Neuromuscular Electrical Stimulation Intensity Research Articles

Intradialytic neuromuscular electrical stimulation with optional virtual reality distraction improves not only muscle strength and functional capacity but also serum albumin level in haemodialysis patients: a pilot randomized clinical trial

BackgroundSarcopenia is highly prevalent in haemodialysis (HD) patients and linked to a poor prognosis regarding comorbidities and premature mortality. Previous studies assessed the effects of neuromuscular electrical stimulation in haemodialysis patients. This study adds to the relevance of neuromuscular electrical stimulation (NMES) applications combined with a virtual reality (VR) distraction to increase intensity, dosage, and efficiency of NMES and slow sarcopenia progression in HD patients.MethodsWe conducted a 12-week multicenter prospective randomised controlled trial. The patients were randomly assigned to one of the three groups: neuromuscular electrical stimulation with or without combined virtual reality distraction or control group.ResultsThe final analysis included 32 haemodialysis patients (mean age of 68 ± 10 years, 26 men). Interaction effects between groups and time (12 weeks) were significant regarding serum albumin levels (p = 0.008) and left quadriceps femoris muscle (QFM) force (p = 0.026). Both endpoints were increased in the NMES compared to the CO group at the end of the intervention. The NMES group increased serum albumin levels significantly after 12 weeks. The main effect of time was an increase in mean right QFM force between beginning and end of the intervention (p = 0.021). Functional capacity improved after 12 weeks in the NMES and NMES + VR but not in the control group, with a significant difference between the three groups (p = 0.022). Weight and body mass index increased in the NMES and NMES + VR groups, albeit not significantly. The effects of VR distraction on NMES efficiency were inconclusive.ConclusionIntradialytic NMES increases serum albumin level, functional capacity, muscle strength in lower limb and in tendency weight and body mass index of HD patients. Effects on VR distraction are inconclusive. Large-scaled follow-up studies on integrated sports programs with NMES and active training in combination with VR as distraction and motivation accelerator are needed.Trial registrationGerman Clinical Trial Register: DRKS00029276 (Retrospectively registered: 30/06/2022).

Does adding neuromuscular electrical stimulation to rehabilitation following total knee arthroplasty lead to a better quadriceps muscle strength recovery? A systematic review.

Patients undergoing total knee arthroplasty (TKA) show postsurgical quadriceps weakness. Neuromuscular electrical stimulation (NMES) has been shown to be an effective treatment for muscle strength recovery in a number of orthopaedic conditions. The aim of this review is to investigate whether adding NMES to TKA rehabilitation leads to a better quadriceps strength recovery in comparison with standardized rehabilitation. A second aim is to investigate which are the most commonly used NMES pulse settings and their effectiveness. A systematic review of literature was conducted on PubMed, Cochrane, Scopus and Web-of-Science. Intervention studies evaluating the effects of a rehabilitation intervention based on quadriceps NMES in patients undergoing TKA were retrieved. Methodological quality was assessed using the risk of bias-2 Cochrane tool. Features of NMES rehabilitation and technical data on NMES settings were extracted from the studies. Four studies met the inclusion criteria. Due to the limited number and the heterogeneity of the selected studies, it was not appropriate to carry out a meta-analysis. All the studies reported higher quadriceps strength in patients undergoing quadriceps NMES, particularly early after TKA. The addition of NMES or traditional strength training shows similar long-term effects. Short duration and low-intensity NMES have limited effects on quadriceps strength. Heterogeneity was found on NMES methodologies and pulse settings. In conclusion, NMES is effective for quadriceps strength recovery following TKA. NMES intensity and duration are essential for good NMES outcomes on quadriceps strength. Further studies on NMES methodologies, pulse features and settings are required to address the gaps in knowledge on NMES following TKA.

Pressure on the Electrode to Reduce Discomfort During Neuromuscular Electrical Stimulation in Individuals With Different Subcutaneous-Fat Thickness: Is the Procedure Effective and Reliable?

The addition of manual pressure on the electrode during neuromuscular electrical stimulation (NMES) has been used to reduce current intensity and perceived discomfort. In this study we aimed to test i) whether this approach affect the reliability of commonly made torque output measurements and ii) whether subcutaneous-fat thickness influence the efficacy of this approach in reducing current intensity and perceived discomfort. Twenty-one men (24 ± 3.1 years) performed knee extension maximal voluntary isometric contractions with and without manual pressure on the NMES femoral nerve electrode (superimposed and resting doublets, 2 pulses at 100 Hz) during two separate sessions. Torque output was measured in an isokinetic dynamometer and thigh subcutaneous-fat thickness assessed with ultrasonography. A scale of perceived discomfort was presented after contractions. Reductions in current intensity ( ) and discomfort during superimposed doublet ( p=0.002 ) and resting doublet ( p=0.002 ) were confirmed for the condition in which pressure was applied to the electrode. Fat thickness was correlated to changes in current intensity (r = 0.63; p = 0.002) and changes in discomfort (r = 0.45; p = 0.04) and no differences between pressure conditions and testing sessions were observed for torque output ( p > 0.05; ICC 0.95). Adding manual pressure during NMES on femoral nerve reduces discomfort and the maximal NMES intensity required to reach maximum torque without affecting torque output magnitude and reliability. Greater reduction in intensity and discomfort were observed in participants with higher subcutaneous-fat thickness levels after adding pressure on the electrode.

Cerebral and muscle near-infrared spectroscopy during lower-limb muscle activity - volitional and neuromuscular electrical stimulation.

Chronic venous insufficiency (CVI) can lead to blood clotting in the deep veins of the legs, a disease known as deep vein thrombosis. An estimated 40 percent of people in the United States have venous insufficiency that may be ameliorated with neuromuscular electrical stimulation (NMES). Near-infrared spectroscopy (NIRS) is a non-invasive optical imaging method for monitoring hemodynamics. NIRS, being an optical technique has no stimulation artefact, can be combined with NMES for theranostics application. In this study, we combined muscle NIRS (mNIRS) with electromyogram (EMG) of the calf muscles to detect blood volume changes (based on total hemoglobin concentration) in the muscle during volitional tiptoe movements at different frequencies. Also, blood volume changes were measured during NMES (using the geko™ device) at different device settings. In the mNIRS+NMES study, we also measured the cerebral hemodynamics using functional NIRS (fNIRS). The mNIRS was conducted using a frequency domain (FD) method (called FDNIRS) that used a multi-distance method to isolate muscle hemodynamics. FDNIRS-EMG study in ten healthy humans found a statistically significant (p<0.05) effect of the tiptoe frequencies on the EMG magnitude (and power) that increased with tiptoe frequency. Also, the muscle blood volume (standing/rest) decreased (p<0.01) with increasing tiptoe frequency and increasing NMES intensity that was statistically significantly (p<0.05) different between males and females. Moreover, increasing NMES intensity led to a statistically significant (p<0.01) increase in the cerebral blood volume - measured with fNIRS. Therefore, combined mNIRS and fNIRS with NMES can provide a theranostics application for brain+muscle in CVI.

Effects of NMES pulse width and intensity on muscle mechanical output and oxygen extraction in able-bodied and paraplegic individuals.

Neuromuscular Electrical Stimulation (NMES) is commonly used in neuromuscular rehabilitation protocols, and its parameters selection substantially affects the characteristics of muscle activation. Here, we investigated the effects of short pulse width (200µs) and higher intensity (short-high) NMES or long pulse width (1000µs) and lower intensity (long-low) NMES on muscle mechanical output and fractional oxygen extraction. Muscle contractions were elicited with 100Hz stimulation frequency, and the initial torque output was matched by adjusting stimulation intensity. Fourteen able-bodied and six spinal cord-injured (SCI) individuals participated in the study. The NMES protocol (75 isometric contractions, 1-s on-3-s off) targeting the knee extensors was performed with long-low or short-high NMES applied over the midline between anterior superior iliac spine and patella protrusion in two different days. Muscle work was estimated by torque-time integral, contractile properties by rate of torque development and half-relaxation time, and vastus lateralis fractional oxygen extraction was assessed by Near-Infrared Spectroscopy (NIRS). Torque-time integral elicited by the two NMES paradigms was similar throughout the stimulation protocol, with differences ranging between 1.4% (p = 0.877; able-bodied, mid-part of the protocol) and 9.9% (p = 0.147; SCI, mid-part of the protocol). Contractile properties were also comparable in the two NMES paradigms. However, long-low NMES resulted in higher fractional oxygen extraction in able-bodied (+ 36%; p = 0.006). Long-low and short-high NMES recruited quadriceps femoris motor units that demonstrated similar contractile and fatigability properties. However, long-low NMES conceivably resulted in the preferential recruitment of vastus lateralis muscle fibers as detected by NIRS.

Intensity and Dose of Neuromuscular Electrical Stimulation Influence Sensorimotor Cortical Excitability.

Neuromuscular electrical stimulation (NMES) of the nervous system has been extensively used in neurorehabilitation due to its capacity to engage the muscle fibers, improving muscle tone, and the neural pathways, sending afferent volleys toward the brain. Although different neuroimaging tools suggested the capability of NMES to regulate the excitability of sensorimotor cortex and corticospinal circuits, how the intensity and dose of NMES can neuromodulate the brain oscillatory activity measured with electroencephalography (EEG) is still unknown to date. We quantified the effect of NMES parameters on brain oscillatory activity of 12 healthy participants who underwent stimulation of wrist extensors during rest. Three different NMES intensities were included, two below and one above the individual motor threshold, fixing the stimulation frequency to 35 Hz and the pulse width to 300 μs. Firstly, we efficiently removed stimulation artifacts from the EEG recordings. Secondly, we analyzed the effect of amplitude and dose on the sensorimotor oscillatory activity. On the one hand, we observed a significant NMES intensity-dependent modulation of brain activity, demonstrating the direct effect of afferent receptor recruitment. On the other hand, we described a significant NMES intensity-dependent dose-effect on sensorimotor activity modulation over time, with below-motor-threshold intensities causing cortical inhibition and above-motor-threshold intensities causing cortical facilitation. Our results highlight the relevance of intensity and dose of NMES, and show that these parameters can influence the recruitment of the sensorimotor pathways from the muscle to the brain, which should be carefully considered for the design of novel neuromodulation interventions based on NMES.

Assessing Discomfort Levels During Facial Neuromuscular Electrical Stimulation Using Discomfort Level Scale: A Preliminary Study.

The primary aim of the current study was to evaluate discomfort levels of facial NMES in healthy volunteers. Eight participants completed the Discomfort Level Scale (DLS) following each motor level facial neuromuscular electrical stimulation (NMES) session. Each participant completed 12 sessions of facial NMES for a total of 96 NMES treatments. Pearson product-moment correlation coefficient demonstrated a significant correlation between the facial NMES intensity level and DLS (p < 0.001). This study demonstrated that the DLS is a useful tool to check for discomfort levels in patients who receive facial NMES. Further, this study provides strong support for the tolerability of facial NMES.

Fatigue in complete spinal cord injury and implications on total delay.

The use of neuromuscular electrical stimulation (NMES) to artificially restore movement in people with complete spinal cord injury (SCI) induces an accelerated process of muscle fatigue. Fatigue increases the time between the beginning of NMES and the onset of muscle force (DelayTOT ). Understanding how much muscle fatigue affects the DelayTOT in people with SCI could help in the design of closed-loop neuroprostheses that compensate for this delay, thus making the control system more stable. The aim of this study was to evaluate the impact of the extent of fatigue on DelayTOT and peak force of the lower limbs in people with complete SCI. Fifteen men-young adults with complete SCI (paraplegia and tetraplegia) and stable health-participated in the experiment. DelayTOT was defined as the time interval between the beginning of NMES application until the onset of muscle force. The electrical intensity of NMES applied was adjusted individually and consisted of the amplitude required to obtain a full extension of the knee (0°), considering the maximum electrically stimulated extension (MESE). Subsequently, 70% of the MESE was applied during the fatigue induction protocol. Significant differences were identified between the moments before and after the fatigue protocol, both for peak force (P≤.026) and DelayTOT (P≤.001). The medians and interquartile range of the DelayTOT were higher in postfatigue (199.0ms) when compared to the moment before fatigue (146.5ms). The medians and interquartile range of the peak force were higher in unfatigued lower limbs (0.43kgf) when compared to the moment postfatigue (0.27kgf). The results support the hypothesis that muscle fatigue influences the increase in DelayTOT and decrease in force production in people with SCI. For future applications, the combined evaluation of the delay and force in SCI patients provides valuable feedback for NMES paradigms. The study will provide potentially critical muscle mechanical evidence for the investigation of the evolution of atrophy.

Measurement of blood lactate as a function of vocal loading and neuromuscular electrical stimulation: Proof of concept

The goal of the current investigation was to establish proof of concept regarding measurement of blood lactate levels as an indicator of laryngeal muscle activity and fatigue, as well as to examine the relationship between blood lactate levels and NMES intensity. Fifteen participants completed a vocal loading exercise while blood lactate was measured prior to, during, and upon completion of the exercise. Acoustic measures of voice production and subjective reports of fatigue/soreness were obtained pre- and post-vocal loading task. The participants were divided into three groups: those who did not receive laryngeal neuromuscular electrical stimulation (NMES), those who received laryngeal NMES at a minimally perceivable level of intensity, and those who received laryngeal NMES at a maximum tolerable level of intensity. Changes in blood lactate levels were observed during the vocal loading task, thus indicating that blood lactate measurements are sensitive enough to reflect laryngeal muscle activity. No consistent pattern between blood lactate levels and NMES intensity or fatigue emerged. Several factors may account for these findings.

Muscle oxygenation dynamics in response to electrical stimulation as measured with near-infrared spectroscopy: A pilot study.

Neuromuscular electrical stimulation (NMES) is used for preventing muscle atrophy and improving muscle strength in patients and healthy people. However, the current intensity of NMES is usually set at a level that causes the stimulated muscles to contract. This typically causes pain. Quantifying the instantaneous changes in muscle microcirculation and metabolism during NMES before muscle contraction occurs is crucial, because it enables the current intensity to be optimally tuned, thereby reducing the NMES-induced muscle pain and fatigue. We applied near-infrared spectroscopy (NIRS) to measure instantaneous tissue oxygenation and deoxygenation changes in 43 healthy young adults during NMES at 10, 15, 20, 25, 30, and 35 mA. Having been stabilized at the NIRS signal baseline, the tissue oxygenation and total hemoglobin concentration increased immediately after stimulation in a dose-dependent manner (P < 0.05) until stimulation was stopped at the level causing muscle contraction without pain. Tissue deoxygenation appeared relatively unchanged during NMES. We conclude that NIRS can be used to determine the optimal NMES current intensity by monitoring oxygenation changes.

Exploring Neuromuscular Electrical Stimulation Intensity Effects on Multifidus Muscle Activity in Adults With Chronic Low Back Pain: An Ultrasound Imaging-Informed Investigation.

Study design:Cross-sectional study.Background:Neuromuscular electrical stimulation (NMES) is an effective tool for stimulating multifidus muscle contractions. Ultrasound imaging (USI) is valid and reliable for quantifying multifidus activity represented by percent thickness change from a resting to contracted state. Thus, USI may be used to help determine optimal NMES intensity.Objectives:To explore NMES intensity effects on multifidus thickening in adults with chronic low back pain (CLBP).Methods:Sixty patients with CLBP participated. L4/5 multifidus ultrasound images were obtained and percent thickness change from a resting to a contracted state was determined at baseline with a limb lift and during NMES application. During NMES, the examiner recorded the intensity, in milliampere, when the multifidus first started to thicken as observed with USI. The examiner also recorded the NMES intensity that resulted in no further multifidus thickening (ie, high-tolerance group) or, in cases where maximal thickening was not observed, the NMES intensity of the submaximal contraction (ie, low-tolerance group). Differences between participants with high versus low NMES tolerance were evaluated.Results:During NMES, the multifidus began thickening at a higher intensity for the high-tolerance group (n = 39), that is, 34 mA, compared with the low-tolerance group (n = 21), that is, 32 mA (P = .001). A greater mean intensity in the high-tolerance group, that is, 62 mA, as compared to 45 mA in the low-tolerance group, resulted in a larger percent thickness change, that is, 30.89% compared to 20.60%, respectively (P < .001).Conclusions:Results provide clinicians with NMES intensity targets to facilitate multifidus muscle thickening, which provides insight into muscle activity.

Therapeutic electrical stimulation and immune status in healthy men.

In physical and rehabilitation medicine, there are few reports on the effects of therapeutic low-frequency electrical stimulation on the immune response of the organism, even though electrical stimulation is used widely in clinical practice and sports medicine. The aim of our study was to examine the possible immunological consequences of moderate transcutaneous neuromuscular electrical stimulation (NMES) for quadriceps muscle strengthening in healthy individuals. The study included twelve healthy male adult volunteers (mean age 42 years) without contraindications for electrical stimulation. At the beginning and immediately after a 20-min session of NMES of quadriceps muscles, peripheral blood was collected to analyse the biochemical blood components (creatinine, creatine kinase, estimated glomerular filtration rate, cortisol), differential white blood cell count and immunological parameters. The intensity of NMES was set at maximum tolerance, eliciting on average about one-sixth of the maximum voluntary isometric contraction of the same leg. No statistically significant differences in the average group level were found in any of the measured biochemical blood components, white blood cell count or immunological parameters after the NMES session. On an individual level, the changes in creatine kinase, estimated glomerular filtration rate, basophils and some immunological parameters correlated with changes in the cortisol level. We can conclude that moderate transcutaneous low-frequency electrical stimulation for quadriceps muscle strengthening used in our study did not induce essential changes in immune status in healthy men.

Neuromuscular electrical stimulation increases serum brain-derived neurotrophic factor in humans.

Brain-derived neurotrophic factor (BDNF) plays several important roles in nervous system function including neuronal growth and plasticity. The purpose of the present study was to clarify whether neuromuscular electrical stimulation (NMES) and voluntary exercise to the same integrated force as by the NMES-induced exercise would enhance serum BDNF. Eleven healthy male subjects completed three interventions (NMES, voluntary exercise, and resting interventions) for 20min on different days. In the NMES intervention, NMES was applied to the quadriceps femoris muscles. The stimulus intensity of NMES was progressively increased to the highest tolerated intensity during the experiment. In the voluntary exercise intervention, subjects performed an isometric knee-extension task; in this intervention, the target torque was calculated in accordance with the integrated force of knee extension obtained during the NMES intervention. In the resting intervention, subjects relaxed in a sitting posture. We measured serum BDNF, blood lactate, heart rate, oxygen uptake, respiratory ratio, and blood pressure. Serum BDNF was increased in the NMES (p = 0.003) and voluntary exercise interventions (p = 0.004) after each intervention. At the post-timepoint, serum BDNF in the NMES intervention was highest among all interventions (p = 0.038) and significantly higher than in the voluntary exercise (p = 0.036) and resting (p = 0.037) interventions. Our results showed that NMES was more effective for enhancing serum BDNF than voluntary exercise at least when employing the same method and integrated force.

Effects of neuromuscular electrical stimulation on contralateral quadriceps function

Because maximal voluntary strength of the knee extensor muscles can be facilitated by the concomitant application of neuromuscular electrical stimulation (NMES) to the contralateral homologous muscle, we aimed to determine whether this was associated with an enhanced neural drive to the agonist muscles. A secondary goal of this study was to examine the potential dose-response relationship between NMES intensity and contralateral facilitation. Twelve healthy men (age: 30 ± 7 yr) completed several maximal voluntary contractions (MVC) of the left knee extensors while the right quadriceps received low-intensity NMES (10% MVC), high-intensity NMES (30% MVC) or no NMES. Supramaximal paired stimuli were delivered to the left quadriceps muscle during and immediately after the MVCs to assess voluntary activation. The EMG activity of vastus lateralis (VL) and biceps femoris (BF) was recorded. MVC torque, voluntary activation and VL EMG activity were higher for both low-intensity and high-intensity NMES compared to no NMES (P < .05), with no difference between the two NMES conditions. The acute application of NMES to the right quadriceps facilitated MVC strength of the contralateral homonymous muscle by enhancing its efferent neural drive. No evident dose-response relationship between NMES intensity and contralateral facilitation was observed.

Review of devices used in neuromuscular electrical stimulation for stroke rehabilitation.

Neuromuscular electrical stimulation (NMES), specifically functional electrical stimulation (FES) that compensates for voluntary motion, and therapeutic electrical stimulation (TES) aimed at muscle strengthening and recovery from paralysis are widely used in stroke rehabilitation. The electrical stimulation of muscle contraction should be synchronized with intended motion to restore paralysis. Therefore, NMES devices, which monitor electromyogram (EMG) or electroencephalogram (EEG) changes with motor intention and use them as a trigger, have been developed. Devices that modify the current intensity of NMES, based on EMG or EEG, have also been proposed. Given the diversity in devices and stimulation methods of NMES, the aim of the current review was to introduce some commercial FES and TES devices and application methods, which depend on the condition of the patient with stroke, including the degree of paralysis.

Acute Feasibility of Neuromuscular Electrical Stimulation in Severely Obese Patients with Obstructive Sleep Apnea Syndrome: A Pilot Study.

Objective. Obesity and obstructive sleep apnea (OSA) are closely interconnected conditions both leading to high cardiovascular risk. Inactivity is frequent and physical activity programs remain difficult in these patients. We investigated the acute feasibility of two neuromuscular electrical stimulation (NMES) modalities in extremely inactive obese patients with OSA. Design. A randomized cross-over study, with two experimental sessions (one per condition: multipath NMES versus conventional NMES). Setting. Outpatient research hospital. Subjects. Twelve patients with obesity, already treated for OSA. Interventions. No intervention. Measures. Feasibility outcomes included NMES current intensity, knee extension force evoked by NMES, and self-reported discomfort. Results. We found higher current intensity, a trend to significantly higher evoked force and lower discomfort during multipath NMES versus conventional NMES, suggesting better tolerance to the former NMES modality. However, patients were rapidly limited in the potential of increasing current intensity of multipath NMES. Conclusion. Both NMES modalities were feasible and relatively well tolerated by obese patients with OSA, even if multipath NMES showed a better muscle response/discomfort ratio than conventional NMES. There is an urgent need for a proof-of-concept study and interventional randomized controlled trials comparing NMES therapy versus current care to justify its utilization in obese and apneic patients with low physical activity levels.

Effects of neuromuscular electrical stimulation combined with effortful swallowing on post‐stroke oropharyngeal dysphagia: a randomised controlled trial

Neuromuscular electrical stimulation (NMES) has been used as a therapeutic intervention for dysphagia. However, the therapeutic effects of NMES lack supporting evidence. In recent years, NMES combined with traditional swallowing therapy has been used to improve functional recovery in patients with post-stroke dysphagia. This study aimed to investigate the effects of effortful swallowing combined with neuromuscular electrical stimulation on hyoid bone movement and swallowing function in stroke patients. Fifty stroke patients with mild dysphagia who were able to swallow against the resistance applied by using NMES and cooperate actively in training were included. This study was designed as a 6-week single-blind, randomised, controlled study. In the experimental group, two pairs of electrodes were placed horizontally in the infrahyoid region to depress the hyoid bone. The NMES intensity was increased gradually until the participants felt a grabbing sensation in their neck and performed an effortful swallow during the stimulation. In the placebo group, the same procedure was followed except for the intensity, which was increased gradually until the participants felt an electrical sensation. All participants underwent this intervention for 30 min per session, 5 sessions per week, for 6 weeks. Videofluoroscopic swallowing studies (VFSS) were carried out before and after the intervention and kinematics of the hyoid bone and swallowing function were analysed based on the VFSS. The experimental group revealed a significant increase in anterior and superior hyoid bone movement and the pharyngeal phase of the swallowing function. This intervention can be used as a novel remedial approach in dysphagic stroke patients.

An effect of physical therapy that low-stimulation intensity of neuromuscular electrical stimulation (NMES) brings

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Neuromuscular Stimulation of Quadriceps in Patients Hospitalised during an Exacerbation of COPD: A Comparison of Low (35 Hz) and High (50 Hz) Frequencies

Neuromuscular electrical stimulation (NMES) has shown to improve skeletal muscle strength and exercise capacity in stable patients with chronic obstructive pulmonary disease (COPD). Variations in NMES protocols are considerable. We aimed to compare changes in muscle strength after high-frequency and low-frequency NMES in patients admitted to hospital with an acute exacerbation of COPD. Patients were referred for inpatient (IP) rehabilitation during hospitalisation for an acute worsening of their COPD. They received 30-minute daily NMES to both quadriceps at a frequency of 35 or 50 Hz. NMES intensity was titrated to patients' tolerance. Isometric quadriceps muscle strength and endurance walking (ESWT) time were measured at baseline and on hospital discharge. A total of 10 patients in each treatment group underwent NMES during hospitalisation (mean [SD] age 68.0 [±7.4] years, FEV1 0.99 L [±0.58], FEV1/FVC 47% [± 27%], MRC 5 [IQR ±1]). There were no significant differences in baseline characteristics between groups. Muscle strength (legs combined) increased in both groups regardless of the NMES frequency used (35 Hz--3.8 ± 4.9; 50 Hz--3.4 ± 5.5 kg). This was only significant within the 35 Hz group. The change in ESWT also showed a trend to increase in both groups (35 Hz--109 ± 92.7; 50 Hz--145.6 ± 94.7). There was no significant difference between groups for either outcome. NMES is a feasible intervention to improve muscle strength in a cohort of patients admitted with an exacerbation of COPD. The response appears to be independent of the frequency used and both were well-tolerated.

EEG controlled neuromuscular electrical stimulation of the upper limb for stroke patients

This paper describes the Brain Computer Interface (BCI) system and the experiments to allow post-acute (<3 months) stroke patients to use electroencephalogram (EEG) to trigger neuromuscular electrical stimulation (NMES)-assisted extension of the wrist/fingers, which are essential pre-requisites for useful hand function. EEG was recorded while subjects performed motor imagery of their paretic limb, and then analyzed to determine the optimal frequency range within the mu-rhythm, with the greatest attenuation. Aided by visual feedback, subjects then trained to regulate their mu-rhythm EEG to operate the BCI to trigger NMES of the wrist/finger. 6 post-acute stroke patients successfully completed the training, with 4 able to learn to control and use the BCI to initiate NMES. This result is consistent with the reported BCI literacy rate of healthy subjects. Thereafter, without the loss of generality, the controller of the NMES is developed and is based on a model of the upper limb muscle (biceps/triceps) groups to determine the intensity of NMES required to flex or extend the forearm by a specific angle. The muscle model is based on a phenomenological approach, with parameters that are easily measured and conveniently implemented.