Functional Electrical Stimulation Research Articles

Functional Electrical Stimulation of the Lateral Knee Muscles Can Reduce Peak Knee Adduction Moment during Stepping: A Pilot Study.

Knee osteoarthritis (KOA) is an age-dependent disease dominantly affected by mechanical loading. Balancing the forces acting on the medial knee compartment has been the focus of KOA interventions. This pilot study investigated the effects of functional electrical stimulation (FES) of the biceps femoris and lateral gastrocnemius on reducing peak knee adduction moment (pKAM) in healthy adults and individuals with medial KOA while stepping on an instrumented elliptical system. Sixteen healthy individuals and five individuals with medial KOA stepped on the robotic stepping system, which measured footplate-reaction forces/torques and ankle kinematics and calculated 3-D knee moments in real time using inverse dynamics. Participants performed four different tasks: regular stepping without FES as the baseline condition, stepping with continuous FES of the lateral gastrocnemius (FESLG), biceps femoris (FESBF), and simultaneous FES of both lateral gastrocnemius and biceps femoris (FESLGBF), throughout the elliptical cycle. The 3-D knee moments, tibia kinematics, and footplate-reaction forces were compared between the baseline and the three FES stepping conditions. Healthy participants demonstrated lower pKAM during each of the three FES conditions compared to baseline (FESLG (p = 0.041), FESBF (p = 0.049), FESLGBF (p = 0.048)). Participants with KOA showed a trend of lower pKAM during FES, which was not statistically significant given the small sample available. Incorporating elliptical + FES as a training strategy is feasible and may help to enhance selective force generation of the targeted muscles and reduce the medial knee compartment loading.

A review of functional electrical stimulation based on brain-computer interface

Individuals with motor dysfunction caused by damage to the central nervous system are unable to transmit voluntary movement commands to their muscles, resulting in a reduced ability to control their limbs. However, traditional rehabilitation methods have problems such as long treatment cycles and high labor costs. Functional electrical stimulation (FES) based on brain-computer interface (BCI) connects the patient's intentions with muscle contraction, and helps to promote the reconstruction of nerve function by recognizing nerve signals and stimulating the moving muscle group with electrical impulses to produce muscle convulsions or limb movements. It is an effective treatment for sequelae of neurological diseases such as stroke and spinal cord injury. This article reviewed the current research status of BCI-based FES from three aspects: BCI paradigms, FES parameters and rehabilitation efficacy, and looked forward to the future development trend of this technology, in order to improve the understanding of BCI-based FES.

Effects of Sling-Suspension-Based Active Shoulder Joint Exercise on Shoulder Joint Subluxation, Pain, Muscle Strength, and Upper Limb Function in Patients with Subacute Stroke.

Background and Objectives: We investigated the effects of sling-suspension-based active shoulder joint exercise training on shoulder joint subluxation, pain, muscle strength, and upper extremity function in patients with subacute stroke. Materials and Methods: Twenty-eight patients with subacute stroke were randomly assigned to either the sling-suspension-based active shoulder joint exercise (SASE) group (n = 14) or the motorized upper extremity exercise (MUEE) group (n = 14). The SASE group actively performed shoulder joint flexion, extension, abduction, adduction, external and internal rotation, and horizontal abduction and adduction using a sling suspension system, whereas the MUEE group underwent an exercise program using a motorized upper extremity exercise machine. All participants underwent a 4-week intervention with 30 min of exercise once a day for 5 days a week. Additionally, both groups received general physical therapy and functional electrical stimulation for 30 min twice a day for 5 days a week. Shoulder joint subluxation was measured by radiographic examination before and after training, and pain was evaluated in the splenius, upper trapezius, and infraspinatus muscles using pressure parameters. In addition, a manual muscle tester was used to assess the muscle strength of the shoulder joint flexors, extensors, abductors, adductors, and external and internal rotators, and the Fugl-Mayer Assessment (FMA) and Manual Functional Test (MFT) were used to evaluate upper extremity function. Results: A significant group-time interaction was observed for pain, with F-values of F(1, 26) = 7.470, p < 0.011 for the splenius and F(1, 26) = 9.623, p < 0.005 for the upper trapezius. A significant time-group interaction was observed for the muscle strength of the shoulder, with F-values of F(1, 26) = 13.211, p < 0.001; F(1, 26) = 4.974, p = 0.035 and F(1, 26) = 9.674, p = 0.004 for flexors, abductors, and external rotators, respectively. A significant time-group interaction was observed in the FMA, with F-values of F(1, 26) = 13.243, p < 0.001. When comparing the interaction effects between time and group for MFT scores, a significant difference was observed, with F-values of F(1, 26) = 32.386, p < 0.001. Conclusions: This study confirmed that sling-suspension-based active shoulder joint exercises are effective in improving shoulder joint subluxation, pain, muscle strength, and upper extremity function in patients with subacute stroke.

Sensing and Control Strategies Used in FES Systems Aimed at Assistance and Rehabilitation of Foot Drop: A Systematic Literature Review.

Functional electrical stimulation (FES) is a rehabilitation and assistive technique used for stroke survivors. FES systems mainly consist of sensors, a control algorithm, and a stimulation unit. However, there is a critical need to reassess sensing and control techniques in FES systems to enhance their efficiency. This SLR was carried out following the PRISMA 2020 statement. Four databases (PubMed, Scopus, Web of Science, Wiley Online Library) from 2010 to 2024 were searched using terms related to sensing and control strategies in FES systems. A total of 322 articles were chosen in the first stage, while only 60 of them remained after the final filtering stage. This systematic review mainly focused on sensor techniques and control strategies to deliver FES. The most commonly used sensors reported were inertial measurement units (IMUs), 45% (27); biopotential electrodes, 36.7% (22); vision-based systems, 18.3% (11); and switches, 18.3% (11). The control strategy most reported is closed-loop; however, most of the current commercial FES systems employ open-loop strategies due to their simplicity. Three main factors were identified that should be considered when choosing a sensor for gait-oriented FES systems: wearability, accuracy, and affordability. We believe that the combination of computer vision systems with artificial intelligence-based control algorithms can contribute to the development of minimally invasive and personalized FES systems for the gait rehabilitation of patients with FDS.

Functional Electrical Stimulation and Brain-Machine Interfaces for Simultaneous Control of Wrist and Finger Flexion.

Brain-machine interface (BMI) controlled functional electrical stimulation (FES) is a promising treatment to restore hand movements to people with cervical spinal cord injury. Recent intracortical BMIs have shown unprecedented successes in decoding user intentions, however the hand movements restored by FES have largely been limited to predetermined grasps. Restoring dexterous hand movements will require continuous control of many biomechanically linked degrees-of-freedom in the hand, such as wrist and finger flexion, that would form the basis of those movements. Here we investigate the ability to restore simultaneous wrist and finger flexion, which would enable grasping with a controlled hand posture and assist in manipulating objects once grasped. We demonstrate that intramuscular FES can enable monkeys with temporarily paralyzed hands to move their fingers and wrist across a functional range of motion, spanning an average 88.6 degrees at the metacarpophalangeal joint flexion and 71.3 degrees of wrist flexion, and intramuscular FES can control both joints simultaneously in a real-time task. Additionally, we demonstrate a monkey using an intracortical BMI to control the wrist and finger flexion in a virtual hand, both before and after the hand is temporarily paralyzed, even achieving success rates and acquisition times equivalent to able-bodied control with BMI control after temporary paralysis in two sessions. Together, this outlines a method using an artificial brain-to-body interface that could restore continuous wrist and finger movements after spinal cord injury.

Hebbian plasticity induced by temporally coincident BCI enhances post-stroke motor recovery

Functional electrical stimulation (FES) can support functional restoration of a paretic limb post-stroke. Hebbian plasticity depends on temporally coinciding pre- and post-synaptic activity. A tight temporal relationship between motor cortical (MC) activity associated with attempted movement and FES-generated visuo-proprioceptive feedback is hypothesized to enhance motor recovery. Using a brain–computer interface (BCI) to classify MC spectral power in electroencephalographic (EEG) signals to trigger FES-delivery with detection of movement attempts improved motor outcomes in chronic stroke patients. We hypothesized that heightened neural plasticity earlier post-stroke would further enhance corticomuscular functional connectivity and motor recovery. We compared subcortical non-dominant hemisphere stroke patients in BCI-FES and Random-FES (FES temporally independent of MC movement attempt detection) groups. The primary outcome measure was the Fugl-Meyer Assessment, Upper Extremity (FMA-UE). We recorded high-density EEG and transcranial magnetic stimulation-induced motor evoked potentials before and after treatment. The BCI group showed greater: FMA-UE improvement; motor evoked potential amplitude; beta oscillatory power and long-range temporal correlation reduction over contralateral MC; and corticomuscular coherence with contralateral MC. These changes are consistent with enhanced post-stroke motor improvement when movement is synchronized with MC activity reflecting attempted movement.

Evidence based therapeutic and assessment techniques to rehabilitate post stroke dysphagia patients-A systematic review.

Dysphagia is most prevalent among post stroke aging adults. This systematic review was conducted to collect evidence-based data regarding assessment and therapeutic techniques used to rehabilitate post stroke dysphagia patients. Four major databases including PubMed, Cochrane Library, Science direct and Google scholar were searched systematically using the defined search strategy to target Randomized Controlled Trials conducted from January 2018 to 2023 using the pre-defined search strategy by three independent reviewers. After following PRISMA guidelines, fifteen articles matched the inclusion criteria. Several evidence based therapies like Neuromuscular Electrical Stimulation Therapy, Effortful Swallowing Training, Tongue Pressure Strength and Accuracy Training, Electrical Stimulation of Hyoid Muscles, Modified Chin Tuck Against Resistance exercise, Oral Neuromuscular Training, and Conventional Speech Therapy with Functional Electrical Stimulation were used frequently for the treatment of old age post stroke dysphagia in different rehabilitation centers. Along with this, a list of different assessment methodologies and tools was made that were used including Functional Oral Intake Scale, Fiber optic Endoscopic Evaluation of Swallowing, Penetration Aspiration Scale, Pooling Scale, Video fluoroscopic Dysphagia Scale, Iowa Oral Performance Instrument, Mann Assessment of Swallowing Ability, and Repetitive Saliva Swallowing Test. Dysphagia is known to be serious complication of stroke. This systematic review shows a significant impact of therapeutic techniques on post stroke dysphagia patients and demonstrates that neuromuscular electrical stimulation therapy is one of the most effective therapeutic techniques used to rehabilitate post stroke dysphagia patients.

Ultrasound-Compatible Electrode for Functional Electrical Stimulation.

Functional electrical stimulation (FES) is a vital method in neurorehabilitation used to reanimate paralyzed muscles, enhance the size and strength of atrophied muscles, and reduce spasticity. FES often leads to increased muscle fatigue, necessitating careful monitoring of the patient's response. Ultrasound (US) imaging has been utilized to provide valuable insights into FES-induced fatigue by assessing changes in muscle thickness, stiffness, and strain. Current commercial FES electrodes lack sufficient US transparency, hindering the observation of muscle activity beneath the skin where the electrodes are placed. US-compatible electrodes are essential for accurate imaging and optimal FES performance, especially given the spatial constraints of conventional US probes and the need to monitor muscle areas directly beneath the electrodes. This study introduces specially designed body-conforming US-compatible FES (US-FES) electrodes constructed with a silver nanowire/polydimethylsiloxane (AgNW/PDMS) composite. We compared the performance of our body-conforming US-FES electrode with a commercial hydrogel electrode. The findings revealed that our US-FES electrode exhibited comparable conductivity and performance to the commercial one. Furthermore, US compatibility was investigated through phantom and in vivo tests, showing significant compatibility even during FES, unlike the commercial electrode. The results indicated that US-FES electrodes hold significant promise for the real-time monitoring of muscle activity during FES in clinical rehabilitative applications.

Combining robotics and functional electrical stimulation for assist-as-needed support of leg movements in stroke patients: A feasibility study

PurposeRehabilitation technology can be used to provide intensive training in the early phases after stroke. The current study aims to assess the feasibility of combining robotics and functional electrical stimulation (FES), with an assist-as-needed approach to support actively-initiated leg movements in (sub-)acute stroke patients. MethodNine subacute stroke patients performed repetitions of ankle dorsiflexion and/or knee extension movements, with and without assistance. The assist-as-needed algorithm determined the amount and type of support needed per repetition. The number of repetitions and range of motion with and without assistance were compared with descriptive statistics. Fatigue scores were obtained using the visual analogue scale (score 0–10). ResultsSupport was required in 44 % of the repetitions for ankle dorsiflexion and in 5 % of the repetitions of knee extension, The median fatigue score was 2.0 (IQR: 0.2) and 4.0 (IQR: 1.5) for knee and ankle, respectively, indicating mild to moderate perceived fatigue. ConclusionThis study demonstrated the feasibility of assist-as-needed assistance through combined robotic and FES support of leg movements in stroke patients. It proved particularly useful for ankle dorsiflexion. Future research should focus on implementing this approach in a clinical setting, to assess clinical applicability and potential effects on leg function.

Combining Functional Electrical Stimulation (FES) to Elicit Hand Movements and a Mechanical Orthosis to Passively Maintain Wrist and Fingers Position in Individuals With Tetraplegia: A Feasibility Test

Combining Functional Electrical Stimulation (FES) to Elicit Hand Movements and a Mechanical Orthosis to Passively Maintain Wrist and Fingers Position in Individuals With Tetraplegia: A Feasibility Test

Effect of Multi-Joint Functional Electrical Stimulation Combined with Conventional Rehabilitation Therapy on Lower Limb Motor Function of Patients with Stroke

Effect of Multi-Joint Functional Electrical Stimulation Combined with Conventional Rehabilitation Therapy on Lower Limb Motor Function of Patients with Stroke

Brain-computer interface on wrist training with or without neurofeedback in subacute stroke: a study protocol for a double-blinded, randomized control pilot trial.

After a stroke, damage to the part of the brain that controls movement results in the loss of motor function. Brain-computer interface (BCI)-based stroke rehabilitation involves patients imagining movement without physically moving while the system measures the perceptual-motor rhythm in the motor cortex. Visual feedback through virtual reality and functional electrical stimulation is provided simultaneously. The superiority of real BCI over sham BCI in the subacute phase of stroke remains unclear. Therefore, we aim to compare the effects of real and sham BCI on motor function and brain activity among patients with subacute stroke with weak wrist extensor strength. This is a double-blinded randomized controlled trial. Patients with stroke will be categorized into real BCI and sham BCI groups. The BCI task involves wrist extension for 60 min/day, 5 times/week for 4 weeks. Twenty sessions will be conducted. The evaluation will be conducted four times, as follows: before the intervention, 2 weeks after the start of the intervention, immediately after the intervention, and 4 weeks after the intervention. The assessments include a clinical evaluation, electroencephalography, and electromyography using motor-evoked potentials. Patients will be categorized into two groups, as follows: those who will be receiving neurofeedback and those who will not receive this feedback during the BCI rehabilitation training. We will examine the importance of motor imaging feedback, and the effect of patients' continuous participation in the training rather than their being passive.Clinical Trial Registration: KCT0008589.

High-intensity interval training with functional electrical stimulation cycling for incomplete spinal cord injury patients: A pilot feasibility study.

Consequences of spinal cord injury (SCI) with a sedentary lifestyle will progress to muscle weakness and muscle atrophy, leading to muscle fatigue. This study aimed to determine the feasibility and preliminary effects of high-intensity interval training (HIIT) using functional electrical stimulation (FES) cycling on changes in thigh muscle volume and muscle strength, in patients with incomplete SCI. Eight incomplete SCI patients (mean age 50 years; 6 women) with stable SCI paraplegia (mean 6.75 years since injury) participated in the HIIT FES cycling (85%-90% peak Watts; 4 × 4-min intervals) three times a week (over 6 weeks). The main outcomes were adherence, participant acceptability, and adverse events. Secondary outcomes were muscle strength (peak torque) and leg volume changes. Our findings revealed that the program was well-received by participants, with high levels of adherence, positive feedback, and satisfaction, suggesting that it could be a promising option for individuals seeking to enhance their lower body strength and muscle mass. Additionally, all participants successfully completed the training without any serious adverse events, indicating that the program is safe for use. Finally, we found that the 6-week HIIT FES leg cycling exercise program resulted in notable improvements in isometric peak torque of the quadriceps (range 13.9%-25.6%), hamstring muscle (18.2%-23.3%), and leg volume (1.7%-18.2%). This study highlights HIIT FES leg cycling exercise program potential as an effective intervention for improving lower limb muscle function.

The history of neuromodulation for lower urinary tract dysfunction: An overview

Electricity has been used since antiquity for medical purposes, including lower urinary tract dysfunction. The advent of artificially produced electricity, the development of battery technology and better knowledge of lower urinary tract physiology, allowed for electrical stimulation as a therapeutic tool. Initially focused on neurogenic bladder dysfunction, functional electrical stimulation (neuromodulation) at low amplitude was developed to treat lower urinary tract dysfunction, with the sacral nerves as primary target. Together with better understanding of the mechanisms of action, technical and hardware developments sacral neuromodulation allowed for excellent results and low morbidity.

A robot-based hybrid lower limb system for Assist-As-Needed rehabilitation of stroke patients: Technical evaluation and clinical feasibility

Background:Although early rehabilitation is important following a stroke, severely affected patients have limited options for intensive rehabilitation as they are often bedridden. To create a system for early rehabilitation of lower extremities in these patients, we combined the robotic manipulator ROBERT® with electromyography (EMG)-triggered functional electrical stimulation (FES) and developed a novel user-driven Assist-As-Needed (AAN) control. The method is based on a state machine able to detect user movement capability, assessed by the presence of an EMG-trigger and the movement velocity, and provide different levels of assistance as required by the patient (no support, FES only, and simultaneous FES and mechanical assistance). Methods:To technically validate the system, we tested 10 able-bodied participants who were instructed to perform specific behaviors to test the system states while conducting knee extension and ankle dorsal flexion exercises. The system was also tested on two stroke patients to establish its clinical feasibility. Results:The technical validation showed that the state machine correctly detected the participants’ behavior and activated the target AAN state in more than 96% of the exercise repetitions. The clinical feasibility test showed that the system successfully recognized the patients’ movement capacity and activated assistive states according to their needs providing the minimal level of support required to exercise successfully. Conclusions:The system was technically validated and preliminarily proved clinically feasible. The present study shows that the novel system can be used to deliver exercises with a high number of repetitions while engaging the participants’ residual capabilities through the AAN strategy.

Mechanomyography reflects the changes in oxygenated hemoglobin during electrically evoked cycling in individuals with spinal cord injury.

Functional electrical stimulation (FES) cycling has been reported to enhance muscle strength and improve muscle fatigue resistance after spinal cord injury (SCI). Despite its proposed benefits, the quantification of muscle fatigue during FES cycling remains poorly documented. This study sought to quantify the relationship between the vibrational performance of electrically-evoked muscles measured through mechanomyography (MMG) and its oxidative metabolism through near-infrared spectroscopy (NIRS) characteristics during FES cycling in fatiguing paralyzed muscles in individuals with SCI. Six individuals with SCI participated in the study. They performed 30 min of FES cycling with MMG and NIRS sensors on their quadriceps throughout the cycling, and the signals were analyzed. A moderate negative correlation was found between MMG root mean square (RMS) and oxyhaemoglobin (O2Hb) [r = -0.38, p = 0.003], and between MMG RMS and total hemoglobin (tHb) saturation [r = -0.31, p = 0.017]. Statistically significant differences in MMG RMS, O2Hb, and tHb saturation occurred during pre- and post-fatigue of FES cycling (p < 0.05). MMG RMS was negatively associated with O2Hb and muscle oxygen derived from NIRS. MMG and NIRS sensors showed good inter-correlations, suggesting a promising use of MMG for characterizing metabolic fatigue at the muscle oxygenation level during FES cycling in individuals with SCI.

Anatomical Registration of Implanted Sensors Improves Accuracy of Trunk Tilt Estimates with a Networked Neuroprosthesis.

For individuals with spinal cord injuries (SCIs) above the midthoracic level, a common complication is the partial or complete loss of trunk stability in the seated position. Functional neuromuscular stimulation (FNS) can restore seated posture and other motor functions after paralysis by applying small electrical currents to the peripheral motor nerves. In particular, the Networked Neuroprosthesis (NNP) is a fully implanted, modular FNS system that is also capable of capturing information from embedded accelerometers for measuring trunk tilt for feedback control of stimulation. The NNP modules containing the accelerometers are located in the body based on surgical constraints. As such, their exact orientations are generally unknown and cannot be easily assessed. In this study, a method for estimating trunk tilt that employed the Gram-Schmidt method to reorient acceleration signals to the anatomical axes of the body was developed and deployed in individuals with SCI using the implanted NNP system. An anatomically realistic model of a human trunk and five accelerometer sensors was developed to verify the accuracy of the reorientation algorithm. Correlation coefficients and root mean square errors (RMSEs) were calculated to compare target trunk tilt estimates and tilt estimates derived from simulated accelerometer signals under a variety of conditions. Simulated trunk tilt estimates with correlation coefficients above 0.92 and RMSEs below 5° were achieved. The algorithm was then applied to accelerometer signals from implanted sensors installed in three NNP recipients. Error analysis was performed by comparing the correlation coefficients and RMSEs derived from trunk tilt estimates calculated from implanted sensor signals to those calculated via motion capture data, which served as the gold standard. NNP-derived trunk tilt estimates exhibited correlation coefficients between 0.80 and 0.95 and RMSEs below 13° for both pitch and roll in most cases. These findings suggest that the algorithm is effective at estimating trunk tilt with the implanted sensors of the NNP system, which implies that the method may be appropriate for extracting feedback signals for control systems for seated stability with NNP technology for individuals who have reduced control of their trunk due to paralysis.

Estimation of minimum foot clearance using a single foot-mounted inertial sensor and personalized foot geometry scan

The real-world measurement of minimum foot clearance (mFC) during the swing phase of gait is critical in efforts to understand and reduce the risk of trip-and-fall incidents in populations with gait impairments. Past research has focused on measuring clearance of a single point on a person’s foot, typically the toe—however, this may overestimate mFC and may even be the wrong region of the foot in cases of gait impairments or interventions. In this work, we present a novel method to reconstruct the swing-phase trajectory of an arbitrary number of points on a person’s shoe and estimate the instantaneous height and location of whole-foot mFC. This is achieved using a single foot-mounted inertial sensor and personalized shoe geometry scan, assuming a rigid-body IMU-shoe system. This combination allows collection and analysis using out-of-lab tests, potentially including clinical environments. Validation of single marker location using the proposed method vs. motion capture showed height errors with bias less than 0.05 mm, and 95% confidence interval of − 8.18 to + 8.09 mm. The method is demonstrated in an example data set comparing different interventions for foot drop, and it shows clear differences among no intervention, functional electrical stimulation, and ankle–foot orthosis conditions. This method offers researchers and clinicians a rich understanding of a person’s gait by providing objective 3D foot kinematics and allowing a unique opportunity to view the regions of the foot where minimum clearance occurs. This information can contribute to a more informed recommendation of specific interventions or assistive technology than is currently possible in standard clinical practice.

A single-center, assessor-blinded, randomized controlled clinical trial to test the safety and efficacy of a novel brain-computer interface controlled functional electrical stimulation (BCI-FES) intervention for gait rehabilitation in the chronic stroke population

BackgroundIn the United States, there are over seven million stroke survivors, with many facing gait impairments due to foot drop. This restricts their community ambulation and hinders functional independence, leading to several long-term health complications. Despite the best available physical therapy, gait function is incompletely recovered, and this occurs mainly during the acute phase post-stroke. Therapeutic options are limited currently. Novel therapies based on neurobiological principles have the potential to lead to long-term functional improvements. The Brain-Computer Interface (BCI) controlled Functional Electrical Stimulation (FES) system is one such strategy. It is based on Hebbian principles and has shown promise in early feasibility studies. The current study describes the BCI-FES clinical trial, which examines the safety and efficacy of this system, compared to conventional physical therapy (PT), to improve gait velocity for those with chronic gait impairment post-stroke. The trial also aims to find other secondary factors that may impact or accompany these improvements and establish the potential of Hebbian-based rehabilitation therapies.MethodsThis Phase II clinical trial is a two-arm, randomized, controlled, longitudinal study with 66 stroke participants in the chronic (> 6 months) stage of gait impairment. The participants undergo either BCI-FES paired with PT or dose-matched PT sessions (three times weekly for four weeks). The primary outcome is gait velocity (10-meter walk test), and secondary outcomes include gait endurance, range of motion, strength, sensation, quality of life, and neurophysiological biomarkers. These measures are acquired longitudinally.DiscussionBCI-FES holds promise for gait velocity improvements in stroke patients. This clinical trial will evaluate the safety and efficacy of BCI-FES therapy when compared to dose-matched conventional therapy. The success of this trial will inform the potential utility of a Phase III efficacy trial.Trial registrationThe trial was registered as ”BCI-FES Therapy for Stroke Rehabilitation” on February 19, 2020, at clinicaltrials.gov with the identifier NCT04279067.

MES-FES Interface Enhances Quadriceps Muscle Response in Sitting Position in Incomplete Spinal Cord Injury: Pilot Study

Purpose: In incomplete spinal cord injury (SCI), there is a partial decrease in motor or sensory or autonomic function. Mainly due to the motor impairment in SCI, a muscle–machine interface is a tool that can bring functional benefits to this population. Objective: To investigate the feasibility of the non-invasive myoelectric signal–functional electrical stimulation (MES-FES) interface on the response of the quadriceps muscle in an individual with incomplete SCI. Methods: This is a quasi-experimental, uncontrolled, longitudinal case report study carried out with an individual with incomplete SCI in the chronic phase. The assessments performed before (pre) and after eight (post8) interventions were neuromuscular assessment (surface electromyography (EMG) in rectus femoris (RF) and vastus lateralis (VL) muscles); muscle strength (load cell); knee extension range of motion (goniometry); spasticity (Modified Ashworth Scale); and quality of life (Spinal Cord Injury Quality-of-Life Questionnaire (SCI-QoL.Br)). The MES-FES interface was associated with physical therapy exercises on the extension knee joint muscle group. Results: Improvement in neuromuscular activation (normalized increase in EMGRMS of 2% (RF) and 3.3% (VL)) and synchronism of the motor units (normalized reduction in EMGMDF of 22.8% (RF) and 5.9% (VL)); 1.4 kgf increase in quadriceps strength; 10.6° increase in knee joint extension amplitude; 1 point spasticity reduction; improved quality of life, confirmed by a 12-point reduction in the SCI-QoL.Br score. Moreover, along with interventions, the participant increased the correct FES activation rate, indicating a user learning curve (ρ = 0.78, p-value = 0.04). Conclusions: The MES-FES interface associated with physical therapy promotes neuromuscular and quality of life improvements in the SCI participant.