Comparison of discomfort associated with surface and percutaneous intramuscular electrical stimulation for persons with chronic hemiplegia

A dry polymer nanocomposite transcutaneous electrode for functional electrical stimulation

BACKGROUND

Functional electrical stimulation (FES) can be used in rehabilitation to aid or improve function in people with paralysis. In clinical settings, it is common practice to use transcutaneous electrodes to apply the electrical stimulation, since they are non-invasive, and can be easily applied and repositioned as necessary. However, the current electrode options available for transcutaneous FES are limited and can have practical disadvantages, such as the need for a wet interface with the skin for better comfort and performance. Hence, we were motivated to develop a dry stimulation electrode which could perform equivalently or better than existing commercially available options.

METHODS

We manufactured a thin-film dry polymer nanocomposite electrode, characterized it, and tested its performance for stimulation purposes with thirteen healthy individuals. We compared its functionality in terms of stimulation-induced muscle torque and comfort level against two other types of transcutaneous electrodes: self-adhesive hydrogel and carbon rubber. Each electrode type was also tested using three different stimulators and different intensity levels of stimulation.

RESULTS

We found the proposed dry polymer nanocomposite electrode to be functional for stimulation, as there was no statistically significant difference between its performance to the other standard electrodes. Namely, the proposed dry electrode had comparable muscle torque generated and comfort level as the self-adhesive hydrogel and carbon rubber electrodes. From all combinations of electrode type and stimulators tested, the dry polymer nanocomposite electrode with the MyndSearch stimulator had the most comfortable average rating.

CONCLUSIONS

The dry polymer nanocomposite electrode is a durable and flexible alternative to existing self-adhesive hydrogel and carbon rubber electrodes, which can be used without the addition of a wet interfacing agent (i.e., water or gel) to perform as well as the current electrodes used for stimulation purposes.

Preventive Effects of Repetitive Peripheral Magnetic Stimulation on Muscle Atrophy in the Paretic Lower Limb of Acute Stroke Patients: A Pilot Study

Objective:

The aim of this study was to investigate the effect of repetitive peripheral magnetic stimulation (rPMS) on muscle atrophy prevention in the rectus femoris muscle (RF) of the paretic limb in acute stroke patients.

Methods:

Twelve acute stroke patients with a National Institute of Health Stroke Scale score >5 and a motor score of the paretic lower limb >2 at admission were divided into an intervention group (rPMS: mean age, 75±6.4 years) and a conventional care group (non-rPMS: mean age, 62±11.8 years). Baseline measurements were performed within 4 days of stroke onset. In the rPMS group, treatment was applied to the paretic thigh only for 2 weeks, 5 days a week, in addition to conventional care. The cross-sectional area (CSA) of the RF was assessed in both limbs using ultrasound at baseline and 2 weeks later. Data on patient characteristics were collected from the clinical records to assess correlations with the CSA rate of change.

Results:

Patients in the rPMS group were significantly older. Although the CSA of the RF did not change significantly on either side in the rPMS group, there was a significant decrease in the CSA on the paretic side in the non-rPMS group. However, no significant difference was observed in the CSA rate of change in the rPMS and non-rPMS groups. The CSA rate of change on the paretic side correlated negatively with age in the rPMS group.

Conclusions:

Our results suggest that rPMS prevents muscle atrophy more effectively in patients in their 60s than in patients more than 70 years old.

The protocol for a multisite, double blind, randomized, placebo-controlled trial of axillary nerve stimulation for chronic shoulder pain

BACKGROUND

Shoulder impingement syndrome is one of the most common causes of shoulder pain, accounting for approximately 30% of all shoulder pain. Approximately 35% of patients with shoulder impingement syndrome are refractory to conservative treatment. For patients who fail conservative treatment, there is no established treatment to successfully treat their chronic pain. Prior randomized control trials have demonstrated efficacy for the use of a single lead intramuscular peripheral nerve stimulation of the axillary nerve at the motor points of the deltoid muscle for treatment of hemiplegic shoulder pain. This is the first controlled trial to utilize the same novel technology to treat shoulder impingement syndrome outside of the stroke population.

METHODS

This is a dual-site, placebo-controlled, double-blinded, randomized control trial. Participants will be randomized to two treatment groups. The intervention group will be treated with active peripheral nerve stimulation of the axillary nerve of the affected shoulder and the control group will be treated with sham peripheral nerve stimulation of the axillary nerve of the affected shoulder. Both groups will receive a standardized exercise therapy program directed by a licensed therapist.

DISCUSSION

This study protocol will allow the investigators to determine if this novel, non-pharmacologic treatment of shoulder pain can demonstrate the same benefit in musculoskeletal patients which has been previously demonstrated in the stroke population.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT03752619. Registered on 26 November 2018.

Effects of Repetitive Peripheral Magnetic Stimulation on Shoulder Subluxations Caused by Stroke: A Preliminary Study

OBJECTIVES

Shoulder subluxation is a common problem after stroke. It causes shoulder pain that affects activities of daily living. This study aimed to investigate the effect of repetitive peripheral magnetic stimulation on shoulder subluxation after stroke.

METHODS

We enrolled 12 consecutive patients who, as a result of stroke, suffered shoulder subluxations, measuring at half of a fingerbreadth or more. All subjects underwent conventional rehabilitation, as well as repetitive peripheral magnetic stimulation of their supraspinatus, posterior deltoid, and infraspinatus muscles. We assessed the following parameters: shoulder subluxation, evaluated as the acromio-humeral interval using measurements taken from X-rays; shoulder pain, evaluated using the Numerical Rating Scale; the active range of motion of shoulder abduction; and the motor impairment of the upper extremities, evaluated using the upper extremity of the Fugl-Meyer Assessment scale.

RESULTS

The acromio-humeral interval before treatment was 22.8 ± 5.7 mm (mean ± SD). It significantly decreased to 19.6 ± 7.0 mm (p = 0.004) after treatment. Shoulder pain (p = 0.039), active range of motion of shoulder abduction (p = 0.016), and total (p = 0.005), subscale A (p = 0.005), and subscale C (p = 0.008) Fugl-Meyer Assessment scores also improved significantly after treatment.

CONCLUSIONS

Repetitive peripheral magnetic stimulation effectively reduced shoulder subluxations and shoulder pain caused by stroke and improved voluntary upper-limb movements in stroke patients.

StartReact effects in first dorsal interosseous muscle are absent in a pinch task, but present when combined with elbow flexion

Objective

To provide a neurophysiological tool for assessing sensorimotor pathways, which may differ for those involving distal muscles in simple tasks from those involving distal muscles in a kinetic chain task, or proximal muscles in both.

Methods

We compared latencies and magnitudes of motor responses in a reaction time paradigm in a proximal (biceps brachii, BB) and a distal (first dorsal interosseous, FDI) muscle following electrical stimuli used as imperative signal (IS) delivered to the index finger. These stimuli were applied during different motor tasks: simple tasks involving either one muscle, e.g. flexing the elbow for BB (FLEX), or pinching a pen for FDI (PINCH); combined tasks engaging both muscles by pinching and flexing simultaneously (PINCH-FLEX). Stimuli were of varying intensity and occasionally elicited a startle response, and a StartReact effect.

Results

In BB, response latencies decreased gradually and response amplitudes increased progressively with increasing IS intensities for non-startling trials, while for trials containing startle responses, latencies were uniformly shortened and response amplitudes similarly augmented across all IS intensities in both FLEX and PINCH-FLEX. In FDI, response latencies decreased gradually and response amplitudes increased progressively with increasing IS intensities in both PINCH and PINCH-FLEX for non-startling trials, but, unlike in BB for the simple task, in PINCH for trials containing startle responses as well. In PINCH-FLEX, FDI latencies were uniformly shortened and amplitudes similarly increased across all stimulus intensities whenever startle signs were present.

Conclusions

Our results suggest the presence of different sensorimotor pathways supporting a dissociation between simple tasks that involve distal upper limb muscles (FDI in PINCH) from simple tasks involving proximal muscles (BB in FLEX), and combined tasks that engage both muscles (FDI and BB in PINCH-FLEX), all in accordance with differential importance in the control of movements by cortical and subcortical structures.

Significance

Simple assessment tools may provide useful information regarding the differential involvement of sensorimotor pathways in the control of both simple and combined tasks that engage proximal and distal muscles.

Functional electrical stimulation of the ankle dorsiflexors during walking in spastic cerebral palsy: a systematic review

AIM

To assess the effect of functional electrical stimulation (FES) of ankle dorsiflexors in children and adolescents with spastic cerebral palsy (CP) during walking.

METHOD

A systematic review was performed using the American Academy of Cerebral Palsy and Developmental Medicine methodology and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Six databases were searched for studies applying interventions to patients aged younger than 20 years. Outcomes were classified according to the International Classification of Functioning, Disability and Health (ICF).

RESULTS

Seven hundred and eighty abstracts were found, 35 articles were fully screened, and 14 articles were used for analysis. Only five articles (three studies) were of level I to III evidence. At ICF participation and activity level, there is limited evidence for a decrease in self-reported frequency of toe-drag and falls. At ICF body structure and function level, there is clear evidence (I-III) that FES increased (active) ankle dorsiflexion angle, strength, and improved selective motor control, balance, and gait kinematics, but decreased walking speed. Adverse events include skin irritation, toleration, and acceptation issues.

INTERPRETATION

There are insufficient data supporting functional gain by FES on activity and participation level. However, evidence points towards a role for FES as an alternative to orthoses in children with spastic CP.

WHAT THIS PAPER ADDS

Effects of functional electrical stimulation (FES) point towards a potential role as an alternative to orthoses for patients with spastic cerebral palsy (CP). Some evidence for a decrease in self-reported frequency of toe-drag and falls with the use of FES in spastic CP. Limited evidence for improvements in activity and participation in patients with spastic CP using FES.

Ottawa Panel Evidence-Based Clinical Practice Guidelines for Post-Stroke Rehabilitation

BACKGROUND AND PURPOSE

The purpose of this project was to create guidelines for 13 types of physical rehabilitation interventions used in the management of adult patients (>18 years of age) presenting with hemiplegia or hemiparesis following a single clinically identifiable ischemic or hemorrhagic cerebrovascular accident (CVA).

METHOD

Using Cochrane Collaboration methods, the Ottawa Methods Group identified and synthesized evidence from comparative controlled trials. The group then formed an expert panel, which developed a set of criteria for grading the strength of the evidence and the recommendation. Patient-important outcomes were determined through consensus, provided that these outcomes were assessed with a validated and reliable scale.

RESULTS

The Ottawa Panel developed 147 positive recommendations of clinical benefit concerning the use of different types of physical rehabilitation interventions involved in post-stroke rehabilitation.

DISCUSSION AND CONCLUSION

The Ottawa Panel recommends the use of therapeutic exercise, task-oriented training, biofeedback, gait training, balance training, constraint-induced movement therapy, treatment of shoulder subluxation, electrical stimulation, transcutaneous electrical nerve stimulation, therapeutic ultrasound, acupuncture, and intensity and organization of rehabilitation in the management of post stroke.

Neuromuscular Electrical Stimulation for Motor Restoration in Hemiparesis

This article assesses the clinical efficacy of established neuromuscular electrical stimulation (NMES) technologies for motor restoration in hemiparesis and provides an overview of evolving technologies. Transcutaneous NMES facilitates motor recovery. However, its impact on physical disability remains uncertain. Transcutaneous NMES also decreases shoulder subluxation, but its effect on shoulder pain remains uncertain. Clinically deployable upper extremity neuroprosthesis systems will not be available until sometime in the distant future. However, there is stronger evidence for the clinical utility of lower extremity neuroprosthesis systems. Evolving technology utilizes semi-implanted or fully implanted systems with more sophisticated control paradigms. Initial experiences with these systems are reviewed and directions for future research are discussed in this article.

Acceleration of myofiber formation in culture by a digitized synaptic signal

Developing myofibers require chemical and electrical stimulation to induce functional muscle tissue. Tissue engineering protocols utilize either or both of these to initiate differentiation ex vivo. Current methodologies typically deliver multi-volt electrical signals, which may be hazardous to developing tissues. In attempts to mimic in vivo muscle development, we stimulated cultured muscle precursor cells with a low-voltage (1 mV) digitized synaptic signal derived from cultured cortical neurons. This synaptic signal induced larger and more adherent myofibers, along with markers of myoblast differentiation, compared to those induced following stimulation with a conventional (28 V) square signal. These findings suggest that stimulation with a digitized synaptic signal may be useful in tissue engineering and physical therapy.

Current and future interventions for glenohumeral subluxation in hemiplegia secondary to stroke

Poststroke shoulder pain is a common issue and can be caused by glenohumeral subluxation. This entity hinders function and quality of life and is caused by changes in tone and loss of fi ne control of the shoulder joints' supporting structures after a stroke. Current treatments are limited in number and effectiveness and have significant problems and limitations to their use. Furthermore, prior to percutaneous implantable neuromuscular electrical stimulation, there was no evidence for any treatment to provide relief for chronic hemiplegic shoulder pain from glenohumeral subluxation. This clinical review provides a comprehensive review of the anatomy, pathogenesis, clinical features, management, and clinical efficacy of current treatment modalities.

Sample size calculation in physical medicine and rehabilitation: a systematic review of reporting, characteristics, and results in randomized controlled trials

OBJECTIVE

To assess systematically the reporting of sample size calculation in randomized controlled trials (RCTs) in 5 leading journals in the field of physical medicine and rehabilitation (PM&R).

DATA SOURCES

The data source was full reports of RCTs in 5 leading PM&R journals (Journal of Rehabilitation Medicine, Archives of Physical Medicine and Rehabilitation, American Journal of Physical Medicine and Rehabilitation, Clinical Rehabilitation, and Disability and Rehabilitation) between January and December of 1998 and 2008. Articles were identified in Medline.

STUDY SELECTION

A total of 111 articles met our inclusion criteria, which include RCTs of human studies in the 5 selected journals.

DATA EXTRACTION

Sample size calculation reporting and trial characteristics were collected for each trial by independent investigators.

DATA SYNTHESIS

In 2008, 57.3% of articles reported sample size calculation as compared with only 3.4% in 1998. The parameters that were commonly used were a power of 80% and alpha of 5%. Articles often failed to report effect size or effect estimates for sample size calculation. Studies reporting sample size calculation were more likely to describe the main outcome and to have a sample size greater than 50 subjects. The study outcome (positive vs negative) was not associated with the likelihood of sample size reporting. Trial characteristics of the 2 periods (1998 vs 2008) were similar except that in 1998 there were more negative studies compared with 2008.

CONCLUSIONS

Although sample size calculation reporting has improved dramatically in 10 years and is comparable with other fields in medicine, it is still not adequate given current publication guidelines.

Review of electrical stimulation in cerebral palsy and recommendations for future directions

Electrical stimulation (ES) for treatment of neuromuscular disorders is introduced. Various forms of ES are defined. Characteristics of cerebral palsy (CP) and treatment options are given. The clinical objectives of ES for CP treatment are stated. A review of the literature for treatment in CP is given. Several common themes within the literature and limitations in prior studies are explored. The majority of studies have used surface stimulation, which has several inherent limitations. To address these limitations, implanted devices may be used. Implanted device systems include percutaneous stimulation systems, and fully implantable leaded systems. While both of these technologies have advantages over surface stimulation, they also have their own limitations. To further address the limitations of percutaneous and fully implantable leaded systems, the Alfred Mann Foundation has developed a completely implantable, telemetered device known as the Radio Frequency Microstimulator (RFM). Results from a study using the RFM for arm rehabilitation in poststroke patients are given. A list of desirable design features for an ES system for CP is given. The next generation microstimulator device under development at the Alfred Mann Foundation is presented. This device may well serve the needs for ES in CP.

A comparison of functional electrical and magnetic stimulation for propelled cycling of paretic patients

OBJECTIVE

To compare isometric torque and cycling power, smoothness and symmetry using repetitive functional magnetic stimulation (FMS) and functional electrical stimulation (FES) in patients with paretic legs with preserved sensibility and in patients without sensibility.

DESIGN

Repeated-measures design.

SETTING

Laboratory setting.

PARTICIPANTS

Eleven subjects with complete spinal cord injury (SCI) and 29 subjects with chronic hemiparesis (16.6+/-5.5mo poststroke) volunteered.

INTERVENTIONS

Using a tricycle testbed, participants were exposed to isometric measurements and ergometric cycling experiments, performed during both 20Hz FMS and FES stimulation. Subjects with hemiparesis and with complete SCI were stimulated at maximally tolerable level and maximal intensity, respectively.

MAIN OUTCOME MEASURES

Maximal isometric pedaling torque and mean ergometric power, smoothness, and symmetry were recorded for voluntary, FES, and FMS conditions.

RESULTS

Two different patterns of the efficacy of FMS were identified. (1) Patients with complete SCI did not benefit (less torque and power was evoked with FMS than with FES, P<.003 and 10(-4) respectively). (2) Patients with hemiplegia and preserved sensibility could improve their torque output (P<.05), smoothness, and symmetry of pedaling (P<.05) with FMS more than with FES.

CONCLUSIONS

FMS is a potential alternative to surface FES of the large thigh musculature in stimulation-supported cycling of patients with partially or completely preserved sensibility.

Intramuscular Electrical Stimulation for Upper Limb Recovery in Chronic Hemiparesis: An Exploratory Randomized Clinical Trial

Background. Surface electrical stimulation (ES) has been shown to improve the motor impairment of stroke survivors. However, surface ES can be painful and motor activation can be inconsistent from session to session. Percutaneous intramuscular ES may be an effective alternative. Objective. Evaluate the effectiveness of percutaneous intramuscular ES in facilitating the recovery of the hemiparetic upper limb of chronic stroke survivors. Methods. A total of 26 chronic stroke survivors were randomly assigned to percutaneous intramuscular ES for hand opening (n = 13) or percutaneous ES for sensory stimulation only (n = 13). The intramuscular ES group received cyclic, electromyography (EMG)-triggered or EMG-controlled ES depending on baseline motor status. All participants received 1 hour of stimulation per day for 6 weeks. After completion of ES, participants received 18 hours of task-specific functional training. The primary outcome measure was the Fugl-Meyer Motor Assessment. Secondary measures included the Arm Motor Ability Test and delay and termination of EMG activity. Outcomes were assessed in a blinded manner at baseline, at the end of ES, at the end of functional training, and at 1, 3, and 6 months follow-up. Results. Repeated measure analysis of variance did not yield any significant treatment, or time by treatment interaction effects for any of the outcome measures. Conclusion. Percutaneous intramuscular ES does not appear to be any more effective than sensory ES in enhancing the recovery of the hemiparetic upper limb among chronic stroke survivors. However, because of the exploratory nature of the study and its inherent limitations, conclusions must be drawn with caution.

The effect of lower limb functional electrical stimulation on gait of children with cerebral palsy

PURPOSE

To examine the effect of lower limb functional electrical stimulation (FES) in children with cerebral palsy.

METHODS

A comprehensive search yielded 37 citations. English articles included in the review applied either surface or percutaneous FES to the lower limb, if subjects were younger than 18 years old, and if the stimulator was removed or off at the time of testing.

RESULTS

Five articles were included in this review, including 3 case reports, 1 single subject, and 1 crossover design. Among the wide range of stimulation protocols, stimulation of the gastrocnemius with or without the tibialis anterior muscle may effect greater gait improvements than stimulating the tibialis anterior muscle alone.

CONCLUSIONS AND RECOMMENDATIONS FOR CLINICAL PRACTICE

Future research differentiating between optimal FES and neuromuscular electrical stimulation protocols as well as more rigorous research designs are needed to provide clinically relevant results.

Changes in spastic muscle tone increase in patients with spinal cord injury using functional electrical stimulation and passive leg movements

Objective: Comparison of cycling interventions to reduce spastic muscle tone increase in patients with spinal cord injury.

Setting: Neuroprosthetic outpatient clinic in a university hospital.

Methods: Five patients with spinal cord injury took part in a crossover study in which the lower limbs (1) were stimulated by functional neuromuscular electrical stimulation (FES) to induce leg cycling movements and (2) were passively moved by an ergometer machine. Patients sat in a comfortable chair fastened to the ergometer while FES was done to induce leg cycling (active session). During the passive leg movement session the ergometer moved their legs for the same period of time at the same velocity and frequency.

Main outcome measures: The change in spastic muscle tone increase before and after each training session was tested with the modified Ashworth Scale and the pendulum test of spasticity (relaxation index and peak velocity).

Results: The averaged data of the relaxation index increased after FES by about 68%. Compared with the slight increase after the passive movement training of 12%, this is statistically significant ( P = 0.01). Peak velocity increased after FES by around 50%, while it was nearly unchanged after the passive intervention (1%); this is also significant ( P = 0.01). This was similar with the peak velocity and the modified Ashworth Scale.

Conclusion: The study presents further interesting aspects of the usefulness of FES in patients with spinal cord injury to reduce spastic muscle tone.

Peripheral repetitive magnetic stimulation induces intracortical inhibition in healthy subjects

OBJECTIVE

Repetitive magnetic stimulation (rMS) is mainly used in transcranial applications. Only a few works have described its potential peripheral use. The aim of this investigation was to determine if conditioning peripheral (paravertebral) rMS of the cervical nerve roots in a group of healthy subjects induces changes in motor cortical excitability.

METHODS

This was measured by means of motor evoked potentials (MEP), motor recruitment curves (RC), intracortical inhibition (ICI) and facilitation, as well as the cortical silent period (CSP) before and after repetitive stimulation. rMS was carried out by applying ten series of stimulation at 120% of resting motor threshold, each lasting 10 seconds with a frequency of 20 Hz. The nerve roots (C7/C8) of the right hand innervating the target muscles (the first dorsal interosseous) were systematically stimulated.

RESULTS

This conditioning rMS caused a significantly longer CSP (p=0.001), increased MEP amplitudes (with a tendency to significance of p=0.06) and raised ICI (p<0.05). These changes were absent on the contralateral side, as well as in the course of RC. In conclusion, previously published results that described a prolonged CSP and increased MEP amplitudes led us to speculate that conditioning peripheral rMS is, like electrical stimulation, capable of influencing motor cortical excitability.

SIGNIFICANCE

rMS might therefore be used in rehabilitative strategies for spasticity, pain or central paresis.

Neuromuscular electrical stimulation versus volitional isometric strength training in children with spastic diplegic cerebral palsy: a preliminary study

BACKGROUND

To date, no reports have investigated neuromuscular electrical stimulation (NMES) to increase muscle force production of children with cerebral palsy (CP) using high-force contractions and low repetitions.

OBJECTIVE

The aims of this study were to determine if isometric NMES or volitional training in children with CP could increase muscle strength and walking speed and to examine the mechanisms that may contribute to increased force production.

METHODS

Eleven children with spastic diplegia were assigned to an NMES training group or to a volitional training group. Participants in the NMES group had electrodes implanted percutaneously to activate the quadriceps femoris and triceps surae muscles. The volitional group trained with maximal effort contractions. Both groups performed a 12-week isometric strength-training program. Maximum voluntary isometric contraction (MVIC) force, voluntary muscle activation, quadriceps and triceps surae cross-sectional area (CSA), and walking speed were measured pre- and post-strength training.

RESULTS

The NMES-trained group had greater increases in normalized force production for both the quadriceps femoris and triceps surae. Similarly, only the NMES group showed an increase in walking speed after training. Changes in voluntary muscle activation explained approximately 67% and 37% of the changes seen in the MVIC of the NMES and volitional groups, respectively. Quadriceps femoris maximum CSA increased significantly for the NMES group only.

CONCLUSIONS

This study was the first to quantitatively show strength gains with the use of NMES in children with CP. These results support the need for future experimental studies that will examine the clinical effectiveness of NMES strength training.

Improving selected hand functions using a noninvasive neuroprosthesis in persons with chronic stroke

BACKGROUND AND PURPOSE

Loss of upper extremity function following stroke remains a major rehabilitation challenge. The purpose of this investigation was to determine whether the Handmaster system (NESS Ltd., Ra'anana, Israel) could improve selected hand functions in persons with chronic upper extremity paresis following stroke.

METHODS

Twenty-nine poststroke subjects consented to participate in a home-based, 3-week, nonrandomized case series trial. Main outcome measures included 3 activities of daily living (ADL) tasks: (1) lifting a 2-handled pot, (2) holding a bag while standing with a cane, and (3) a subject-selected-ADL. Secondary outcomes included lifting a 600-g weight, grip strength, electrically induced finger motion, Fugl-Meyer spherical grasp, and perceived pain scale.

RESULTS

Comparing baseline to study end point with the neuroprosthesis, the percent of successful trials with lifting the pot, weight, and bag (0% v 93%, 14% v 100%, and 17% v 93%, respectively) increased significantly. All subjects performed successfully their selected ADL and improved their Fugl-Meyer scores using the neuroprosthesis. Grip strength (6.4 +/- 7.3N v 17.7 +/- 6.2N) and active finger motion (0.5 +/- 1.2 cm v 8.4 +/- 2.6 cm) also improved with the neuroprosthesis. Pain scores significantly decreased in subjects reporting pain at baseline. Responses to questionnaire were favorable regarding the utility and therapeutic benefits of the device.

CONCLUSIONS

We conclude that the Handmaster is a safe and effective noninvasive neuroprosthesis for improving the studied hand functions and impairments in selected persons with chronic hemiplegia secondary to stroke.

Effect of training programs and exercise in adult stroke patients: literature review

INTRODUCTION

An increasing number of training programs are proposed for the rehabilitation of patients after stroke, with positive results published but without formal validation, and without recommendations regarding indications for specific techniques and procedures.

OBJECTIVE

To review data from the literature about training and exercise programs for stroke patients and to describe the efficacy, limitations, and effect of such programs on organ systems.

METHODS

A search of MedLINE and relevant medical journals for articles of clinical trials, meta-analyses, and literature reviews pertaining to physical training and exercise programs after stroke.

RESULTS

We found 58 articles reporting on various training and exercise techniques (walking, cardiovascular training, muscle strengthening, and others) and their results (on the cardiovascular, musculoskeletal, and neurologic systems, as well as functional status) in hemiplegic stroke patients.

DISCUSSION-CONCLUSION

Training and exercise programs have value in stroke rehabilitation, and published results are, in general, promising. However, differences in the populations tested, methods, and criteria for analysis do not allow for recommending specific procedures.

Modeling and Control Considerations for Powered Lower-Limb Orthoses: A Design Study for Assisted STS

Lower-limb orthotic devices may be used to aid or restore mobility to the impaired user. Powered orthoses, in particular, hold great potential in improving the quality of life for individuals with locomotor difficulties because active control of an orthosis can aid limb movement in common tasks that may even be impossible if unaided. However, these devices have primarily remained the products of research labs with the number of effective commercial applications for the laity being nearly nonexistent. This paper provides an overview of the current status of powered orthoses and goes on to discuss key issues in modeling and control of powered orthoses so that designers can have a unified framework in developing user-oriented devices. Key concepts are demonstrated for a powered knee-orthosis intended for assisting the sit-to-stand task, and both pneumatic muscle and dc motor actuators are considered in this conceptual design study. In the final analysis, we conclude that the ability to provide sit-to-stand assistance is profoundly dependent on the type of control signal employed to control the actuator from the user–orthosis interface.

Magnetic Stimulation of the Quadriceps Femoris Muscle

OBJECTIVE

The objective of this study was to compare pain induced by magnetic stimulation of the quadriceps femoris (QF) muscle with that induced by transcutaneous neuromuscular electrical stimulation (NMES).

DESIGN

Magnetic stimulation and transcutaneous NMES were applied to QF muscles of 17 normal volunteers. The intensity of each mode of stimulation was increased in a stepwise manner. Peak torque values of isometric contractions of QF muscles and visual analog scale (VAS) scores were recorded at each intensity level. The VAS scores of the two stimulating modalities were compared at the intensity-generating same peak torque values.

RESULTS

The median VAS scores for electrical and magnetic stimulation were 5.7 and 0.3, respectively. The median difference between the VAS scores for electrical and magnetic stimulation was 3.7 (range, 1.7-8.5). The mean of the maximum peak torque obtained from each subject was higher in magnetic stimulation than in electrical stimulation (9.5 +/- 4.8 vs. 4.4 +/- 2.9 Nm).

CONCLUSIONS

Magnetic stimulation of the QF muscle produced less pain at the same level of isometric peak torque than did transcutaneous NMES. Magnetic stimulation is a potential alternative to transcutaneous NMES, especially for persons with intact or residual sensory function.

A critical review of interfaces with the peripheral nervous system for the control of neuroprostheses and hybrid bionic systems

Considerable scientific and technological efforts have been devoted to develop neuroprostheses and hybrid bionic systems that link the human nervous system with electronic or robotic prostheses, with the main aim of restoring motor and sensory functions in disabled patients. A number of neuroprostheses use interfaces with peripheral nerves or muscles for neuromuscular stimulation and signal recording. Herein, we provide a critical overview of the peripheral interfaces available and trace their use from research to clinical application in controlling artificial and robotic prostheses. The first section reviews the different types of non-invasive and invasive electrodes, which include surface and muscular electrodes that can record EMG signals from and stimulate the underlying or implanted muscles. Extraneural electrodes, such as cuff and epineurial electrodes, provide simultaneous interface with many axons in the nerve, whereas intrafascicular, penetrating, and regenerative electrodes may contact small groups of axons within a nerve fascicle. Biological, technological, and material science issues are also reviewed relative to the problems of electrode design and tissue injury. The last section reviews different strategies for the use of information recorded from peripheral interfaces and the current state of control neuroprostheses and hybrid bionic systems.

Patterns of lower extremity innervation in pediatric spinal cord injury

STUDY DESIGN

Retrospective review.

OBJECTIVES

To identify relationships between lower extremity innervation and level of injury, mechanism of injury, and age at injury in a pediatric population with spinal cord injury (SCI). Secondarily, relationships between innervation and completeness of injury, time since injury, race, and sex were evaluated.

SETTING

Pediatric orthopedic referral hospital, Philadelphia, Pennsylvania.

METHODS

Records of 190 subjects, ages 1-21 years, were reviewed. Data collected from the medical record included lower extremity muscle innervation, American Spinal Injury Association (ASIA) level and class, mechanism of injury, age at injury, time since injury, race, and sex. To determine innervation, lower extremity muscles had been tested using surface electrical stimulation and identified as being innervated or denervated. If a muscle responded weakly, strength duration testing was performed. For analysis via logistic regression, subjects were grouped based upon level and mechanism of injury.

RESULTS

A relationship (P<0.0001) was found between ASIA level and lower extremity innervation of all muscles and between length of time since injury and lower extremity innervation for some muscles. Following multiple logistic regression, only ASIA level remained as an independent predictor of lower extremity innervation status.

CONCLUSION

Our results show that lower extremity innervation does differ based on the level of the injury. Denervation began to be seen with injuries in the lower thoracic region and more predominantly with injuries in the lumbar region. This supports our hypothesis that the incidence of lower motor neuron injuries would increase as injuries became more caudal. Our hypotheses of a relationship between innervation status and mechanism of injury and age at injury were not supported. This information is important in determining treatment strategies, eligibility for electrical stimulation techniques, and potential regenerative strategies.

SPONSORSHIP

This study was funded by Shriners Hospitals for Children, Grant #8530.

Strengthening of Partially Denervated Knee Extensors Using Percutaneous Electric Stimulation in a Young Man With Spinal Cord Injury

OBJECTIVE

To evaluate the effects of percutaneous electric stimulation on knee extensor strength and muscle hypertrophy, gait, and energy cost of walking in a young man with partial denervation of the knee extensors.

DESIGN

One-way repeated measures.

SETTING

Pediatric orthopedic hospital.

PARTICIPANT

A man in his early twenties, who had an L2 American Spinal Injury Association class D spinal cord injury, presented with strength deficits in his left knee extensors and reported falling frequently. When walking, his left knee remained locked in extension throughout stance. Electromyographic testing revealed chronic denervation and reinnervation changes.

INTERVENTION

Because of sensory difficulties with surface stimulation, a percutaneous electrode was surgically implanted near the femoral nerve. The subject exercised isometrically with a research grade stimulator for 1 hour a day until his strength plateaued.

MAIN OUTCOME MEASURES

Quadriceps femoris strength and hypertrophy, gait, and energy cost of walking were recorded preintervention, every 2 months during the strengthening phase, and 2 months after withdrawal.

RESULTS

Voluntary isometric torque improved from 7 to 14.8Nm (112%) and decreased to 8.5Nm after stimulation was withdrawn. Mean circumferential measures of the thigh improved from 12.3 to 13.5cm (9.8%) and then decreased to 13.1cm. Gait kinematics and kinetics were unchanged, although the subject reported greater stability in his left knee and fewer falls.

CONCLUSIONS

The study indicates that percutaneous electric stimulation could be used to strengthen partially denervated muscle and to affect function. However, gains in strength may not be maintained once treatment is withdrawn.

Comparison of percutaneous and surface functional electrical stimulation during gait in a child with hemiplegic cerebral palsy

The purpose of this brief report was to compare the immediate effects of surface functional electrical stimulation (S-FES) and percutaneous functional electrical stimulation (P-FES) of the tibialis anterior applied during gait in a child with hemiplegic cerebral palsy. A three-dimensional gait analysis was conducted while an 11-yr-old girl with right hemiplegia walked with S-FES, P-FES, and no stimulation. The results indicated that both P-FES and S-FES increased dorsiflexion at initial contact, peak dorsiflexion in swing, and mean dorsiflexion in swing compared with walking without stimulation. The increase in dorsiflexion was greater with P-FES as compared with S-FES. Ankle absorption work was improved with both types of stimulation, whereas ankle generation work increased only with P-FES. This report suggests that S-FES and P-FES may have different immediate effects on gait due to issues such as muscle contraction strength, sensory feedback, and control systems for stimulation.

Use of functional electrical stimulation to augment traditional orthopaedic surgery in children with cerebral palsy

The purpose of this study was to compare the functional outcomes of traditional lower extremity orthopaedic surgery to more limited surgery augmented with functional electrical stimulation (FES) applied while walking. Seventeen ambulatory children with cerebral palsy participated in this prospective pretest-posttest control group study. The surgical group (nine subjects) underwent traditional orthopaedic procedures. The FES group (eight subjects) underwent placement of percutaneous intramuscular FES electrodes and limited orthopaedic surgical procedures. Postoperatively, they were provided with an FES home walking program. One year after intervention, all children (combined data) showed improvements in passive range of motion, gait spatiotemporal parameters, and gross motor function (P < 0.05). No differences were seen between groups before or after intervention. The FES group underwent 4.5 fewer ablative procedures per child than the surgical group. These results suggest that FES in combination with more limited surgery may provide similar functional gains with fewer ablative procedures than traditional orthopaedic surgery.

Direct effect of percutaneous electric stimulation during gait in children with hemiplegic cerebral palsy: a report of 2 cases

The feasibility of using percutaneous intramuscular functional electric stimulation (FES) in children with cerebral palsy (CP) as a method to improve ankle kinematics and kinetics during gait was investigated. Two children with right hemiplegic CP had percutaneous intramuscular electrodes implanted into the gastrocnemius and tibialis anterior muscles of the involved limb. FES was provided during the gait cycle using force-sensing foot switches to detect gait phase transitions. The children ambulated using FES under 3 conditions (gastrocnemius on, tibialis anterior on, gastrocnemius and tibialis anterior on). For each condition, two 45-minute walking sessions were conducted per day for 1 week. Immediately after each week of practice, a gait analysis was performed at the subject's self-selected walking speed for that stimulation condition and without stimulation. Both children demonstrated improvements in ankle dorsiflexion angle at initial contact, peak dorsiflexion during swing, mean dorsiflexion during swing, and ankle work during early stance with tibialis anterior stimulation alone and combined gastrocnemius and tibialis anterior stimulation. Improvements in ankle work were found during late stance for both children with all stimulation conditions. These results suggest that percutaneous intramuscular FES was effective in improving aspects of ankle kinematics and kinetics of 2 children with hemiplegic CP.

Pain Management in Trauma Patients

Trauma is a major cause of mortality throughout the world. In recent years, major advances have been made in the management of trauma, the end result of which has been reduced mortality and enhanced function. One of these areas is pain control. Improved pain management has not only led to increased comfort in trauma patients, but has also been shown to reduce morbidity and improve long-term outcomes. This review focuses on the treatment of pain in the setting of acute injury and on pain management in trauma patients who go on to develop chronic pain. Emphasis is placed on pharmacologic interventions, invasive and noninvasive pain management techniques, analgesia in challenging patients, and pain control in commonly encountered trauma conditions.

Intramuscular hand neuroprosthesis for chronic stroke survivors

The purpose of this study was to assess the feasibility of a percutaneous hand neuroprosthesis system for stroke survivors. Case reports of 4 chronic stroke survivors who were implanted with percutaneous intramuscular electrodes in various muscles of the forearm for hand grasp and release are presented. A percutaneous hand neuroprosthesis was able to open a spastic hemiparetic hand as long as the upper limb was in a resting position, the wrist and proximal forearm were supported, participants did not try to assist the stimulation, and an individual other than the participant modulated the stimulation. However, when participants tried to assist the stimulation or complete a functional task, hand opening was significantly reduced due to increased finger flexor hypertonia, even with increased stimulation intensity. Similarly, electrically stimulated hand opening was significantly reduced following voluntary hand closure. Techniques that provide real-time modulation of hypertonia with closed loop control, control strategies that are independent of the contralateral limb, and methods to enhance proximal control must be developed to demonstrate the feasibility of a hand neuroprosthesis system for persons with hemiparesis.

Neuromuscular electrical stimulation for motor relearning in hemiparesis

Neuromuscular electrical stimulation may have an important role in improving the motor function of stroke survivors. Active, repetitive movement training mediated by transcutaneous cyclic and EMG-triggered NMES may facilitate the motor recovery of stroke survivors. Multicenter, double-blinded, randomized clinical trials should be pursued to confirm the motor-relearning effects of transcutaneous NMES and to define appropriate prescriptive specifications. Intramuscular EMG-controlled NMES may be superior to transcutaneous systems and is presently undergoing preliminary randomized clinical trials. Neuroprostheses systems may provided the highest level of goal-oriented activity and cognitive investments, which may lead to significant motor relearning. Implementation of clinically viable neuroprosthesis systems, however, will probably require additional technical developments including more reliable control paradigms and methods for blocking undesirable muscle contractions. In view of the dynamic nature of the present health care environment, the future of NMES technology is difficult to predict. By necessity, scientists and clinicians must continue to explore new ideas and to improve on the present systems. Components will be smaller, more durable, and more reliable. Control issues will remain critical for both motor relearning and neuroprosthetic applications, and the implementation of cortical control is likely to dictate the nature of future generations of NMES systems. Finally, consumers will direct future developments. In the present health care environment, where cost has become an overwhelming factor in the development and implementation of new technology, the consumer will become one of technology's greatest advocates. The usual drive toward greater complexity will be tempered by the practical issues of clinical implementation, where patient acceptance is often a function of a tenuous balance between the burden or cost associated with using a system and the system's impact on the user's life.

Neuroprostheses for the upper extremity

Functional electrical stimulation (FES) neuroprostheses can be used to replace lost motor and sensory function in persons with neurological disorders. FES technology has subsequently been shown effective and safe in restoring hand function in adults with spinal cord injury. The freehand system consists of an implanted receiver-stimulator, an external shoulder position sensor, and an external control unit. Commands are originated by voluntary movement of the contralateral shoulder and are measured by the sensor. There are several types of electrodes: epimysial, intramuscular, nerve cuff, and intraneural. Neuroprostheses are recommended within the context of all available reconstructive options for the upper limbs. Voluntary tendon transfers are the first choice. The clinical outcomes as measured by improvement on scales of impairment, activities of daily living, and satisfaction are rewarding. The next step in improvement of the motor function of person with spinal cord injury will be the addition of a controllable second upper extremity and the elimination of additional external hardware.

Intramuscular electromyographically controlled neuromuscular electrical stimulation for upper limb recovery in chronic hemiplegia

We report three cases of survivors of chronic stroke who were treated with active repetitive movement training of the paretic finger extensors mediated by intramuscular electromyographically controlled neuromuscular electrical stimulation for the purpose of motor relearning. These case reports demonstrate the feasibility of using intramuscular electromyographically controlled neuromuscular electrical stimulation for facilitating the upper limb motor recovery of chronic stroke survivors with mild to moderate hemiplegia.

Intramuscular electromyographically controlled neuromuscular electrical stimulation for ankle dorsiflexion recovery in chronic hemiplegia

We report three cases of survivors of chronic stroke treated with active repetitive movement training of the paretic ankle dorsiflexors mediated by intramuscular electromyographically controlled neuromuscular electrical stimulation (NMES). These case reports demonstrate the feasibility of using intramuscular electromyographically controlled NMES for facilitating ankle dorsiflexion recovery among survivors chronic stroke with moderate hemiplegia. Relevant issues for clinical implementation and future investigations are reviewed.

Comparing stimulation-induced pain during percutaneous (intramuscular) and transcutaneous neuromuscular electric stimulation for treating shoulder subluxation in hemiplegia

OBJECTIVE

To determine whether percutaneous (intramuscular) neuromuscular electric stimulation (perc-NMES) is less painful than transcutaneous neuromuscular electric stimulation (trans-NMES) for treating shoulder subluxation in hemiplegia.

DESIGN

Double-blind, crossover trial.

SETTING

University-affiliated tertiary care hospital.

PARTICIPANTS

A convenience sample of 10 hemiplegic subjects with at least 1 fingerbreadth of glenohumeral subluxation.

INTERVENTIONS

All subjects received 3 randomly ordered pairs of perc-NMES and trans-NMES to the supraspinatus and posterior deltoid muscles of the subluxated shoulder. Both types of stimulation were optimized to provide full joint reduction with minimal discomfort.

MAIN OUTCOME MEASURES

Pain was assessed after each stimulation with a 10-cm visual analog scale (VAS) and the McGill Pain Questionnaire, using the Pain Rating Index (PRI) scoring method. Subjects were asked which type of stimulation they would prefer for 6 weeks of treatment. Wilcoxon's signed-rank test was used to compare median differences in VAS and PRI between perc-NMES and trans-NMES.

RESULTS

Median VAS scores for perc-NMES and trans-NMES were 1 and 5.7, respectively (p = .007). Median PRI scores for perc-NMES and trans-NMES were 7 and 19.5, respectively (p = .018). Nine of the 10 subjects preferred perc-NMES to trans-NMES for treatment.

CONCLUSION

Data suggest that perc-NMES is less painful than trans-NMES in the treatment of shoulder subluxation in hemiplegia.

Selectivity and sensitivity of intramuscular and transcutaneous electromyography electrodes

We evaluated the differences in selectivity and sensitivity of intramuscular fine-wire electrodes and transcutaneous electrodes in detecting dynamic electromyography (EMG) signals from extensor digitorum (EDC) and extensor carpi radialis (ECR) muscles during isolated EDC and ECR contractions in two able-bodied subjects. Intramuscular fine-wire electrodes differentiated EDC and ECR EMG activities better than transcutaneous electrodes, and intramuscular fine-wire electrodes recorded higher amplitude signals than transcutaneous electrodes. Data suggest that intramuscular fine-wire electrodes are more selective and sensitive than transcutaneous electrodes in detecting EMG signals from adjacent forearm muscles.

Minimizing discomfort with surface neuromuscular stimulation

The purpose of this study was to evaluate the effects of stimulus parameters, electrode types, and electrode positions on the perception of discomfort during lower extremity surface neuromuscular stimulation. Ten normal and eight neurologically impaired (four incomplete spinal cord and four stroke) subjects were enrolled. Neurologically impaired subjects had some sensation, although it was often reduced. Parameters of the stimulation were varied in a way that produced the same level of ankle dorsiflexion, as measured with a goniometer. Discomfort was assessed after each stimulation with a 0-10 verbal scale (0, no discomfort; 10, worst pain). Increasing the pulse frequency was associated with increased discomfort for subjects in both groups (p > 0.05). Increasing the pulse duration was associated with increased discomfort in the neurologically impaired subjects (p > 0.05), but not in the normal subjects (p > 0.05). The electrode size and type had no effects on discomfort (p > 0.05). Stimulation of the peroneal nerve over the fibular head was better tolerated than the direct motor point stimulation of the tibialis anterior motor point (p < 0.05). The data suggest that to minimize discomfort, surface stimulation should be applied over nerves rather than motor points, and frequency and pulse duration should be set as low as possible for a given degree of contraction.

Selective stimulation of cat sciatic nerve using an array of varying-length microelectrodes

Restoration of motor function to individuals who have had spinal cord injuries or stroke has been hampered by the lack of an interface to the peripheral nervous system. A suitable interface should provide selective stimulation of a large number of individual muscle groups with graded recruitment of force. We have developed a new neural interface, the Utah Slanted Electrode Array (USEA), that was designed to be implanted into peripheral nerves. Its goal is to provide such an interface that could be useful in rehabilitation as well as neuroscience applications. In this study, the stimulation capabilities of the USEA were evaluated in acute experiments in cat sciatic nerve. The recruitment properties and the selectivity of stimulation were examined by determining the target muscles excited by stimulation via each of the 100 electrodes in the array and using force transducers to record the force produced in these muscles. It is shown in the results that groups of up to 15 electrodes were inserted into individual fascicles. Stimulation slightly above threshold was selective to one muscle group for most individual electrodes. At higher currents, co-activation of agonist but not antagonist muscles was observed in some instances. Recruitment curves for the electrode array were broader with twitch thresholds starting at much lower currents than for cuff electrodes. In these experiments, it is also shown that certain combinations of electrode pairs, inserted into an individual fascicle, excite fiber populations with substantial overlap, whereas other pairs appear to address independent populations. We conclude that the USEA permits more selective stimulation at much lower current intensities with more graded recruitment of individual muscles than is achieved by conventional cuff electrodes.

A critical review of neuromuscular electrical stimulation for treatment of motor dysfunction in hemiplegia

The purpose of this review is to critically assess the clinical efficacy of neuromuscular electrical stimulation in treating motor dysfunction in hemiplegia. Three distinct applications are reviewed in the areas of motor relearning, shoulder dysfunction, and neuroprostheses. Assessment of clinical efficacy and recommendations on clinical implementation are based on the weight of published scientific evidence. With respect to motor relearning, evidence supports the use of neuromuscular electrical stimulation to facilitate recovery of muscle strength and coordination in hemiplegia. However, effects on physical disability are uncertain. With respect to shoulder dysfunction, neuromuscular electrical stimulation decreases shoulder subluxation, at least in the short term. However, effects on shoulder pain and disability are also uncertain. With respect to neuroprosthesis systems, clinically deployable upper extremity systems must await the development of more sophisticated control methods and greater fundamental understanding of motor dysfunction in hemiplegia. The evidence for clinical feasibility of lower extremity neuroprostheses is stronger, and investigations on clinical efficacy should be pursued. In summary, the application of neuromuscular electrical stimulation for motor relearning and shoulder dysfunction are ready for more rigorous scientific and clinical assessment via large, multicenter, randomized clinical trials. However, additional investigations are needed to demonstrate the clinical feasibility of neuroprostheses applications.