Noninvasive Electromagnetic Neuromodulation of the Central and Peripheral Nervous System for Upper-Limb Motor Strength and Functionality in Individuals with Cervical Spinal Cord Injury: A Systematic Review and Meta-Analysis.

(1) Background: Restoring arm and hand function is one of the priorities of people with cervical spinal cord injury (cSCI). Noninvasive electromagnetic neuromodulation is a current approach that aims to improve upper-limb function in individuals with SCI. The aim of this study is to review updated information on the different applications of noninvasive electromagnetic neuromodulation techniques that focus on restoring upper-limb functionality and motor function in people with cSCI. (2) Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were used to structure the search protocol. A systematic review of the literature was performed in three databases: the Cochrane Library, PubMed, and Physiotherapy Evidence Database (PEDro). (3) Results: Twenty-five studies were included: four were on transcranial magnetic stimulation (TMS), four on transcranial direct current stimulation (tDCS), two on transcutaneous spinal cord stimulation (tSCS), ten on functional electrical stimulation (FES), four on transcutaneous electrical nerve stimulation (TENS), and one on neuromuscular stimulation (NMS). The meta-analysis could not be completed due to a lack of common motor or functional evaluations. Finally, we realized a narrative review of the results, which reported that noninvasive electromagnetic neuromodulation combined with rehabilitation at the cerebral or spinal cord level significantly improved upper-limb functionality and motor function in cSCI subjects. Results were significant compared with the control group when tSCS, FES, TENS, and NMS was applied. (4) Conclusions: To perform a meta-analysis and contribute to more evidence, randomized controlled trials with standardized outcome measures for the upper extremities in cSCI are needed, even though significant improvement was reported in each non-invasive electromagnetic neuromodulation study.

Frequency-Specific Effects of Noninvasive Median Nerve Stimulation on Gastric Slow Wave Activity in Humans.

OBJECTIVES: The present study explored the effects of different frequencies of noninvasive median nerve stimulation (nMNS) on two autonomic responses: gastric slow waves under water-loading condition and heart rate variability (HRV). To the best of our knowledge, this is the first study to document the effects of different frequencies of nMNS on gastric slow waves (GSW) in humans under 5-minute water-loading condition. MATERIALS AND METHODS: Twenty healthy adult participants were fitted with a noninvasive body-surface gastric mapping, electrocardiogram (ECG), and a transcutaneous electrical nerve stimulation device and administered with four different nMNS frequencies (placebo-0 Hz, 40 Hz, 120 Hz, and 200 Hz) on four separate counterbalanced days. After the baseline and stimulation periods, a 5-minute water-load test was applied, and a post-water-load period also is recorded for ECG and GSW activity. Time-domain HRV parameters are analyzed with repeated-measures one-way analysis of variance (ANOVA) and a post hoc Tukey multiple comparison test. Parameters that failed normality tests underwent a Freidman test with a post hoc Dunn multiple comparison test. GSW data are analyzed with repeated-measures mixed-effects ANOVA. RESULTS: In empty stomach (baseline vs stimulation), only the 40-Hz frequency statistically significantly (p = 0.0129) increased GSW amplitude in comparison with its own baseline. In full (distended) stomach, 40-Hz and 200-Hz stimulations showed a statistically significant difference (post hoc multiple comparison adjusted, p = 0.0016 and p = 0.0183, respectively) in the Gastric Rhythm Index in comparison with the change obtained by placebo stimulation (baseline vs poststimulation periods); 120-Hz nMNS showed a statistically significant difference (p = 0.0300) in the stress index in comparison with the decrease observed in the placebo group. However, 120-Hz nMNS did not induce a statistically significant change in gastric electrical activity compared to placebo stimulation. The nMNS did not follow the linear "dose-response" relationship between nMNS frequency and gastric/HRV parameters. CONCLUSIONS: The 40-Hz and 200-Hz nMNS frequencies showed the most promising results in response to gastric distension, in addition to 40 Hz for an empty stomach. Further research is essential to explore the potential therapeutic effects of these frequencies on gastric diseases such as gastroparesis, gastroesophageal reflux disease, and functional dyspepsia that can be used in wrist wearables.

The Role of Continuous Theta Burst Stimulation on Primary Motor Cortex in Improving Bladder Function in Post-stroke Patients: A Case Report.

Neurogenic bladder (NB) is a frequently encountered post-stroke complication, characterized by symptoms, such as urinary incontinence, dysuria, increased frequency, and urgency. Here, we present a case of a 75-year-old male with urgent urination, frequent urination, urinary incontinence, conspicuous discomfort during urination, and an unpleasant smell in the urine following a stroke. By reviewing the patient's previous medical records of stroke and ruling out other potential causes for bladder dysfunction, a diagnosis of NB could be established. We implemented conventional physical therapy, pelvic floor muscle training with the electromyography biofeedback device, and continuous theta burst stimulation (cTBS) on the contralesional primary motor cortex area to manage bladder function. To the best of our knowledge, this is the first case report on cTBS applied to manage NB after stroke. Our treatment has demonstrated remarkable efficacy in enhancing bladder and kidney function, improving the overall quality of life, and alleviating anxiety and depression symptoms in this patient. This case study concludes that the noninvasive neuromodulation approach exhibits significant potential in the clinical field when addressing this specific patient population.

Technical Report: Efficacy and Safety of Low-Intensity Transcranial Magnetic Stimulation in the Remission of Depressive Symptoms in Patients With Treatment-Resistant Depression in Mexico.

Transcranial magnetic stimulation (TMS) is a non-invasive neuromodulation technique that induces action potentials in the stimulated cortical area and has been approved by the Food and Drug Administration (FDA) for the treatment of major depressive disorder (MDD). The prevalence of MDD in Mexico almost tripled after the COVID-19 pandemic. In this study, we evaluated the safety and therapeutic effects of low-intensity TMS (Li-TMS) - characterized by inducing electric currents below the action potential threshold on the cerebral cortex - in 41 subjects diagnosed with treatment-resistant depression (TRD). A Li-TMS device dispensed repetitive magnetic pulses at 30 mT for 60 minutes during 20 sessions (once daily from Monday to Saturday) with the theta burst pattern. Our results suggest that Li-TMS is a safe therapy with antidepressant effects, demonstrated by the decrease in Beck Depression Inventory (BDI) scores and lessening of depressive symptoms.