Development of a method to maximize the transcutaneous electrical nerve stimulation intensity in women with fibromyalgia

Efficacy of neuromodulation on the treatment of fibromyalgia: A network meta-analysis

OBJECTIVE

Several types of neuromodulation have been investigated for the treatment of fibromyalgia, but they show varied efficacy on pain, functioning, comorbid depression and comorbid anxiety. Whether some types of neuromodulation or some factors are associated with a better response also awaits clarification.

METHODS

We conducted a systematic review and network meta-analysis of randomized controlled trials to evaluate the efficacy of neuromodulation in patients with fibromyalgia. We searched PubMed, EMBASE, the Cochrane Central Register of Controlled Trials and PsycINFO before March 2022. We employed a frequentist random-effects network meta-analysis.

RESULTS

Forty trials involving 1541 participants were included. Compared with sham control interventions, several types of transcranial direct current stimulation (tDCS), transcranial random noise stimulation (tRNS), and high-frequency repetitive transcranial magnetic stimulation (rTMS) were associated with significant reduction of pain, depression, anxiety, and improvement in functioning. Many significantly effective treatment options involve stimulation of the primary motor cortex or dorsolateral prefrontal cortex.

CONCLUSION

We concluded that several types of rTMS, tDCS and tRNS may have the potential to be applied for clinical purposes.

Treating fibromyalgia with electrical neuromodulation: A systematic review and meta-analysis

OBJECTIVE

Several types of electrical neuromodulation (such as transcranial direct current stimulation, tDCS; transcutaneous electrical nerve stimulation) have been applied in the treatment of fibromyalgia. These trials had different outcome measurements, such as subjective pain, pain threshold, depression, anxiety, and functioning. We intended to integrate data from different trials into a meta-analysis to clearly present the clinical value of electrical neuromodulation in fibromyalgia.

METHODS

A systematic review and meta-analysis of randomized controlled trials comparing the effect of all types of electrical neuromodulation in patients with fibromyalgia was conducted. The main outcome was subjective pain; the secondary outcomes included depression, anxiety, and functioning.

RESULTS

Twenty-five studies and 1061 fibromyalgia patients were included in the quantitative analysis. Active electrical neuromodulation and active tDCS both showed significant effects on subjective pain, depression, and functioning. For different anode tDCS electrode positions, only F3-F4 revealed a significant effect on depression. Meta-regression tDCS effects on depression were significantly associated with age.

CONCLUSIONS

Electrical neuromodulation is significantly effective in treating pain, depression, and functioning in patients with fibromyalgia.

SIGNIFICANCE

The results may help clinicians to arrange effective treatment plans for patients with fibromyalgia, especially in those patients who reveal limited response to pharmacotherapy and psychotherapy.

Characterising the Features of 381 Clinical Studies Evaluating Transcutaneous Electrical Nerve Stimulation (TENS) for Pain Relief: A Secondary Analysis of the Meta-TENS Study to Improve Future Research

Background and Objectives: Characterising the features of methodologies, clinical attributes and intervention protocols, of studies is valuable to advise directions for research and practice. This article reports the findings of a secondary analysis of the features from studies screened as part of a large systematic review of TENS (the meta-TENS study). Materials and Methods: A descriptive analysis was performed on information associated with methodology, sample populations and intervention protocols from 381 randomised controlled trials (24,532 participants) evaluating TENS delivered at a strong comfortable intensity at the painful site in adults with pain, irrespective of diagnosis. Results: Studies were conducted in 43 countries commonly using parallel group design (n = 334) and one comparator group (n = 231). Mean ± standard deviation (SD) study sample size (64.05 ± 58.29 participants) and TENS group size (27.67 ± 21.90 participants) were small, with only 13 of 381 studies having 100 participants or more in the TENS group. Most TENS interventions were ‘high frequency’ (>10 pps, n = 276) and using 100 Hz (109/353 reports that stated a pulse frequency value). Of 476 comparator groups, 54.2% were active treatments (i.e., analgesic medication(s), exercise, manual therapies and electrophysical agents). Of 202 placebo comparator groups, 155 used a TENS device that did not deliver currents. At least 216 of 383 study groups were able to access other treatments whilst receiving TENS. Only 136 out of 381 reports included a statement about adverse events. Conclusions: Clinical studies on TENS are dominated by small parallel group evaluations of high frequency TENS that are often contaminated by concurrent treatment(s). Study reports tended focus on physiological and clinical implications rather than the veracity of methodology and findings. Previously published criteria for designing and reporting TENS studies were neglected and this should be corrected in future research using insights gleaned from this analysis.

Test-Retest Reliability and Responsiveness of PROMIS Sleep Short Forms Within an RCT in Women With Fibromyalgia

Background: Nonrestorative sleep is commonly reported by individuals with fibromyalgia, but there is limited information on the reliability and responsiveness of self-reported sleep measures in this population.

Objectives: (1) Examine the reliability and validity of the Patient-Reported Outcomes Measurement Information System (PROMIS) sleep measures in women with fibromyalgia, and (2) Determine the responsiveness of the PROMIS sleep measures to a daily transcutaneous electrical nerve stimulation (TENS) intervention in women with fibromyalgia over 4 weeks compared with other measures of restorative sleep.

Methods: In a double-blinded, dual-site clinical trial, 301 women with fibromyalgia were randomly assigned to utilize either Active-TENS, Placebo-TENS, or No-TENS at home. Measures were collected at baseline and after 4 weeks of treatment. To assess self-reported sleep, the participants completed three PROMIS short forms: Sleep Disturbance, Sleep-Related Impairment, Fatigue, and the Pittsburgh Sleep Quality Index (PSQI). To assess device-measured sleep, actigraphy was used to quantify total sleep time, wake after sleep onset, and sleep efficiency. Linear mixed models were used to examine the effects of treatment, time, and treatment*time interactions.

Results: The PROMIS short forms had moderate test–retest reliability (ICC 0.62 to 0.71) and high internal consistency (Cronbach's alpha 0.89 to 0.92). The PROMIS sleep measures [mean change over 4 weeks, 95% confidence interval (CI)], Sleep Disturbance: −1.9 (−3.6 to −0.3), Sleep-Related Impairment: −3 (−4.6 to −1.4), and Fatigue: −2.4 (−3.9 to −0.9) were responsive to improvement in restorative sleep and specific to the Active-TENS group but not in the Placebo-TENS [Sleep Disturbance: −1.3 (−3 to 0.3), Sleep-Related Impairment: −1.2 (−2.8 to 0.4), Fatigue: −1.1 (−2.7 to 0.9)] or No-TENS [Sleep Disturbance: −0.1 (−1.6 to 1.5), Sleep-Related Impairment: −0.2 (−1.7 to 1.4), Fatigue: –.3 (−1.8 to 1.2)] groups. The PSQI was responsive but not specific with improvement detected in both the Active-TENS: −0.9 (−1.7 to −0.1) and Placebo-TENS: −0.9 (−1.7 to 0) groups but not in the No-TENS group: −0.3 (−1.1 to 0.5). Actigraphy was not sensitive to any changes in restorative sleep with Active-TENS [Sleep Efficiency: −1 (−2.8 to 0.9), Total Sleep Time: 3.3 (−19.8 to 26.4)].

Conclusion: The PROMIS sleep measures are reliable, valid, and responsive to improvement in restorative sleep in women with fibromyalgia.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT01888640.

Higher Pain Sensitivity Predicts Efficacy of a Wearable Transcutaneous Electrical Nerve Stimulation Device for Persons With Fibromyalgia: A Randomized Double-Blind Sham-Controlled Trial

OBJECTIVES

This study investigated the efficacy of a transcutaneous electrical nerve stimulation (TENS) device (Quell®) for persons with symptoms due to fibromyalgia (FM).

MATERIALS AND METHODS

One hundred nineteen (N = 119) subjects were randomly assigned to use an active (N = 62) or sham (N = 57) TENS for three months. All subjects completed baseline questionnaires and were administered quantitative sensory testing (QST). Subjects completed the Patients' Global Impression of Change (PGIC, primary outcome measure) and other mailed questionnaires (secondary outcome measures) at six weeks and three months.

RESULTS

The subjects averaged 50.4 ± 13.5 years of age, 93.3% were female, and 79.8% were Caucasian. Most showed benefit from using the TENS, but no differences between groups were found on the primary outcome measure after three months (active 3.87 ± 1.85, sham 3.73 ± 1.80, 95% confidence interval [CI] [-0.60, 0.88], p = 0.707). Those with more hypersensitivity showed most improvement on the PGIC at six weeks (0.22, 95% CI [0.01, 0.43], p = 0.042) and three months (0.20, 95% CI [0.00, 0.41], p = 0.049) and among those with higher sensitivity based on QST, the active TENS group showed the most benefit with TENS compared with the sham treatment (1.20, 95% CI [0.22, 2.18], p = 0.017). No TENS-related serious adverse events were reported. Subjects in the sham group correctly identified their treatment 87.5% of the time, while, surprisingly, subjects in the active group correctly identified their treatment only 17.4% of the time.

CONCLUSION

This study found no differences between those who were exposed to maximal-frequency active stimulation or minimal-frequency sham stimulation from a wearable TENS in reducing FM-related symptoms. However, those with greater hypersensitivity showed most benefit from TENS. Additional studies to help determine the role individual differences play in the use of TENS in managing FM-related symptoms are needed.

The effectiveness and safety of electrotherapy in the management of fibromyalgia

Treating fibromyalgia is a challenging task for physicians. With its multifaceted features, fibromyalgia requires a comprehensive management strategy focusing on both the pharmacological and non-pharmacological treatment options. During the last decades, there has been growing evidence regarding the role of electrotherapy in fibromyalgia treatment. In this regard, the present article aimed to review the recent literature on the effectiveness and safety of the electrotherapy in the treatment of fibromyalgia. A literature search was conducted through PubMed/MEDLINE and Scopus databases. Transcutaneous electrical nerve stimulation (TENS), non-invasive brain stimulation (transcranial direct current/magnetic stimulation), and light amplification by stimulated emission of radiation (LASER) emerged as the most commonly examined electrotherapy techniques in fibromyalgia. Currently, there is growing data regarding the effectiveness of electrotherapy in the management of fibromyalgia-related pain. Besides, non-invasive electrotherapy techniques are related to no/minor side effects. Further studies are warranted to identify the optimal treatment protocols for each electrotherapy modality.

Electrical Stimulation of Muscle: Electrophysiology and Rehabilitation

The generation of action potentials in intramuscular motor and sensory axons in response to an imposed external current source can evoke muscle contractions and elicit widespread responses throughout the nervous system that impact sensorimotor function. The benefits experienced by individuals exposed to several weeks of treatment with electrical stimulation of muscle suggest that the underlying adaptations involve several physiological systems, but little is known about the specific changes elicited by such interventions.

Remote Analgesic Effects Of Conventional Transcutaneous Electrical Nerve Stimulation: A Scientific And Clinical Review With A Focus On Chronic Pain

BACKGROUND

Transcutaneous electrical nerve stimulation (TENS) is a safe, noninvasive treatment for chronic pain that can be self-administered. Conventional TENS involves stimulation of peripheral sensory nerves at a strong, non-painful level. Following the original gate-control theory of pain, stimulation is typically near the target pain. As another option, remote stimulation may also be effective and offers potential advantages.

OBJECTIVE

This narrative review examines mechanisms underlying the remote analgesic effects of conventional TENS and appraises the clinical evidence.

METHODS

A literature search for English-language articles was performed on PubMed. Keywords included terms related to the location of TENS . Citations from primary references and textbooks were examined for additional articles.

RESULTS

Over 30 studies reported remote analgesic effects of conventional TENS. The evidence included studies using animal models of pain, experimental pain in humans, and clinical studies in subjects with chronic pain. Three types of remote analgesia were identified: at the contralateral homologous site, at sites distant from stimulation but innervated by overlapping spinal segments, and at unrelated extrasegmental sites.

CONCLUSION

There is scientific and clinical evidence that conventional TENS has remote analgesic effects. This may occur through modulation of pain processing at the level of the dorsal horn, in brainstem centers mediating descending inhibition, and within the pain matrix. A broadening of perspectives on how conventional TENS produces analgesia may encourage researchers, clinicians, and medical-device manufacturers to develop novel ways of using this safe, cost-effective neuromodulation technique for chronic pain.

Constitutional risk factors for focal neuropathies in patients referred for electromyography

BACKGROUND AND PURPOSE

It is well established that patient-related constitutional features predispose to focal peripheral neuropathies. Some of these risk factors were investigated in common focal neuropathies encountered in patients referred for electromyography.

METHODS

Gender, age, height and body mass index (BMI) were analysed retrospectively as risk factors for 11 focal neuropathies. In all, 9686 patients (age range 18-96 years; 58% women) were included from three different centres, with identical methods and equipment.

RESULTS

High BMI was related to carpal tunnel syndrome (CTS), ulnar neuropathy at the elbow (UNE), combined CTS and UNE, meralgia paraesthetica and lumbar radiculopathy. In women, CTS and Morton's metatarsalgia were more common, whilst long thoracic neuropathies, suprascapular neuropathies and UNE were more common in men. Older age increased the risk for CTS, UNE, Morton's metatarsalgia and radiculopathies.

CONCLUSIONS

Age, gender and BMI are important risk factors for many common focal neuropathies.