Repetitive peripheral magnetic stimulation to reduce pain or improve sensorimotor impairments: A literature review on parameters of application and afferents recruitment

Sensorimotor Integration in Chronic Low Back Pain

OBJECTIVE

Chronic low back pain (CLBP) impacts on spine movement. Altered sensorimotor integration can be involved. Afferents from the lumbo-pelvic area might be processed differently in CLBP and impact on descending motor control. This study aimed to determine whether afferents influence the corticomotor control of paravertebral muscles in CLBP. Fourteen individuals with CLBP (11 females) and 13 pain-free controls (8 females) were tested with transcranial magnetic stimulation (TMS) to measure the motor-evoked potential [MEP] amplitude of paravertebral muscles. Noxious and non-noxious electrical stimulation, and magnetic stimulation in the lumbo-sacral area were used as afferent stimuli and triggered 20 to 200 ms prior to TMS. EMG modulation elicited by afferent stimulation alone was measured to control net motoneuron excitability. MEP/EMG ratio was used as a measure of corticospinal excitability with control of net motoneuron excitability. MEP/EMG ratio was larger at 60, 80 and 100-ms intervals in CLBP compared to controls, and afferent stimulations alone reduced EMG amplitude greater in CLBP than controls at 100 ms. Our results suggest alteration in sensorimotor integration in CLBP highlighted by a greater facilitation of the descending corticospinal input to paravertebral muscles. Our results can help to optimise interventions by better targeting mechanisms.

Cortical Mechanisms Underlying Effects of Repetitive Peripheral Magnetic Stimulation on Dynamic and Static Postural Control in Patients with Chronic Non-Specific Low Back Pain: A Double-Blind Randomized Clinical Trial

INTRODUCTION

Patients with chronic non-specific low back pain (CNLBP) often experience impaired postural control, contributing to pain recurrence. Although repetitive peripheral magnetic stimulation (rPMS) combined with core muscle training (CMT) could improve postural control, its neural mechanism remains unclear. This study aims to investigate the postural control-related cortical mechanism of the effect of rPMS on patients with CNLBP.

METHODS

This unicentric, prospective, randomized, double-blind, controlled trial was conducted in a public hospital from May to December 2023. A total of 40 patients (27 females and 13 males, mean age 29.38 ± 7.72) with CNLBP were randomly assigned to either the rPMS group (real rPMS with CMT) or the sham-rPMS group (sham-rPMS with CMT) for 12 sessions over 4 weeks. The rPMS was applied to the lumbar paravertebral multifidus muscle on the painful side. Pain and disability were quantified using the visual analog scale (VAS) and Oswestry dysfunction index (ODI) pre- and post-intervention. Furthermore, the sway area and velocity of the center of pressure (COP) were measured using a force platform. The cortical activities in 6 regions of interest during 4 tasks (standing with eyes open/closed on a stable/unstable plane) were recorded by functional near-infrared spectroscopy (fNIRS) pre- and post-intervention. The repeated measure ANOVA was applied for statistical analysis. Spearman's correlation was used to determine the relationships between variables.

RESULTS

After the intervention, the rPMS group showed decreased pain intensity (p = 0.001) and sway area (unstable eyes-closed task) (p = 0.046) compared to the sham-rPMS group. Additionally, the rPMS group exhibited increased activation in left primary motor cortex (M1) (p = 0.042) and reduced in left supplementary motor area (SMA) (p = 0.045), whereas the sham-rPMS group showed no significant changes. The increased activation of left M1 was negatively correlated to the reduction of pain intensity (r = - 0.537, p = 0.018) and sway area (r = - 0.500, p = 0.029) under the static balancing task. Furthermore, there was a positive correlation between sway velocity and VAS (r = 0.451, p = 0.046) post-rPMS intervention.

CONCLUSION

Repetitive peripheral magnetic stimulation combined with core muscle training demonstrated better analgesic effects and postural control improvements, compared to sham-stimulation. This may be attributed to the increased activation of the left primary motor cortex.

CLINICAL TRIAL REGISTRATION

The trial was registered on ClinicalTrials.gov (ChiCTR2300070943).

Repetitive peripheral magnetic stimulation for preventing shoulder subluxation after stroke: a randomized controlled trial

BACKGROUND

Shoulder subluxation caused by paralysis after stroke is a serious issue affecting shoulder pain and functional prognosis. However, its preventive treatment has not been fully investigated.

AIM

To investigate the effects of repetitive peripheral magnetic stimulation (rPMS) on the prevention of shoulder subluxation.

DESIGN

A single-center, parallel-group, prospective randomized, open-blinded, end-point study.

SETTING

Convalescent rehabilitation ward.

POPULATION

We included 50 inpatients in the convalescent rehabilitation ward with post-stroke, having upper limb paralysis, and the acromio-humeral interval (AHI) was within 1/2 finger-breadth.

METHODS

A blinded computer-based allocation system was used to randomly assign patients into two groups: 1) conventional rehabilitation plus rPMS therapy (rPMS group, N=25); and 2) conventional rehabilitation alone (control group, N=25). Blinded assessors evaluated the patients before the intervention (T0), 6 weeks after (T1), and 12 weeks after (T2). The primary outcome was the change in AHIs from T0 to T1 between the groups. In contrast, the secondary outcomes were shoulder pain, spasticity, active range of motion, and Fugl-Meyer Assessment upper extremity (FMA-UE) score.

RESULTS

Twenty-two patients in the rPMS group and 24 in the control group completed T1, whereas 16 in the rPMS group and 11 in the control group completed T2. The change in AHI was significantly lower in the rPMS group than in the control group ([95% CI, -5.15 to -0.390], P=0.023). Within-group analysis showed that AHI in the rPMS group did not change significantly, whereas it increased in the control group (P=0.004). There were no significant differences between T1 and T2 within or between the groups. Moreover, AHI did not show differences in patients with severe impairment but decreased in the rPMS group in patients with mild impairment (P=0.001).

CONCLUSIONS

The rPMS may be a new modality for preventing shoulder subluxation. The association between motor impairment and the sustained effect needs to be further examined.

CLINICAL REHABILITATION IMPACT

Applying rPMS to the muscles of the paralyzed shoulder after a stroke may prevent shoulder subluxation.

Peripheral magnetic stimulation for chronic peripheral neuropathic pain: A systematic review and meta-analysis

OBJECTIVES

To provide a systematic review of the literature on the effects of peripheral magnetic stimulation (PMS) in the treatment of chronic peripheral neuropathic pain.

METHODS

A systematic search of MEDLINE, EMBASE, CENTRAL, CINHAL, Web of Science, and ProQuest was conducted from inception to July 2023 to identify studies of any design published in English language that enrolled adult patients (≥18 years) that received PMS for treatment of a chronic peripheral neuropathic pain disorder (pain > 3 months).

RESULTS

Twenty-three studies were identified which included 15 randomized controlled trials (RCTs), five case series, two case reports, and one non-randomized trial. PMS regimens varied across studies and ranged from 5 to 240 min per session over 1 day to 1 year of treatment. Results across included studies were mixed, with some studies suggesting benefits while others showing no significant differences. Of nine placebo-controlled RCTs, four reported statistically significant findings in favor of PMS use. In the meta-analysis, PMS significantly reduced pain scores compared to control within 0-1 month of use (mean difference -1.64 on a 0-10 numeric rating scale, 95% confidence interval -2.73 to -0.56, p = 0.003, I2 = 94%, 7 studies [264 participants], very low quality of evidence), but not at the 1-3 months and >3 months of PMS use (very low and low quality of evidence, respectively). Minimal to no adverse effects were reported with PMS use.

DISCUSSION

There is limited and low-quality evidence to make definitive recommendations on PMS usage, however, the available data is encouraging, especially for short-term applications of this novel modality. Large high-quality randomized controlled trials are required to establish definitive efficacy and safety effects of PMS.

Spinal magnetic stimulation to treat chronic back pain: a feasibility study in veterans

Aim: Chronic low back pain represents a significant societal problem leading to increased healthcare costs and quality of life. This study was designed to evaluate the feasibility and effectiveness of non-invasive spinal electromagnetic simulation (SEMS) to treat nonspecific chronic low back pain (CLBP). Methods: A single-site prospective study was conducted to evaluate SEMS in reducing pain and improving disability. A total of 17 patients received SEMS two to three sessions a week. The Numeric Rating Scale and the Modified Oswestry Disability Questionnaire were used to assess pain and disability. Results: Participants receiving SEMS exhibited statistically significant reductions in pain and disability. Conclusion: Current results suggest that non-invasive SEMS can be an effective treatment in reducing pain and improving disability associated with CLBP.

Sensory Stimulation of the Triceps Surae Muscle Complex Modulates Spinal Reflex Responses-A Comparison between Tapotement Massage and Repetitive Peripheral Magnetic Stimulation (rPMS)

BACKGROUND

The reduction of muscular hypertonia is important in the treatment of various diseases or rehabilitation. This study aims to test the efficacy of a 5 Hz mechanical muscle stimulation (tapotement massage) in comparison to a 5 Hz repetitive peripheral magnetic stimulation (rPMS) on the neuromuscular reflex response.

METHODS

In a randomized control trial, 15 healthy volunteers were administered with either 5 Hz rPMS, tapotement massage, or rPMS sham stimulation. The posterior tibial nerve was stimulated with rPMS and sham stimulation. The Achilles tendon was exposed to a mechanically applied high-amplitude 5 Hz repetitive tendon tapotement massage (rTTM). The tendon reflex (TR) was measured for the spinal response of the soleus muscle.

RESULTS

After rPMS, there was a reduction of the TR response (-9.8%, p ≤ 0.034) with no significant changes after sham stimulation. Likewise, TR decreased significantly (-17.4%, p ≤ 0.002) after Achilles tendon tapotement intervention.

CONCLUSIONS

These findings support the hypothesis that both afferent 5 Hz sensory stimulations contributed to a modulation within the spinal and/or supraspinal circuits, which resulted in a reduction of the spinal reflex excitability. The effects could be beneficial for patients with muscle hypertonia and could improve the functional results of rehabilitation programs.

[Application of peripheral magnetic stimulation in physiotherapeutic practice. (A literature review)]

Search and development of new physiotherapeutic technologies of regenerative medicine for the treatment of patients with different diseases is an urgent task of modern medicine.

OBJECTIVE

To analyze scientific data on the effectiveness of the peripheral magnetic stimulation (PMS) application in patients with different diseases.

MATERIAL AND METHODS

An analysis of publications in databases of electronic resources (PEDro, PubMed, Embase, eLibrary, Cochrane Library) over the past 20 years was carried out, the results of PMS application in patients with different nosologies were presented.

RESULTS

The majority of the presented articles confirm the clinical effectiveness of PMS application mainly in patients with diseases of the nervous system, spine and genitourinary system.

CONCLUSION

Further research to confirm the effectiveness of the therapeutic impact of magnetic stimulation in patients with other nosologies is needed.

Safety and Feasibility of Functional Repetitive Neuromuscular Magnetic Stimulation of the Gluteal Muscles in Children and Adolescents with Bilateral Spastic Cerebral Palsy

Background: For children and adolescents affected by bilateral spastic cerebral palsy (BSCP), non-invasive neurostimulation with repetitive neuromuscular magnetic stimulation (rNMS) combined with physical exercises, conceptualized as functional rNMS (frNMS), represents a novel treatment approach. Methods: In this open-label study, six children and two adolescents (10.4 ± 2.5 years) with BSCP received a frNMS intervention targeting the gluteal muscles (12 sessions within 3 weeks). Results: In 77.1% of the sessions, no side effects were reported. In 16.7%, 6.3% and 5.2% of the sessions, a tingling sensation, feelings of pressure/warmth/cold or very shortly lasting pain appeared, respectively. frNMS was highly accepted by families (100% adherence) and highly feasible (97.9% of treatment per training protocol). A total of 100% of participants would repeat frNMS, and 87.5% would recommend it. The Canadian Occupational Performance Measure demonstrated clinically important benefits for performance in 28% and satisfaction in 42% of mobility-related tasks evaluated by caregivers for at least one follow-up time point (6 days and 6 weeks post intervention). Two patients accomplished goal attainment for one mobility-related goal each. One patient experienced improvement for both predefined goals, and another participant experienced improvement in one and outreach of the other goal as assessed with the goal attainment scale. Conclusions: frNMS is a safe and well-accepted neuromodulatory approach that could improve the quality of life, especially in regard to activity and participation, of children and adolescents with BSCP. Larger-scaled studies are needed to further explore the effects of frNMS in this setting.

Neuromodulation in Pediatric Migraine using Repetitive Neuromuscular Magnetic Stimulation: A Feasibility Study

Migraine has a relevant impact on pediatric health. Non-pharmacological modalities for its management are urgently needed. This study assessed the safety, feasibility, acceptance, and efficacy of repetitive neuromuscular magnetic stimulation (rNMS) in pediatric migraine. A total of 13 patients with migraine, ≥6 headache days during baseline, and ≥1 myofascial trigger point in the upper trapezius muscles (UTM) received six rNMS sessions within 3 weeks. Headache frequency, intensity, and medication intake were monitored using headache calendars; headache-related impairment and quality of life were measured using PedMIDAS and KINDL questionnaires. Muscular involvement was assessed using pressure pain thresholds (PPT). Adherence yielded 100%. In 82% of all rNMS sessions, no side effects occurred. All participants would recommend rNMS and would repeat it. Headache frequency, medication intake, and PedMIDAS scores decreased from baseline to follow-up (FU), trending towards statistical significance (p = 0.089; p = 0.081, p = 0.055). A total of 7 patients were classified as responders, with a ≥25% relative reduction in headache frequency. PPT above the UTM significantly increased from pre- to post-assessment, which sustained until FU (p = 0.015 and 0.026, respectively). rNMS was safe, feasible, well-accepted, and beneficial on the muscular level. The potential to reduce headache-related symptoms together with PPT changes of the targeted UTM may underscore the interplay of peripheral and central mechanisms conceptualized within the trigemino-cervical complex.

Effects of combined treatment with transcranial and peripheral electromagnetic stimulation on performance and pain recovery from delayed onset muscle soreness induced by eccentric exercise in young athletes. A randomized clinical trial

Background: There is a common interest in finding a common consensus in the approach of athletes suffering from DOMS with the aim of accelerating recovery and thereby enhancing performance. The objective of this study was to observe the effects of a paired-associative transcranial and peripheral electromagnetic stimulation on young athletes suffering from DOMS, induced by 1 h of eccentric and plyometric exercises. Methods: Forty-eight young athletes participated in this randomized control trial: 13 were assigned to the peripheral group (P); 12 were in the control group (Cont); 11 were assigned to the transcranial group (T) and 12 were included in the paired-associative group (Comb). The Visual Analogue Scale (VAS) of pain perception and the mechanical Pressure Pain Threshold (PPT) were the tools used to analyze the symptoms of DOMS. On the other hand, the Half Squat (HS) test evaluated with an accelerometer, and the 30 m sprint velocity (30-mSP) test were used to observe the evolution of the sports performance of the lower limbs. All evaluations were performed before and after the eccentric exercise session that caused DOMS, as well as at 24-48, and 72 h afterward. Results: The AS group improved the symptoms of the induced DOMS, since significant positive differences were observed in the VAS and PPT compared to the other groups (p < 0.001). In addition, the AS group showed a significant improvement in the HS and the 30-mSP tests (p < 0.001). Based on the results a treatment with both peripheral and transcranial electromagnetic stimulation improves recovery and performance in athletes at 72 h, although these data would need to be verified in future research with a larger sample size. Conclusion: Paired-associative electromagnetic stimulation improved DOMS symptomatology, velocity, and sports performance in the lower limbs.

Functional Repetitive Neuromuscular Magnetic Stimulation (frNMS) Targeting the Tibialis Anterior Muscle in Children with Upper Motor Neuron Syndrome: A Feasibility Study

Non-invasive neurostimulation as an adjunctive intervention to task-specific motor training is an approach to foster motor performance in patients affected by upper motor neuron syndrome (UMNS). Here, we present first-line data of repetitive neuromuscular magnetic stimulation (rNMS) in combination with personalized task-specific physical exercises targeting the tibialis anterior muscle to improve ankle dorsiflexion (functional rNMS (frNMS)). The main objective of this pilot study was to assess the feasibility in terms of adherence to frNMS, safety and practicability of frNMS, and satisfaction with frNMS. First, during 10 training sessions, only physical exercises were performed (study period (SP) A). After a 1 week break, frNMS was delivered during 10 sessions (SPC). Twelve children affected by UMNS (mean age 8.9 ± 1.6 years) adhered to 93% (SPA) and 94% (SPC) of the sessions, and omittance was not related to the intervention itself in any case. frNMS was safe (no AEs reported in 88% of sessions, no AE-related discontinuation). The practicability of and satisfaction with frNMS were high. Patient/caregiver-reported outcomes revealed meaningful benefits on the individual level. The strength of the ankle dorsiflexors (MRC score) clinically meaningfully increased in four participants as spasticity of ankle plantar flexors (Tardieu scores) decreased in four participants after SPC. frNMS was experienced as a feasible intervention for children affected by UMNS. Together with the beneficial effects achieved on the individual level in some participants, this first study supports further real-world, large-scale, sham-controlled investigations to investigate the specific effects and distinct mechanisms of action of frNMS.

Addressing gross motor function by functional repetitive neuromuscular magnetic stimulation targeting to the gluteal muscles in children with bilateral spastic cerebral palsy: benefits of functional repetitive neuromuscular magnetic stimulation targeting the gluteal muscles

Background

Impaired selective motor control, weakness and spasticity represent the key characteristics of motor disability in the context of bilateral spastic cerebral palsy. Independent walking ability is an important goal and training of the gluteal muscles can improve endurance and gait stability. Combining conventional physical excercises with a neuromodulatory, non-invasive technique like repetitive neuromuscular magnetic stimulation probably enhances effects of the treatment. This prospective study aimed to assess the clinical effects of repetitive neuromuscular magnetic stimulation in combination with a personalized functional physical training offered to children and adolescents with bilateral spastic cerebral palsy.

Methods

Eight participants Gross Motor Function Classification System level II and III (10.4 ± 2y5m; 50% Gross Motor Function Classification System level II) received a personalized intervention applying functional repetitive neuromuscular magnetic stimulation (12 sessions within 3 weeks; 12,600 total stimuli during each session). At baseline and follow up the following assessments were performed: 10-m-walking-test, 6-min-walking-test, GMFM-66. Six weeks after the end of treatment the patient-reported outcome measure Gait Outcome Assessment List was completed.

Results

GMFM-66 total score improved by 1.4% (p = 0.002), as did scoring in domain D for standing (1.9%, p = 0.109) and domain E for walking, jumping and running (2.6%, p = 0.021). Gait speed or distance walked during 6 min did not improve from baseline to follow up. Patient-reported outcome showed improvement in 4 patients in altogether 14 ratings. Caregiver-reported outcome reported benefits in 3 participants in altogether 10 ratings.

Conclusion

Repetitive neuromuscular magnetic stimulation promises to be a meaningful, non-invasive treatment approach for children and adolescents with bilateral spastic cerebral palsy that could be offered in a resource-efficient manner to a broad number of patients. To further investigate the promising effects of repetitive neuromuscular magnetic stimulation and its mechanisms of action, larger-scaled, controlled trials are needed as well as comprehensive neurophysiological investigations.

Magnetic Peripheral Nerve Stimulation (mPNS) for Chronic Pain

Purpose

To assess magnetic peripheral nerve stimulation (mPNS) for the treatment of chronic or chronic and intractable neuropathic pain with a retrospective review case series.

Patients and methods

Twenty-four patients with predominantly neuropathic post-traumatic or postoperative pain were treated as per protocol and followed for 3 months.

Results

Data were analyzed as an observational, one-armed, convenience sample. Graphical evidence backed up by a mixed model for repeated measures statistical analysis showed a highly significant reduction of pain at one month out from initial treatment with mPNS. At one month, there was a 3.8 average reduction in pre-pain scores using a visual analogue scale (VAS), and that relief was generally durable measured out to three months. Two-thirds of patients, deemed responders, showed an 87% reduction in pain. Opioid reduction was seen in 58.3% of responders as well.

Conclusion

mPNS appears promising for the treatment of chronic or chronic and intractable neuropathic pain for many of the same indications as traditional electrical peripheral nerve stimulation (PNS). No invasive techniques or implants are needed for mPNS.

Top-down and bottom-up stimulation techniques combined with action observation treatment in stroke rehabilitation: a perspective

Stroke is a central nervous system disease that causes structural lesions and functional impairments of the brain, resulting in varying types, and degrees of dysfunction. The bimodal balance-recovery model (interhemispheric competition model and vicariation model) has been proposed as the mechanism of functional recovery after a stroke. We analyzed how combinations of motor observation treatment approaches, transcranial electrical (TES) or magnetic (TMS) stimulation and peripheral electrical (PES) or magnetic (PMS) stimulation techniques can be taken as accessorial physical therapy methods on symptom reduction of stroke patients. We suggest that top-down and bottom-up stimulation techniques combined with action observation treatment synergistically might develop into valuable physical therapy strategies in neurorehabilitation after stroke. We explored how TES or TMS intervention over the contralesional hemisphere or the lesioned hemisphere combined with PES or PMS of the paretic limbs during motor observation followed by action execution have super-additive effects to potentiate the effect of conventional treatment in stroke patients. The proposed paradigm could be an innovative and adjunctive approach to potentiate the effect of conventional rehabilitation treatment, especially for those patients with severe motor deficits.

Effects of peripheral electromagnetic stimulation after an eccentric exercise-induced delayed-onset muscle soreness protocol in professional soccer players: a randomized controlled trial

Introduction: To examine the effects of peripheral electromagnetic stimulation in male professional soccer players on markers of Delayed Onset Muscular Soreness (DOMS), induced by a protocol of exercise (60 min of eccentric and plyometric). Methods: A randomized controlled trial with fourty-five professional soccer players aged 22.33 ± 4.82 years participated in the study. Twenty-three participants were assigned to the experimental group with peripheral electromagnetic stimulation (5 stimulations of 5 s at 100 HZ with 55 s of rest for a total of 5 min of treatment) and the remaining 22 participants were assigned to the control group. Pain pressure threshold (PPT) of the vastus medialis, the Visual Analogue Scale-Fatigue (VAS-F), half squat (HS) test and the maximum voluntary contraction of the quadriceps were assessed. All evaluations were performed before and after 1 h of the eccentric exercise induced DOMS, as well as at post 24-48, and 72 h. Results: Group-by-time interaction was observed in PPT of the vastus medialis (p = 0.040) with a medium effect size (η² p = 0.069). From 48 to 72 h the experimental group showed an increase of PPT compared to control group (p = 0.015). There was no group-by-time interaction for HS, quadriceps strength and VAS-F (p > 0.05). Discussion: Peripheral electromagnetic stimulation in male professional soccer players did not produce significant improvements in the power and strength of the lower limbs but decreased the peripheral sensitization of the vastus medialis after eccentric exercise protocol. Clinical Trial Registration: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=384050&isReview=true, Identifier: ACTRN12622000841774.

Case report: A combination of mirror therapy and magnetic stimulation to the sacral plexus relieved phantom limb pain in a patient

Phantom limb pain (PLP) is a common sequela of amputation, experienced by 50-80% of amputees. Oral analgesics as the first-line therapy have limited effects. Since PLP usually affects activities of daily living and the psychological conditions of patients, effective treatments are imperatively needed. In this case study, a 49-year-old man was admitted to our hospital because of uncontrollable paroxysmal pain in his missing and residual leg. Due to severe injuries in a truck accident, the right lower limb of the patient was surgically amputated ~5 years ago. Around 1 month after amputation, he felt pain in his lost leg and PLP was diagnosed. Then, he started taking oral analgesics, but the pain still occurred. After admission on July 9, 2022, the patient received treatments of mirror therapy and magnetic stimulation to the sacral plexus. 1-month treatments reduced the frequency and intensity of pain in the phantom limb and the stump, without any adverse events. Analysis of high-resolution three-dimensional T1-weighted brain volume images at the end of 2-month treatments showed alterations in the thickness of cortex regions related to pain processing, compared to that before treatment. This case study gives us hints that one or both interventions of mirror therapy and sacral plexus magnetic stimulation effectively relieved PLP and stump limb pain. These non-invasive, low-cost and easily conducted treatments could be good options for PLP. But randomized controlled trials with a large number of cases are required to confirm their efficacy and safety.

Effects of repetitive peripheral magnetic stimulation vs. conventional therapy in the management of carpal tunnel syndrome: a pilot randomized controlled trial

Background

Carpal tunnel syndrome (CTS) is a prevalent entrapment neuropathy resulting in hand pain, numbness and/or weakness, which significantly impairs hand function in daily activities. Repetitive peripheral magnetic stimulation (rPMS) is a potential therapeutic option for focal peripheral nerve disease and may be beneficial for CTS treatment. We aimed to compare the effects of rPMS and conventional therapy in the management of CTS.

Methods

A blinded assessor randomly assigned 24 participants with electrodiagnostically-confirmed mild or moderate CTS to either rPMS or conventional therapy. Both groups were briefed on disease progression and tendon-gliding exercises. In the intervention group, the rPMS protocol, five sessions of rPMS-with a frequency of 10 Hz, 10 pulses/train, and 100 trains/session-were performed over a period of 2 weeks, with three sessions in the first week and two sessions in the second week. At baseline and the end of the second week, the Boston Carpal Tunnel Questionnaire, pinch strength, and electrodiagnostic results were evaluated.

Results

The rPMS group demonstrated significantly greater within-group improvement in symptom severity scores (2.3 vs. 1.6, p = 0.009) and pinch strength (10.6 lbs vs. 13.8 lbs, p < 0.001). Regarding electrodiagnostic parameters, sensory nerve action potential (SNAP) amplitude was significantly increased (8.7 µV vs. 14.3 µV, p = 0.002) within the group treated with rPMS. With conventional therapy, there were no statistically significant within-group differences. Multiple linear regression models showed that there were no significant differences in other outcomes in between-group comparisons.

Conclusions

Five sessions of rPMS resulted in significant reduction in symptom severity, improvement in pinch strength and increase in SNAP amplitude. Future research should investigate the clinical utility of rPMS using a larger sample and longer treatment and follow-up durations.

Effects of repetitive peripheral magnetic stimulation for the upper limb after stroke: Meta-analysis of randomized controlled trials

Introduction

Repetitive peripheral magnetic stimulation (rPMS) can stimulate profound neuromuscular tissues painlessly to evoke action potentials in motor axons and induce muscle contraction for treating neurological conditions. It has been increasingly used in stroke rehabilitation as an easy-to-administer approach for therapeutic neuromodulation.

Objective

We performed this meta-analysis of randomized controlled trials to systematically evaluate the effects of rPMS for the upper limb in patients with stroke, including motor impairment, muscle spasticity, muscle strength, and activity limitation outcomes.

Methods

The meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. PubMed, EMBASE, Web of Science, Cochrane Library, and Physiotherapy Evidence Database (PEDro) were searched for articles published before June 2022. Forest plots were employed to estimate the pooled results of the included studies, and the I2 statistical analysis was used to identify the source of heterogeneity. Publication bias was examined by Egger's regression tests or visual inspection of the funnel plots.

Results

The database searches yielded 1052 potential eligible literature; of them, five randomized controlled trials met the eligible criteria, involving a total of 188 participants. Patients in the rPMS group showed better improvement in motor impairment as measured by the FM-UE (MD: 5.39 [95% CI, 4.26 to 6.52]; P < 0.001; I2 = 0%) compared with the control group. Among the secondary outcomes, no difference was found in the improvement of muscle spasticity (SMD: 0.36 [95% CI, -0.05 to 0.77]; P = 0.08; I2 = 41%). There was a significant difference in the proximal (SMD: 0.58 [95% CI, 0.10 to 1.06]; P = 0.02; I2 = 0%) but not the distal muscle strength (SMD: 1.18 [95% CI, -1.00 to 3.36]; P = 0.29; I2 = 93%). Moreover, the activity limitation outcomes were significantly improved with rPMS intervention (SMD: 0.59 [95% CI, 0.08 to 1.10]; P = 0.02; I2 = 0%).

Conclusion

This meta-analysis showed that rPMS might improve upper limb motor impairment, proximal muscle strength, and activity limitation outcomes but not muscle spasticity and distal strength in patients after stroke. Due to the limited number of studies, further randomized clinical trials are still warranted for more accurate interpretation and clinical recommendation.

Advances in biotechnology and clinical therapy in the field of peripheral nerve regeneration based on magnetism

Peripheral nerve injury (PNI) is one of the most common neurological diseases. Recent studies on nerve cells have provided new ideas for the regeneration of peripheral nerves and treatment of physical trauma or degenerative disease-induced loss of sensory and motor neuron functions. Accumulating evidence suggested that magnetic fields might have a significant impact on the growth of nerve cells. Studies have investigated different magnetic field properties (static or pulsed magnetic field) and intensities, various magnetic nanoparticle-encapsulating cytokines based on superparamagnetism, magnetically functionalized nanofibers, and their relevant mechanisms and clinical applications. This review provides an overview of these aspects as well as their future developmental prospects in related fields.

A study of flex miniaturized coils for focal nerve magnetic stimulation

BACKGROUND

Peripheral magnetic stimulation (PMS) is emerging as a complement to standard electrical stimulation (ES) of the peripheral nervous system (PNS). PMS may stimulate sensory and motor nerve fibers without the discomfort associated with the ES used for standard nerve conduction studies. The PMS coils are the same ones used in transcranial magnetic stimulation (TMS) and lack focality and selectiveness in the stimulation.

PURPOSE

This study presents a novel coil for PMS, developed using Flexible technologies, and characterized by reduced dimensions for a precise and controlled targeting of peripheral nerves.

METHODS

We performed hybrid electromagnetic (EM) and electrophysiological simulations to study the EM exposure induced by a novel miniaturized coil (or mcoil) in and around the radial nerve of the neuro-functionalized virtual human body model Yoon-Sun, and to estimate the current threshold to induce magnetic stimulation (MS) of the radial nerve. Eleven healthy subjects were studied with the mcoil, which consisted of two 15 mm diameter coils in a figure-of-eight configuration, each with a hundred turns of a 25 μm copper-clad four-layer foil. Sensory nerve action potentials (SNAPs) were measured in each subject using two electrodes and compared with those obtained from standard ES. The SNAPs conduction velocities were estimated as a performance metric.

RESULTS

The induced electric field was estimated numerically to peak at a maximum intensity of 39 V/m underneath the mcoil fed by 70 A currents. In such conditions, the electrophysiological simulations suggested that the mcoil elicits SNAPs originating at 7 mm from the center of the mcoil. Furthermore, the numerically estimated latencies and waveforms agreed with those obtained during the PMS experiments on healthy subjects, confirming the ability of the mcoil to stimulate the radial nerve sensory fibers.

CONCLUSION

Hybrid EM-electrophysiological simulations assisted the development of a miniaturized coil with a small diameter and a high number of turns using flexible electronics. The numerical dosimetric analysis predicted the threshold current amplitudes required for a suprathreshold peripheral nerve sensory stimulation, which was experimentally confirmed. The developed and now validated computational pipeline will be used to improve the performances (e.g., focality and minimal currents) of new generations of mcoil designs.

The effects of combined high-frequency repetitive transcranial magnetic stimulation and cervical nerve root magnetic stimulation on upper extremity motor recovery following stroke

Introduction

Upper limb motor impairments after stroke cause patients partial or total loss of the capability of performing daily living, working, and social activities, which significantly affects the quality of life (QoL) of patients and brings a heavy burden to their families and society. As a non-invasive neuromodulation technique, transcranial magnetic stimulation (TMS) can act not only on the cerebral cortex, but also on peripheral nerves, nerve roots, and muscle tissues. Previous studies have shown that magnetic stimulation on the cerebral cortex and peripheral tissues has a positive effect on the recovery of upper limb motor function after stroke, however, few studies have reported the combination of the two.

Objective

This study was to investigate whether high frequency repetitive transcranial magnetic stimulation (HF-rTMS) combined with cervical nerve root magnetic stimulation more effectively ameliorates upper limb motor function in stroke patients. We hypothesized that the combination of the two can achieve a synergistic effect and further promotes functional recovery.

Methods

Sixty patients with stroke were randomly divided into four groups and received real or sham rTMS stimulation and cervical nerve root magnetic stimulation consecutively before other therapies, once daily over five fractions per week for a total of 15 times. We evaluated the upper limb motor function and activities of daily living of the patients at the time of pre-treatment, post-treatment, and 3-month follow up.

Results

All patients completed study procedures without any adverse effects. The upper limb motor function and activities of daily living improved in patients of each group were improved after treatment (post 1) and 3 months after treatment (post 2). Combination treatment was significantly better than single treatments alone or sham.

Conclusion

Both rTMS and cervical nerve root magnetic stimulation effectively promoted upper limb motor recovery in patients with stroke. The protocol combining the two is more beneficial for motor improvement and patients can easily tolerate it.

Clinical trial registration

https://www.chictr.org.cn/, identifier ChiCTR2100048558.

Paired corticomotoneuronal stimulation of the preactivated ankle dorsiflexor: an open-label study of magnetic and electrical painless protocols

Paired corticomotoneuronal stimulation (or electrical PCMS: ePCMS) is the repetitive pairing of an electrical stimulus to a nerve with a transcranial magnetic stimulation of the primary motor cortex (TMS-of-M1) to noninvasively influence spinal plasticity. We compared ePCMS with the new painless PCMS protocol pairing a magnetic stimulus to the nerve with TMS-of-M1 (mPCMS) in the preactivated tibial anterior muscle (TA). Sixteen healthy adults participated in two sessions (mPCMS, ePCMS), each with 180 pairs of [low-intensity TMS-of-M1 + nerve stimulation] at 0.2 Hz. TA motor-evoked potentials (MEP) to single-pulse TMS at pre-PCMS, immediately and 30 min after PCMS, were cluster-analyzed to discriminate responders and non-responders. Paired-pulse TMS-of-M1 and F-waves were also tested and BDNF polymorphism influence was explored. Both PCMS protocols significantly increased MEP amplitudes (n = 9 responders each), but the time-course differed with mPCMS inducing larger MEP increase over time. The number of BDNF-methionine carriers tended to be larger than Val66Val in mPCMS and the reverse in ePCMS, thus warranting further investigations. The MEP changes of the preactivated TA likely occurred at the pre-motoneuronal level and larger mPCMS after-effects over time may be related to the afferents recruited. mPCMS seems relevant to be tested in future studies as a painless noninvasive approach to induce sustained pre-motoneuronal plasticity in spinal cord injury.

Feasibility of Functional Repetitive Neuromuscular Magnetic Stimulation (frNMS) Targeting the Gluteal Muscle in a Child with Cerebral Palsy: A Case Report

BACKGROUND

Motor impairment due to spasticity, weakness, and insufficient selective motor control is a key feature of cerebral palsy (CP). For standing and walking, the gluteal muscles play an important role. Physical therapy represents an evidence-based treatment to promote strength and endurance but may be limited to address selective motor control. Treatment incorporating neurostimulating techniques may increase the therapeutic benefits in these situations.

PURPOSE

The aim of this case report was to evaluate the feasibility, safety and clinical effects of a customized protocol of functional repetitive neuromuscular magnetic stimulation (frNMS).

METHODS

This case report describes a frNMS protocol applied to the gluteal muscles in an 8-year old boy with bilateral spastic CP. The protocol combines 12 sessions of customized physiotherapeutic exercises with simultaneous electromagnetic stimulation.

RESULTS

frNMS protocol was adhered to as planned, no relevant adverse events were observed. At day fourafter the intervention the patient reported clinical benefits and improvements of standing and walking assessed by Gross Motor Function Measure dimensions D (+5.1%) and E (+4.2%) were documented. Body sway as measured by center of pressure displacement during posturography decreased.

CONCLUSION

Clinical studies are warranted to assess effects of frNMS and its mechanisms of action in a controlled setting.

Repetitive Peripheral Magnetic Stimulation Combined with Motor Imagery Changes Resting-State EEG Activity: A Randomized Controlled Trial

Repetitive peripheral magnetic stimulation is a novel non-invasive technique for applying repetitive magnetic stimulation to the peripheral nerves and muscles. Contrarily, a person imagines that he/she is exercising during motor imagery. Resting-state electroencephalography can evaluate the ability of motor imagery; however, the effects of motor imagery and repetitive peripheral magnetic stimulation on resting-state electroencephalography are unknown. We examined the effects of motor imagery and repetitive peripheral magnetic stimulation on the vividness of motor imagery and resting-state electroencephalography. The participants were divided into a motor imagery group and motor imagery and repetitive peripheral magnetic stimulation group. They performed 60 motor imagery tasks involving wrist dorsiflexion movement. In the motor imagery and repetitive peripheral magnetic stimulation group, we applied repetitive peripheral magnetic stimulation to the extensor carpi radialis longus muscle during motor imagery. We measured the vividness of motor imagery and resting-state electroencephalography before and after the task. Both groups displayed a significant increase in the vividness of motor imagery. The motor imagery and repetitive peripheral magnetic stimulation group exhibited increased β activity in the anterior cingulate cortex by source localization for electroencephalography. Hence, combined motor imagery and repetitive peripheral magnetic stimulation changes the resting-state electroencephalography activity and may promote motor imagery.

Outpatient Approach to Resistant and Refractory Migraine in Children and Adolescents: a Narrative Review

PURPOSE OF REVIEW

Migraine is one of the top reasons for consulting a pediatric neurologist. Although the majority of children and adolescents who receive evidence-based first-line interventions for migraine will improve substantially, a subset of patients develop resistant or refractory migraine.

RECENT FINDINGS

In this review, we summarize the level of evidence for a variety of acute and preventive treatment options to consider in children and adolescents with resistant or refractory migraine. We describe the level of evidence for interventional procedures (onabotulinumtoxinA injections, greater occipital and other nerve blocks), neuromodulation (single-pulse transcranial magnetic stimulation, external trigeminal nerve stimulation, remote electrical neuromodulation, and non-invasive vagal nerve stimulation), calcitonin gene-related peptide (CGRP) pathway antagonists (anti-CGRP monoclonal antibodies and gepants), psychological therapies, and manual therapies (acupuncture, craniosacral therapy, massage and physical therapy, and spinal manipulation).

Repetitive peripheral magnetic stimulation for impairment and disability in people after stroke

BACKGROUND

Repetitive peripheral magnetic stimulation (rPMS) is a non-invasive treatment method that can penetrate to deeper structures with painless stimulation to improve motor function in people with physical impairment due to brain or nerve disorders. rPMS for people after stroke has proved to be a feasible approach to improving activities of daily living and functional ability. However, the effectiveness and safety of this intervention for people after stroke remain uncertain. This is an update of the review published in 2019.

OBJECTIVES

To assess the effects of rPMS for improving activities of daily living and functional ability in people after stroke.

SEARCH METHODS

We searched the Cochrane Stroke Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL), in the Cochrane Library; MEDLINE; Embase; the Cumulative Index to Nursing and Allied Health Literature (CINAHL); PsycINFO; the Allied and Complementary Medicine Database (AMED); OTseeker: Occupational Therapy Systematic Evaluation of Evidence; the Physiotherapy Evidence Database (PEDro); Ichushi-Web; and six ongoing trial registries on 5 October 2021. We screened reference lists and contacted experts in the field. We placed no restrictions on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) conducted to assess the therapeutic effect of rPMS for people after stroke. The following comparisons were eligible for inclusion: 1) active rPMS only compared with 'sham' rPMS (a very weak form of stimulation or a sound only); 2) active rPMS only compared with no intervention; 3) active rPMS plus rehabilitation compared with sham rPMS plus rehabilitation; and 4) active rPMS plus rehabilitation compared with rehabilitation only.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion in the review. The same review authors assessed methods and risk of bias, undertook data extraction, and evaluated the certainty of the evidence using the GRADE approach. We contacted trial authors to request unpublished information if necessary. Any disagreements were resolved through discussion.

MAIN RESULTS

We included four trials (three parallel-group RCTs and one cross-over trial) involving a total of 139 participants. This result was unchanged from the review published in 2019. Blinding of participants and physicians was well reported in three trials, with no information on whether personnel were blinded in one trial. We judged the overall risk of bias across trials as low. Only two trials (with 63 and 18 participants, respectively) provided sufficient information to be included in the meta-analysis. We found no clear effect of rPMS on activities of daily living at the end of treatment (mean difference (MD) -3.00, 95% confidence interval (CI) -16.35 to 10.35; P = 0.66; 1 trial; 63 participants; low-certainty evidence) and at the end of follow-up (MD -2.00, 95% CI -14.86 to 10.86; P = 0.76; 1 trial; 63 participants; low-certainty evidence) when comparing rPMS plus rehabilitation versus sham rPMS plus rehabilitation. We found no statistical difference in improvement of upper limb function at the end of treatment (MD 2.00, 95% CI -4.91 to 8.91; P = 0.57; 1 trial; 63 participants; low-certainty evidence) and at the end of follow-up (MD 4.00, 95% CI -2.92 to 10.92; P = 0.26; 1 trial; 63 participants; low-certainty evidence) when comparing rPMS plus rehabilitation versus sham rPMS plus rehabilitation. We observed a decrease in spasticity of the elbow at the end of follow-up (MD -0.41, 95% CI -0.89 to 0.07; 1 trial; 63 participants; low-certainty evidence) when comparing rPMS plus rehabilitation versus sham rPMS plus rehabilitation. In terms of muscle strength, rPMS treatment was not associated with improved muscle strength of the ankle dorsiflexors at the end of treatment (MD 3.00, 95% CI -2.44 to 8.44; P = 0.28; 1 trial; 18 participants; low-certainty evidence) when compared with sham rPMS. No studies provided information on lower limb function or adverse events, including death. Based on the GRADE approach, we judged the certainty of evidence related to the primary outcome as low, owing to the small sample size of the studies.

AUTHORS' CONCLUSIONS

There is insufficient evidence to permit the drawing of any conclusions about routine use of rPMS for people after stroke. Additional trials with large sample sizes are needed to provide robust evidence for rPMS after stroke.

The Facial Skin Blood Flow Change of Stroke Patients with Facial Paralysis after Peripheral Magnetic Stimulation: A Pilot Study

Background: Facial paralysis (FP) is a common symptom after stroke, which influences the quality of life and prognosis of patients. Recently, peripheral magnetic stimulation (PMS) shows potential effects on peripheral and central nervous system damage. However, the effect of PMS on FP after stroke is still unclear. Methods: In this study, we applied PMS on the facial nerve of nine stroke patients with FP. At the same time, laser speckle contrast imaging (LSCI) was used to explore the facial skin blood flow (SkBF) in 19 healthy subjects and nine stroke patients with FP before and after the PMS intervention. The whole face was divided into 14 regions to compare the SkBF in different sub-areas. Results: In baseline SkBF, we found that there were no significant differences in the SkBF between the left and right faces in the healthy subjects. However, there was a significant difference in the SkBF between the affected and unaffected faces in Region 7 (Chin area, p = 0.046). In the following five minutes after the PMS intervention (Pre_0–5 min), the SkBF increased in Region 5 (p = 0.014) and Region 7 (p = 0.046) and there was an increasing trend in Region 3 (p = 0.088) and Region 6 (p = 0.069). In the five to ten minutes after the intervention (Post_6–10 min), the SkBF increased in Region 5 (p = 0.009), Region 6 (p = 0.021) and Region 7 (p = 0.023) and there was an increasing trend in Region 3 (p = 0.080) and left and right whole face (p = 0.051). Conclusions: These pilot results indicate that PMS intervention could increase facial skin blood flow in stroke patients with FP. A further randomized controlled trial can be performed to explore its possible clinical efficacy.

Body representation underlies response of proprioceptive acuity to repetitive peripheral magnetic stimulation

Proprioceptive acuity is of great significance in basic research exploring a possible neural mechanism of fine motor control and in neurorehabilitation practice promoting motor function recovery of limb-disabled people. Moreover, body representation relies on the integration of multiple somatic sensations, including proprioception that is mainly generated in muscles and tendons of human joints. This study aimed to examine two hypotheses: First, different extension positions of wrist joint have different proprioceptive acuities, which might indicate different body representations of wrist joint in the brain. Second, repetitive peripheral magnetic stimulation (rPMS) applied peripherally to the forearm radial nerve and extensors could change proprioceptive acuity at the wrist joint. Thirty-five healthy participants were recruited then randomly divided into the real stimulation group (n = 15) and the sham stimulation group (n = 20). The participants’ non-dominant side wrist joint position sense was tested at six extension positions within the physiological joint motion range (i.e., 10°, 20°, 30°, 40°, 50°, 60°) both before stimulation and after stimulation. Results showed that proprioceptive bias (arithmetic difference of target position and replicated position) among six extension positions could be divided into lower-extension position (i.e., 10°, 20°, 30°) and higher-extension position (i.e., 40°, 50°, 60°). One session rPMS could influence proprioceptive bias in lower-extension position but not in higher-extension position. However, proprioceptive precision (standard deviation within lower-extension position and higher-extension position) was not influenced. To conclude, proprioceptive bias may vary between different wrist extension positions due to different hand postures being related to changes in body representation, and different functions relating to proprioceptive bias and proprioceptive precision may underlie two aspects of body representation.

Response Predictors of Repetitive Neuromuscular Magnetic Stimulation in the Preventive Treatment of Episodic Migraine

Background

Repetitive neuromuscular magnetic stimulation (rNMS) of the trapezius muscles showed beneficial effects in preventing episodic migraine. However, clinical characteristics that predict a favorable response to rNMS are unknown. The objective of this analysis is to identify such predictors.

Methods

Thirty participants with a diagnosis of episodic migraine (mean age: 24.8 ± 4.0 years, 29 females), who were prospectively enrolled in two non-sham-controlled studies evaluating the effects of rNMS were analyzed. In these studies, the interventional stimulation of the bilateral trapezius muscles was applied in six sessions and distributed over two consecutive weeks. Baseline and follow-up assessments included the continuous documentation of a headache calendar over 30 days before and after the stimulation period, the Migraine Disability Assessment Score (MIDAS) questionnaire (before stimulation and 90 days after stimulation), and measurements of pain pressure thresholds (PPTs) above the trapezius muscles by algometry (before and after each stimulation session). Participants were classified as responders based on a ≥25% reduction in the variable of interest (headache frequency, headache intensity, days with analgesic intake, MIDAS score, left-sided PPTs, right-sided PPTs). Post-hoc univariate and multivariate binary logistic regression analyses were performed.

Results

Lower headache frequency (P = 0.016) and intensity at baseline (P = 0.015) and a migraine diagnosis without a concurrent tension-type headache component (P = 0.011) were significantly related to a ≥25% reduction in headache frequency. Higher headache frequency (P = 0.052) and intensity at baseline (P = 0.014) were significantly associated with a ≥25% reduction in monthly days with analgesic intake. Lower right-sided PPTs at baseline were significantly related to a ≥25% increase in right-sided PPTs (P = 0.0.015) and left-sided PPTs (P =0.030). Performance of rNMS with higher stimulation intensities was significantly associated with a ≥25% reduction in headache intensity (P = 0.046).

Conclusions

Clinical headache characteristics at baseline, the level of muscular hyperalgesia, and stimulation intensity may inform about how well an individual patient responds to rNMS. These factors may allow an early identification of patients that would most likely benefit from rNMS.

Repetitive Peripheral Magnetic Stimulation to Improve Ankle Function and Gait in Cerebral Palsy at Adulthood: An open-label Case Study

Repetitive peripheral magnetic stimulation (rPMS) is noninvasive and painless. It drives plasticity of the primary motor cortex (M1) in children with cerebral palsy (CP) and this improves the ankle function and gait. Our study explored whether rPMS of muscles could influence motricity in an adult CP case. A 30-year-old woman with mixed CP participated in four sessions (S1 to S4, one per week) where rPMS was applied bilaterally on leg and trunk muscles (tibialis anterior-TA, hamstrings, transverse abdominis, paraspinal multifidus). Clinical scores and M1 excitability (probed by transcranial magnetic stimulation) were tested at pre-rPMS at S1 (baseline) and S4, then 40 days later (follow-up). The active ankle dorsiflexion was significantly increased and the plantar flexors resistance to stretch reduced as compared to baseline. The improvement of the ankle function was carried-over to the quality of locomotor patterns. Changes persisted until follow-up and were paralleled by drastic changes of M1 excitability. These original findings of rPMS influence on M1 plasticity and motricity are promising for the functional improvement of adult people living with CP and should be replicated in larger-sampled studies.

Effects of different modalities of afferent stimuli of the lumbo-sacral area on control of lumbar paravertebral muscles

Somatosensory feedback to the central nervous system is essential to plan, perform and refine spine motor control. However, the influence of somatosensory afferent input from the trunk on the motor output to trunk muscles has received little attention. The objective was to compare the effects of distinct modalities of afferent stimulation on the net motoneuron and corticomotor excitability of paravertebral muscles. Fourteen individuals were recruited. Modulation of corticospinal excitability (motor-evoked potential [MEP]) of paravertebral muscles was measured when afferent stimuli (cutaneous noxious and non-noxious, muscle contraction) were delivered to the trunk at 10 intervals prior to transcranial magnetic stimulation. Each peripheral stimulation was applied alone, and subsequent EMG modulation was measured to control for net motoneuron excitability. MEP modulation and MEP/EMG ratio were used as measures of corticospinal excitability with and without control of net motoneuron excitability, respectively. MEP and EMG modulation were smaller after evoked muscle contraction than after cutaneous noxious and non-noxious stimuli. MEP/EMG ratio was not different between stimulation types. Both MEP and EMG amplitudes were reduced after evoked muscle contraction, but not when expressed as MEP/EMG ratio. Noxious and non-noxious stimulation had limited impact on all variables. Distinct modalities of peripheral afferent stimulation of the lumbo-sacral area differently modulated responses of paravertebral muscles, but without an influence on corticospinal excitability with control of net motoneuron excitability. Muscle stimulation reduced paravertebral activity and was best explained by spinal mechanisms. The impact of afferent stimulation on back muscles differs from the effects reported for limb muscles.

Checklist on the Quality of the Repetitive Peripheral Magnetic Stimulation (rPMS) Methods in Research: An International Delphi Study

An increasing number of clinical research studies have used repetitive peripheral magnetic stimulation (rPMS) in recent years to alleviate pain or improve motor function. rPMS is non-invasive, painless, and administrated over peripheral nerve, spinal cord roots, or a muscle using a coil affixed to the skin and connected to a rapid-rate magnetic stimulator. Despite the clinical impact and scientific interest, the methodological inconsistencies or incomplete details and findings between studies could make the rPMS demonstration difficult to replicate. Given the lack of guidelines in rPMS literature, the present study aimed at developing a checklist to improve the quality of rPMS methods in research. An international panel of experts identified among those who had previously published on the topic were enrolled in a two-round web-based Delphi study with the aim of reaching a consensus on the items that should be reported or controlled in any rPMS study. The consensual rPMS checklist obtained comprises 8 subject-related items (e.g., age, sex), 16 methodological items (e.g., coil type, pulse duration), and 11 stimulation protocol items (e.g., paradigm of stimulation, number of pulses). This checklist will contribute to new interventional or exploratory rPMS research to guide researchers or clinicians on the methods to use to test and publish rPMS after-effects. Overall, the checklist will guide the peer-review process on the quality of rPMS methods reported in a publication. Given the dynamic nature of a consensus between international experts, it is expected that future research will affine the checklist.

Effects of Repetitive Peripheral Magnetic Stimulation through Hand Splint Materials on Induced Movement and Corticospinal Excitability in Healthy Participants

Repetitive peripheral magnetic stimulation (rPMS) is a non-invasive neuromodulation technique. Magnetic fields induced by rPMS pass through almost all materials, and it has clinical applications for neurorehabilitation. However, the effects of rPMS through clothing and orthosis on induced movement and corticospinal excitability remain unclear. The aim of this study was to determine whether rPMS induces movement and enhances corticospinal excitability through hand splint materials. rPMS was applied directly to the skin (L0) and through one (L1) or two (L2) layers of splint material in 14 healthy participants at 25-Hz, 2-s train per 6 s for a total of 20 min. rPMS was delivered to the forearm with the stimulus intensity set to 1.5-times the train intensity-induced muscle contractions under the L0 condition. We recorded induced wrist movements during rPMS and motor-evoked potentials of the extensor carpi radialis pre- and post-application. The results showed that rPMS induced wrist movements in L0 and L1, and it facilitated corticospinal excitability in L0 but not in L1 and L2. This suggests that rPMS can make electromagnetic induction on periphery even when applied over clothing and orthosis and demonstrates the potential clinical applications of this technique for neurorehabilitation.

Using Hebbian-Type Stimulation to Rescue Arm Function After Stroke: Study Protocol for a Randomized Clinical Trial

Background

Upper-extremity hemiplegia after stroke remains a significant clinical problem. The supplementary motor area (SMA) is vital to the motor recovery outcomes of chronic stroke patients. Therefore, rebuilding the descending motor tract from the SMA to the paralyzed limb is a potential approach to restoring arm motor function after stroke. Paired associative stimulation (PAS), which is based on Hebbian theory, is a potential method for reconstructing the connections in the impaired motor neural circuits. The study described in this protocol aims to assess the effects of cortico–peripheral Hebbian-type stimulation (HTS), involving PAS, for neural circuit reconstruction to rescue the paralyzed arm after stroke.

Methods

The study is a 4-month double-blind randomized sham-controlled clinical trial. We will recruit 90 post-stroke individuals with mild to moderate upper limb paralysis. Based on a 1:1 ratio, the participants will be randomly assigned to the HTS and sham groups. Each participant will undergo 5-week HTS or sham stimulation. Assessments will be conducted at baseline, immediately after the 5-week treatment, and at a 3-month follow-up. The primary outcome will be the Wolf Motor Function Test (WMFT). The secondary outcomes will be Fugl-Meyer Assessment for Upper Extremity (FMA-UE), Functional Independence Measure (FIM), and functional near-infrared spectroscopy (fNIRS) parameters. The adverse events will be recorded throughout the study.

Discussion

Upper-limb paralysis in stroke patients is due to neural circuit disruption, so the reconstruction of effective motor circuits is a promising treatment approach. Based on its anatomical structure and function, the SMA is thought to compensate for motor dysfunction after focal brain injury at the cortical level. Our well-designed randomized controlled trial will allow us to analyze the clinical efficacy of this novel Hebbian theory-based neuromodulation strategy regarding promoting the connection between the cortex and peripheral limb. The results may have significance for the development and implementation of effective neurorehabilitation treatments.

Clinical Trial Registration

[www.ClinicalTrials.gov], identifier [ChiCTR2000039949].

Peripheral magnetic theta burst stimulation to muscles can effectively reduce spasticity: a randomized controlled trial

BACKGROUND

Spasticity is a common complication of many neurological diseases and despite contributing much disability; the available therapeutic options are limited. Peripheral magnetic stimulation is one promising option. In this study, we investigated whether peripheral intermittent theta burst stimulation (piTBS) will reduce spasticity when applied directly on spastic muscles.

METHODS

In this sham-controlled study, eight successive sessions of piTBS were applied directly to spastic muscles with supra threshold intensity. Assessment was done by modified Ashworth scale (mAS) and estimated Botulinum toxin dose (eBTD) at baseline and after the 8th session in both active and sham groups.

RESULTS

A total of 120 spastic muscles of 36 patients were included in the analysis. Significant reduction of mAS and eBTD was found in the active compared to sham group (p < 0.001). The difference in mAS was also significant when tested in upper limb and lower limb subgroups. The degree of reduction in mAS was positively correlated with the baseline scores in the active group.

CONCLUSION

piTBS could be a promising method to reduce spasticity and eBTD. It consumes less time than standard high frequency protocols without compromising treatment efficacy.

TRIAL REGISTRATION

Clinical trial registry number: PACTR202009622405087. Retrospectively Registered 14th September, 2020.

Neuromuscular Stimulation as an Intervention Tool for Recovery from Upper Limb Paresis after Stroke and the Neural Basis

Neuromodulators at the periphery, such as neuromuscular electrical stimulation (NMES), have been developed as add-on tools to regain upper extremity (UE) paresis after stroke, but this recovery has often been limited. To overcome these limits, novel strategies to enhance neural reorganization and functional recovery are needed. This review aims to discuss possible strategies for enhancing the benefits of NMES. To date, NMES studies have involved some therapeutic concerns that have been addressed under various conditions, such as the time of post-stroke and stroke severity and/or with heterogeneous stimulation parameters, such as target muscles, doses or durations of treatment and outcome measures. We began by identifying factors sensitive to NMES benefits among heterogeneous conditions and parameters, based on the “progress rate (PR)”, defined as the gains in UE function scores per intervention duration. Our analysis disclosed that the benefits might be affected by the target muscles, stroke severity and time period after stroke. Likewise, repetitive peripheral neuromuscular magnetic stimulation (rPMS) is expected to facilitate motor recovery, as already demonstrated by a successful study. In parallel, our efforts should be devoted to further understanding the precise neural mechanism of how neuromodulators make UE function recovery occur, thereby leading to overcoming the limits. In this study, we discuss the possible neural mechanisms.

Time course changes in corticospinal excitability during repetitive peripheral magnetic stimulation combined with motor imagery

Repetitive peripheral magnetic stimulation (rPMS) induces proprioceptive afferents and facilitates corticospinal excitability. Short-term sessions of rPMS combined with motor imagery (MI) enhance corticospinal excitability more than rPMS alone. However, it is not clear how long the intervention of rPMS combined with MI would be needed to facilitate corticospinal excitability. Therefore, we investigated the time course change in corticospinal excitability during the combination of rPMS and MI. Thirteen healthy volunteers participated in a 20-min intervention under the following three experimental conditions on different days: rPMS, MI, and rPMS combined with MI (rPMS + MI). In the rPMS and rPMS + MI, the participants were delivered rPMS, which was 25 Hz, 2 s/train at 1.5 × of the train intensity induced muscle contractions, through the wrist extensor muscles. In the MI and rPMS + MI, the participants repeatedly imagined wrist movements for 2 s. Motor evoked potentials (MEPs) were recorded from the extensor carpi radialis (ECR) and flexor carpi radialis (FCR) muscles every 5 min for each condition. The MEP amplitudes of the ECR after > 10 min of intermittent rPMS combined with MI were greater than baseline. The MEP amplitude of the ECR in rPMS + MI was greater than that in rPMS condition after 20 min of intervention. The present results suggest that over 10 min of intermittent rPMS combined with MI facilitates corticospinal excitability, and that the effect of rPMS combined with MI on corticospinal excitability might be greater than that of rPMS alone.

Theta-Burst Stimulation of Forearm Muscles in Patients With Complex Regional Pain Syndrome: Influence on Brain and Clinical Outcomes

Objective: Complex regional pain syndrome (CRPS) is a common pain condition characterized by the changes in the brain that are not yet addressed by conventional treatment regimens. Repetitive peripheral magnetic stimulation (rPMS) of muscles is painless and non-invasive and can influence these changes (the induction of brain plasticity) to reduce pain and improve motricity. In patients with CRPS, this open-label pilot study tested rPMS after-effects on the pain intensity and sensorimotor control of the upper limb along with the excitability changes of the primary motor cortex (M1).

Methods: Eight patients with CRPS were enrolled in a single-session program. Patients were tested at pre- and post-rPMS over the flexor digitorum superficialis (FDS) muscle. The clinical outcomes were pain intensity, proprioception, active range of motion (ROM), and grip strength. M1 excitability was tested using the single- and paired-pulse transcranial magnetic stimulation (TMS) of M1.

Results: In our small sample study, rPMS reduced instant and week pain, improved proprioception and ROM, and reduced the hemispheric imbalance of several TMS outcomes. The more M1 contralateral to the CRPS side was hyperactivated at baseline, the more pain was reduced.

Discussion: This open-label pilot study provided promising findings for the use of rPMS in CRPS with a focus on M1 plastic changes. Future randomized, placebo-controlled clinical trials should confirm the existence of a causal relationship between the TMS outcomes and post-rPMS decrease of pain. This will favor the development of personalized treatments of peripheral non-invasive neurostimulation in CRPS.

Complex Regional Pain Syndrome. A Comprehensive Review on Neuroplastic Changes Supporting the Use of Non-invasive Neurostimulation in Clinical Settings

Background: Complex regional pain syndrome (CRPS) is a rare debilitating disorder characterized by severe pain affecting one or more limbs. CRPS presents a complex multifactorial physiopathology. The peripheral and sensorimotor abnormalities reflect maladaptive changes of the central nervous system. These changes of volume, connectivity, activation, metabolism, etc., could be the keys to understand chronicization, refractoriness to conventional treatment, and developing more efficient treatments. Objective: This review discusses the use of non-pharmacological, non-invasive neurostimulation techniques in CRPS, with regard to the CRPS physiopathology, brain changes underlying chronicization, conventional approaches to treat CRPS, current evidence, and mechanisms of action of peripheral and brain stimulation. Conclusion: Future work is warranted to foster the evidence of the efficacy of non-invasive neurostimulation in CRPS. It seems that the approach has to be individualized owing to the integrity of the brain and corticospinal function. Non-invasive neurostimulation of the brain or of nerve/muscles/spinal roots, alone or in combination with conventional therapy, represents a fertile ground to develop more efficient approaches for pain management in CRPS.

Repetitive Peripheral Magnetic Stimulation (rPMS) in Subjects With Lumbar Radiculopathy: An Electromyography-guided Prospective, Randomized Study

BACKGROUND/AIM

Lumbar radiculopathy refers to the disruption of one or more lumbosacral nerve root functions, usually causing radiating pain and functional impairments.

PATIENTS AND METHODS

We aimed to analyze the role of repetitive peripheral magnetic stimulation (rPMS) alone or in association with physiokinesiotherapy (PKT) in treating lumbar radiculopathy. A total of 41 patients diagnosed with lumbar radiculopathy were randomly allocated to the rPMS group and the rPMS plus PKT group. Subjects were then administered a total of 10 treatment sessions.

RESULTS

A statistically significant improvement was highlighted in both groups in terms of pain score, and electromyography (EMG) analysis depicted a far superior functional recovery in the rPMS plus PKT group.

CONCLUSION

rPMS can constitute an effective treatment for subjects with lumbar radiculopathy and its association with a complex physical rehabilitation program could improve the outcome in these patients.

Repetitive peripheral magnetic stimulation for the assessment of wrist spasticity: reliability, validation and correlation with clinical measures

PURPOSE

To determine feasibility and reliability of using repetitive peripheral magnetic stimulation (rPMS) to induce wrist extension movement for the assessment of spasticity in wrist flexors, instead of the passive stretch used in the modified Tardieu scale.

METHODS

Spasticity was assessed with the index of movement restriction (iMR), calculated as the difference between the range of maximum wrist passive movement and the rPMS-induced movement, in 12 healthy subjects (HS), 12 acute stroke patients without spasticity (AS) and 12 chronic stroke patients with spasticity (CS). Test-retest reliability and clinical correlation were assessed in CS patients before Botulinum neurotoxin type A (BoNT-A) treatment.

RESULTS

In comparison to HS and AS patients, CS patients showed statistically significant reduction of rPMS-induced movement amplitude, velocity, and acceleration. The mean iMR was 2.8 (SD = 2.6) in HS, 13.0 (SD = 11.2) in AS and 59.2 (SD = 23.4) in CS. This score significantly reduced to 41.1 (SD = 19.7) in CS after BoNT-A (p < 0.01). Test-retest reliability was very good, with an intraclass correlation coefficient ranging between 0.85 and 0.99 for the variables analysed.

CONCLUSIONS

We have shown good reliability and feasibility of a new method providing quantifiable data for the assessment of spasticity and its response to BoNT-A treatment.IMPLICATIONS FOR REHABILITATIONThe muscle contraction induced by repetitive peripheral magnetic stimulation (rPMS) in paretic muscles of post-stroke patients was used to assess spasticity.The index of movement restriction (iMR), calculated as the difference between the maximum passive range of movement and the rPMS induced movement, improved after botulinum toxin treatment.Measuring spastic reactions to rPMS provides quantifiable and reliable data for follow-up and assessment of therapeutic benefits.

Effect of repetitive peripheral magnetic stimulation combined with motor imagery on the corticospinal excitability of antagonist muscles

OBJECTIVE

Repetitive peripheral magnetic stimulation (rPMS) combined with motor imagery facilitates the corticospinal excitability of the agonist muscles. However, the effects of rPMS combined with motor imagery on the corticospinal excitability of the antagonist muscles are unclear. This is an important aspect for applying rPMS in neurorehabilitation for sensorimotor dysfunction. Therefore, we investigated the real-time changes of corticospinal excitability of antagonist muscles during rPMS combined with motor imagery.

METHODS

Fourteen healthy volunteers underwent four different experimental conditions: rest, rPMS, motor imagery, and rPMS combined with motor imagery (rPMS + motor imagery). In the rPMS and rPMS + motor imagery conditions, rPMS (25 Hz, 1600 ms/train, 1.5× of the motor threshold) was delivered to the dorsal side of the forearm. In motor imagery and rPMS + motor imagery, the participant imagined wrist extension movements. Transcranial magnetic stimulation was delivered to record motor-evoked potentials of the antagonist muscle during experimental interventions.

RESULTS

The motor-evoked potential (normalized by rest condition) values indicated no difference between rPMS, motor imagery, and rPMS + motor imagery.

CONCLUSION

These results suggest that rPMS combined with motor imagery has no effect on the corticospinal excitability of the antagonist muscles and highlight the importance of investigating the effects of rPMS combined with motor imagery at the spinal level.

Acute effects of repetitive peripheral magnetic stimulation following low-intensity isometric exercise on muscle swelling for selective muscle in healthy young men

Repetitive peripheral magnetic stimulation (rPMS) is a non-invasive stimulator that can induce strong muscle contraction in selective regions. This study aimed to measure acute changes in skeletal muscle thickness induced by rPMS following a low-intensity exercise. Fifteen healthy young men performed an isometric knee extensor exercise at 30% of maximum strength consisting of three sets of 10 contractions on their dominant leg. rPMS was then applied on the vastus lateralis (VL) at the maximum intensity of the rPMS device. Muscle thicknesses of the rectus femoris (RF) and VL were measured using an ultrasound device and were compared among baseline, post-exercise, and post-rPMS. There were significant increases in muscle thickness of both the RF and VL post-exercise compared with baseline values (RF: baseline; 24.7 ± 2.4, post-exercise; 25.3 ± 2.4 mm, p = .034, VL: baseline; 27.0 ± 2.8, post-exercise; 27.4 ± 2.8 mm, p = .006). Compared with post-exercise, there was a significant increase post-rPMS in only the VL (VL: post-rPMS; 28.3 ± 2.9 mm, p = .002). These findings suggest that low-intensity isometric exercise can induce acute increases in muscle thickness (muscle swelling) in synergist muscles, and rPMS following exercise can induce further acute muscle swelling via repetitive muscle contraction.

Modulation of the Corticomotor Excitability by Repetitive Peripheral Magnetic Stimulation on the Median Nerve in Healthy Subjects

Objective: We aimed to examine the effects of repetitive peripheral nerve magnetic stimulation (rPNMS) on the excitability of the contralateral motor cortex and motor function of the upper limb in healthy subjects.

Methods: Forty-six healthy subjects were randomly assigned to either a repetitive peripheral nerve magnetic stimulation group (n = 23) or a sham group (n = 23). The repetitive peripheral nerve magnetic stimulation group received stimulation using magnetic pulses at 20 Hz, which were applied on the median nerve of the non-dominant hand, whereas the sham group underwent the same protocol without the stimulation output. The primary outcome was contralateral transcranial magnetic stimulation (TMS)-induced corticomotor excitability for the abductor pollicis brevis of the stimulated hand in terms of resting motor threshold (rMT), the slope of recruitment curve, and peak amplitude of motor evoked potential (MEP), which were measured at baseline and immediately after each session. The secondary outcomes were motor hand function including dexterity and grip strength of the non-dominant hand assessed at baseline, immediately after stimulation, and 24 h post-stimulation.

Results: Compared with the sham stimulation, repetitive peripheral nerve magnetic stimulation increased the peak motor evoked potential amplitude immediately after the intervention. The repetitive peripheral nerve magnetic stimulation also increased the slope of the recruitment curve immediately after intervention and enhanced hand dexterity after 24 h. However, the between-group difference for the changes was not significant. The significant changes in hand dexterity and peak amplitude of motor evoked potential after repetitive peripheral nerve magnetic stimulation were associated with their baseline value.

Conclusions: Repetitive peripheral nerve magnetic stimulation may modulate the corticomotor excitability together with a possible lasting improvement in hand dexterity, indicating that it might be helpful for clinical rehabilitation.

A 12-Week, Prospective, Non-Comparative, Non-Randomized Study of Magnetic Muscle Stimulation for Improvement of Body Satisfaction With the Abdomen and Buttocks

Background and Objective

Magnetic muscle stimulation (MMS) is a relatively new energy‐based technology that provides a non‐invasive option for body contouring through stimulation and toning of underlying skeletal muscles. This study was conducted to examine the safety, efficacy, and body satisfaction scores of MMS using a CoolToneTM prototype for the aesthetic improvement of abdominal and buttock contour.

Study Design/Materials and Methods

This was a prospective, non‐comparative, non‐randomized, 12‐week, multicenter study. Male and female participants aged 22‐65 years received 4 MMS treatment sessions to the abdomen and/or buttocks. Body Satisfaction Questionnaire (BSQ) scores for abdomen and/or buttocks were assessed at baseline, immediately post final treatment, at 4 weeks (primary endpoint), and 12 weeks post final treatment. Subject‐rated Global Aesthetic Improvement Scale (SGAIS) was assessed at 4 weeks post final treatment (secondary endpoint), and 12 weeks post final treatment. Additional efficacy assessment included abdominal circumference obtained by 3D imaging at baseline, immediately post final treatment, and at 4 and 12 weeks post final treatment. A Subject Experience Questionnaire (SEQ) was used to assess treatment satisfaction and perspectives at 4 weeks and 12 weeks post final treatment. Adverse events (AEs) were monitored throughout the study.

Results

A total of 110 participants were recruited, who were 75% female, 80% Caucasian (mostly non‐Hispanic), average age of 39.5 years (range 22–59) with an average body mass index (BMI) of 23.3 kg/m2 (range 18–29.9). At the 4‐week post final treatment visit, the average BSQ score for participants receiving abdominal treatment (n = 93) was significantly improved with a 5.1 average increase in total score from baseline (possible score range 10–50) and by a 5.5 average increase from baseline for participants receiving buttocks treatment (n = 32) (p < 0.05). At 4 weeks post final treatment, the proportion of participants with SGAIS scores >“Improved” was 68.1% for participants receiving treatment of the abdomen (n = 94), and 81.8% for those receiving buttocks treatment (n = 33). The mean total decrease from baseline in waist circumference was significant at all time points. At the 12‐week post final treatment visit, SEQ data revealed that a majority of participants were “Satisfied” or “Very Satisfied” with overall treatment results and “Agreed” or “Strongly Agreed” that they were motivated to maintain results either by working out or by additional treatment. A total of 6 AEs related to the device and/or treatment were reported, which resolved spontaneously during the study.

Conclusion

Treatment of the abdomen and/or buttocks with MMS was well‐tolerated and demonstrated significant improvement in aesthetic appearance through the 12‐week post final treatment study duration. As a stand‐alone treatment, MMS expands the range of options for individualized treatment planning for patients seeking abdominal and/or gluteal muscle toning. © 2020 The Authors. Lasers in Surgery and Medicine published by Wiley Periodicals, Inc.

Preventive Effects of Repetitive Peripheral Magnetic Stimulation on Muscle Atrophy in the Paretic Lower Limb of Acute Stroke Patients: A Pilot Study

Objective:

The aim of this study was to investigate the effect of repetitive peripheral magnetic stimulation (rPMS) on muscle atrophy prevention in the rectus femoris muscle (RF) of the paretic limb in acute stroke patients.

Methods:

Twelve acute stroke patients with a National Institute of Health Stroke Scale score >5 and a motor score of the paretic lower limb >2 at admission were divided into an intervention group (rPMS: mean age, 75±6.4 years) and a conventional care group (non-rPMS: mean age, 62±11.8 years). Baseline measurements were performed within 4 days of stroke onset. In the rPMS group, treatment was applied to the paretic thigh only for 2 weeks, 5 days a week, in addition to conventional care. The cross-sectional area (CSA) of the RF was assessed in both limbs using ultrasound at baseline and 2 weeks later. Data on patient characteristics were collected from the clinical records to assess correlations with the CSA rate of change.

Results:

Patients in the rPMS group were significantly older. Although the CSA of the RF did not change significantly on either side in the rPMS group, there was a significant decrease in the CSA on the paretic side in the non-rPMS group. However, no significant difference was observed in the CSA rate of change in the rPMS and non-rPMS groups. The CSA rate of change on the paretic side correlated negatively with age in the rPMS group.

Conclusions:

Our results suggest that rPMS prevents muscle atrophy more effectively in patients in their 60s than in patients more than 70 years old.

[Migraine in childhood and adolescence-neurostimulation as a future innovative approach in terms of a multimodal treatment regimen]

Although migraine is a relevant health issue in children and adolescents, clinical care and research are still underrepresented and underfunded in this field. Quality of life can be significantly reduced when living with frequent episodes of pain. Due to the high level of vulnerability of the developing brain during adolescence, the risk of chronification and persistence into adulthood is high. In this narrative review, we describe the corner stones of a patient-centered, multimodular treatment regimen. Further, an update on the pathophysiology of migraine is given considering the concept of a periodically oscillating functional state of the brain in migraine patients ("migraine is a brain state"). Besides central mechanisms, muscular structures with the symptoms of muscular pain, tenderness, or myofascial trigger points play an important role. Against this background, the currently available nonpharmacological and innovative neuromodulating approaches are presented focusing on the method of repetitive peripheral magnetic stimulation.

Modulation of H-reflex responses and frequency-dependent depression by repetitive spinal electromagnetic stimulation: From rats to humans and back to chronic spinal cord injured rats

The lack of propagation of signals through survived fibers is among the major reasons for functional loss after incomplete spinal cord injury (SCI). Our recent results of animal studies demonstrate that spinal electromagnetic stimulation (SEMS) can enhance transmission in damaged spinal cord, and this type of modulation depends on the function of NMDA receptors at the neuronal networks below the injury level. Here, our pilot human study revealed that administration of repetitive SEMS induced long‐lasting modulation of H‐responses in both healthy and participants with chronic SCI. In order to understand the mechanisms underlying these effects, we have used an animal model and examined effects of SEMS on H‐responses. Effects of SEMS on H‐responses, frequency‐dependent depression (FDD) of H‐reflex, and possible underlying mechanisms have been examined in both naïve and rats with SCI. Our results demonstrate that consistent with the effects of SEMS on H‐reflex seen in humans, repetitive SEMS induced similar modulation in excitability of peripheral nerve responses in both non‐injured and rats with SCI. Importantly, our results confirmed the reduced FDD of H‐reflex in SCI animals and revealed that SEMS was able to recover FDD in rats with chronic SCI. Using intraspinal injections of the NMDA receptor blocker MK‐801, we have identified NMDA receptors as an important contributor to these SEMS‐induced effects in rats with SCI. These results identify SEMS as a novel non‐invasive technique for modulation of neuro‐muscular circuits and, importantly, modulation of spinal networks after chronic SCI.

Repetitive peripheral magnetic stimulation improves severe upper limb paresis in early acute phase stroke survivors

BACKGROUND

It is very difficult for patients with severe upper extremity (UE) paresis after stroke to achieve full recovery because of the lack of a definitive approach for improving severe UE paresis immediately after onset.

OBJECTIVE

to investigate the effects of repetitive peripheral magnetic stimulation (rPMS) on severe UE paresis during early acute phase of stroke.

METHODS

Nineteen participants with severe UE disability met the criteria. 10 subjects received 15-20 minutes of rPMS prior to standard care per session, while 9 age- and severity-matched subjects received two times 20 minutes of standard care. Outcome measures included UE motor section of the Fugl-Meyer Motor Assessment Scale (FMA-UE), Wolf motor function test (WMFT), and box and block test (BBT).

RESULTS

The rPMS group received treatment (average sessions: 7.8) after a median 9.2 days from stroke (16.5 sessions after 5 days for control). To adjust the different treatment durations, we defined "progress rate" as the gains of UE function scores divided by treatment duration. The progress rate was significantly different in FMA-UE and WMFT, but not in BBT.

CONCLUSIONS

The present study suggested beneficial effects of rPMS on severe UE paresis during early acute phase of stroke.

Numerical Analysis of Eddy Current Distribution in Submental Region Induced by Magnetic Stimulation for Treating Dysphagia

Induced contraction of the suprahyoid muscles via magnetic stimulation is considered to be effective for the rehabilitation of dysphagia. In our previous study, a magnetic stimulation coil with a U-shaped core for stimulating the suprahyoid muscles was developed based on the results of numerical analysis using a simplified human head model. It was confirmed that magnetic stimulation by the coil causes large contraction of the muscles. However, the human head has a complex structure that includes bone structures through which current cannot easily pass. To accurately predict the current density distribution induced by magnetic stimulation, a model that accurately describes the human head is required for numerical analysis. Therefore, in this study, numerical analysis using the finite element method with a human head model that includes the bone structure obtained from computed tomography scans was performed. The results for the model with bone structure show that the coil with a U-shaped core can stimulate the motor points of the suprahyoid muscles in the middle of the submental region. When compared with the current density observed in a model without the bone structure, that in the model with the bone structure was reduced by 29% at a point 20 mm below the mandibular surface. It is thus necessary to perform a numerical analysis using a model with the bone structure to obtain accurate analysis results.