Effect of pulsed magnetic field therapy on pain reported by human volunteers in a laboratory model of acute pain †

A new neuromodulation method in chronic migraine; non-ınvasive pulsed radiofrequency, a single-blinded, randomised, controlled trial

OBJECTIVE

Non-invasive pulsed radiofrequency (NipRF) therapy, a neuromodulation method for peripheral nerves, is a new treatment modality for pain. We aimed to show the changes in pain severity and frequency per month in chronic migraine with NipRF treatment.

METHODS

We treated patients diagnosed with chronic migraine according to the International Classification of Headache Disorders III beta diagnostic criteria. In half of the patients, we applied pulsed radiofrequency (pRF) treatment with transcutaneous electrodes to the greater occipital nerve (GON) trace. In the other half, we applied the GON block under ultrasound guidance. The Migraine Disability Assessment Scale (MIDAS) was administered to the participants, and those with scores > 2 were included in the study. Pain intensity and frequency were evaluated using the visual analog scale (VAS) and a headache diary completed before and 4 weeks after treatment.

RESULTS

When both groups were compared, the pre- and post-treatment VAS scores and headache frequencies were similar. Comparing the pre-treatment and post-treatment values within the groups, VAS scores and headache frequency decreased significantly after treatment in both groups (p < 0.001).

CONCLUSION

In this study, we observed that NipRF treatment is safe and effective for treating chronic migraine. Pain intensity and frequency decreased with NipRF treatment, similar to that in the GON block group.

CLINICAL TRIALS REGISTRATION NUMBER

NCT05499689, Date: 08/11/2022.

Effects of a Concentric Rare-Earth Magnet on Menstrual Cycle Pain: A Parallel Group Randomized Pilot Study

Background Based on prior reports of the use of magnets to treat pain, our goal was to determine if a concentric rare-earth alternating-pole magnet reduced period pain versus a sham-magnet.  Methods Participants were females (N=36, 18 to 35 years) who regularly experienced menstrual period pain ≥ six on the numeric pain rating scale (NPRS) of 0-10. Subjects were excluded if they took pain medication on the study day or had implanted pacemakers/metallic devices or secondary dysmenorrhea. Participants were randomized to wear a concentric neodymium-iron boron active-magnet (surface-field of 0.4 Tesla) or a sham magnet. The participant and investigator applying the device were blinded to the device used. The device was placed at the abdominal location of the reported greatest pain for 40-minutes, during which time the subject was able to conduct the normal activity. Pain scores were reported prior to device wearing and afterward. Participants with post-treatment NPRS ratings reduced by ≥ 35% from their pretreatment pain ratings were scored as having reduced pain; reductions < 35% were scored as no meaningful pain change. The threshold of 35% was chosen based on a survey of 10 women as to the level of pain reduction they viewed as meaningful to them. Of the 36 women in this pilot study, 19 wore an active-magnet and 17 wore a sham-magnet. Analyses were based on chi-square and Mann-Whitney statistical tests. Results  Pre-treatment pain scores (mean ± SD) were similar for both groups. Magnet-vs-sham pre-treatment scores were, respectively, 7.16 ± 0.85 vs. 6.94 ± 1.20 (p=0.330). Corresponding median values for the magnet (N=19) and sham (N=17) groups respectively were seven pre-treatment and four post-treatment vs. six pre-treatment and six post-treatment. Post-treatment scores for magnet treated subjects (4.16 ± 2.20) were significantly less (p=0.027) than for sham-treated (5.53 ± 1.50). Of the 19 who wore a magnet, 11 experienced meaningful pain-reduction, and eight did not. Of the 17 who wore a sham, three experienced meaningful pain-reduction, and 14 did not. Magnet and sham wearing responses were statistically significant via chi-square analysis (chi-square=6.12, p=0.013). Percentage reduction in pain score was 41.8% ± 31.1% for magnet-treated vs. 20.8% ± 16.1%, for sham-treated (p<0.05). Conclusions Results suggest that short-term wearing of the magnet herein investigated, produces a meaningful menstrual-pain reduction in some women. Thus, further expanded research seems warranted to determine if longer wearing times result in even greater pain reductions.

No effect of a pulsed magnetic field on induced ischemic muscle pain. A double-blind, randomized, placebo-controlled trial

Empirical evidence supporting the effectiveness of pulsed (electro)magnetic field (PEMF) therapy on chronic and acute pain is equivocal. In the current randomized, double-blind, placebo-controlled experiment, impact of a commercially available whole-body PEMF mat on acute ischemic muscle pain induced in the forearm was studied with the participation of 70 healthy volunteers. The device emitted a pulsed magnetic field with a repetition frequency of 2.05Hz and a maximum flux density of 25.3μT (rms). The highest dB/dt was 48mT/s. No differences between the groups receiving actual and sham PEMF were found in terms of pain threshold, pain tolerance, heart rate, and perceived decrease of pain. However, participants' expectation concerning the effectiveness of the intervention improved pain tolerance and affected perceived change of pain. In conclusion, the used PEMF device had no specific effect on acute ischemic muscle pain, while the contribution of the placebo effect was considerable.

Pulsed magnetic field treatment as antineuropathic pain therapy

No satisfactory effective therapy is still available to treat trauma- or disease-induced neuropathic pain, and current available treatment options have several side effects. Pulsed magnetic field (PMF) treatments are receiving growing interest as a therapeutic approach for several neuronal diseases. Although the exact mechanism of action of PMF treatments is unknown, reported findings represent a promising alternative therapeutic choice for the management of neuropathic pain. PMF treatments can supply new strategies for the therapy of life-threatening neuropathic pain due to its antihyperglycemic, anti-inflammatory, antihyperalgesic, antiallodynic, and neuroimmunomodulatory actions. In this review, I summarized the several recent findings about antineuropathic actions of PMF treatment in experimental animals with neuropathic pain induced by disease and/or damage.

Pulsed magnetic field enhances therapeutic efficiency of mesenchymal stem cells in chronic neuropathic pain model

Cell-based or magnetic field therapies as alternative approaches to pain management have been tested in several experimental pain models. The aim of this study therefore was to investigate the actions of the cell-based therapy (adipose tissue derived mesenchymal stem cells; ADMSC) or pulsed magnetic field (PMF) therapy and magneto-cell therapy (combination of ADMSC and PMF) in chronic constriction nerve injury model (CCI). The actions of individual ADMSC (route dependent [systemic or local], time-dependent [a day or a week after surgery]), or PMF and their combination (magneto-cell) therapies on hyperalgesia and allodynia were investigated by using thermal plantar test and a dynamic plantar aesthesiometer, respectively. In addition, various cytokine levels (IL-1β, IL-6, and IL-10) of rat sciatic nerve after CCI were analyzed. Following the CCI, both latency and threshold significantly decreased. ADMSC or PMF significantly increased latencies and thresholds. The combination of ADMSC with PMF even more significantly increased latency and threshold when compared with ADMSC alone. However, ADMSC-induced decrease in pro-inflammatory or increase in anti-inflammatory cytokines levels were partially prevented by PMF treatments. Present findings may suggest that both cell-based and magnetic therapies can effectively attenuate chronic neuropathic pain symptoms. Combined magneto-cell therapy may also efficiently reverse neuropathic signs. Bioelectromagnetics. 38:255-264, 2017. © 2017 Wiley Periodicals, Inc.

Effect of pulsed electromagnetic field therapy on experimental pain: A double-blind, randomized study in healthy young adults

Previous studies suggested that pulsed electromagnetic field (PEMF) therapy can decrease pain. To date, however, it remains difficult to determine whether the analgesic effect observed in patients are attributable to a direct effect of PEMF on pain or to an indirect effect of PEMF on inflammation and healing. In the present study, we used an experimental pain paradigm to evaluate the direct effect of PEMF on pain intensity, pain unpleasantness, and temporal summation of pain. Twenty-four healthy subjects (mean age 22 ± 2 years; 9 males) participated in the experiment. Both real and sham PEMF were administered to every participant using a randomized, double-blind, cross-over design. For each visit, PEMF was applied for 10 minutes on the right forearm using a portable device. Experimental pain was evoked before (baseline) and after PEMF with a 9 cm(2) Pelletier-type thermode, applied on the right forearm (120 s stimulation; temperature individually adjusted to produce moderate baseline pain). Pain intensity and unpleasantness were evaluated using a 0-100 numerical pain rating scale. Temporal summation was evaluated by comparing pain intensity ratings obtained at the end of tonic nociceptive stimulation (120 s) with pain intensity ratings obtained after 60 s of stimulation. When compared to baseline, there was no change in pain intensity and unpleasantness following the application of real or sham PEMF. PEMF did not affect temporal summation. The present observations suggest that PEMF does not directly influence heat pain perception in healthy individuals.

Comparison of 2 methods of non-invasive treatment between transcutaneous electrical stimulation and pulsed electromagnetic field stimulation as replacement of invasive manual acupuncture

The aim of this study was to find the non-invasive optimal alternative method for Manual Acupuncture. Existing researches had reported that Transcutaneous Electrical Acupoint Stimulation (TEAS) was an effective treatment method instead of manual acupuncture. In place of the TEAS, we suggested the Pulsed Electromagnetic Fields (PEMFs). Thus, we designed the PEMFs system which can stimulate only an acupoint. There have been no researches which reported therapeutic effect when stimulating at an identical acupoint by TEAS and PEMFs. Hence, this study investigated the therapeutic effect on the muscle fatigue after the strenuous knee extension/flexion exercise by two stimulations. We selected the stimulation method of both TEAS and PEMFs by using 2Hz biphasic rectangular wave pulse and pulse width 0.2ms. The magnetic flux was the 30.92mT (309.2gauss) at 2 Hz. The electromyogram (EMG) and the maximal voluntary contraction (MVC) at rectus femoris were measured. The Median Frequency (MF) at TEAS group was significantly effective at 6 minutes (p=0.499). The PEMFs group was recovered to the MF rapidly after 4 minutes (p=0.166). The results of the peak torque indicated that both non-stimulation group and TEAS group did not recover to the peak torque at pre-exercise during the recovery period (p<0.05). In contrast, the significant treatment effect of PEMFs group was found after 14 minutes (p=0.135). The results of this study demonstrated that PEMFs were better than TEAS as a non-invasive method to replace the manual acupuncture.

The therapeutic effect of a pulsed electromagnetic field on the reproductive patterns of male Wistar rats exposed to a 2.45-GHz microwave field

INTRODUCTION

Environmental exposure to man-made electromagnetic fields has been steadily increasing with the growing demand for electronic items that are operational at various frequencies. Testicular function is particularly susceptible to radiation emitted by electromagnetic fields.

OBJECTIVES

This study aimed to examine the therapeutic effects of a pulsed electromagnetic field (100 Hz) on the reproductive systems of male Wistar rats (70 days old).

METHODS

The experiments were divided into five groups: microwave sham, microwave exposure (2.45 GHz), pulsed electromagnetic field sham, pulsed electromagnetic field (100 Hz) exposure, and microwave/pulsed electromagnetic field exposure. The animals were exposed for 2 hours/day for 60 days. After exposure, the animals were sacrificed, their sperm was used for creatine and caspase assays, and their serum was used for melatonin and testosterone assays.

RESULTS

The results showed significant increases in caspase and creatine kinase and significant decreases in testosterone and melatonin in the exposed groups. This finding emphasizes that reactive oxygen species (a potential inducer of cancer) are the primary cause of DNA damage. However, pulsed electromagnetic field exposure relieves the effect of microwave exposure by inducing Faraday currents.

CONCLUSIONS

Electromagnetic fields are recognized as hazards that affect testicular function by generating reactive oxygen species and reduce the bioavailability of androgen to maturing spermatozoa. Thus, microwave exposure adversely affects male fertility, whereas pulsed electromagnetic field therapy is a non-invasive, simple technique that can be used as a scavenger agent to combat oxidative stress.