Effects Of Magnetic Stimulation Research Articles

Functional Magnetic Neuromuscular Stimulation vs. Routine Physiotherapy in the Critically Ill for Prevention of ICU Acquired Muscle Loss: A Randomised Controlled Trial

Background and Objectives: Muscle loss is a known complication of ICU admission. The aim of the study was to investigate the effect of neuromuscular functional magnetic stimulation (FMS) on quadriceps muscle thickness in critically ill patients. Materials and Methods: Among ICU patients one quadriceps was randomized to FMS (Tesla Stym,Iskra Medical, Ljubljana, Slovenia) stimulation and the other to control care. Quadriceps thickness was measured by ultrasound (US) in transversal and longitudinal planes at enrolment, Days 3–5, and Days 9–12. The trial stopped early following an interim analysis comparing muscle thickness differences between groups using repeated measures ANOVA. Results: Of 18 patients randomized, 2 died before completing the trial. The final analysis reported included 16 patients (female 38%, age 68 ± 10 years, SOFA 10.8 ± 2.7). Three mild skin thermal injuries were noted initially, which were later avoided with proper positioning of FMS probe. Primary outcome comparison showed that quadriceps thickness in transversal and longitudinal planes decreased in the non-stimulated legs and, but it did not change in FMS legs (−4.1 mm (95%CI: −9.4 to −0.6) vs. −0.7 mm (95%CI: −4.1 to −0.7) (p = 0.03) and −4.4 mm (95%CI: −8.9 to −1.1) vs. −1.5 mm (95%CI: −2.6 to −2.2) (p = 0.02), respectively) (ANOVA difference between groups p = 0.036 and 0.01, respectively). Conclusions: In the critically ill, neuromuscular FMS is feasible and safe with precautions applied to avoid possible skin thermal injury. FMS decreases the loss of quadriceps muscle thickness.

Correction of immune disorders under the influence of pharmacotherapy and extracorporeal magnetic stimulation with patients after surgical treatment of prostate adenoma

BACKGROUND: The course of benign prostatic hyperplasia is associated with immunological disorders at the systemic and local level. Despite the wide arsenal of pharmacological agents for the treatment of benign prostatic hyperplasia, some patients undergo surgical treatment. Postoperative management programmes should be aimed at reducing the risks of complications, including infectious-inflammatory complications. In this regard, the inclusion of immunomodulatory pharmacotherapy and therapeutic physical factors in the course of reconstructive treatment is reasonable and justified. AIM: To study the role of the complex effect of pharmacotherapy and extracorporeal magnetic stimulation in the correction of immune disorders with the patients after surgical treatment of benign prostatic hyperplasia. MATERIALS AND METHODS: There have been observed 88 patients after surgical treatment of benign prostatic hyperplasia, who underwent a medical rehabilitation at stages II and III. At stage II 43 patients in the comparison group underwent standardized drug therapy, individual exercise therapy; in the main group 45 patients additionally were prescribed immunomodulatory therapy with Tameritis. At stage III the patients of the comparison group continued pharmacotherapy, exercise therapy, and transrectal magnetic therapy; in the main group 45 patients were additionally prescribed extracorporeal magnetic stimulation. A method of enzyme-linked immunosorbent assay was used to study the content of interleukins (IL); IPSS-QOL (International Prostate Symptom Score – Quality-of-Life) and SF-36 (The Short Form-36) were used to assess the quality of life. Confidence level (р) 0.05. RESULTS: After the second inpatient stage of rehabilitation the patients of the main group after surgical treatment of benign prostatic hyperplasia had a decrease the level of pro-inflammatory IL by 47.5% on average (p 0.01) with an increase in the level of anti-inflammatory IL-10 by 36.2% (p 0.01). After the III outpatient rehabilitation stage, a positive dynamics significantly increased and amounted to 63.2% (p 0.01) and 51.9% (p 0.01), reaching the normative values in the population. It should be noted that the achieved results have been preserved in a long time. In the comparison group the positive dynamics was significantly lower (p 0.05; p 0.01) in all the cases after the II and III stages of rehabilitation. The patients of the main group were observed a decrease in the severity of urinary disorders (p 0.01), restoration of quality of life (p 0.05) according to IPSS-QOL and SF-36 questionnaires at significant inter-group values (p 0.05) with the same confidence. CONCLUSION: The integrated use of pharmacotherapy and extracorporeal magnetic stimulation with the patients after surgical treatment of benign prostatic hyperplasia provides significant correction of immune disorders, restoration of physical and mental health.

Meta-analysis of the curative effect of sacral nerve magnetic stimulation on neurogenic bladder after spinal cord injury.

The curative effect of sacral nerve magnetic stimulation on the neurogenic bladder (NB) after spinal cord injury (SCI) is unclear. This study made a meta-analysis of the curative effect of sacral nerve magnetic stimulation on the NB after SCI and put forward a theoretical basis for the clinical treatment of this disease. The databases of PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, WanFang Data, VIP, and CBM were searched by computer, and the randomized controlled trials of sacral nerve magnetic stimulation in the treatment of NB after SCI were collected. The retrieval time was from the establishment of the database to September 25, 2023. Meta-analysis was performed with Stata 15.0 software. This study finally included 10 articles, including 537 patients. Meta-analysis shows that the sacral nerve magnetic stimulation treatment group can effectively improve urodynamics: the maximum bladder capacity increases (mean difference [MD], 40.76 [95% confidence interval (CI), 33.24-48.28]; P ˂ .05), the bladder capacity increases at the beginning of urination (MD, 12.82 [95% CI, 11.02-14.62]; P ˂ .05), and the residual urine volume decreases (MD, -38.08 [95% CI, -51.36 to -24.79]; P˂.05). In the aspect of urination diary, the sacral nerve magnetic stimulation treatment group also has advantages compared with the conventional treatment group: the increase in single urine volume (MD, 22.49 [95% CI, 18.68-26.30]; P˂.05), the maximum urine volume (MD, 32.84 [95% CI, 22.37-43.30]; P˂.05), and the decrease in urination times (MD, -2.23 [95% CI, -3.13 to -1.33]; P˂.05). After the treatment of sacral nerve magnetic stimulation, the quality of life of patients can be improved: quality-of-life score (MD, -0.62 [95% CI, -0.91 to -0.34]; P˂.05). Combined with functional magnetic stimulation of the sacral nerve, routine treatment is superior to routine treatment in improving the clinical symptoms of patients with NB after SCI.

Effect of cerebrospinal dual-site magnetic stimulation on freezing of gait in Parkinson’s disease

Addressing levodopa-unresponsive freezing of gait (FOG) in Parkinson’s disease (PD) presents a significant challenge. A randomized double-blinded trial evaluated the effects of repetitive transcranial magnetic stimulation (rTMS) in conjunction with transcutaneous magnetic spinal cord stimulation among 57 PD individuals experiencing levodopa-unresponsive FOG. Patients were randomized to receive dual-site stimulation involving bilateral primary motor cortex of the lower leg (M1-LL) and the lumbar spinal cord, single-site stimulation targeting bilateral M1-LL alone, or sham stimulation for 10 sessions. Low-frequency rTMS induced remarkable improvements in FOG, gait, and motor functions compared to sham at 1 day and 1 month postintervention. Notably, the dual-site protocol demonstrated superior efficacy in mitigating FOG and improving gait compared to the single-site approach, which correlated with a pronounced increase in short-interval intracortical inhibition of the abductor pollicis brevis. These findings underscore the potential of the cerebrospinal dual-site regimen as a promising approach for levodopa-unresponsive FOG and gait in PD.

Age and visual cortex inhibition: a TMS-MRS study.

Paired-pulse transcranial magnetic stimulation is a valuable tool for investigating inhibitory mechanisms in motor cortex. We recently demonstrated its use in measuring cortical inhibition in visual cortex, using an approach in which participants trace the size of phosphenes elicited by stimulation to occipital cortex. Here, we investigate age-related differences in primary visual cortical inhibition and the relationship between primary visual cortical inhibition and local GABA+ in the same region, estimated using magnetic resonance spectroscopy. GABA+ was estimated in 28 young (18 to 28years) and 47 older adults (65 to 84years); a subset (19 young, 18 older) also completed a paired-pulse transcranial magnetic stimulation session, which assessed visual cortical inhibition. The paired-pulse transcranial magnetic stimulation measure of inhibition was significantly lower in older adults. Uncorrected GABA+ in primary visual cortex was also significantly lower in older adults, while measures of GABA+ that were corrected for the tissue composition of the magnetic resonance spectroscopy voxel were unchanged with age. Furthermore, paired-pulse transcranial magnetic stimulation-measured inhibition and magnetic resonance spectroscopy-measured tissue-corrected GABA+ were significantly positively correlated. These findings are consistent with an age-related decline in cortical inhibition in visual cortex and suggest paired-pulse transcranial magnetic stimulation effects in visual cortex are driven by GABAergic mechanisms, as has been demonstrated in motor cortex.

The effect of repetitive magnetic stimulation on neuronal apoptosis and PI3K/Akt protein expression in rats with incomplete spinal cord injury.

The pathological and physiological process of spinal cord injury is complex, and there is currently no effective treatment method. Magnetic stimulation is an emerging electromagnetic therapy method in recent years, and studies have shown its potential to reduce cell apoptosis. This study used an improved Allen's method to replicate an incomplete spinal cord injury rat model, and repetitive magnetic stimulation (rMS) intervention was performed on the rats for 21 days. The research plan consists of two parts. The first part aims to observe the effects of rMS on motor function and neuronal cell apoptosis in rats. The Basso-Beattie-Bresnahan (BBB) score results indicate that rMS promotes the recovery of motor function in rats; H&E staining showed that rMS improved spinal cord structural damage and inflammatory infiltration; TUNEL and NeuN staining suggest that rMS can reduce cell apoptosis and promote neuronal cell survival. The second part aims to explore the mechanism of action of rMS. Immunofluorescence staining showed that after rMS intervention, the positive counts of PI3K and Akt increased, whereas the positive counts of caspase-3 decreased. Western blot showed that after rMS intervention, the expression of phospho-phosphatidylinositol-3 kinase (p-PI3K)/PI3K, phospho (p)-Akt/Akt, and Bcl-2 increased, whereas the expression of Bcl-2-associated X protein(Bax) and caspase-3 decreased. In summary, rMS can significantly reduce cell apoptosis in the damaged spinal cord and promote neuronal cell survival. Its mechanism of action may be related to promoting the expression of PI3K/Akt pathway proteins, upregulating the antiapoptotic protein Bcl-2, downregulating the proapoptotic protein Bax, and thereby inhibiting the expression of apoptotic protein caspase-3. NEW & NOTEWORTHY Spinal cord injury is a serious disabling central nervous system disease. Recently, research on magnetic stimulation therapy for spinal cord injury has been increasing, and its potential has gradually attracted the attention of experts. This study found that repetitive magnetic stimulation (rMS) can improve motor function and reduce neuronal apoptosis in spinal cord injury rats. The mechanism may be related to increasing the expression of phosphatidylinositol-3 kinase (PI3K)/Akt protein, thereby inhibiting cell apoptosis and promoting neuronal survival.

Effects of concurrent optical and magnetic stimulation in hard-to-heal wounds: a real-world evidence case series.

This work explores concurrent optical and magnetic stimulation (COMS) effects on hard-to-heal wounds in real-world settings. In this case series, participants received COMS 1-3 times per week for up to 12 weeks alongside standard wound care. A total of 27 patients (18 female and nine male) were included. Mean age was 72 years. Participants' wounds that were unresponsive to standard wound care included: venous leg ulcers (VLUs, n=13); mixed leg ulcers (MLUs, n=4); diabetic foot ulcers (DFUs, n=1); pressure ulcers (PUs, n=5); and traumatic wounds (TWs, n=4). On average, COMS was applied twice a week, resulting in an overall mean wound area reduction of 69%. In 24 participants, COMS was used primarily to achieve wound closure by the end of the 12-week period, of which: 12 were classified as complete wound closure (50%; VLUs=8, PUs=3 and TW=1); four as likely-to-heal (17%; VLUs=2 and MLUs=2); four as 'improved' (17%; MLU=1, DFU=1 and TWs=2); and four as 'non-responding' (17%; VLUs=3 and MLU=1). The best results were achieved in PUs and VLUs (respectively 100% and 62% categorised as completely healed). When used in participants where its purpose was other than that of achieving wound closure, COMS was successfully used to debride two PUs, and for wound bed preparation in one TW. In this case series, COMS showed positive effects and appeared to be beneficial in healing different types of hard-to-heal wounds in community health and homecare settings. Novel COMS therapy aspects emerged: (1) positive outcomes for PU and VLU treatment; (2) COMS as a potential debridement tool when sharp debridement is unfeasible; and (3) COMS as a promising method to prepare wound beds for subsequent skin grafting or skin replacement procedures.

Magnetic Stimulation of Gigantocellular Reticular Nucleus with Iron Oxide Nanoparticles Combined Treadmill Training Enhanced Locomotor Recovery by Reorganizing Cortico-Reticulo-Spinal Circuit.

Gigantocellular reticular nucleus (GRNs) executes a vital role in locomotor recovery after spinal cord injury. However, due to its unique anatomical location deep within the brainstem, intervening in GRNs for spinal cord injury research is challenging. To address this problem, this study adopted an extracorporeal magnetic stimulation system to observe the effects of selective magnetic stimulation of GRNs with iron oxide nanoparticles combined treadmill training on locomotor recovery after spinal cord injury, and explored the possible mechanisms. Superparamagnetic iron oxide (SPIO) nanoparticles were stereotactically injected into bilateral GRNs of mice with moderate T10 spinal cord contusion. Eight-week selective magnetic stimulation produced by extracorporeal magnetic stimulation system (MSS) combined with treadmill training was adopted for the animals from one week after surgery. Locomotor function of mice was evaluated by the Basso Mouse Scale, Grid-walking test and Treadscan analysis. Brain MRI, anterograde virus tracer and immunofluorescence staining were applied to observe the tissue compatibility of SPIO in GRNs, trace GRNs' projections and evaluate neurotransmitters' expression in spinal cord respectively. Motor-evoked potentials and H reflex were collected for assessing the integrity of cortical spinal tract and the excitation of motor neurons in anterior horn. (1) SPIO persisted in GRNs for a minimum of 24 weeks without inducing apoptosis of GRN cells, and degraded slowly over time. (2) MSS-enabled treadmill training dramatically improved locomotor performances of injured mice, and promoted cortico-reticulo-spinal circuit reorganization. (3) MSS-enabled treadmill training took superimposed roles through both activating GRNs to drive more projections of GRNs across lesion site and rebalancing neurotransmitters' expression in anterior horn of lumbar spinal cord. These results indicate that selective MSS intervention of GRNs potentially serves as an innovative strategy to promote more spared fibers of GRNs across lesion site and rebalance neurotransmitters' expression after spinal cord injury, paving the way for the structural remodeling of neural systems collaborating with exercise training, thus ultimately contributing to the reconstruction of cortico-reticulo-spinal circuit.

Model-based analysis of the acute effects of transcutaneous magnetic spinal cord stimulation on micturition after spinal cord injury in humans.

After spinal cord injuries (SCIs), patients may develop either detrusor-sphincter dyssynergia (DSD) or urinary incontinence, depending on the level of the spinal injury. DSD and incontinence reflect the loss of coordinated neural control among the detrusor muscle, which increases bladder pressure to facilitate urination, and urethral sphincters and pelvic floor muscles, which control the bladder outlet to restrict or permit bladder emptying. Transcutaneous magnetic stimulation (TMS) applied to the spinal cord after SCI reduced DSD and incontinence. We defined, within a mathematical model, the minimum neuronal elements necessary to replicate neurogenic dysfunction of the bladder after a SCI and incorporated into this model the minimum additional neurophysiological features sufficient to replicate the improvements in bladder function associated with lumbar TMS of the spine in patients with SCI. We created a computational model of the neural circuit of micturition based on Hodgkin-Huxley equations that replicated normal bladder function. We added interneurons and increased network complexity to reproduce dysfunctional micturition after SCI, and we increased the density and complexity of interactions of both inhibitory and excitatory lumbar spinal interneurons responsive to TMS to provide a more diverse set of spinal responses to intrinsic and extrinsic activation of spinal interneurons that remains after SCI. The model reproduced the re-emergence of a spinal voiding reflex after SCI. When we investigated the effect of monophasic and biphasic TMS at two frequencies applied at or below T10, the model replicated the improved coordination between detrusor and external urethral sphincter activity that has been observed clinically: low-frequency TMS (1 Hz) within the model normalized control of voiding after SCI, whereas high-frequency TMS (30 Hz) enhanced urine storage. Neuroplasticity and increased complexity of interactions among lumbar interneurons, beyond what is necessary to simulate normal bladder function, must be present in order to replicate the effects of SCI on control of micturition, and both neuronal and network modifications of lumbar interneurons are essential to understand the mechanisms whereby TMS reduced bladder dysfunction after SCI.

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.

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. 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 4weeks. 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. 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. 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. The trial was registered on ClinicalTrials.gov (ChiCTR2300070943).

Design of a 1 × 4 micro-magnetic stimulation device and its targeted, coordinated regulation on LTP of Schaffer-CA1 in the hippocampus of rats

Magnetic technology has been a hotspot of neuromodulation research in recent years. However, magnetic coil is limited by their size, and it is impossible to realize precise targeted magnetic stimulation to the target area at the cellular scale. To this end, this study designs a 1 × 4 array micro-magnetic stimulation (μMS) device with four sub-millimeter-sized elements, enabling precise magnetic stimulation of the CA1-CA3-DG tri-synaptic positions in the rat hippocampal region. First, it is determined that 70 KHz/2 mT/1 min magnetic stimulation parameter has a modulatory effect on the long-term potentiation (LTP) of Schaffer-CA1 in rat hippocampus. Then, a 1 × 4 array μMS device is used to perform magnetic stimulation at 70 KHz/2 mT/1 min, targeting the CA1, CA3, and DG regions individually with single-point magnetic stimulation; and multi-region magnetic stimulation is applied to the double-point targeting regions of CA1-CA3, CA1-DG, and CA3-DG, as well as the triple-point targeting region of CA1-CA3-DG, so as to investigate the regulation of LTP by single-region magnetic stimulation and multi-region magnetic stimulation. The experimental results indicate that, in the case of single-region magnetic stimulation, the magnitude of the increase in LTP in the CA1 region is the greatest, followed by the CA3 region, while the effect of magnetic stimulation on the DG region is less pronounced. In multi-region magnetic stimulation, synergistic magnetic stimulation of the three-point CA1-CA3-DG results in a greater increase in LTP compared to stimulation of two individual areas, and the enhancement of LTP induction with multi-region magnetic stimulation surpasses that of single-region stimulation. This study has implications for the collaborative targeted magnetic stimulation application of arrayed micro-magnetic devices.

Effects of central intermittent theta-burst stimulation combined with repetitive peripheral magnetic stimulation on upper limb function in stroke patients.

Intermittent theta-burst stimulation and repetitive peripheral magnetic stimulation can improve motor function in poststroke patients, but the therapeutic effect of this combination remains unclear. To determine the effects of central intermittent theta-burst stimulation and repetitive peripheral magnetic stimulation on upper limb function. Fifty-six subacute stroke patients were randomly assigned to three groups: the CMS (n = 18), peripheral magnetic stimulation (PMS) (n = 19) and CPS (n = 19) groups. The CMS group received intermittent theta-burst stimulation and peripheral false stimulation, while the PMS group received repetitive peripheral magnetic stimulation and central false stimulation once a day for five days a week over four weeks. The CPS group received intermittent theta-burst stimulation and repetitive peripheral magnetic stimulation simultaneously once daily for four weeks. The Fugl-Meyer Assessment, Action Research Arm Test, Modified Barthel Index and Modified Ashworth Scale evaluated outcomes before and after four weeks of treatment. The motor function scores of all groups were significantly increased after treatment compared with before treatment, while the Modified Ashworth Scale score showed no significant change. There was a significant difference in the motor function score of the CPS group compared with that of the CMS and PMS groups, but there was no significant improvement in the Modified Ashworth Scale score. Combining the two treatment methods can improve patients' motor function and daily living abilities but cannot improve muscle tone.

Correction of immune disorders under the influence of pharmacotherapy and extracorporal magnetic stimulation in patients after surgical treatment of prostate adenoma

Abstract. The literature analysis shows that benign prostatic hyperplasia is associated with chronic prostatitis in 50–70 % of cases. Moreover, the course of benign prostatic hyperplasia is associated with immunological disorders at the systemic and local levels. The presence of a chronic, sluggish process is accompanied by endogenous intoxication, which leads to a gradual decrease in the body’s immune reactivity. Purpose of the study. To study the role of the complex effects of pharmacotherapy and extracorporeal magnetic stimulation (EMS) in the correction of immune disorders in patients after surgical treatment of prostate adenoma. Material and methods. Observations were carried out on 88 patients after surgical treatment of pancreatic adenoma, who underwent medical rehabilitation at stages II and III. At stage II, in the comparison group (CG), 43 patients received standardized drug therapy and individual physical therapy; in the main group (MG), 45 patients additionally received immunomodulatory therapy with Tamerit. At stage III in the GS, patients continued pharmacotherapy, exercise therapy and transrectal magnetic therapy; in the OG, 45 patients were additionally prescribed EMS. To study the content of interleukins (IL), the enzyme-linked immunosorbent assay method was used; To assess the quality of life, the IPSS-QOL (International Prostate Symptom Score — Quality-of-Life) questionnaire and SF-36 (The Short Form-36) were used.Significance level — p < 0.05. Results. After the II inpatient stage of rehabilitation in patients with OH after surgical treatment of pancreatic adenoma, the level of proinflammatory ILs decreased on average by 47.5 % (p < 0.01) with an increase in the level of anti-inflammatory IL-10 by 36.2 % (p < 0.01). After the third outpatient stage of rehabilitation, the positive dynamics increased significantly and amounted to 63.2 % (p < 0.01) and 51.9 % (p < 0.01), reaching normative values in the population. It should be noted that the achieved results are maintained in the long term. In the GS, in all cases after stages II and III of rehabilitation, the positive dynamics were significantly lower (p < 0.05 — p < 0.01). With the same reliability, in the group there was a decrease in the severity of urinary disorders (p < 0.01), restoration of quality of life (p < 0.05) according to the IPSS-QOL and SF-36 questionnaires with significant intergroup values (p < 0.05). Conclusion. The integrated use of pharmacotherapy and EMS in patients after surgical treatment of pancreatic adenoma provides significant correction of immune disorders and restoration of physical and mental health.

Cellular mechanisms underlying carry-over effects after magnetic stimulation

Magnetic fields are widely used for neuromodulation in clinical settings. The intended effect of magnetic stimulation is that neural activity resumes its pre-stimulation state right after stimulation. Many theoretical and experimental works have focused on the cellular and molecular basis of the acute neural response to magnetic field. However, effects of magnetic stimulation can still last after the termination of the magnetic stimulation (named “carry-over effects”), which could generate profound effects to the outcome of the stimulation. However, the cellular and molecular mechanisms of carry-over effects are largely unknown, which renders the neural modulation practice using magnetic stimulation unpredictable. Here, we investigated carry-over effects at the cellular level, using the combination of micro-magnetic stimulation (µMS), electrophysiology, and computation modeling. We found that high frequency magnetic stimulation could lead to immediate neural inhibition in ganglion neurons from Aplysia californica, as well as persistent, carry-over inhibition after withdrawing the magnetic stimulus. Carry-over effects were found in the neurons that fired action potentials under a variety of conditions. The carry-over effects were also observed in the neurons when the magnetic field was applied across the ganglion sheath. The state of the neuron, specifically synaptic input and membrane potential fluctuation, plays a significant role in generating the carry-over effects after magnetic stimulation. To elucidate the cellular mechanisms of such carry-over effects under magnetic stimulation, we simulated a single neuron under magnetic stimulation with multi-compartment modeling. The model successfully replicated the carry-over effects in the neuron, and revealed that the carry-over effect was due to the dysfunction of the ion channel dynamics that were responsible for the initiation and sustaining of membrane excitability. A virtual voltage-clamp experiment revealed a compromised Na conductance and enhanced K conductance post magnetic stimulation, rendering the neurons incapable of generating action potentials and, therefore, leading to the carry over effects. Finally, both simulation and experimental results demonstrated that the carry-over effects could be controlled by disturbing the membrane potential during the post-stimulus inhibition period. Delineating the cellular and ion channel mechanisms underlying carry-over effects could provide insights to the clinical outcomes in brain stimulation using TMS and other modalities. This research incentivizes the development of novel neural engineering or pharmacological approaches to better control the carry-over effects for optimized clinical outcomes.

Explaining transcranial magnetic stimulation effects on grasping movements by electric field modeling in healthy persons and stroke patients

Explaining transcranial magnetic stimulation effects on grasping movements by electric field modeling in healthy persons and stroke patients

Study on the Effect of Repetitive Peripheral Magnetic Stimulation Combined with Conventional Rehabilitation Measures on Shoulder Dysfunction in Early Stroke

Objective: To study the effect of repetitive peripheral magnetic stimulation (rPMS) combined with conventional rehabilitation measures on shoulder dysfunction in early stroke. Methods: 60 patients with shoulder dysfunction in early stroke were selected, and all of them were admitted to our hospital from August 2021 to August 2023. The patients were randomly grouped into a control group (conventional rehabilitation measures intervention, 30 cases) and an intervention group (rPMS and conventional rehabilitation measures intervention, 30 cases) according to the lottery method. The pain scores, shoulder mobility, and motor function scores of the two groups were compared. Results: The pain score was lower in the intervention group, and the shoulder mobility and motor function scores were higher in the intervention group (P < 0.05) as compared to that of the control group. Conclusion: The effect of combining rPMS and conventional rehabilitation measures in treating shoulder dysfunction in early stroke was remarkable and should be popularized.

Transcranial magnetic stimulation effects support an oscillatory model of ERP genesis

Whether prestimulus oscillatory brain activity contributes to the generation of post-stimulus-evoked neural responses has long been debated, but findings remain inconclusive. We first investigated the hypothesized relationship via EEG recordings during a perceptual task with this correlational evidence causally probed subsequently by means of online rhythmic transcranial magnetic stimulation. Both approaches revealed a close link between prestimulus individual alpha frequency (IAF) and P1 latency, with faster IAF being related to shorter latencies, best explained via phase-reset mechanisms. Moreover, prestimulus alpha amplitude predicted P3 size, best explained via additive (correlational and causal evidence) and baseline shift mechanisms (correlational evidence), each with distinct prestimulus alpha contributors. Finally, in terms of performance, faster prestimulus IAF and shorter P1 latencies were both associated with higher task accuracy, while lower prestimulus alpha amplitudes and higher P3 amplitudes were associated with higher confidence ratings. Our results are in favor of the oscillatory model of ERP genesis and modulation, shedding new light on the mechanistic relationship between prestimulus oscillations and functionally relevant evoked components.

Trans-spinal magnetic stimulation induces co-activation of the diaphragm and biceps in healthy subjects.

The present study was designed to examine the effect of trans-spinal magnetic stimulation on bilateral respiratory and forelimb muscles in healthy subjects. Two wings of a figure-of-eight magnetic coil were placed on the dorsal vertebrae, from the fifth cervical to the second thoracic dorsal vertebra with a center at the seventh cervical vertebra. The surface electromyograms of bilateral diaphragm and biceps were recorded in response to trans-spinal magnetic stimulation with 20%-100% maximum output of the stimulatory device in male (n = 12) and female participants (n = 8). Trans-spinal magnetic stimulation can induce a co-activation of bilateral diaphragm and biceps when the stimulation intensity is above 60%. The onset latency was comparable between the left and right sides of the muscles, suggesting bilateral muscles could be simultaneously activated by trans-spinal magnetic stimulation. In addition, the intensity-response curve of the biceps was shifted upward compared with that of the diaphragm in males, indicating that the responsiveness of the biceps was greater than that of the diaphragm. This study demonstrated the feasibility of utilizing trans-spinal magnetic stimulation to co-activate the bilateral diaphragm and biceps. We proposed that this stimulatory configuration can be an efficient approach to activate both respiratory and forelimb muscles.

TsMS combined with EA promotes functional recovery and axonal regeneration via mediating the miR-539-5p/Sema3A/PlexinA1 signalling axis in sciatic nerve-injured rats

Enhancing axonal regeneration is one of the most important processes in treating nerve injuries. Both magnetic and electrical stimulation have the effect of promoting nerve axon regeneration. But few study has investigated the effects of trans-spinal magnetic stimulation (TsMS) combined with electroacupuncture (EA) on nerve regeneration in rats with sciatic nerve injury. In this study, we compared the improvement of neurological function in rats with sciatic nerve crush injuries after 4 weeks of different interventions (EA, TsMS, or TsMS combined with EA). We further explored the morphological and molecular biological alterations following sciatic nerve injury by HE, Masson, RT-PCR, western blotting, immunofluorescence staining and small RNA transcriptome sequencing. The results showed that TsMS combined with EA treatment significantly promoted axonal regeneration, increased the survival rate of neurons, and suppressed denervation atrophy of the gastrocnemius muscle. Subsequent experiments suggested that the combination treatment may play an active role by mediating the miR-539-5p/Sema3A/PlexinA1 signaling axis.

Meta-analysis of the effectiveness and safety of magnetic stimulation for chronic pelvic pain.

To systematically assess the effectiveness and safety of magnetic stimulation (MS) for treating chronic prostatitis (CP) and chronic pelvic pain syndrome (CPPS) through a meta-analysis. A comprehensive search of databases including PubMed, The Cochrane Library, EMbase, VIP, Web of Science, WanFang, China Biology Medicine disc (CBMdisc), and China National Knowledge Internet (CNKI) databases was conducted to retrieve randomized controlled trials (RCTs) on MS interventions for CPPS from inception to the present. The search employed keywords such as "MS", "CPPS", and "prostatitis". Data analysis was performed using RevMan 5.4 software, focusing on NIH-Chronic Prostatitis Symptom Index (NIH-CPSI), maximal urinary flow rate (Qmax), and international index of erectile function-5 (IIEF-5) score. Eight RCTs involving 636 patients were included. Our meta-analysis revealed that extracorporeal MS significantly reduced NIH-CPSI scores [MD = -6.65; 95% CI (-8.15, -5.15), P < 0.00001] and improved Qmax [MD = 2.98; 95% CI (1.36, 4.59), P = 0.0003] compared to the control group. Although a trend toward improved IIEF-5 scores was observed [MD = 0.81; 95% CI (-0.34, 1.95), P = 0.17], the results were not significant. MS is effective in alleviating clinical symptoms and enhancing Qmax in patients with CP/CPPS.