Functional electrical stimulation after spinal cord injury: current use, therapeutic effects and future directions

Potential role of hippocampal neurogenesis in spinal cord injury induced post-trauma depression

It has been reported both in clinic and rodent models that beyond spinal cord injury directly induced symptoms, such as paralysis, neuropathic pain, bladder/bowel dysfunction, and loss of sexual function, there are a variety of secondary complications, including memory loss, cognitive decline, depression, and Alzheimer's disease. The large-scale longitudinal population-based studies indicate that post-trauma depression is highly prevalent in spinal cord injury patients. Yet, few basic studies have been conducted to address the potential molecular mechanisms. One of possible factors underlying the depression is the reduction of adult hippocampal neurogenesis which may come from less physical activity, social isolation, chronic pain, and elevated neuroinflammation after spinal cord injury. However, there is no clear consensus yet. In this review, we will first summarize the alteration of hippocampal neurogenesis post-spinal cord injury. Then, we will discuss possible mechanisms underlie this important spinal cord injury consequence. Finally, we will outline the potential therapeutic options aimed at enhancing hippocampal neurogenesis to ameliorate depression.

Biomimetic Peripheral Nerve Stimulation Promotes the Rat Hindlimb Motion Modulation in Stepping: An Experimental Analysis

Peripheral nerve stimulation is an effective neuromodulation method in patients with lower extremity movement disorders caused by stroke, spinal cord injury, or other diseases. However, most current studies on rehabilitation using sciatic nerve stimulation focus solely on ankle motor regulation through stimulation of common peroneal and tibial nerves. Using the electrical nerve stimulation method, we here achieved muscle control via different sciatic nerve branches to facilitate the regulation of lower limb movements during stepping and standing. A map of relationships between muscles and nerve segments was established to artificially activate specific nerve fibers with the biomimetic stimulation waveform. Then, characteristic curves depicting the relationship between neural electrical stimulation intensity and joint control were established. Finally, by testing the selected stimulation parameters in anesthetized rats, we confirmed that single-cathode extraneural electrical stimulation could activate combined movements to promote lower limb movements. Thus, this method is effective and reliable for use in treatment for improving and rehabilitating lower limb motor dysfunction.

Exercise Responses During Outdoor Versus Virtual Reality Indoor Arm+FES-Leg Cycling in Individuals with Spinal Cord Injury

Background: Virtual reality (VR)-enhanced indoor hybrid cycling in people with spinal cord injury (SCI) can be comparable to outdoor hybrid cycling. Method: Eight individuals with chronic thoracic-lesion SCI performed voluntary arm and electrically assisted leg cycling on a hybrid recumbent tricycle. Exercises were conducted outdoors and indoors incorporating VR technology in which the outdoor environment was simulated on a large flat screen monitor. Electrical stimulation was applied bilaterally to the leg muscle groups. Oxygen uptake (VO2), heart rate, energy expenditures, and Ratings of Perceived Exertion were measured over a 30-minute outdoor test course that was also VR-simulated indoors. Immediately after each exercise, participants completed questionnaires to document their perceptual-psychological responses. Results: Mean 30-minute VO2 was higher for indoor VR exercise (average VO2-indoor VR-exercise: 1316 ± mL/min vs. outdoor cycling: 1255 ± 53 mL/min; highest VO2-indoor VR-exercise: 1615 ± 67 mL/min vs. outdoor cycling: 1725 ± 67 mL/min). Arm and leg activity counts were significantly higher during indoor VR-assisted hybrid functional electrical stimulation (FES) cycling than outdoors; 42% greater for the arms and 23% higher for the legs (P < 0.05). Similar responses were reported for exercise effort and perceptual-psychological outcomes during both modes. Conclusion: This study proposes that combining FES and VR technology provides new opportunities for physical activity promotion or exercise rehabilitation in the SCI population, since these modes have similar "dose-potency" and self-perceived effort. Human Research Ethics Committee of the University of Sydney Ref. No. 01-2010/12385.

Electrical stimulation enhances mitochondrial trafficking as a neuroprotective mechanism against chemotherapy-induced peripheral neuropathy

Electrical stimulation (ESTIM) has shown to be an effective symptomatic treatment to treat pain associated with peripheral nerve damage. However, the neuroprotective mechanism of ESTIM on peripheral neuropathies is still unknown. In this study, we identified that ESTIM has the ability to enhance mitochondrial trafficking as a neuroprotective mechanism against chemotherapy-induced peripheral neuropathies (CIPNs). CIPN is a debilitating and painful sequalae of anti-cancer chemotherapy treatment which results in degeneration of peripheral nerves. Mitochondrial dynamics were analyzed within axons in response to two different antineoplastic mechanisms by chemotherapy drug treatments paclitaxel and oxaliplatin in vitro. Mitochondrial trafficking response to chemotherapy drug treatment was observed to decrease in conjunction with degeneration of distal axons. Using low-frequency ESTIM, we observed enhanced mitochondrial trafficking to be a neuroprotective mechanism against CIPN. This study confirms ESTIM enhances regeneration of peripheral nerves by increased mitochondrial trafficking.

Concordance between needle electromyography and manual muscle test findings for muscles with motor grades 0 and 1

INTRODUCTION

When it is difficult to determine whether a muscle is grade 0 or 1, manual muscle test (MMT) accuracy can be further improved by using needle electromyography (EMG) as a supplementary and confirmatory examination tool.

OBJECTIVE

To evaluate concordance between needle EMG and MMT findings for key muscles with motor grades 0 and 1 on the International Standards of Neurological Classification of Spinal Cord Injury (ISNCSCI) examination, and to potentially improve the prognosis for grade 0 muscles with proven muscle activity based on needle EMG findings.

DESIGN

A retrospective analysis.

SETTING

Inpatient tertiary rehabilitation facility.

INTERVENTIONS

Not applicable.

PATIENTS

One hundred seven patients with spinal cord injury (SCI) admitted for rehabilitation (n = 1218 key muscles, grades 0 or 1).

MAIN OUTCOME MEASURES

Inter-rater reliability between MMTs and needle EMG was analyzed using Cohen's kappa coefficient (κ). A Mantel Haenszel linear-by-linear association chi-square test was used to determine whether the presence of motor unit action potentials (MUAPs) in muscles graded 0 on the initial MMT at admission was associated with MMT grades at discharge and readmission.

RESULTS

Moderate-to-substantial agreement between needle EMG and MMT findings was observed (κ = 0.671, p < .01). Concerning key upper and lower extremity muscles, moderate and substantial agreement was identified, respectively. The lowest agreement was noted for C6 muscles. During follow up, 68.8% of muscles with proven MUAPs showed improved motor grades.

CONCLUSIONS

At initial assessment, distinguishing between motor grades 0 and 1 is imperative because motor grade 1 muscles are more likely to have a better prognosis for improvement. Moderate-to-substantial agreement was observed between MMT and needle EMG findings. The MMT is a reliable method of muscle grading, yet needle EMG may be of value in certain clinical situations to evaluate for the presence of MUAPs when evaluating motor function.

Electrical stimulation promotes functional recovery after spinal cord injury by activating endogenous spinal cord-derived neural stem/progenitor cell: an in vitro and in vivo study

BACKGROUND CONTEXT

Electrical stimulation is a noninvasive treatment method that has gained popularity in the treatment of spinal cord injury (SCI). Activation of spinal cord-derived neural stem/progenitor cell (SC-NSPC) proliferation and differentiation in the injured spinal cord may elicit considerable neural regenerative effects.

PURPOSE

This study aimed to explore the effect of electrical stimulation on the neurogenesis of SC-NSPCs.

STUDY DESIGN

This study analyzed the effects of electrical stimulation on neurogenesis in rodent SC-NSPCs in vitro and in vivo and evaluated functional recovery and neural circuitry improvements with electrical stimulation using a rodent SCI model.

METHODS

Rats (20 rats/group) were assigned to sham (Group 1), SCI only (Group 2), SCI + electrode implant without stimulation (Group 3), and SCI + electrode with stimulation (Group 4) groups to count total SC-NSPCs and differentiated neurons and to evaluate morphological changes in differentiated neurons. Furthermore, the Basso, Beattie, and Bresnahan scores were analyzed, and the motor- and somatosensory-evoked potentials in all rats were monitored.

RESULTS

Biphasic electrical currents enhanced SC-NSPC proliferation differentiation and caused qualitative morphological changes in differentiated neurons in vitro. Electrical stimulation promoted SC-NSPC proliferation and neuronal differentiation and improved functional outcomes and neural circuitry in SCI models. Increased Wnt3, Wnt7, and β-catenin protein levels were also observed after electrical stimulation.

CONCLUSIONS

Our study proved the beneficial effects of electrical stimulation on SCI. The Wnt/β-catenin pathway activation may be associated with this relationship between electrical stimulation and neuronal regeneration after SCI.

CLINICAL SIGNIFICANCE

The study confirmed the benefits of electrical stimulation on SCI based on cellular, functional, electrophysiological, and histological evidence. Based on these findings, we expect electrical stimulation to make a positive and significant difference in SCI treatment strategies.

State of the Art and Current Challenges on Electroactive Biomaterials and Strategies for Neural Tissue Regeneration

The loss or failure of an organ/tissue stands as one of the healthcare system's most prevalent, devastating, and costly challenges. Strategies for neural tissue repair and regeneration have received significant attention due to their particularly strong impact on patients' well-being. Many research efforts are dedicated not only to control the disease symptoms but also to find solutions to repair the damaged tissues. Neural tissue engineering (TE) plays a key role in addressing this problem and significant efforts are being carried out to develop strategies for neural repair treatment. In the last years, active materials allowing to tune cell-materials interaction are being increasingly used, representing a recent paradigm in TE applications. Among the most important stimuli influencing cell behavior are the electrical and mechanical ones. In this way, materials with the ability to provide this kind of stimuli to the neural cells seem to be appropriate to support neural TE. In this scope, this review summarizes the different biomaterials types used for neural TE, highlighting the relevance of using active biomaterials and electrical stimulation. Furthermore, this review provides not only a compilation of the most relevant studies and results but also strategies for novel and more biomimetic approaches for neural TE.

Temporary diaphragm pacing for patients at risk of prolonged mechanical ventilation after extensive aortic repair

Objective

Prolonged mechanical ventilation (MV) after extensive aortic reconstructive surgery is common. Studies have demonstrated that diaphragm pacing (DP) improves lung function in patients with unilateral diaphragm paralysis. The goal of this study is to determine whether this technology can be applied to complex aortic repair to reduce prolonged MV and other respiratory sequelae.

Methods

A retrospective review was performed of patients who underwent temporary DP after extensive aortic reconstructive surgery between 2019 and 2022. The primary end point was prolonged MV incidence. Other measured end points included diaphragm electromyography improvement, length of hospitalization, duration of intensive care unit stay, and reintubation rates.

Results

Fourteen patients deemed at high risk of prolonged MV based on their smoking and respiratory history underwent DP after extensive aortic repair. The mean age was 70.2 years. The indications for aortic repair were a thoracoabdominal aortic aneurysm (n = 8, including 2 ruptured, 2 symptomatic, and 1 mycotic), a perivisceral aneurysm (n = 4), and a perivisceral coral reef aorta (n = 2). All patients had a significant smoking history (active or former) or other risk factors for ventilator-induced diaphragmatic dysfunction and prolonged MV. The mean total duration of MV postoperatively was 31.9 hours (range, 8.1-76.5 hours). The total average pacing duration was 4.4 days. Two patients required prolonged MV, with an average of 75.4 hours. Two patients required reintubation. No complications related to DP wire placement or removal occurred.

Conclusions

DP is safe and feasible for patients at high risk of pulmonary insufficiency after extensive aortic reconstructive surgery.

Boosting brain-computer interfaces with functional electrical stimulation: potential applications in people with locked-in syndrome

Individuals with a locked-in state live with severe whole-body paralysis that limits their ability to communicate with family and loved ones. Recent advances in brain-computer interface (BCI) technology have presented a potential alternative for these people to communicate by detecting neural activity associated with attempted hand or speech movements and translating the decoded intended movements to a control signal for a computer. A technique that could potentially enrich the communication capacity of BCIs is functional electrical stimulation (FES) of paralyzed limbs and face to restore body and facial movements of paralyzed individuals, allowing to add body language and facial expression to communication BCI utterances. Here, we review the current state of the art of existing BCI and FES work in people with paralysis of body and face and propose that a combined BCI-FES approach, which has already proved successful in several applications in stroke and spinal cord injury, can provide a novel promising mode of communication for locked-in individuals.

The Orthotic Effects of Different Functional Electrical Stimulation Protocols on Walking Performance in Individuals with Incomplete Spinal Cord Injury: A Case Series

Background

Functional electrical stimulation (FES) of paralyzed muscles can facilitate walking after spinal cord injury (SCI).

Objectives

To test the orthotic effects of different FES walking protocols on lower joint kinematics and walking speed.

Methods

Three adults with incomplete SCI participated in this study. Their lower extremity motor scores and 10-meter walk test results were as follows: subject A: 50, 1.05 m/s, subject B: 44, 0.29 m/s, and subject C: 32, 0.27 m/s. Participants completed four conditions of over-ground walking including no FES and three bilateral FES-walking protocols as follows: multi-muscle stimulation (stimulation of quadriceps and gastrocnemius in the stance phase, and hamstring and tibialis anterior in the swing phase), drop foot (tibialis anterior stimulation), and flexor withdrawal (common peroneal nerve stimulation). The FES system obtained gait phase information from foot switches located under the individuals' heels. Three-dimensional kinematic analysis was undertaken to measure minimum toe clearance (MTC); ankle, knee, and hip range of motion (ROM); stride length; and stride speed.

Results

Compared to no-FES walking, MTC increased during drop foot (all subjects), flexor withdrawal (subjects A and B), and multi-muscle stimulation (subjects B and C) protocols. A significant decrease in ankle ROM was seen with drop foot (all subjects), flexor withdrawal (subjects A), and multi-muscle stimulation (subjects A and C) protocols. Hip ROM increased with drop foot (subjects B and C), flexor withdrawal (subject B), and multi-muscle stimulation (subject C) protocols.

Conclusion

Three FES walking protocols induced positive kinematic changes as indicated by increased MTC, decreased ankle ROM, and increased hip ROM during walking in subjects with incomplete SCI.

Generation of direct current electrical fields as regenerative therapy for spinal cord injury: A review

Electrical stimulation (ES) shows promise as a therapy to promote recovery and regeneration after spinal cord injury. ES therapy establishes beneficial electric fields (EFs) and has been investigated in numerous studies, which date back nearly a century. In this review, we discuss the various engineering approaches available to generate regenerative EFs through direct current electrical stimulation and very low frequency electrical stimulation. We highlight the electrode-tissue interface, which is important for the appropriate choice of electrode material and stimulator circuitry. We discuss how to best estimate and control the generated field, which is an important measure for comparability of studies. Finally, we assess the methods used in these studies to measure functional recovery after the injury and treatment. This work reviews studies in the field of ES therapy with the goal of supporting decisions regarding best stimulation strategy and recovery assessment for future work.

A review of combined neuromodulation and physical therapy interventions for enhanced neurorehabilitation

Rehabilitation approaches for individuals with neurologic conditions have increasingly shifted toward promoting neuroplasticity for enhanced recovery and restoration of function. This review focuses on exercise strategies and non-invasive neuromodulation techniques that target neuroplasticity, including transcranial magnetic stimulation (TMS), vagus nerve stimulation (VNS), and peripheral nerve stimulation (PNS). We have chosen to focus on non-invasive neuromodulation techniques due to their greater potential for integration into routine clinical practice. We explore and discuss the application of these interventional strategies in four neurological conditions that are frequently encountered in rehabilitation settings: Parkinson's Disease (PD), Traumatic Brain Injury (TBI), stroke, and Spinal Cord Injury (SCI). Additionally, we discuss the potential benefits of combining non-invasive neuromodulation with rehabilitation, which has shown promise in accelerating recovery. Our review identifies studies that demonstrate enhanced recovery through combined exercise and non-invasive neuromodulation in the selected patient populations. We primarily focus on the motor aspects of rehabilitation, but also briefly address non-motor impacts of these conditions. Additionally, we identify the gaps in current literature and barriers to implementation of combined approaches into clinical practice. We highlight areas needing further research and suggest avenues for future investigation, aiming to enhance the personalization of the unique neuroplastic responses associated with each condition. This review serves as a resource for rehabilitation professionals and researchers seeking a comprehensive understanding of neuroplastic exercise interventions and non-invasive neuromodulation techniques tailored for specific diseases and diagnoses.

Effects of a combined progressive resistance training and functional electrical stimulation-evoked cycling exercise on lower limb muscle strength of individuals with incomplete spinal cord injury: A randomized controlled study

Objectives

This study was conducted to investigate the effects of combined progressive resistance training (PRT) and functional electrical stimulation-evoked leg cycling exercise (FES-LCE) on isometric peak torque and muscle volume in individuals with incomplete spinal cord injury.

Patients and methods

In the single-blind, randomized controlled trial performed between April 2015 and August 2016, 28 participants were randomized between two exercise interventions (FES-LCE+PRT and FES-LCE alone), and training was conducted over 12 weeks. The isometric muscle peak torque and muscle volume for both lower limbs were measured at the baseline and after 6 and 12 weeks. Linear mixed-model analysis of variance was performed to test the effects of FES-LCE+PRT versus FES-LCE on each outcome measure over time via an intention-to-treat analysis.

Results

Twenty-three participants (18 males, 5 females; mean age: 33.4±9.7 years; range 21 to 50 years) completed study (10 in the FES-LCE+PRT group, and 13 in the FES-LCE group). The 12-week pre-and posttraining change for left hamstrings' muscle peak torque in the FES-LCE+PRT group (mean difference=4.5±7.9 Nm, 45% change, p<0.05) was consistently higher than that in the FES-LCE group (mean difference=2.4±10.3 Nm, 4% change; p<0.018). The improvement in the right quadriceps muscle's peak torque of the FES-LCE+PRT group (mean difference=19±7.6 Nm, 31% change, p<0.05) was more significant compared to the FES-LCE group. The left muscle volume showed a remarkable increase after 12 weeks in the FES-LCE+PRT group (mean difference=0.3±9.3 L, 7% change, p<0.05).

Conclusion

The combination of PRT and FES-LCE was better in improving lower limb muscle strength and volume in chronic incomplete individuals with spinal cord injury.

Electrical stimulation for the treatment of spinal cord injuries: A review of the cellular and molecular mechanisms that drive functional improvements

Spinal cord injury (SCI) is a devastating condition that causes severe loss of motor, sensory and autonomic functions. Additionally, many individuals experience chronic neuropathic pain that is often refractory to interventions. While treatment options to improve outcomes for individuals with SCI remain limited, significant research efforts in the field of electrical stimulation have made promising advancements. Epidural electrical stimulation, peripheral nerve stimulation, and functional electrical stimulation have shown promising improvements for individuals with SCI, ranging from complete weight-bearing locomotion to the recovery of sexual function. Despite this, there is a paucity of mechanistic understanding, limiting our ability to optimize stimulation devices and parameters, or utilize combinatorial treatments to maximize efficacy. This review provides a background into SCI pathophysiology and electrical stimulation methods, before exploring cellular and molecular mechanisms suggested in the literature. We highlight several key mechanisms that contribute to functional improvements from electrical stimulation, identify gaps in current knowledge and highlight potential research avenues for future studies.

STIMGRASP: A Home-Based Functional Electrical Stimulator for Grasp Restoration in Daily Activities

Thousands of people currently suffer from motor limitations caused by SCI and strokes, which impose personal and social challenges. These individuals may have a satisfactory recovery by applying functional electrical stimulation that enables the artificial restoration of grasping after a muscular conditioning period. This paper presents the STIMGRASP, a home-based functional electrical stimulator to be used as an assistive technology for users with tetraplegia or hemiplegia. The STIMGRASP is a microcontrolled stimulator with eight multiplexed and independent symmetric biphasic constant current output channels with USB and Bluetooth communication. The system generates pulses with frequency, width, and maximum amplitude set at 20 Hz, 300 µs/phase, and 40 mA (load of 1 kΩ), respectively. It is powered by a rechargeable lithium-ion battery of 3100 mAh, allowing more than 10 h of continuous use. The development of this system focused on portability, usability, and wearability, resulting in portable hardware with user-friendly mobile app control and an orthosis with electrodes, allowing the user to carry out muscle activation sequences for four grasp modes to use for achieving daily activities.

A motor learning-based postural intervention with a robotic trunk support trainer to improve functional sitting in spinal cord injury: case report

STUDY DESIGN

Single-subject-research-design.

OBJECTIVES

To improve seated postural control in a participant with spinal cord injury (SCI) with a robotic Trunk-Support-Trainer (TruST).

SETTING

Laboratory.

METHODS

TruST delivered "assist-as-needed" forces on the participant's torso during a motor learning-and-control-based intervention (TruST-intervention). TruST-assistive forces were progressed and matched to the participant's postural trunk control gains across six intervention sessions. The T-shirt test was used to capture functional improvements while dressing the upper body. Kinematics were used to compute upper body excursions (cm) and velocity (cm2), and sitting workspace area (cm2). Functional trunk dynamometry was used to examine muscle force (Kg). Surface electromyography (sEMG) was applied to measure trunk muscle activity. The Borg Rating of Perceived Exertion (RPE) was used to monitor physical exertion during TruST-intervention. A two-standard-deviation bandwidth method was adopted for data interpretation.

RESULTS

After TruST-intervention, the participant halved the time needed to don and doff a T-shirt, increased muscle force of trunk muscles (mean = 3 kg), acquired a steadier postural sitting control without vision (mean excursion baseline: 76.0 ± 2 SD = 5.25 cm and post-intervention: 44.1 cm; and mean velocity baseline: 3.0 ± 2 SD = 0.2 cm/s and post-intervention: 1.8 cm/s), and expanded his sitting workspace area (mean baseline: 36.7 ± 2 SD = 36.6 cm2 and post-intervention: 419.2 cm2). The participant increased his tolerance to counteract greater TruST-force perturbations in lateral and posterior directions. Furthermore, abdominal muscle activity substantially augmented after completion of TruST-intervention across all perturbation directions.

CONCLUSIONS

Our data indicate a potential effectiveness of TruST-intervention to promote functional sitting in SCI.

A Wirelessly Powered 4-Channel Neurostimulator for Reconstructing Walking Trajectory

A wirelessly powered four-channel neurostimulator was developed for applying selective Functional Electrical Stimulation (FES) to four peripheral nerves to control the ankle and knee joints of a rat. The power of the neurostimulator was wirelessly supplied from a transmitter device, and the four nerves were connected to the receiver device, which controlled the ankle and knee joints in the rat. The receiver device had functions to detect the frequency of the transmitter signal from the transmitter coil. The stimulation site of the nerves was selected according to the frequency of the transmitter signal. The rat toe position was controlled by changing the angles of the ankle and knee joints. The joint angles were controlled by the stimulation current applied to each nerve independently. The stimulation currents were adjusted by the Proportional Integral Differential (PID) and feed-forward control method through a visual feedback control system, and the walking trajectory of a rat's hind leg was reconstructed. This study contributes to controlling the multiple joints of a leg and reconstructing functional motions such as walking using the robotic control technology.

Effect of transcutaneous abdominal electrical stimulation in people with constipation due to spinal cord injuries: a pilot study

OBJECTIVE

To evaluate the effect of abdominal electrical stimulation (EE) on bowel movement frequency and feces consistency and expelled amount in people with constipation due to spinal cord injuries (SCI).

METHOD

This is an experimental, crossover, randomized pilot study with two treatment groups: conventional intestinal rehabilitation and conventional rehabilitation associated with EE via 8- and 20-Hz Functional Electrical Stimulation (FES) of the abdominal muscles. Both groups were followed for two weeks with daily 30-minute EE sessions. Participants were hospitalized in a rehabilitation institute in the municipality of São Paulo. Data were analyzed using descriptive and inferential statistics.

RESULTS

This study included 10 people with SCI, of which most were male (70%), with a mean age of 39 years (SD = 16.37). EE, associated with conventional treatment, was more effective in increasing defecation frequency (p = 0.029) and amount of feces expelled (p = 0.031).

CONCLUSION

Abdominal EE, associated with conventional treatment, helped to increase defecation frequency and amount of feces expelled in people with constipation due to SCI. This pilot study will serve as the basis for a future clinical trial with greater sampling and statistical evidence.

BCI-FES With Multimodal Feedback for Motor Recovery Poststroke

An increasing number of research teams are investigating the efficacy of brain-computer interface (BCI)-mediated interventions for promoting motor recovery following stroke. A growing body of evidence suggests that of the various BCI designs, most effective are those that deliver functional electrical stimulation (FES) of upper extremity (UE) muscles contingent on movement intent. More specifically, BCI-FES interventions utilize algorithms that isolate motor signals-user-generated intent-to-move neural activity recorded from cerebral cortical motor areas-to drive electrical stimulation of individual muscles or muscle synergies. BCI-FES interventions aim to recover sensorimotor function of an impaired extremity by facilitating and/or inducing long-term motor learning-related neuroplastic changes in appropriate control circuitry. We developed a non-invasive, electroencephalogram (EEG)-based BCI-FES system that delivers closed-loop neural activity-triggered electrical stimulation of targeted distal muscles while providing the user with multimodal sensory feedback. This BCI-FES system consists of three components: (1) EEG acquisition and signal processing to extract real-time volitional and task-dependent neural command signals from cerebral cortical motor areas, (2) FES of muscles of the impaired hand contingent on the motor cortical neural command signals, and (3) multimodal sensory feedback associated with performance of the behavioral task, including visual information, linked activation of somatosensory afferents through intact sensorimotor circuits, and electro-tactile stimulation of the tongue. In this report, we describe device parameters and intervention protocols of our BCI-FES system which, combined with standard physical rehabilitation approaches, has proven efficacious in treating UE motor impairment in stroke survivors, regardless of level of impairment and chronicity.

Effects of trunk muscle activation on trunk stability, arm power, blood pressure and performance in wheelchair rugby players with a spinal cord injury

Objective: In wheelchair rugby (WR) athletes with tetraplegia, wheelchair performance may be impaired due to (partial) loss of innervation of upper extremity and trunk muscles, and low blood pressure (BP). The objective was to assess the effects of electrical stimulation (ES)-induced co-contraction of trunk muscles on trunk stability, arm force/power, BP, and WR performance.Design: Cross-sectional study.Setting: Rehabilitation research laboratory and WR court.Participants: Eleven WR athletes with tetraplegia.Interventions: ES was applied to the rectus abdominis, obliquus externus abdominis and erector spinae muscles. For every test, the ES condition was compared to the non-ES condition.Outcome measures: Stability was assessed with reaching tasks, arm force/power with an isokinetic test on a dynamometer, BP during an ES protocol and WR skill performance with the USA Wheelchair Rugby Skill Assessment.Results: Overall reaching distance (ES 14.6 ± 7.5 cm, non-ES 13.4 ± 8.2 cm), and BP showed a significant increase with ES. Arm force (ES 154 ± 106 N, non-ES 148 ± 102 N) and power (ES 37 ± 26 W, non-ES 36 ± 25 W), and WR skills were not significantly improved.Conclusion: ES-induced trunk muscle activation positively affects trunk stability and BP, but not arm force/power. No effects were found in WR skill performance, probably due to abdominal strapping. More research is needed to assess different ES (training) protocols and longitudinal effects.

The Diagnosis and Management of Cardiometabolic Risk and Cardiometabolic Syndrome after Spinal Cord Injury

Individuals with spinal cord injuries (SCI) commonly present with component risk factors for cardiometabolic risk and combined risk factors for cardiometabolic syndrome (CMS). These primary risk factors include obesity, dyslipidemia, dysglycemia/insulin resistance, and hypertension. Commonly referred to as “silent killers”, cardiometabolic risk and CMS increase the threat of cardiovascular disease, a leading cause of death after SCI. This narrative review will examine current data and the etiopathogenesis of cardiometabolic risk, CMS, and cardiovascular disease associated with SCI, focusing on pivotal research on cardiometabolic sequelae from the last five years. The review will also provide current diagnosis and surveillance criteria for cardiometabolic disorders after SCI, a novel obesity classification system based on percent total body fat, and lifestyle management strategies to improve cardiometabolic health.

The science and engineering behind sensitized brain-controlled bionic hands

Advances in our understanding of brain function, along with the development of neural interfaces that allow for the monitoring and activation of neurons, have paved the way for brain-machine interfaces (BMIs), which harness neural signals to reanimate the limbs via electrical activation of the muscles or to control extracorporeal devices, thereby bypassing the muscles and senses altogether. BMIs consist of reading out motor intent from the neuronal responses monitored in motor regions of the brain and executing intended movements with bionic limbs, reanimated limbs, or exoskeletons. BMIs also allow for the restoration of the sense of touch by electrically activating neurons in somatosensory regions of the brain, thereby evoking vivid tactile sensations and conveying feedback about object interactions. In this review, we discuss the neural mechanisms of motor control and somatosensation in able-bodied individuals and describe approaches to use neuronal responses as control signals for movement restoration and to activate residual sensory pathways to restore touch. Although the focus of the review is on intracortical approaches, we also describe alternative signal sources for control and noninvasive strategies for sensory restoration.

Concordance between the international standards for neurological classification of spinal cord injury motor examination and needle electromyography findings in muscles with a motor power grade of zero or trace

CONTEXT/OBJECTIVE

To evaluate the accuracy of the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) motor examination in individuals with spinal cord injury (SCI) with motor grade 0 or 1 and analyze its degree of concordance with needle electromyography (EMG) findings for each key muscle.

DESIGN

Retrospective study.

SETTING

University hospital in Goyang, Korea.

PARTICIPANTS

Individuals with SCI admitted to the Department of Rehabilitation from January 2013 to June 2019.

INTERVENTIONS

In the enrolled persons, needle EMG was performed on muscles with motor grade 0 or 1 on ISNCSCI examination, and muscle contraction was confirmed through the detection of motor unit action potential.

OUTCOME MEASURES

The agreement between motor examination and needle EMG findings was analyzed.

RESULTS

In 175 key muscles, needle EMG findings in 115 and 60 muscles evaluated as grades 0 and 1 on ISNCSCI examination showed 80% and 50% agreements, respectively. We found a fair agreement between motor examination and needle EMG findings (κ = 0.309, P < 0.0001). Moreover, statistically significant agreement was seen only in T1, L2, and S1 key muscles (κ = 1, P < 0.0001; κ = 0.359, P = 0.019; and κ = 0.521, P = 0.004, respectively).

CONCLUSIONS

It is important to accurately distinguish between grade 0 and 1 motor power to maximize the positive outcomes from rehabilitation treatment and predict the possibility of recovery in individuals with SCI. Therefore, to improve the accuracy of motor examination and the American Spinal Injury Association Impairment Scale, needle EMG confirmation could be considered for muscles with motor grade 0 or 1 in individuals with SCI.

Efeito da eletroestimulação abdominal transcutânea no quadro de constipação em pessoas com lesão medular: estudo piloto

RESUMO Objetivo: Avaliar o efeito da eletroestimulação (EE) abdominal sobre a frequência de evacuações, a consistência e a quantidade de fezes em pessoas com constipação decorrente da lesão medular (LM). Método: Estudo piloto experimental do tipo crossover-randomizado em dois grupos de tratamento: convencional de reabilitação intestinal e convencional associado à EE com Functional Electrical Stimulation (FES) de 8 e 20 Hz aplicados na musculatura abdominal. Ambos os grupos em seguimento por duas semanas, com 30 minutos de sessão diária de EE. Os participantes estavam internados em um instituto de reabilitação da cidade de São Paulo. Os dados foram analisados por meio de estatística descritiva e inferencial. Resultados: Participaram do estudo 10 pessoas com LM, a maioria do sexo masculino (70%), com média de idade de 39 anos (DP = 16,37). A EE, associada ao tratamento convencional, mostrou-se mais eficaz no aumento da frequência evacuatória (p = 0,029) e na quantidade de fezes (p = 0,031). Conclusão: A EE abdominal associada ao tratamento convencional auxiliou no aumento da frequência evacuatória e na quantidade de fezes no quadro de constipação em pessoas com LM. Este estudo piloto servirá como base para um futuro ensaio clínico com maior amostragem e comprovação estatística.

Computational Study on Spatially Distributed Sequential Stimulation for Fatigue Resistant Neuromuscular Electrical Stimulation

Neuromuscular electrical stimulation (NMES) is used to artificially induce muscle contractions of paralyzed limbs in individuals with stroke or spinal cord injury, however, the therapeutic efficacy can be significantly limited by rapid fatiguing of the targeted muscle. A unique stimulation method, called spatially distributed sequential stimulation (SDSS), has been shown clinically to reduce fatiguing during FES, but further improvement is needed. The purpose of this study was to gain a better understanding of SDSS-induced neural activation in the human lower leg using a computational approach. We developed a realistic finite element model of the lower leg to investigate SDSS, by solving the electric field generated by SDSS and predicting neural activation. SDSS applied at 10 Hz was further compared with conventional transcutaneous stimulation that delivered electrical pulses at 40 Hz through a single electrode. We found that SDSS electrically activated multiple sub-populations of motor neurons within the TA muscle that fired at frequencies ranging between 10 Hz and 40 Hz. This complex nerve activation pattern depicts the mechanism of action of SDSS for reducing muscle fatigue during NMES.

Effect of 8-week treadmill running with peroneal muscle functional electrical stimulation on laterally deviated centre of plantar pressure position and star excursion balance test performance

Introduction

Ankle sprain is a common injury that can have long-term sequelae resulting in pain, swelling and a reduction of physical activity participation. Previous research has shown a laterally deviated centre of pressure (COP) during running gait increases the risk of lateral ankle sprain. As a method of altering COP, electrical stimulation has been considered.

Method

A group of 14 healthy males were randomly allocated to case control groups which were single blinded. The intervention involved an 8-week training programme of functional electrical stimulation to the peroneal muscles during treadmill running, with a sham control group. Outcomes were COP position and star excursion balance test. Statistical analysis was through SPSS using a combination of MANOVA, T-tests and Wilcoxon signed rank.

Results

There was a significant difference in the results post intervention at max pressure for intervention M = 0.7(±0.7) and control M = -6.0 (±4.6) conditions; t(6) = -2.9, p < 0.05.

Conclusion

It has been demonstrated that FES can alter COP during max pressure in running gait after an 8-week training programme, although carry over effect appears limited and further testing is required.

A Comparison Between Body Weight-Supported Treadmill Training and Conventional Over-Ground Training in Dogs With Incomplete Spinal Cord Injury

In human medicine there was no evidence registered of a significant difference in recovery between body weight-supported treadmill training (BWSTT) and conventional over-ground (COGI). There isn't any similar study in veterinary medicine. Thus, this study aimed to compare the locomotor recovery obtained in incomplete SCI (T11–L3 Hansen type I) post-surgical dogs following BWSTT or COGI protocols, describing their evolution during 7 weeks in regard to OFS classifications. At admission, dogs were blindly randomized in two groups but all were subjected to the same protocol (underwater treadmill training) for the first 2 weeks. After, they were divided in the BWSTT group (n = 10) and the COGI group (n = 10) for the next 2 weeks, where they performed different training. In both groups locomotor training was accompanied by functional electrical stimulation (FES) protocols. Results reported statistically significant differences between all OFS evaluations time-points (p < 0.001) and between the two groups (p < 0.001). In particular with focus on T1 to T3 a two-way repeated measures ANOVA was performed and similar results were obtained (p = 0.007). Functional recovery was achieved in 90% (17/19) of all dogs and 100% recovered bladder function. The BWSTT group showed 100% (10/10) recovery within a mean time of 4.6 weeks, while the COGI group had 78% (7/9) within 6.1 weeks. Therefore, BWSTT leads to a faster recovery with a better outcome in general.

Diaphragm Pacing and a Model for Respiratory Rehabilitation After Spinal Cord Injury

BACKGROUND AND PURPOSE

Cervical spinal cord injury (CSCI) can cause severe respiratory impairment. Although mechanical ventilation (MV) is a lifesaving standard of care for these patients, it is associated with diaphragm atrophy and dysfunction. Diaphragm pacing (DP) is a strategy now used acutely to promote MV weaning and to combat the associated negative effects. Initial reports indicate that DP also may promote neuromuscular plasticity and lead to improvements in spontaneous diaphragm activation and respiratory function. These outcomes suggest the need for reevaluation of respiratory rehabilitation for patients with CSCI using DP and consideration of new rehabilitation models for these patients and their unique care needs.

SUMMARY OF KEY POINTS

This article discusses the rationale for consideration of DP as a rehabilitative strategy, particularly when used in combination with established respiratory interventions. In addition, a model of respiratory rehabilitation and recovery (RRR) is presented, providing a framework for rehabilitation and consideration of DP as an adjuvant rehabilitation approach. The model promotes goals such as respiratory recovery and independence, and lifelong respiratory health, via interdisciplinary care, respiratory training, quantitative measurement, and use of adjuvant strategies such as DP. Application of the model is demonstrated through a description of an inpatient rehabilitation program that applies model components to patients with CSCI who require DP.

RECOMMENDATIONS FOR CLINICAL PRACTICE

As DP use increases for patients with acute CSCI, so does the need and opportunity to advance rehabilitation approaches for these patients. This perspective article is a critical step in addressing this need and motivating the advancement of rehabilitation strategies for CSCI patients. (See Video Abstract, Supplemental Digital Content, available at: http://links.lww.com/JNPT/A348).

The Potential Role of Inflammation in Modulating Endogenous Hippocampal Neurogenesis After Spinal Cord Injury

Currently there are approximately 291,000 people suffering from a spinal cord injury (SCI) in the United States. SCI is associated with traumatic changes in mobility and neuralgia, as well as many other long-term chronic health complications, including metabolic disorders, diabetes mellitus, non-alcoholic steatohepatitis, osteoporosis, and elevated inflammatory markers. Due to medical advances, patients with SCI survive much longer than previously. This increase in life expectancy exposes them to novel neurological complications such as memory loss, cognitive decline, depression, and Alzheimer's disease. In fact, these usually age-associated disorders are more prevalent in people living with SCI. A common factor of these disorders is the reduction in hippocampal neurogenesis. Inflammation, which is elevated after SCI, plays a major role in modulating hippocampal neurogenesis. While there is no clear consensus on the mechanism of the decline in hippocampal neurogenesis and cognition after SCI, we will examine in this review how SCI-induced inflammation could modulate hippocampal neurogenesis and provoke age-associated neurological disorders. Thereafter, we will discuss possible therapeutic options which may mitigate the influence of SCI associated complications on hippocampal neurogenesis.

Transcutaneous electrical diaphragmatic stimulation reduces the duration of invasive mechanical ventilation in patients with cervical spinal cord injury: retrospective case series

Study design

Retrospective case series.

Objectives

To compare individuals with cervical spinal cord injury (SCI) submitted to transcutaneous electrical diaphragmatic stimulation (TEDS) or a standard weaning protocol (SWP) according to the following variables: invasive mechanical ventilation (IMV) time, ventilator weaning time, intensive care unit (ICU) length of stay, and overall hospital length of stay.

Settings

Tertiary university hospital. Clinical Hospital of Campinas State University—UNICAMP—Campinas (SP), Brazil.

Methods

Retrospective case study investigating ICU patients submitted to tracheostomy due to cervical SCI at a tertiary university hospital (Clinical Hospital of Campinas State University, Brazil). Data were extracted from medical records of patients seen between January 2007 and December 2016. According to medical records, four patients were submitted to TEDS and six to a SWP. Provision of training to patients in the TEDS group was based on consensus medical decision, preference of the physical therapy team and availability of electrostimulation equipment in the ICU.

Results

Total IMV time in the TEDS and the SWP group was 33 ± 15 and 60 ± 22 days, respectively. Length of stay in ICU in the TEDS and the SWP group was 31 ± 18 and 63 ± 45 days, respectively.

Conclusion

TEDS appears to influence the duration of IMV as well as the length of stay in ICU. This physiotherapeutic intervention may be a potentially promising tool for treatment of patients with SCI. However, randomized clinical trials are warranted to support this assumption.

Comparison of wire and disc electrodes to electrically activate the inspiratory muscles in dogs

OBJECTIVE

To compare the effectiveness of wire versus disc electrodes to activate the inspiratory muscles via high frequency spinal cord stimulation.

DESIGN

Animal study.

SETTING

Research laboratory.

ANIMALS

Dogs (n = 5) INTERVENTIONS: In separate trials, spinal cord stimulation (SCS) was applied via disc (DE) and two parallel wire electrodes (WE) on the ventral epidural space at the T2-T3 spinal region.

MAIN OUTCOME MEASURE(S)

Airway pressure (P) and inspired volume (V) generation following stimulation with DE and WE were compared. Given our previous success with (DE), outcome variables with this electrode were used as our gold standard to which all comparisons were made.

RESULTS

Two configurations of WE using monopolar stimulation (MS) resulted in P and V that were similar to those generated with MS with DE. For example, MS with parallel WE connected together to function as a common cathode (Y-connection) and a 2-channel system (separate cathodes with a remote ground), resulted in P that were 91 ± 6 and 92 ± 4%, respectively, of those achieved with DE (NS for both). Bipolar stimulation with parallel WE using a Y-connection and with a 2-channel system, resulted in P that were 96 ± 4 and 94 ± 4%, of the P achieved with DE (NS for both).

CONCLUSION(S)

These results suggest that specific configurations of WE, which can be placed via minimally invasive techniques, provide comparable activation of the inspiratory muscles compared to DE and may be a useful technique to restore ventilatory support in persons with spinal cord injury.

Long-Term Follow-Up of Patients With Ventilator-Dependent High Tetraplegia Managed With Diaphragmatic Pacing Systems

OBJECTIVE

To explore participants' experiences after implantation of a diaphragmatic pacing system (DPS).

DESIGN

Cross-sectional, observational study using self-report questionnaires.

SETTING

Participants were recruited from 6 Spinal Cord Injury Model System centers across the United States (Craig Hospital, CO; Jefferson/Magee Rehabilitation Hospital, PA; Kessler Rehabilitation Center, NJ; University of Miami, FL; The Shirly Ryan Ability Lab, IL; Shepherd Center, GA).

INTERVENTIONS

Not applicable.

PARTICIPANTS

Men and women (N=28) with tetraplegia were enrolled in the study between November 2012 and January 2015.

MAIN OUTCOME MEASURES

Participants completed self-report questionnaires focused on their DPS usage and mechanical ventilation, as well as their experiences and satisfaction with the DPS.

RESULTS

DPS is a well-tolerated and highly successful device to help individuals living with spinal cord injury who are dependent on ventilators achieve negative pressure, ventilator-free breathing. A small percentage of participants reported complications, including broken pacing wires and surgery to replace or reposition wires.

CONCLUSIONS

This study provides insight into the usage patterns of DPS and both the potential negative and positive effects that DPS can have on the life of the user. Knowledge gained from this study can provide a foundation for further discussion about the benefits and potential risks of using a DPS to inform an individual's decision to pursue a DPS implant.

Clinical Benefits and System Design of FES-Rowing Exercise for Rehabilitation of Individuals with Spinal Cord Injury: A Systematic Review

OBJECTIVE

To comprehensively and critically appraise the clinical benefits and engineering designs of functional electrical stimulation (FES)-rowing for management of individuals with spinal cord injury (SCI).

DATA SOURCES

Electronic database searches were conducted in Cumulative Index to Nursing & Allied Health Literature, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Excerpta Medica database, Emcare, Medline, PubMed, Scopus, and Web of Science databases from inception to May 12, 2020.

STUDY SELECTION

Search terms used were synonyms of "spinal cord injury" for Population and "Electric Stimulation (Therapy)/ and rowing" for Intervention. Two reviewers independently assessed articles based on the following inclusion criteria: recruited individuals with SCI; had aerobic FES-rowing exercise as study intervention; reported cardiovascular, muscular, bone mineral density, or metabolic outcomes; and examined engineering design of FES-rowing systems. Of the 256 titles that were retrieved in the primary search, 24 were included in this study.

DATA EXTRACTION

Study characteristics, quality, participants' characteristics, test descriptions, and results were independently extracted by 2 reviewers. The quality of studies was assessed with the Downs and Black checklist.

DATA SYNTHESIS

Comparison of peak oxygen consumption (V̇_o2peak) rates showed that V̇_o2peak during FES-rowing was significantly higher than arm-only exercise; FES-rowing training improved V̇_o2peak by 11.2% on average (95% confidence interval, 7.25-15.1), with a 4.1% (95% confidence interval, 2.23-5.97) increase in V̇_o2peak per month of training. FES-rowing training reduced bone density loss with increased time postinjury. The rowing ergometer used in 2 studies provided motor assistance during rowing. Studies preferred manual stimulation control (n=20) over automatic (n=4).

CONCLUSIONS

Our results suggest FES-rowing is a viable exercise for individuals with SCI that can improve cardiovascular performance and reduce bone density loss. Further randomized controlled trials are needed to better understand the optimal set-up for FES-rowing that maximizes the rehabilitation outcomes.

Closed-Loop Plantar Cutaneous Augmentation by Electrical Nerve Stimulation Increases Ankle Plantarflexion During Treadmill Walking

Ankle plantarflexion plays an important role in forward propulsion and anterior-posterior balance during locomotion. This component of gait is often critically impacted by neurotraumas and neurological diseases. We hypothesized that augmenting plantar cutaneous feedback, via closed-loop distal-tibial nerve stimulation, could increase ankle plantarflexion during walking. To test the hypothesis, one intact rat walked on a motorized treadmill with implanted electronic device and electrodes for closed-loop neural recording and stimulation. Constant-current biphasic electrical pulse train was applied to distal-tibial nerve, based on electromyogram recorded from the medial gastrocnemius muscle, to be timed with the stance phase. The stimulation current threshold to evoke plantar cutaneous feedback was set at 30 μA (1·T), based on compound action potential evoked by stimulation. The maximum ankle joint angle at plantarflexion, during the application of stimulation currents of 3.3·T and 6.6·T, respectively, was increased from 149.4° (baseline) to 165.4° and 161.6°. The minimum ankle joint angle at dorsiflexion was decreased from 59.4° (baseline) to 53.1°, during the application of stimulation currents of 3.3·T, but not changed by 6.6·T. Plantar cutaneous augmentation also changed other gait kinematic parameters. Stance duty factor was increased from 51.9% (baseline) to 65.7% and 64.0%, respectively, by 3.3·T and 6.6·T, primarily due to a decrease in swing duration. Cycle duration was consistently decreased by the stimulation. In the control trial after two stimulation trials, a strong after-effect was detected in overall gait kinematics as well as ankle plantarflexion, suggesting that this stimulation has the potential for producing long-term changes in gait kinematics.

Effects of Functional Electrical Stimulation Cycling of Different Duration on Viscoelastic and Electromyographic Properties of the Knee in Patients with Spinal Cord Injury

The benefits of functional electrical stimulation during cycling (FES-cycling) have been ascertained following spinal cord injury. The instrumented pendulum test was applied to chronic paraplegic patients to investigate the effects of FES-cycling of different duration (20-min vs. 40-min) on biomechanical and electromyographic characterization of knee mobility. Seven adults with post-traumatic paraplegia attended two FES-cycling sessions, a 20-min and a 40-min one, in a random order. Knee angular excursion, stiffness and viscosity were measured using the pendulum test before and after each session. Surface electromyographic activity was recorded from the rectus femoris (RF) and biceps femoris (BF) muscles. FES-cycling led to reduced excursion (p < 0.001) and increased stiffness (p = 0.005) of the knee, which was more evident after the 20-min than 40-min session. Noteworthy, biomechanical changes were associated with an increase of muscle activity and changes in latency of muscle activity only for 20-min, with anticipated response times for RF (p < 0.001) and delayed responses for BF (p = 0.033). These results indicate that significant functional changes in knee mobility can be achieved by FES-cycling for 20 min, as evaluated by the pendulum test in patients with chronic paraplegia. The observed muscle behaviour suggests modulatory effects of exercise on spinal network aimed to partially restore automatic neuronal processes.

Use of Surface EMG in Clinical Rehabilitation of Individuals With SCI: Barriers and Future Considerations

Surface electromyography (sEMG) is a widely used technology in rehabilitation research and provides quantifiable information on the myoelectric output of a muscle. In this perspective, we discuss the barriers which have restricted the wide-spread use of sEMG in clinical rehabilitation of individuals with spinal cord injury (SCI). One of the major obstacles is integrating the time-consuming aspects of sEMG in the already demanding schedule of physical therapists, occupational therapists, and other clinicians. From the clinicians' perspective, the lack of confidence to use sEMG technology is also apparent due to their limited exposure to the sEMG technology and possibly limited mathematical foundation through educational and professional curricula. Several technical challenges include the limited technology-transfer of ever-evolving knowledge from sEMG research into the off-the-shelf EMG systems, lack of demand from the clinicians for systems with advanced features, lack of user-friendly intuitive interfaces, and the need for a multidisciplinary approach for accurate handling and interpretation of data. We also discuss the challenges in the application and interpretation of sEMG that are specific to SCI, which are characterized by non-standardized approaches in recording and interpretation of EMGs due to the physiological and structural state of the spinal cord. Addressing the current barriers will require a collaborative, interdisciplinary, and unified approach. The most relevant steps could include enhancing user-experience for students pursuing clinical education through revised curricula through sEMG-based case studies/projects, hands-on involvement in the research, and formation of a common platform for clinicians and technicians for self-education and knowledge share.

Feasibility and Safety of Bilateral Hybrid EEG/EOG Brain/Neural-Machine Interaction

Cervical spinal cord injuries (SCIs) often lead to loss of motor function in both hands and legs, limiting autonomy and quality of life. While it was shown that unilateral hand function can be restored after SCI using a hybrid electroencephalography/electrooculography (EEG/EOG) brain/neural hand exoskeleton (B/NHE), it remained unclear whether such hybrid paradigm also could be used for operating two hand exoskeletons, e.g., in the context of bimanual tasks such as eating with fork and knife. To test whether EEG/EOG signals allow for fluent and reliable as well as safe and user-friendly bilateral B/NHE control, eight healthy participants (six females, mean age 24.1 ± 3.2 years) as well as four chronic tetraplegics (four males, mean age 51.8 ± 15.2 years) performed a complex sequence of EEG-controlled bilateral grasping and EOG-controlled releasing motions of two exoskeletons visually presented on a screen. A novel EOG command performed by prolonged horizontal eye movements (>1 s) to the left or right was introduced as a reliable switch to activate either the left or right exoskeleton. Fluent EEG control was defined as average “time to initialize” (TTI) grasping motions below 3 s. Reliable EEG control was assumed when classification accuracy exceeded 80%. Safety was defined as “time to stop” (TTS) all unintended grasping motions within 2 s. After the experiment, tetraplegics were asked to rate the user-friendliness of bilateral B/NHE control using Likert scales. Average TTI and accuracy of EEG-controlled operations ranged at 2.14 ± 0.66 s and 85.89 ± 15.81% across healthy participants and at 1.90 ± 0.97 s and 81.25 ± 16.99% across tetraplegics. Except for one tetraplegic, all participants met the safety requirements. With 88 ± 11% of the maximum achievable score, tetraplegics rated the control paradigm as user-friendly and reliable. These results suggest that hybrid EEG/EOG B/NHE control of two assistive devices is feasible and safe, paving the way to test this paradigm in larger clinical trials performing bimanual tasks in everyday life environments.

Bladder and Bowel Management in Dogs With Spinal Cord Injury

Spinal cord injury in companion dogs can lead to urinary and fecal incontinence or retention, depending on the severity, and localization of the lesion along the canine nervous system. The bladder and gastrointestinal dysfunction caused by lesions of the autonomic system can be difficult to recognize, interpret and are easily overlooked. Nevertheless, it is crucial to maintain a high degree of awareness of the impact of micturition and defecation disturbances on the animal's condition, welfare and on the owner. The management of these disabilities is all the more challenging that the autonomic nervous system physiology is a complex topic. In this review, we propose to briefly remind the reader the physiology of micturition and defecation in dogs. We then present the bladder and gastrointestinal clinical signs associated with sacral lesions (i.e., the L7-S3 spinal cord segments and nerves) and supra-sacral lesions (i.e., cranial to the L7 spinal cord segment), largely in the context of intervertebral disc herniation. We summarize what is known about the natural recovery of urinary and fecal continence in dogs after spinal cord injury. In particular we review the incidence of urinary tract infection after injury. We finally explore the past and recent literature describing management of urinary and fecal dysfunction in the acute and chronic phase of spinal cord injury. This comprises medical therapies but importantly a number of surgical options, some known for decades such as sacral nerve stimulation, that might spark some interest in the field of spinal cord injury in companion dogs.

Opposite modulations of corticospinal excitability by intermittent and continuous peripheral electrical stimulation in healthy subjects

Peripheral electrical stimulation (PES) modulates the excitability of the corticospinal tract (CST). This modulation of CST excitability depends on the PES intensity, defined by the amplitude and the width of each pulse, the total pulse number, the stimulation frequency, and the intervention duration. Another key PES parameter is the stimulation pattern; little is known about how PES pattern affects CST excitability, as previous studies did not control other PES parameters. Here, we investigated the effect of the net difference in PES pattern on CST excitability. We use three controlled PESs, intermittent PES (30 Hz) (stimulation trains at 30 Hz with pauses), continuous PES (12 Hz) (constant stimulation at 12 Hz without pauses), and continuous PES (30 Hz) with the same stimulation frequency as the intermittent PES (30 Hz), to compare the effect of the stimulation frequency. The motor evoked potentials (MEPs) and somatosensory evoked potentials (SEPs) of healthy subjects were recorded before and after these three types of PESs in separate sessions. We found that intermittent PES (30 Hz) increased MEP amplitudes, whereas continuous PES (12 and 30 Hz) decreased amplitudes. A significant change in subcortical SEP component occurred during continuous PES (12 and 30 Hz), but not intermittent PES (30 Hz), whereas cortical SEP components showed similar behavior in three types of PESs. We conclude that (1) opposing modulations of CST excitability were induced by the differences in the PES pattern, and (2) these modulations appear to be mediated through different processes in the sensorimotor system. Our findings suggest the possibility that it may be preferable to select the PES pattern in therapeutic interventions based on the putative desired effect and the neural structure being targeted.

Reorganization of Higher-Order Somatosensory Cortex After Sensory Loss from Hand in Squirrel Monkeys

Unilateral dorsal column lesions (DCL) at the cervical spinal cord deprive the hand regions of somatosensory cortex of tactile activation. However, considerable cortical reactivation occurs over weeks to months of recovery. While most studies focused on the reactivation of primary somatosensory area 3b, here, for the first time, we address how the higher-order somatosensory cortex reactivates in the same monkeys after DCL that vary across cases in completeness, post-lesion recovery times, and types of treatments. We recorded neural responses to tactile stimulation in areas 3a, 3b, 1, secondary somatosensory cortex (S2), parietal ventral (PV), and occasionally areas 2/5. Our analysis emphasized comparisons of the responsiveness, somatotopy, and receptive field size between areas 3b, 1, and S2/PV across DCL conditions and recovery times. The results indicate that the extents of the reactivation in higher-order somatosensory areas 1 and S2/PV closely reflect the reactivation in primary somatosensory cortex. Responses in higher-order areas S2 and PV can be stronger than those in area 3b, thus suggesting converging or alternative sources of inputs. The results also provide evidence that both primary and higher-order fields are effectively activated after long recovery times as well as after behavioral and electrocutaneous stimulation interventions.

A Computational Internal Model to Quantify the Effect of Sensorimotor Augmentation on Motor Output

The aging process, as well as neurological disorders, causes a decline in sensorimotor functions, which can often bring degraded motor output. As a means of compensation for such sensorimotor deficiencies, sensorimotor augmentation has been actively investigated. Consequently, exoskeleton devices or functional electrical stimulation could augment the muscle activity, while textured surfaces or electrical nerve stimulations could augment the sensory feedback. However, it is not easy to precisely anticipate the effects of specific augmentation because sensory feedback and motor output interact with each other as a closed-loop operation via the central and peripheral nervous systems. A computational internal model can play a crucial role in anticipating such an effect of augmentation therapy on the motor outcome. Still, no existing internal sensorimotor loop model has been represented in a complete computational form facilitating the anticipation. This paper presents such a computational internal model, including numerical values representing the effect of sensorimotor augmentation. With the existing experimental results, the model performance was evaluated indirectly. The change of sensory gain affects motor output inversely, while the change of motor gain did not change or minimally affects the motor output.Clinical Relevance- The presented computational internal model will provide a simple and easy tool for clinicians to design therapeutic intervention using sensorimotor augmentation.

A Review of Different Stimulation Methods for Functional Reconstruction and Comparison of Respiratory Function after Cervical Spinal Cord Injury

Background

Spinal cord injury (SCI) is a common severe trauma in clinic, hundreds of thousands of people suffer from which every year in the world. In terms of injury location, cervical spinal cord injury (CSCI) has the greatest impact. After cervical spinal cord injury, the lack of innervated muscles is not enough to provide ventilation and other activities to complete the respiratory function. In addition to the decline of respiratory capacity, respiratory complications also have a serious impact on the life of patients. The most commonly used assisted breathing and cough equipment is the ventilator, but in recent years, the functional electrical stimulation method is being used gradually and widely.

Methods

About hundred related academic papers are cited for data analysis. They all have the following characteristics: (1) basic conditions of patients were reported, (2) patients had received nerve or muscle stimulation and the basic parameters, and (3) the results were evaluated based on some indicators.

Results

The papers mentioned above are classified as four kinds of stimulation methods: muscle electric/magnetic stimulation, spinal dural electric stimulation, intraspinal microstimulation, and infrared light stimulation. This paper describes the stimulation principle and application experiment. Finally, this paper will compare the indexes and effects of typical stimulation methods, as well as the two auxiliary methods: training and operation.

Conclusions

Although there is limited evidence for the treatment of respiratory failure by nerve or muscle stimulation after cervical spinal cord injury, the two techniques seem to be safe and effective. At the same time, light stimulation is gradually applied to clinical medicine with its strong advantages and becomes the development trend of nerve stimulation in the future.

Clinical Efficacy of Short-Term Peripheral Nerve Stimulation in Management of Facial Pain Associated With Herpes Zoster Ophthalmicus

Objective

Peripheral nerve stimulation may be an alternative option to treat severe facial pain. We assessed the application of peripheral nerve stimulation for pain management in patients with herpes zoster ophthalmicus.

Method

A retrospective analysis was conducted in patients suffering severe facial pain caused by ophthalmic herpetic lesions. We identified the change in pain severity before and after peripheral nerve stimulation for up to 12 months.

Results

Eighteen patients were enrolled. Their mean age was 70.8 ± 9.5 years. Fifteen patients presented with subacute pain for 1–3 months, and three patients suffered postherpetic neuralgia. Dramatic relief from pain was achieved in 83% of patients (15 out of 18) upon initial removal of the stimulator, with pain reduction of > 50%. The long-term analgesic effect was reported at the 6- and 12-month follow-ups, with reductions in the visual analog scale of 4.8 ± 1.2 (n = 18) and 5.4 ± 1.4 (n = 11), respectively. The prevalence of postherpetic neuralgia was 7% (1 out of 15) in the subacute pain group. No obvious adverse effect was observed.

Conclusion

Peripheral nerve stimulation may be an efficacious and safe approach for pain control in patients with herpes zoster ophthalmicus.

Orientation of the Mitotic Spindle in Blood Vessel Development

Angiogenesis requires coordinated endothelial cell specification, proliferation, and collective migration. The orientation of endothelial cell division is tightly regulated during the earliest stages of blood vessel formation in response to morphogenetic cues and the controlled orientation of the mitotic spindle. Consequently, oriented cell division is a vital mechanism in vessel morphogenesis, and defective spindle orientation can perturb the spatial arrangement of daughter cells and consequently contribute to several diseases related to vascular development. Many factors affect endothelial cell proliferation and orientation and therefore blood vessel formation, with the relationship between improper spindle orientation in endothelial cells and various diseases extensively studied. Here we review the molecular mechanisms driving the orientation of endothelial cell division, particularly with respect to the mitotic spindle, and how these processes affect vascular development, disease pathogenesis, and their potential as novel targets.

Integrating Bioelectrical Currents and Ca2+ Signaling with Biochemical Signaling in Development and Pathogenesis

Roles of bioelectrical signals are increasingly recognized in excitable and nonexcitable non-neural tissues. Diverse ion-selective channels, pumps, and gap junctions participate in bioelectrical signaling, including those transporting calcium ions (Ca2+). Ca2+ is the most versatile transported ion, because it serves as an electrical charge carrier and a biochemical regulator for multiple molecular binding, enzyme, and transcription activities. We aspire to learn how bioelectrical signals crosstalk to biochemical/biomechanical signals. In this study, we review four recent studies showing how bioelectrical currents and Ca2+ signaling affect collective dermal cell migration during feather bud elongation, affect chondrogenic differentiation in limb development, couple with mechanical tension in aligning gut smooth muscle, and affect mitochondrial function and skeletal muscle atrophy. We observe bioelectrical signals involved in several developmental and pathological conditions in chickens and mice at multiple spatial scales: cellular, cellular collective, and subcellular. These examples inspire novel concept and approaches for future basic and translational studies.