Spinal Stimulation Research Articles

Six-Month Follow-up of a Trial of Spinal Cord Burst Stimulation vs Placebo Stimulation and Disability in Patients With Chronic Radicular Pain After Lumbar Spine Surgery

This follow-up study examines back pain–related disability at 6 months following a randomized trial of spinal cord burst stimulation for chronic radicular pain after lumbar spine surgery.

Safety and Feasibility of Cervical and Thoracic Transcutaneous Spinal Cord Stimulation to Improve Hand Motor Function in Children With Chronic Spinal Cord Injury

ObjectiveIn adults with cervical spinal cord injury (SCI), transcutaneous spinal stimulation (scTS) has improved upper extremity strength and control. This novel noninvasive neurotherapeutic approach combined with training may modulate the inherent developmental plasticity of children with SCI, providing even greater improvements than training or stimulation alone. Because children with SCI represent a vulnerable population, we first must establish the safety and feasibility of any potential novel therapeutic approach. The objectives of this pilot study were to determine the safety, feasibility, and proof of principle of cervical and thoracic scTS for short-term effect on upper extremity strength in children with SCI. Materials and MethodsIn this nonrandomized, within-subject repeated measure design, seven participants with chronic cervical SCI performed upper extremity motor tasks without and with cervical (C3–C4 and C6–C7) and thoracic (T10–T11) site scTS. Safety and feasibility of using cervical and thoracic sites scTS were determined by the frequency count of anticipated and unanticipated risks (eg, pain, numbness). Proof-of-principle concept was tested via change in force production during hand motor tasks. ResultsAll seven participants tolerated cervical and thoracic scTS across the three days, with a wide range of stimulation intensities (cervical sites = 20–70 mA and thoracic site = 25–190 mA). Skin redness at the stimulation sites was observed in four of 21 assessments (19%) and dissipated in a few hours. No episode of autonomic dysreflexia was observed or reported. Hemodynamic parameters (systolic blood pressure and heart rate) remained within stable limits (p > 0.05) throughout the assessment time points at baseline, with scTS, and after the experiment. Hand-grip and wrist-extension strength increased (p < 0.05) with scTS. ConclusionsWe indicated that short-term application of scTS via two cervical and one thoracic site is safe and feasible in children with SCI and resulted in immediate improvements in hand-grip and wrist-extension strength in the presence of scTS. Clinical Trial RegistrationThe Clinicaltrials.gov registration number for the study is NCT04032990.

Transcutaneous spinal stimulation in people with and without spinal cord injury: Effect of electrode placement and trains of stimulation on threshold intensity.

Transcutaneous spinal cord stimulation (TSS) is purported to improve motor function in people after spinal cord injury (SCI). However, several methodology aspects are yet to be explored. We investigated whether stimulation configuration affected the intensity needed to elicit spinally evoked motor responses (sEMR) in four lower limb muscles bilaterally. Also, since stimulation intensity for therapeutic TSS (i.e., trains of stimulation, typically delivered at 15-50 Hz) is sometimes based on the single-pulse threshold intensity, we compared these two stimulation types. In non-SCI participants (n = 9) and participants with a SCI (n = 9), three different electrode configurations (cathode-anode); L1-midline (below the umbilicus), T11-midline and L1-ASIS (anterior superior iliac spine; non-SCI only) were compared for the sEMR threshold intensity using single pulses or trains of stimulation which were recorded in the vastus medialis, medial hamstring, tibialis anterior, medial gastrocnemius muscles. In non-SCI participants, the L1-midline configuration showed lower sEMR thresholds compared to T11-midline (p = 0.002) and L1-ASIS (p < 0.001). There was no difference between T11-midline and L1-midline for participants with SCI (p = 0.245). Spinally evoked motor response thresholds were ~13% lower during trains of stimulation compared to single pulses in non-SCI participants (p < 0.001), but not in participants with SCI (p = 0.101). With trains of stimulation, threshold intensities were slightly lower and the incidence of sEMR was considerably lower. Overall, stimulation threshold intensities were generally lower with the L1-midline electrode configuration and is therefore preferred. While single-pulse threshold intensities may overestimate threshold intensities for therapeutic TSS, tolerance to trains of stimulation will be the limiting factor in most cases.

ID: 214352 Microdissection of the Swine Spinal Cord to Reveal Lumbar and Thoracic Rootlets

Spinal cord epidural stimulation (SCS) is a safe and effective therapy of chronic pain. The most common complication for SCS is lead migration, resulting in inefficient stimulation. In addition, the shunting of current or activation of the dorsal rootlets may result in contraction of back muscles, via activation of motor fibers recruited at lower stimulation amplitudes. Activation of these rootlets could cause electromyography (EMG) bleed-through into the evoked compound action potential (ECAPs) recordings, as well as cause side effect during SCS therapy. In some cases, motor activation may limit the range of stimulation to levels below what is required for pain therapy.

ID: 199213 Artificial Intelligence-Driven Closed-Loop SCS: Optimizing Patient Outcomes Using a Comprehensive Measure of Well-being

Introduction: Closing the loop involves using sensed signals from the patient to provide feedback to modify the system output to reach a desired therapy goal. Some chronic diseases, like diabetes, have clear biomarkers and normal ranges that can be applied across the population (e.g., HbA1c, blood glucose). However, in chronic pain, the challenge in closing the loop is much more complicated; i.e., there are many signals that could be used to the close the loop, optimal values may be patient specific, and a single domain may not always adequately capture effectiveness. We propose an approach where signals used to close the loop in patients with chronic pain are related to the therapeutic goals, namely improvement in pain and/or quality of life (QOL). We evaluate this approach in early pilots of chronic pain patients with Spinal Cords Stimulation (SCS).

Broad and Asymmetric Lower Extremity Myotomes: Results From Intraoperative Direct Electrical Stimulation of the Lumbosacral Spinal Roots.

Retrospective review of prospectively collected data. This study aimed to accurately map the lower extremity muscles innervated by the lumbar spinal roots by directly stimulating the spinal roots during surgery. Innervation of the spinal roots in the lower extremities has been estimated by clinical studies, anatomic studies, and animal experiments. However, there have been discrepancies between studies. Moreover, there are no studies that have studied the laterality of lower limb innervation. In 73 patients with lumbar degenerative disease, a total of 147 spinal roots were electrically stimulated and the electromyographic response was recorded at the vastus medialis (VM), gluteus medius (GM), tibialis anterior (TA), biceps femoris (BF), and gastrocnemius (GC). The asymmetry index (AI) was obtained using the following equation to represent the left-right asymmetry in the compound muscle action potential (CMAP) amplitude. Paired t tests were used to compare CMAP amplitudes on the right and left sides. Differences in the AI among the same spinal root groups were determined using one-way analysis of variance. The frequency of CMAP elicitation in VM, GM, TA, BF, and GC were 100%, 75.0%, 50.0%, 83.3%, and 33.3% in L3 spinal root stimulation, 90.4%, 78.8%, 59.6%, 73.1%, and 59.6% in L4 spinal root stimulation, 32.2%, 78.0%, 93.2%, 69.5%, and 83.1% in L5 spinal root stimulation, and 40.0%, 100%, 80.0%, 70.0%, and 80.0% in S1 spinal root stimulation, respectively. The most frequent muscle with maximum amplitude of the CMAP in L3, L4, L5, and S1 spinal root stimulation was the VM, GM, TA, and GM, respectively. Unilateral innervation occurred at high rates in the TA in L4 root stimulation and the VM in L5 root stimulation in 37.5% and 42.3% of patients, respectively. Even in patients with bilateral innervation, a 20% to 38% AI of CMAP amplitude was observed. The spinal roots innervated a much larger range of muscles than what is indicated in general textbooks. Furthermore, a non-negligible number of patients showed asymmetric innervation of lower limb by the lumbar spinal roots.

Exoskeleton gait training with spinal cord neuromodulation.

Neuromodulating the locomotor network through spinal cord electrical stimulation (SCES) is effective for restoring function in individuals with gait deficits. However, SCES alone has limited effectiveness without concurrent locomotor function training that enhances activity-dependent plasticity of spinal neuronal networks by sensory feedback. This mini review discusses recent developments in using combined interventions, such as SCES added to exoskeleton gait training (EGT). To develop personalized therapies, it is crucial to assess the state of spinal circuitry through a physiologically relevant approach that identifies individual characteristics of spinal cord function to develop person-specific SCES and EGT. The existing literature suggests that combining SCES and EGT to activate the locomotor network can have a synergistic rehabilitative effect on restoring walking abilities, somatic sensation, and cardiovascular and bladder function in paralyzed individuals.

Gastroprotective effect of electrical spinal cord stimulation may be mediated by glucocorticoids produced in response to this stimulation

We demonstrated previously that stress-induced glucocorticoids are gastroprotective hormones but not ulcerogenic ones (Filaretova et al., 2016). Recently electrical spinal cord stimulation began to be used for both experimental studies of motor functions regulation and rehabilitation of motor functions in patients with spinal cord injury (Gerasimenko et al., 2021; Moshonkina et al., 2016). The spinal cord stimulation directed to the activation of spinal locomotor related networks affected visceral systems as well. Recently in our teamwork we have shown that the electrical spinal cord stimulation can cause an increase in blood glucocorticoid level accompanied by a gastroprotective effect (Filaretova et al., 2022). The aim of the present work was to verify the hypothesis that the gastroprotective effect of the electrical spinal cord stimulation may be mediated by glucocorticoids produced in response to this stimulation. Gastric injury was induced in anesthetized rats by prolonged gastric ischemia/reperfusion (I/R, 30 min occlusion of celiac artery followed by 3 h of reperfusion) or indomethacin administration (IM, 35 mg/kg, sc). For spinal stimulation, stainless steel wire electrodes were fixed in fasciae between T11-12 and L1–L2 vertebrae of anesthetized animals. Motor evoked responses in hindlimbs muscles to spinal stimulation were recorded. Spinal stimulation at 30 Hz was carried out with a subthreshold current for inducing muscle contractions (80% of the threshold). Sham-stimulated (control) rats were subjected to the same manipulations except for the stimulation itself. To test the participation of glucocorticoids in the gastroprotective effect of the stimulation, two approaches were used: pretreatment by the inhibitor of glucocorticoid synthesis, metyrapone (30 mg/kg, i.p.) and the antagonist of glucocorticoid receptors RU-38486 (20 mg/kg, i.p.). The concentration of corticosterone in blood plasma was determined using commercial ELISA kits. In control rats the spinal cord stimulation resulted in an increase of blood corticosterone level 1 h later. The spinal stimulation, applied 1 h before the onset of ulcerogenic stimuli, also significantly attenuated gastric erosion formation induced by I/R and IM as well. Metyrapone injected shortly before the stimulation caused a fast inhibition of corticosterone response and reversed the gastroprotective effect stimulation. The gastroprotective effect of the stimulation was also prevented by the pretreatment rats with glucocorticoid receptor antagonist RU-38486. The obtained results indicate on contribution of glucocorticoids to gastroprotective effect of spinal cord stimulation. In conclusion, the findings support the hypothesis that the gastroprotective effect of the electrical spinal cord stimulation may be mediated by glucocorticoids produced in response to this stimulation. The study was supported by the Ministry of Education and Science of the Russian Federation (agreement No. 075-15-2020-921 for the creation and development of the world-class scientific center “Pavlov Center “Integrative Physiology - to medicine, high-tech healthcare and technologies of stress resistance”). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Ventral and dorsal cervical spinal cord electrical epidural stimulation facilitated respiration differently in the presence of opioids in human via different neural circuits

Opioid overdose is one of the leading causes of overdose related deaths in the United States of America, accounting for 70.6% of overdose fatalities in 2019 alone. A leading cause of death among opioid overdoses is respiratory depression. Epidural electrical stimulation (EES) emerges as a novel approach of facilitating rhythmic motor activities such as locomotion and respiration. Previous studies conducted in humans and rodent models demonstrated respiratory augmentations induced by EES delivered to the dorsal cervical spinal cord. Importantly, EES at the dorsal cervical spinal cord opposes opioid-induced respiratory depression in human. To reveal the mechanism underpins how cervical EES modulate the respiratory neural circuit, we conducted this comparative study between dorsal cervical EES to the ventral EES in patients with opioid-induced respiratory suppression or depression. We hypothesize that the ventral cervical EES activates the local motor neuronal pools while the dorsal EES recruits both sensory and motor cervical circuits as well as accesses supraspinal structures such as medulla. We recruited and consented 25 patients who underwent anterior (ventral) cervical spinal cord surgery and compared the effect of ventral cervical EES to to the effect of dorsal cervical ESS in a dataset that we collected from 18 patients undergoing cervical spinal surgery. In the 25 patients, the EES was deliver to the ventral surface of spinal cord ranging from cervical level 3 to 7 (C3 to C7) for no more than 90 seconds at the optimal intensity ranging from 0.5 mA to 5 mA with stimulation frequencies 5 Hz or 30 Hz. In both the dorsal and ventral EES groups, the subjects were anesthetized with low dose or high dose remifentanil that partially or completely depressed voluntary respiration. We observed three main differences between the dorsal and ventral cervical EEST in regulating respiration in the presence of remifentanil. First, dorsal cervical EES induced the resetting of inspiratory rhythm while ventral cervical EES did not. Second, dorsal but not ventral cervical EES induced longer lasting respiratory modulation after the stimulation stopped. Third, dorsal cervical EES induced both frequency and amplitude changes of respiration while ventral cervical EES modulated the amplitude of the respiration more significantly. These observations suggest that the dorsal and ventral cervical EES facilitate respiration via different neural circuits. This work was supported by the National Institute of Drug Abuse in the National Institutes of Health: R01 DA047637, Louis and Harold Price Foundation, H &amp; H Evergreen Foundation, and J. Yang Family Foundation. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

At-home void training with spinal epidural stimulation in an individual with chronic spinal cord injury using advanced customized software

Bladder dysfunction is a highly prevalent quality of life issue in individuals with chronic spinal cord injury (SCI). The current study examined control of storage and emptying with neuromodulation in an SCI individual newly implanted with a spinal cord epidural stimulation (scES) electrode array. The goals of this pilot trial were 1) to enable dynamic human in-the-loop, sensor feedback, learning algorithm-controlled neuromodulation of micturition pathways in the home environment, and 2) to improve the transition from bladder storage to voiding in the home-setting by flexibly adjusting preset parameters in accordance with real-time physiological responses to bladder distention (e.g., sensations of fullness). Application of scES with a neurostimulator attached to a 16-electrode array was first examined in a controlled lab setting during filling cystometry by interactively identifying optimal stimulation parameters (cathode/anode configuration, stimulation frequency and amplitude) for storage and voiding. Efficacy was then tested in the lab for six-hour periods during natural bladder filling, followed by at-home use. The current report is on the first of four participants, a 40-year-old male T3 level of injury (AIS A) approximately 12 years post-injury, who entered the study having high filling pressures and low voiding efficiency. At-home daily training with scES (cohorts determined with prior in-lab mapping experiments) revealed effective storage at low fill pressure and efficient voiding, which improved over time. A major advantage of this system is afforded by the versatility of the multi-electrode array and technology advancements (STIMX) allowing for smooth transition from the storage to emptying phase, enabled by the ability to activate multiple spinal cord regions and associated functions with a single electrode placement and device using numerous cohorts simultaneously. Our next step is to develop a closed-loop, adaptive, real-time processing system that is used to automatically modulate epidural stimulation parameters based on acquired multi-modal sensor data. Funding provided by NIH Roadmap Initiative - Office of Strategic Coordination, Other Transactions, SPARC Program Award # OT2OD024898, University of Louisville Hospital, and Medtronic Inc. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Modeling Electric Fields in Transcutaneous Spinal Direct Current Stimulation: A Clinical Perspective.

Clinical findings suggest that transcutaneous spinal direct current stimulation (tsDCS) can modulate ascending sensitive, descending corticospinal, and segmental pathways in the spinal cord (SC). However, several aspects of the stimulation have not been completely understood, and realistic computational models based on MRI are the gold standard to predict the interaction between tsDCS-induced electric fields and anatomy. Here, we review the electric fields distribution in the SC during tsDCS as predicted by MRI-based realistic models, compare such knowledge with clinical findings, and define the role of computational knowledge in optimizing tsDCS protocols. tsDCS-induced electric fields are predicted to be safe and induce both transient and neuroplastic changes. This could support the possibility to explore new clinical applications, such as spinal cord injury. For the most applied protocol (2-3 mA for 20-30 min, active electrode over T10-T12 and the reference on the right shoulder), similar electric field intensities are generated in both ventral and dorsal horns of the SC at the same height. This was confirmed by human studies, in which both motor and sensitive effects were found. Lastly, electric fields are strongly dependent on anatomy and electrodes' placement. Regardless of the montage, inter-individual hotspots of higher values of electric fields were predicted, which could change when the subjects move from a position to another (e.g., from the supine to the lateral position). These characteristics underlines the need for individualized and patient-tailored MRI-based computational models to optimize the stimulation protocol. A detailed modeling approach of the electric field distribution might contribute to optimizing stimulation protocols, tailoring electrodes' configuration, intensities, and duration to the clinical outcome.

Assessment of Dorsiflexion Ability across Tasks in Persons with Subacute SCI after Combined Locomotor Training and Transcutaneous Spinal Stimulation.

In people with spinal cord injury (SCI), transcutaneous spinal stimulation (TSS) has an immediate effect on the ability to dorsiflex the ankle, but persistent effects are not known. Furthermore, TSS has been associated with improved walking, increased volitional muscle activation, and decreased spasticity when combined with locomotor training (LT). In this study, the persistent impact of combined LT and TSS on dorsiflexion during the swing phase of walking and a volitional task in participants with SCI is determined. Ten participants with subacute motor-incomplete SCI received 2 weeks of LT alone (wash-in phase), followed by 2 weeks of either LT + TSS (TSS at 50 Hz) or LT + TSSSham (intervention phase). There was no persistent effect of TSS on dorsiflexion during walking and inconsistent effects on the volitional task. There was a strong positive correlation between the dorsiflexor ability for both tasks. There was a moderate effect of 4 weeks of LT on increased dorsiflexion during the task (d = 0.33) and walking (d = 0.34) and a small effect on spasticity (d = -0.2). Combined LT + TSS did not show persistent effects on dorsiflexion ability in people with SCI. Four weeks of locomotor training was associated with increased dorsiflexion across tasks. Improvements in walking observed with TSS may be due to factors other than improved ankle dorsiflexion.

Transcranial magnetic stimulation attenuates hypertension in spontaneously hypertensive rats

Repetitive transcranial magnetic stimulation (TMS) is of two types, including continuous theta-burst stimulation (cTBS) and intermittent theta-burst stimulation (iTBS), which is currently applied in various neuropsychiatric disorders. This study aimed to explore the effect of cTBS and iTBS on hypertension and the mechanism using male spontaneously hypertensive rat (SHR) and Wistar-Kyoto (WKY) rat models. Norepinephrine and epinephrine levels were determined using enzyme immunoassay kits. About 60, 80, and 100% of the motor threshold were used for stimulation. The systolic blood pressure (SBP; 168 ± 3 vs. 189 ± 3 mmHg), diastolic blood pressure (DBP; 134 ± 5 vs. 158 ± 4 mmHg), and mean artery pressure (MAP; 146 ± 3 vs. 170 ± 3 mmHg) were attenuated after cTBS (100%) stimulation on T4 of male SHR. The SBP (165 ± 4 vs. 189 ± 3 mmHg), DBP (136 ± 4 vs. 159 ± 2 mmHg), and MAP (146 ± 3 vs. 169 ± 2 mmHg) were alleviated after cTBS (100%) stimulation on L2. The blood pressure was also attenuated after iTBS (100%) stimulation on T4 or L2 of male SHR. The stimulation of cTBS or iTBS on S2 spinal column did not affect the blood pressure of male SHR rats. The stimulation of cTBS or iTBS has no effect on the blood pressure in male WKY rats. Norepinephrine and epinephrine levels in the male SHR rat kidneys were reduced after cTBS or iTBS stimulation on T4 and L2. These results indicated that TMS attenuates hypertension after spinal column stimulation via reduction of catecholamines. Thus, treatment with TMS may be a strategy for hypertension therapy in the future.NEW & NOTEWORTHY Repetitive transcranial magnetic stimulation (TMS) is currently applied in various neuropsychiatric disorders. The aim of this study was to explore the effect of TMS on hypertension and its mechanism. We found TMS attenuates hypertension after T4 or L2 spinal column stimulation via reduction of catecholamines in male spontaneously hypertensive rat. Treatment with TMS may be a strategy for hypertension therapy in the future.

Precision neuromodulation: Promises and challenges of spinal stimulation for multi-modal rehabilitation.

Spinal cord injury results in multiple, simultaneous sensorimotor deficits. These include, but are not limited to, full or partial paralysis of muscles below the lesion, muscle spasms, spasticity, and neuropathic pain. Bowel, bladder, and sexual dysfunction are also prevalent. Yet, the majority of emerging spinal stimulation-based therapies focus on a single issue: locomotor rehabilitation. Despite the enormous potential of these translational advances to transform the lives of people living with spinal cord injury, meaningful recovery in other domains deemed critical priorities remains lacking. Here, we highlight the importance of considering the diverse patterns of neural transmission that underlie clinically similar presentations when developing spinal stimulation-based therapies. We also motivate advancement of multi-modal rehabilitation paradigms, which leverage the dense interconnectivity of sensorimotor spinal networks and the unique ability of electrical stimulation to modulate these networks to facilitate and guide simultaneous rehabilitation across domains.

A case study of percutaneous epidural stimulation to enable motor control in two men after spinal cord injury

Two persons with chronic motor complete spinal cord injury (SCI) were implanted with percutaneous spinal cord epidural stimulation (SCES) leads to enable motor control below the injury level (NCT04782947). Through a period of temporary followed by permanent SCES implantation, spinal mapping was conducted primarily to optimize configurations enabling volitional control of movement and training of standing and stepping as a secondary outcome. In both participants, SCES enabled voluntary increased muscle activation and movement below the injury and decreased assistance during exoskeleton-assisted walking. After permanent implantation, both participants voluntarily modulated induced torques but not always in the intended directions. In one participant, percutaneous SCES enabled motor control below the injury one-day following temporary implantation as confirmed by electromyography. The same participant achieved independent standing with minimal upper extremity self-balance assistance, independent stepping in parallel bars and overground ambulation with a walker. SCES via percutaneous leads holds promise for enhancing rehabilitation and enabling motor functions for people with SCI.

Spinal cord epidural stimulation for motor and autonomic function recovery after chronic spinal cord injury: A case series and technical note.

Traumatic spinal cord injury (tSCI) is a debilitating condition, leading to chronic morbidity and mortality. In recent peer-reviewed studies, spinal cord epidural stimulation (scES) enabled voluntary movement and return of over-ground walking in a small number of patients with motor complete SCI. Using the most extensive case series (n = 25) for chronic SCI, the present report describes our motor and cardiovascular and functional outcomes, surgical and training complication rates, quality of life (QOL) improvements, and patient satisfaction results after scES. This prospective study occurred at the University of Louisville from 2009 to 2020. scES interventions began 2-3 weeks after surgical implantation of the scES device. Perioperative complications were recorded as well as long-term complications during training and device related events. QOL outcomes and patient satisfaction were evaluated using the impairment domains model and a global patient satisfaction scale, respectively. Twenty-five patients (80% male, mean age of 30.9 ± 9.4 years) with chronic motor complete tSCI underwent scES using an epidural paddle electrode and internal pulse generator. The interval from SCI to scES implantation was 5.9 ± 3.4 years. Two participants (8%) developed infections, and three additional patients required washouts (12%). All participants achieved voluntary movement after implantation. A total of 17 research participants (85%) reported that the procedure either met (n = 9) or exceeded (n = 8) their expectations, and 100% would undergo the operation again. scES in this series was safe and achieved numerous benefits on motor and cardiovascular regulation and improved patient-reported QOL in multiple domains, with a high degree of patient satisfaction. The multiple previously unreported benefits beyond improvements in motor function render scES a promising option for improving QOL after motor complete SCI. Further studies may quantify these other benefits and clarify scES's role in SCI patients.

The main non-invasive neuromodulatory techniques: an infographic

INTRODUCTION: This infographic aims to present the main non-invasive neuromodulatory techniques that can be used to assess and/or modulate central nervous system excitability. Single- and paired-pulse transcranial magnetic stimulation (TMS) can be used to assess brain excitability through the delivery of magnetic pulses over the cerebral cortex. The motor evoked potential is an indirect measure of motor cortex excitability and is the most used cortical measure of excitability. RESULTS: Neuromodulation may be achieved through several techniques, which may be used to promote top-down or bottom-up effects. Among the top-down techniques is direct current stimulation (DCS) which can change its nomenclature according to the stimulation target, for example, transcranial (tDCS), or cerebellar (ctDCS). In addition, also can be included in top-down techniques the transcranial random noise stimulation (tRNS), transcranial alternate current stimulation (tACS), and repetitive TMS (rTMS). On other hand, the bottom-up techniques include the peripheral electrical stimulation (PES), transcutaneous auricular vagus nerve stimulation (taVNS), transcutaneous spinal direct current stimulation (tsDCS), and repetitive peripheral magnetic stimulation (rPMS). CONCLUSION: The neuromodulatory effects are dependent on several parameters that can be specific to physical principles (electrical or magnetic). For example, in repetitive P/TMS the frequency, type and angular orientation of coil, distance between the coil and the brain, pulse waveform, and pattern of stimulation are presented as important parameters able to interfere with the quality of stimulation. The same can be observed in tDCS, ctDCS, and tsDCS with the polarity and shape and montage of electrode, intensity, site and duration of stimulation, and current density.

Corticospinal interface to restore voluntary control of joint torque in a paralyzed forearm following spinal cord injury in non-human primates.

The corticospinal tract plays a major role in the control of voluntary limb movements, and its damage impedes voluntary limb control. We investigated the feasibility of closed-loop brain-controlled subdural spinal stimulation through a corticospinal interface for the modulation of wrist torque in the paralyzed forearm of monkeys with spinal cord injury at C4/C5. Subdural spinal stimulation of the preserved cervical enlargement activated multiple muscles on the paralyzed forearm and wrist torque in the range from flexion to ulnar-flexion. The magnitude of the evoked torque could be modulated by changing current intensity. We then employed the corticospinal interface designed to detect the firing rate of an arbitrarily selected "linked neuron" in the forearm territory of the primary motor cortex (M1) and convert it in real time to activity-contingent electrical stimulation of a spinal site caudal to the lesion. Linked neurons showed task-related activity that modulated the magnitude of the evoked torque and the activation of multiple muscles depending on the required torque. Unlinked neurons, which were independent of spinal stimulation and located in the vicinity of the linked neurons, exhibited task-related or -unrelated activity. Thus, monkeys were able to modulate the wrist torque of the paralyzed forearm by modulating the firing rate of M1 neurons including unlinked and linked neurons via the corticospinal interface. These results suggest that the corticospinal interface can replace the function of the corticospinal tract after spinal cord injury.

Minimally invasive interventional therapy for pain

Pain interventional therapy, known as the most promising medical technology in the 21st century, refers to clinical treatment technology based on neuroanatomy, neuroimaging, and nerve block technology to treat pain diseases. Compared with traditional destructive surgery, interventional pain therapy is considered a better and more economical choice of treatment. In recent years, a variety of minimally invasive pain interventional therapy techniques, such as neuroregulation, spinal cord electrical stimulation, intervertebral disc ablation, and intrasheath drug infusion systems, have provided effective solutions for the treatment of patients with post-herpetic neuralgia, complex regional pain syndrome, cervical/lumbar disc herniation, and refractory cancer pain.

The effect of spinal magnetic stimulation on the management of functional constipation in adults

BackgroundFunctional constipation is a type of functional bowel disorder characterized by difficult defecation with a sense of incomplete evacuation. It is a common disorder with an increasing prevalence, and the underlying cause is poorly identified. Nonpharmacological management of functional constipation includes lifestyle and dietary modification, regular physical activity, advice about toileting posture, and behavioral therapy. Biofeedback training as part of the behavioral training showed great efficacy with long-term results. Spinal magnetic stimulation is the application of extracorporeal magnetic stimuli to the spinal nerves and deep pelvic muscles to enhance bowel evacuation without surgical drawbacks. This study was designed to enhance bowel elimination in functional constipation patients through the dual effect of biofeedback and spinal magnetic stimulation. This work aimed to study the efficacy of spinal magnetic stimulation and biofeedback training versus biofeedback alone in the management of functional constipation.ResultsThere was a statistically significant difference between before and after the intervention in both studied groups regarding the mean weekly spontaneous bowel movement, a Numerical Rating Scale for pain assessment, and the Patient Assessment of Constipation Quality of Life questionnaire. When comparing the two groups after the intervention, the spinal magnetic stimulation showed superiority in the mean weekly spontaneous bowel movement and manometric anal pressure at rest.ConclusionsSpinal magnetic stimulation in addition to biofeedback pelvic floor muscle training could increase the mean weekly complete spontaneous bowel movements and manometric anal pressure at rest in patients with functional constipation. It did not show any additive benefits in improving pain during defecation or patient quality of life.Trial registrationClinicalTrials.gov, 0305398. https://register.clinicaltrials.gov/prs/app/action/SelectProtocol?sid=S000BQ0H&selectaction=Edit&uid=U0004JW0&ts=2&cx=-xmnims