEP. Moreover, BRS and BEI were inversely related to clinical pain, cold pressor pain, depression, trait anxiety, sleep problems, and fatigue. Reduced function of the three baroreflex branches implies diminished resources for autonomic inotropic, chronotropic, and vascular regulation in fibromyalgia. Blunted stress reactivity indicates a limited capacity for autonomic cardiovascular adjustment to situational requirements. The associations of BRS and BEI with pain perception may reflect the antinociceptive effects arising from baroreceptor afferents, where reduced baroreflex function may contribute to the hyperalgesia characterizing fibromyalgia. The associations with affective impairments, sleep problems, and fatigue suggest that baroreflex dysfunctions are also involved in the secondary symptoms of the disorder.

Addition of Slowly Repeated Evoked Pain Responses to Clinical Symptoms Enhances Fibromyalgia Diagnostic Accuracy

OBJECTIVE

Fibromyalgia is a chronic pain syndrome characterized by central sensitization. A novel protocol based on slowly repeated evoked pain (SREP) appears to be a useful marker of pain sensitization in fibromyalgia patients. Whether SREP enhances diagnostic accuracy beyond key clinical symptoms that characterize fibromyalgia has not been examined.

METHODS

Fifty fibromyalgia patients, 30 rheumatoid arthritis patients, and 50 healthy individuals were evaluated to assess clinical pain, as well as fatigue, insomnia, pain catastrophizing, and negative mood. The SREP protocol consisted of a series of nine low-intensity painful pressure stimuli of five seconds' duration with 30-second interstimulus intervals. SREP sensitization was indexed by increases in pain intensity ratings across stimuli.

RESULTS

SREP sensitization was observed in fibromyalgia but not in rheumatoid arthritis or healthy individuals. As expected, fibromyalgia patients exhibited a more negative psychosocial profile than did rheumatoid arthritis patients and healthy individuals. SREP was positively associated with clinical pain, fatigue, insomnia, and catastrophizing, but not with negative mood. SREP discriminated fibromyalgia cases from rheumatoid arthritis and healthy individuals even when current clinical pain was included in the analysis. Combining fatigue, insomnia, and SREP led to near perfect diagnostic accuracy (99%) in differentiating fibromyalgia from healthy individuals and 86.3% accuracy in discriminating fibromyalgia from rheumatoid arthritis.

CONCLUSIONS

These results provide further evidence of SREP as a marker of pain sensitization in fibromyalgia and suggest that it captures aspects of fibromyalgia not fully captured by clinical features. Combining SREP with assessment of clinical features could potentially improve fibromyalgia diagnosis.

Effects of Exergames on Brain Dynamics in Women with Fibromyalgia: A Randomized Controlled Trial

Background: Exergames are non-immersive versions of virtual reality that involve physical exercise and have shown several benefits on physical fitness and quality of life in women with fibromyalgia. However, the effects on brain dynamics are still unknown. Aim: the aim was to evaluate the effects of a 24-week exergame intervention on resting brain dynamics in women with fibromyalgia in a single-blinded, randomized controlled trial. Methods: Fifty-six women with fibromyalgia were assessed for eligibility; 55 fulfilled the inclusion criteria. The exercise group completed a 24-week exergame-based intervention that focused on mobility, postural control, upper and lower limb coordination, aerobic fitness, and strength. This group received two 60-min sessions per week. We measured electroencephalographic (EEG) signals from 19 channels. Participants were also divided into two subgroups according to the duration of their symptoms. The intervention was more effective in the group with a shorter duration of symptoms, showing between-group differences in F8, T5 and T4. Conclusion: Exergames may lead to changes in brain dynamics that could be related to increased cerebral blood flow.