Description
Functional electrical stimulation (FES) involves the use of an orthotic device or exercise equipment with microprocessor-controlled electrical muscular stimulation. These devices are being developed to restore function and improve health in patients with damaged or destroyed nerve pathways (e.g., spinal cord injury [SCI], stroke, multiple sclerosis, cerebral palsy).

For individuals who have loss of hand and upper-extremity function due to SCI or stroke who receive FES, the evidence includes a few small case series. Relevant outcomes are functional outcomes and quality of life. Interpretation of the evidence is limited by the low number of patients studied and lack of data demonstrating the utility of FES outside the investigational setting. It is uncertain whether FES can restore some upper-extremity function or improve the quality of life. The evidence is insufficient to determine the effects of the technology on health outcomes.

For individuals who have chronic foot drop who receive FES, the evidence includes randomized controlled trials (RCTs), a systematic review, and a longitudinal cohort study. Relevant outcomes are functional outcomes and quality of life. For chronic poststroke foot drop, 2 RCTs comparing FES with a standard ankle-foot orthosis (AFO) showed improved patient satisfaction with FES but no significant differences between groups in objective measures such as walking. The cohort study assessed patients’ ability to avoid obstacles while walking on a treadmill using FES versus AFO. Although the FES group averaged a 4.7% higher rate of avoidance, the individual results between devices ranged widely. One RCT with 53 subjects examining neuromuscular stimulation for foot drop in patients with multiple sclerosis showed a reduction in falls and improved patient satisfaction compared with an exercise program but did not demonstrate a clinically significant benefit in walking speed. The other RCT showed that at 12 months, both FES and AFO had improved walking speed, but the difference in improvement between the 2 devices was not significant. A reduction in falls is an important health outcome. However, it was not a primary study outcome and should be corroborated. The literature on FES in children with cerebral palsy includes a systematic review of small studies with within-subject designs. Further study is needed. The evidence is insufficient to determine the effects of the technology on health outcomes.

For individuals who have SCI at segments T4 to T12 who receive FES, the evidence includes case series. Relevant outcomes are functional outcomes and quality of life. No controlled trials were identified on FES for standing and walking in patients with SCI. However, case series are considered adequate for this condition because there is no chance for unaided ambulation in this population with SCI at this level. Some studies have reported improvements in intermediate outcomes, but improvements in health outcomes (e.g., ability to perform activities of daily living, quality of life) have not been demonstrated. The evidence is insufficient to determine the effects of the technology on health outcomes.

For individuals who have SCI who receive FES exercise equipment, the evidence includes prospective within-subject comparisons. Relevant outcomes are symptoms, functional outcomes, and quality of life. The evidence on FES exercise equipment consists primarily of within-subject, pretreatment to posttreatment comparisons. Evidence was identified on 2 commercially available FES cycle ergometer models for the home, the RT300 series and the REGYS/ERGYS series. There is limited evidence on the RT300 series. None of the studies showed an improvement in health benefits, and 1 analysis of use for 314 individuals over 20,000 activity sessions with a Restorative Therapies device showed that a majority of users used the device for 34 minutes per week. Two percent of individuals with SCI used the device for an average of 6 days per week, but caloric expenditure remained low. Compliance was shown in 1 study to be affected by the age of participants and level of activity prior to the study. Studies on the REGYS/ERGYS series have more uniformly shown an improvement in physiologic measures of health and in sensory and motor function. A limitation of these studies is that they all appear to have been conducted in supervised in research centers. No studies were identified on long-term home use of ERGYS cycle ergometers. The feasibility and long-term health benefits of using this device in the home is uncertain. The evidence is insufficient to determine the effects of the technology on health outcomes.

Background  
Functional electrical stimulation
FES is an approach to rehabilitation that applies low-level electrical current to stimulate functional movements in muscles affected by nerve damage. It focuses on the restoration of useful movements, like standing, stepping, pedaling for exercise, reaching, or grasping.

FES devices consist of an orthotic and a microprocessor-based electronic stimulator with one or more channels for delivery of individual pulses through surface or implanted electrodes connected to the neuromuscular system. Microprocessor programs activate the channels sequentially or in unison to stimulate peripheral nerves and trigger muscle contractions to produce functionally useful movements that allow patients to sit, stand, walk, cycle, or grasp. Functional neuromuscular stimulators are closed-loop systems that provide feedback information on muscle force and joint position, thus allowing constant modification of stimulation parameters, which are required for complex activities (e.g., walking). These systems are contrasted with open-loop systems, which are used for simple tasks (e.g., muscle strengthening alone); healthy individuals with intact neural control benefit the most from this technology.

Applications, described in more detail in the Rationale section, include upper-extremity grasping function after spinal cord injury and stroke, lifting the front of the foot during ambulation in individuals with foot drop, ambulation and exercise for patients with spinal cord injury. Some devices are used primarily for rehabilitation rather than home use. This evidence review focuses on devices intended for home use.

Regulatory Status
A variety of FES devices have been cleared by the U.S. Food and Drug Administration (FDA) and are available for home use. Table 1 provides examples of devices designed to improve hand and foot function as well as cycle ergometers for home exercise. The date of the FDA clearance is for the first 510(k) clearance identified for a marketed device. Many devices have additional FDA clearances as the technology evolved, each in turn listing the most recent device as the predicate.

Table 1. Functional Electrical Stimulation Devices Cleared by the FDA

FDA: U.S. Food and Drug Administration.

To date, the Parastep^® Ambulation System (Sigmedics) is the only noninvasive functional walking neuromuscular stimulation device to receive premarket approval from the FDA. The Parastep device is approved to “enable appropriately selected skeletally mature spinal cord injured patients (level C6 to T12) to stand and attain limited ambulation and/or take steps, with assistance if required, following a prescribed period of physical therapy training in conjunction with rehabilitation management of spinal cord injury.”¹ FDA product code: MKD.

Related Policies
10405 Microprocessor-Controlled Prostheses for the Lower Limb
10404 Myoelectric Prosthetic Components for the Upper Limb
10304 Powered Exoskeleton for Ambulation in Patients with Lower-Limb Disabilities

Policy:
Neuromuscular stimulation is considered INVESTIGATIONAL as a technique to restore function following nerve damage or nerve injury. This includes its use in the following situations.

• As a technique to provide ambulation in patients with spinal cord injury
• To provide upper extremity function in patients with nerve damage (e.g., spinal cord injury or post-stoke)
• To improve ambulation in patients with foot drop caused by nerve damage (e.g., post stroke, cerebral palsy or in those with multiple sclerosis)

Robotic-assisted rehabilitation and robot-assisted orthotics of the upper limb and lower limb are considered INVESTIGATIONAL for stroke and for all other indications (e.g., incomplete spinal cord injury, neuromuscular diseases such as cerebral palsy and multiple sclerosis and Parkinson's disease; not an all-inclusive list) because of insufficient evidence of their effectiveness.

Policy Guidelines
Please see the Codes table for details.

Benefit Application
BlueCard^®/National Account Issues
This policy does not refer to commercially available exercycles that use electrical muscle stimulation technology as a means of physical therapy and exercise for spinal cord injury patients. These exercycles are sometimes called functional neuromuscular exercisers. The goals for using these devices may be to promote cardiovascular conditioning, prevent muscle atrophy and/or maintain bone mass. The patient’s legs are wrapped in fabric strips that contain electrodes to stimulate the muscles, thus permitting the patient to pedal. Plans may wish to review their policies on durable medical equipment and physical therapy services when reviewing electrical muscle stimulation exercycles. Some might consider this a physical therapy modality.

State or federal mandates (e.g., FEP) may dictate that all devices approved by FDA may not be considered investigational and, thus, these devices may be assessed only on the basis of their medical necessity.

Rationale
This evidence review was created in March 1996 and has been updated regularly with searches of the PubMed database. The most recent literature update was performed through Feb. 6, 2023.

Evidence reviews assess the clinical evidence to determine whether the use of a technology improves the net health outcome. Broadly defined, health outcomes are the length of life, quality of life, and ability to function, including benefits and harms. Every clinical condition has specific outcomes that are important to patients and to managing the course of that condition. Validated outcome measures are necessary to ascertain whether a condition improves or worsens; and whether the magnitude of that change is clinically significant. The net health outcome is a balance of benefits and harms.

To assess whether the evidence is sufficient to draw conclusions about the net health outcome of a technology, 2 domains are examined: the relevance and the quality and credibility. To be relevant, studies must represent one or more intended clinical use of the technology in the intended population and compare an effective and appropriate alternative at a comparable intensity. For some conditions, the alternative will be supportive care or surveillance. The quality and credibility of the evidence depend on study design and conduct, minimizing bias and confounding that can generate incorrect findings. The randomized controlled trial (RCT) is preferred to assess efficacy; however, in some circumstances, nonrandomized studies may be adequate. Randomized controlled trials are rarely large enough or long enough to capture less common adverse events and long-term effects. Other types of studies can be used for these purposes and to assess generalizability to broader clinical populations and settings of clinical practice.

Promotion of greater diversity and inclusion in clinical research of historically marginalized groups (e.g., people of color [African American, Asian, Black, Latino and Native American]; LGBTQIA [lesbian, gay, bisexual, transgender, queer, intersex, asexual); women; and people with disabilities [physical and invisible]) allows policy populations to be more reflective of and findings more applicable to our diverse members. While we also strive to use inclusive language related to these groups in our policies, use of gender-specific nouns (e.g., women, men, sisters, etc.) will continue when reflective of language used in publications describing study populations.

Upper-Extremity Function After Spinal Cord Injury and Stroke
Clinical Context and Therapy Purpose
One application of functional electrical stimulation (FES) is to restore upper-extremity functions such as grasp-release, forearm pronation, and elbow extension in patients with stroke, or C5 and C6 tetraplegia (quadriplegia).

The following PICO was used to select literature to inform this review.

Populations
The relevant population of interest is patients with loss of hand and upper-extremity function due to spinal cord injusry (SCI) or stroke.

Interventions
The therapy being considered is FES. NeuroControl Corp. developed the Freehand System, an implantable upper-extremity neuroprosthesis, to improve the ability to grasp, hold, and release objects for patients with tetraplegia due to C5 or C6 SCI. NeuroControl is no longer in business, but FES centers in the United States and United Kingdom provide maintenance for implanted devices.

The NESS H200 (previously known as the Handmaster NMS I system) is an upper-extremity device that uses a forearm splint and surface electrodes. The device, controlled by a user-activated button, is intended to provide hand function (fine finger grasping, larger palmar grasping) for patients with C5 tetraplegia or stroke.

Other hand stimulators that have been cleared for marketing in the United States are:

• ReGrasp by Rehabtronics
• MyndMove by MyndTec. This device is currently being studied in a clinical trial for rehabilitation.

Comparators
The following practices are currently being used to make decisions about FES for upper-extremity paresis: standard of care.

Outcomes
The general outcomes of interest are functional outcomes and quality of life. Specific outcomes of interest include the ability to grasp, hold, and lift objects, along with other selected activities of daily living (ADL).

Available literature indicates training and follow-up for 3 weeks to 2 months.

Study Selection Criteria
Methodologically credible studies were selected using the following principles:

• To assess efficacy outcomes, comparative controlled prospective trials were sought, with a preference for RCTs.
• In the absence of such trials, comparative observational studies were sought, with a preference for prospective studies.
• To assess long-term outcomes and adverse events, single-arm studies that capture longer periods of follow-up and/or larger populations were sought.
• Studies with duplicative or overlapping populations were excluded.

Review of Evidence
FreeHand System
Much of the early published evidence assessing upper-extremity devices to restore function in patients with SCIs reported on experience with the Freehand System, an implantable device no longer marketed in the United States.^2,3,4,5

Handmaster
Studies with the first version of the NESS H200 (Handmaster), were reported in patients with upper-extremity paresis following stroke and SCI (see Tables 2 and 3).

Alon et al. (2003) evaluated the Handmaster device in 7 subjects with C5 or C6 SCI who practiced using the device daily in an effort to regain the ability to grasp, hold, and release objects.⁶ All patients were observed 2 to 3 times during the week for 3 weeks, and they were evaluated on their ability to perform the following tasks: pick up a telephone, eat food with a fork, perform an individually selected ADL task, and perform 2 tasks relating to grasping, holding, and releasing certain items. At the end of the study, all 7 subjects successfully used the device for each required task. Improvements occurred in secondary measures of grip strength, finger linear motion, and Fugl-Meyer Assessment scores (the instrument assesses sensorimotor recovery after stroke).

Alon et al. (2002), reporting on a case series of 29 patients, investigated whether the Handmaster system could improve select hand function in persons with chronic upper-extremity paresis following stroke.⁷ The main outcome measures were 3 ADL tasks: lifting a 2-handled pot, holding a bag while standing with a cane, and another ADL chosen by the patient. At the end of the 3-week study period, the percentage of successful trials compared with baseline were lifting pot, 93% versus 0%; lifting 600-gram weight, 100% versus 14%; and lifting bag, 93% versus 17%. All subjects performed their selected ADLs successfully and improved their Fugl-Meyer Assessment scores using the neuroprosthesis.

Snoek et al. (2000) reported on use of the Handmaster NMS I, another upper-extremity device, for a series of 10 patients with cervical SCIs.8, After 2 months of training, performance on a defined set of tasks and 1 or more tasks chosen by the patient was evaluated. In 6 patients, a stimulated grasp and release with either 1 or both grasp modes (key and palmar pinch) of the Handmaster was possible. Four patients could perform the set of tasks with but not without the Handmaster.

Table 2. Key Case Series Characteristics

SCI: spinal cord injury

Table 3. Key Case Series Results

ADL: activities of daily living; NA: not applicable.

MyndMove
Anderson et al. (2022) conducted a multi-center, single-blind, parallel-group, RCT comparing FES delivered by the MyndMove device (n = 27) to conventional therapy (n = 24) in adults with C4 to C7 SCI.⁹ The FES therapy consisted of 36 to 40 one-hour sessions within a 14-week period, while conventional therapy consisted of the same time frame, but participants received upper limb conventional therapy instead. The primary outcome was the change in baseline of spinal cord injury independence measure III - self-care (SCIM-SC) scores. Both groups gained a mean of 2 points in SCIM-SC scores at the end of treatment, which was clinically meaningful, and this impact persisted at the end of the study (24 weeks from the 1st session). However, there was no statistically significant difference between the groups on any outcomes. This trial was limited by the small number of participants (power was not reached) and interruptions of therapy sessions due to the COVID-19 pandemic lockdown in the U.S. and Canada. Additionally, the participants in the FES group were likely more severely impaired than those in the conventional therapy group based on baseline characteristics. Randomization was stratified by site and not on severity of injury.

Section Summary: Upper-Extremity Function After Spinal Cord Injury and Stroke
The evidence on FES for the upper limbs in patients with SCI or stroke includes a limited number of small case series and an RCT. Interpretation of the evidence for upper-extremity neuroprostheses for these populations is limited by the small number of patients studied and lack of data demonstrating its utility outside the investigational (study) setting.

Functional Electrical Stimulation for Chronic Foot Drop
Clinical Context and Therapy Purpose
Other FES devices have been developed to provide FES for patients with foot drop. Foot drop is weakness of the foot and ankle that causes reduced dorsiflexion and difficulty with ambulation. It can have various causes such as cerebral palsy, stroke, or multiple sclerosis. Functional electrical stimulation of the peroneal nerve has been suggested for these patients as an aid in raising the toes during the swing phase of ambulation.

The following PICO was used to select literature to inform this review.

Populations
The relevant population of interest is patients with chronic foot drop due to stroke, multiple sclerosis, or cerebral palsy.

Interventions
The therapy being considered is FES.

With these devices, a pressure sensor detects heel-off and initial contact during walking. A signal is then sent to the stimulation cuff, initiating or pausing the stimulation of the peroneal nerve, which activates the foot dorsiflexors. Examples of such devices used for treatment of foot drop are:

• WalkAide by Innovative Neurotronics (formerly NeuroMotion)
• L300 Go by Bioness
• MyGait by Otto Bock
• ODFS (Odstock Dropped Foot Stimulator) and ODFS Pace XL by Odstock.

Comparators
The following therapies are currently being used to make decisions about foot drop: standard of care and ankle-foot orthoses (AFO).

Outcomes
The general outcomes of interest are functional outcomes and quality of life. Ability to walk is the primary outcome of interest. There are established measures of walking, mobility and quality of life. These include:

• 10-meter walk test (10MWT): Assesses the time it takes to walk 10 meters
• 6-minute walk test (6MWT): assesses the distance walked in 6 minutes
• Timed Up-and-Go: assesses the time required to get up from a chair and take a step
• Stroke Impact Scale (SIS)

Based on available literature, follow-up would ideally be 6 months to 1 year.

Study Selection Criteria
Methodologically credible studies were selected using the following principles:

• To assess efficacy outcomes, comparative controlled prospective trials were sought, with a preference for RCTs.
• In the absence of such trials, comparative observational studies were sought, with a preference for prospective studies.
• To assess long-term outcomes and adverse events, single-arm studies that capture longer periods of follow-up and/or larger populations were sought.
• Studies with duplicative or overlapping populations were excluded.

Review of Evidence
Stroke
Systematic reviews
Two meta-analyses evaluated FES in treatment of patients with foot drop secondary to stroke (Tables 4 through 6).

da Cunha et al. (2020) performed a meta-analysis of 14 parallel-group or crossover studies (N = 1,115) of FES applied to the paretic peroneal nerve.10, Compared with supervised exercises alone, FES was not superior in improving gait speed. Functional electrical stimulation significantly improved balance as assessed with the Berg Balance Scale (BBS; ranging from 0 to 56, with higher scores indicating improvement) and functional mobility as assessed by the Timed Up-and-Go test; however, heterogeneity was high for these outcomes. The overall quality of evidence was assessed as low.

Nascimento et al. (2020) performed a meta-analysis of 11 parallel-group studies (N = 1135) of AFO or FES.11, Walking speed was significantly improved compared with no treatment with both AFOs and FES. In comparisons of active treatments, AFO and FES did not significantly differ in outcomes of walking speed or balance as measured by the BBS. However, both analyses included few studies (4 and 2 studies, respectively). The overall quality of evidence was assessed as moderate.

Table 4. Comparison of Studies Included in Meta-Analysis

Table 5. Meta-Analysis Characteristics

RCT: randomized controlled trial.

Table 6. Meta-Analysis Results

BBS: Berg Balance Scale; CI: confidence interval; MD: mean difference: SMD: standardized mean difference.

Randomized Controlled Trials
Three multicenter RCTs were identified on FES for dropped foot (see Tables 7 and 8).

Hachisuka et al. (2021) compared FES with a dropped foot stimulator (WalkAide) with no device treatment in a randomized, open-label trial in 119 patients with post-stroke foot drop who were at least 4 months post-stroke.¹² At 4 weeks, there were no significant differences between groups in the primary endpoint of change from baseline in 6MWT or the secondary endpoint of change from baseline in 10MWT.

Functional electrical stimulation with a dropped foot stimulator (WalkAide) was compared with an AFO in a 2014 industry-sponsored multicenter non-inferiority trial (NCT01087957) that included 495 Medicare-eligible individuals who were at least 6 months poststroke.¹³ A total of 399 individuals completed the 6-month study. Primary outcome measures were the 10MWT, a composite measure of daily function, and device-related serious adverse events. Seven secondary outcome measures assessed function and quality of life. The intention-to-treat analysis found that both groups improved walking performance over the 6 months, and the FES device was found noninferior to the AFO for the primary outcome measures. Only the WalkAide group showed significant improvements from baseline to 6 months on several secondary outcome measures, but there were no statistically significant between-group differences for any outcome.

The Functional Ambulation: Standard Treatment versus Electronic Stimulation Therapy (FASTEST) Trial in Chronic Post-Stroke Subjects With Foot Drop (NCT01138995) was a 2013 industry-sponsored, single-blinded, multicenter trial that randomized 197 stroke patients to 30 weeks of a dropped foot stimulator (NESS L300) or a conventional AFO.¹⁴ The AFO group received transcutaneous electrical nerve stimulation at each physical therapy visit during the first 2 weeks to provide a sensory control for stimulation of the peroneal nerve received by the NESS L300 group. Evaluation by physical therapists blinded to group assignment found that both groups improved gait speed and other secondary outcome measures over time, with a similar improvement in the 2 groups. There were no between-group differences in the number of steps per day at home, which was measured by an activity monitor over a week. User satisfaction was higher with the foot drop stimulator.

O'Dell et al. (2014) reported on a secondary analysis of data from the FASTEST study.¹⁵ Comfortable gait speed was assessed in the 99 individuals from the NESS L300 group at 6, 12, 30, 36, and 42 weeks, with and without the use of the foot drop stimulator. A responder was defined as one achieving a minimal clinically important difference of 0.1 m/s on the 10MWT or advancing by at least 1 Perry Ambulation Category (which measures functional walking ability in the home or community). Noncompleters were classified as nonresponders. Seventy percent of participants completed the assessments at 42 weeks, and 67% of participants were classified as responders. Of the 32 participants classified as nonresponders, 2 were nonresponders, and 30 were noncompleters. The percentage of patients in the conventional AFO group classified as responders at 30 weeks was not reported. There were 160 adverse events, of which 92% were classified as mild. Fifty percent of the adverse events were related to reversible skin issues, and 27% were falls.

Table 7. Key RCT Characteristics

AFO: ankle-foot orthosis; FASTEST: Functional Ambulation: Standard Treatment vs. Electronic Stimulation Therapy Trial in Chronic Post-Stroke Subjects With Foot Drop;  RCT: randomized controlled trial.

Table 8. Key RCT Results

6MWT: 6-minute walk test; 10MWT; 10-meter walk test; AFO: ankle-foot orthosis; FASTEST: Functional Ambulation: Standard Treatment vs. Electronic Stimulation Therapy Trial in Chronic Post-Stroke Subjects With Foot Drop; NS: nonsignificant; RCT: randomized controlled trial; SIS: stroke impact scale.

Limitations in study design and conduct are shown in Table 9. The primary limitation for both studies was unequal loss to follow-up, with higher loss to follow-up in the FES group. Inability to tolerate the electrical stimulation has been noted in some studies.

Table 9. Study Design and Conduct Limitations

The study limitations stated in this table are those notable in the current review; this is not a comprehensive gaps assessment.
^a Allocation key: 1. Participants not randomly allocated; 2. Allocation not concealed; 3. Allocation concealment unclear; 4. Inadequate control for selection bias.
^b Blinding key: 1. Not blinded to treatment assignment; 2. Not blinded outcome assessment; 3. Outcome assessed by treating physician.
^c Selective Reporting key: 1. Not registered; 2. Evidence of selective reporting; 3. Evidence of selective publication.
^d Data Completeness key: 1. High loss to follow-up or missing data; 2. Inadequate handling of missing data; 3. High number of crossovers; 4. Inadequate handling of crossovers; 5. Inappropriate exclusions; 6. Not intent to treat analysis (per protocol for noninferiority trials).
^e Power key: 1. Power calculations not reported; 2. Power not calculated for primary outcome; 3. Power not based on clinically important difference.
^f Statistical key: 1. Analysis is not appropriate for outcome type: (a) continuous; (b) binary; (c) time to event; 2. Analysis is not appropriate for multiple observations per patient; 3. Confidence intervals and/or p values not reported; 4.Comparative treatment effects not calculated.

Longitudinal Cohort Study
Berenpas et al. (2019) compared the effectiveness of implanted FES versus AFO in helping stroke patients with foot drop avoid obstacles while walking (“gait adaptability”).¹⁶ Two cohorts were studied: the first (n = 10) was followed for 26 weeks; the second (n = 12) was followed for 52 weeks. All study participants had experienced stroke more than 6 months prior and regularly used an AFO. A within-subjects repeated measures design was used. Gait adaptability was tested by having participants walk on a treadmill while obstacles were suddenly dropped in front of the paretic leg. Before implantation of the device, participants were tested using only the AFO (at 2 or 3 km/h). Patients were then implanted with a 4-channel peroneal nerve stimulator (ActiGait). Testing was then conducted with FES and with AFO at 2 weeks postimplantation, then at 8 weeks, 26 weeks, and, for the second cohort, 52 weeks. Available response time (ART) was calculated “as the time between obstacle release and the moment the toe would have crossed the front edge of the obstacle in the case of an unaltered step.” Available response time was stratified into 3 categories based on at what point in the gait cycle the obstacle was dropped: 450 to 600 ms (mid stance), 300 to 450 ms (late stance/early swing), and 150 to 300 ms (mid swing). Results showed FES success rates were an average of 4.7% higher than with AFO (55.4% vs. 50.7%; p = .03). Significant differences were seen between the 3 ARTs (p < .001), with higher success rates with longer ARTs. The individual results ranged widely in differences between devices — at 26 weeks they ranged from -29% to 85%. The small sample size and absence of control group limit the study’s generalizability, but larger controlled studies would be difficult given the requirements of the intervention.

Multiple Sclerosis
Randomized Controlled Trials
Several RCTs have evaluated FES in patients with multiple sclerosis and foot drop (see Tables 10 and 11).

Prokopiusova et al. (2020) performed a randomized trial that compared FES (combined with postural correction) and neuroproprioceptive facilitation and inhibition physiotherapy for 2 months in patients with multiple sclerosis and foot drop.17, Main study outcomes were assessed immediately after and 2 months after program completion and included 2-minute walk test, timed 25-foot walk test, Timed Up-and-Go test, Activities-Specific Balance Confidence Scale (ABC), and BBS. While the group treated with FES experienced significant improvements immediately after program completion in ABC and BBS, none of these outcomes significantly differed between groups at either time point. The study was limited by a lack of blinding of patients and clinicians.

Renfrew et al. (2019) compared clinical effectiveness of FES versus AFO in their multicenter randomized trial.¹⁸ The study took place over 12 months and included 85 treatment-naive patients with multiple sclerosis who had had foot drop for more than 3 months. The patients were randomized to receive either an Odstock Dropped Foot Stimulator (n = 42) or AFO (n = 43). By 12 months, 32 patients (38%) had dropped out of the study. Outcome measurements were taken at baseline, 3, 6, and 12 months (except the Psychological Impact Score, which was measured only at 12 months). The primary outcome measure was the 5-minute self-selected walk test in which participants walked at their preferred pace around a 9.5-m elliptical course for 5 minutes and total distance was recorded. Other outcomes included the timed 25-foot walk test, Multiple Sclerosis Impact Scale-29 (MSIS-29; higher scores indicate a greater impact on life), and the ABC (higher score indicates more confidence). Results are shown in Table 11. Also measured were orthotic effects and oxygen cost of walking. Clinically significant orthotic and therapeutic effects were deemed an observed increase in walking speed of ≥0.05 m/s. The FES group saw a clinically significant ongoing orthotic effect for both walk tests at 3, 6, and 12 months, but the AFO group did not. For total orthotic effect at 12 months, the AFO results for the 5-minute self-selected walk test were clinically significant, but the FES were not. Although both devices improved walking speed at 12 months, the differences in their effects were not significant.

Two publications from 1 RCT were identified on use of a dropped foot stimulator in patients with multiple sclerosis (see Tables 10 and 11). Barrett et al. (2009) assessed FES to improve walking performance in patients with multiple sclerosis.¹⁹ Fifty-three patients with secondary progressive multiple sclerosis and unilateral dropped foot were randomized to an 18-week program of an Odstock Dropped Foot Stimulator device or a home exercise program. Patients in the stimulator group were encouraged to wear the device most of the day, switching it on initially for short walks and increasing daily for 2 weeks, after which they could use the device without restriction. Subjects in the control group were taught a series of exercises tailored to the individual to be done twice daily. Six patients in the FES group and 3 in the exercise group dropped out, leaving 20 in the FES group and 24 in the exercise group. The primary outcome measure was the 10MWT. At 18 weeks, the exercise group walked significantly faster than the FES group (p = .028).

A 2010 publication by the same investigators reported on the impact of the treatment on ADL.²⁰ Results of 53 patients from the trial previously described were reported, using the Canadian Occupational Performance Measure. The Canadian Occupational Performance Measure is a validated semi-structured interview (higher scores indicate improvement) originally designed to assist occupational therapy interventions. The interviews at baseline identified 265 problems of which 260 activities were related to walking and mobility. Subjective evaluation at 18 weeks showed greater improvements in performance and satisfaction scores in the FES group (35% of the identified problems increased by a score of 2 or more) than in the exercise group (17% of problems increased by a score of 2 or more). The median satisfaction rating improved from 2.2 to 4.0 in the FES group and remained stable (2.6 to 2.4) in the exercise group. The median number of falls recorded per patient over the 18-week study was 5 in the FES group and 18 in the exercise group. About 70% of the falls occurred while not using the FES device or an AFO.

Table 10. Summary of Key RCT Characteristics

AFO: ankle-foot orthosis; EU: European Union; FES: functional electrical stimulation;  RCT: randomized controlled trial.

Table 11. Summary of Key RCT Results

10MWT; 10-meter walk test; ABC: Activities-Specific Balance Confidence Scale; AFO: ankle-foot orthosis; BBS: Berg Balance Scale; FES: functional electrical stimulation;  MSIS-29 (physical): Multiple Sclerosis Impact Scale physical subscale; m/s: meters per second; NR: not reported; SD: standard deviation; RCT: randomized controlled trial.
^a At 12 months without use of FES/AFO.

Limitations in relevance and design and conduct are denoted in Tables 12 and 13. In Barrett et al. (2009), power calculations were based on the 10MWT measure only and indicated that 25 subjects would be required in each group, patients were highly selected, clinical assessors also provided treatment (compromising blinding), and the validity and reliability of the 3-minute walk test had not been confirmed (fatigue prevented use of the validated 6MWT). In addition, subjects in the exercise group were told they would receive a stimulator at the end of the trial, which may have biased exercise adherence and retention in the trial.

Table 12. Study Relevance Limitations

The study limitations stated in this table are those notable in the current review; this is not a comprehensive gaps assessment.
^a Population key: 1. Intended use population unclear; 2. Study population is unclear; 3. Study population not representative of intended use; 4. Enrolled populations do not reflect relevant diversity; 5. Other.
^b Intervention key: 1. Not clearly defined; 2. Version used unclear; 3. Delivery not similar intensity as comparator; 4. Not the intervention of interest (e.g., proposed as an adjunct but not tested as such); 5: Other.
^c Comparator key: 1. Not clearly defined; 2. Not standard or optimal; 3. Delivery not similar intensity as intervention; 4. Not delivered effectively; 5. Other.
^d Outcomes key: 1. Key health outcomes not addressed; 2. Physiologic measures, not validated surrogates; 3. Incomplete reporting of harms; 4. Not establish and validated measurements; 5. Clinically significant difference not prespecified; 6. Clinically significant difference not supported; 7. Other.
^e Follow-Up key: 1. Not sufficient duration for benefit; 2. Not sufficient duration for harms; 3. Other.

Table 13. Study Design and Conduct Limitations

The study limitations stated in this table are those notable in the current review; this is not a comprehensive gaps assessment.
^a Allocation key: 1. Participants not randomly allocated; 2. Allocation not concealed; 3. Allocation concealment unclear; 4. Inadequate control for selection bias.
^b Blinding key: 1. Not blinded to treatment assignment; 2. Not blinded outcome assessment; 3. Outcome assessed by treating physician.
^c Selective Reporting key: 1. Not registered; 2. Evidence of selective reporting; 3. Evidence of selective publication.
^d Data Completeness key: 1. High loss to follow-up or missing data; 2. Inadequate handling of missing data; 3. High number of crossovers; 4. Inadequate handling of crossovers; 5. Inappropriate exclusions; 6. Not intent to treat analysis (per protocol for noninferiority trials).
^e Power key: 1. Power calculations not reported; 2. Power not calculated for primary outcome; 3. Power not based on clinically important difference.
^f Statistical key: 1. Analysis is not appropriate for outcome type: (a) continuous; (b) binary; (c) time to event; 2. Analysis is not appropriate for multiple observations per patient; 3. Confidence intervals and/or p values not reported; 4.Comparative treatment effects not calculated.

Cerebral Palsy
Systematic reviews
Three systematic reviews were identified on the use of a dropped foot stimulator for children with cerebral palsy. Table 14 compares the trials included in each review and Table 15 describes the characteristics of each review.

Cauraugh et al. (2010) conducted a systematic review and meta-analysis of 17 studies on FES and gait in children with cerebral palsy.²¹ Fourteen studies used a pretest-posttest that included a within-subjects design. A total of 238 participants had FES. Included were studies on acute FES, FES, and therapeutic FES (continuous subthreshold stimulation). Five studies examined FES, one of which examined percutaneous FES. Impairment was assessed by 3 outcome measures: range of motion, torque/movement, and strength/force. Activity limitations were assessed by 6 outcome measures: gross motor functions, gait parameters, hopping on 1 foot, 6MWT, Leg Ability Index, and Gillette Gait Index. Moderate effect sizes were found for impairment (0.616) and activity limitations (0.635). Studies selected for the review lacked blinding and were heterogeneous for outcome measures. Reviewers did not report whether any study used a commercially available device.

Zhu et al. (2022) conducted a systematic review and meta-analysis of 9 RCTs (N = 282) on FES and gait in children with cerebral palsy, including more recent studies than other systematic reviews.²² Of the children included across studies, 142 were in the FES therapy group and 140 were in the control group, which included comfort treatment, general nursing, or other physical therapy. All studies were included in analysis of walking speed and step length, with no significant heterogeneity among studies. Meta-analysis demonstrated that walking speed was increased after FES compared with the control group (standard mean difference [SMD], 0.82; 95% confidence interval [CI], 0.57 to 1.07; p < .0001). Additionally, FES increased the walking step length compared to the control group (SMD, 1.34; 95% CI, 1.07 to 1.60; p < .0001). Most studies had limitations in blinding methods of participants, and most of them were single-blind studies. Additionally, there is an overall lack of high-quality RCTs contributing to evidence, and authors concluded that more research with larger populations was needed.

Chen et al. (2023) also conducted a systematic review of 14 RCTs measuring the impact of FES on mobility in children with cerebral palsy.²³ Included RCTs compared FES with placebo or conventional therapy (N = 421). While there was overlap of studies included in Cauraugh et al. (2010), Chen et al. (2023) also included unique studies. Compared with the control group, children who received FES demonstrated greater improvement in walking speed (7 studies, n = 213; SMD, 0.29; 95% CI, 0.02 to 0.57; p = .04) and the standing, walking, running, and jumping dimension of the Gross Motor Function Measure (9 studies, n = 302; SMD, 1.24; 95% CI, 0.64 to 1.83; p < .0001). Five RCTs (n = 198) reported on adverse effects of FES, and no adverse events were reported in any trial. Participants were not blinded in any of the studies and therapists were not blinded in most of the studies. Long-term effects of FES could not be determined based on the short duration of follow-up of included studies. Additionally, parameters and location of the stimulation differed across studies. Despite risk of bias identified across trials, the studies included in this systematic review were deemed to be of moderate quality using the Grading of Recommendations, Assessment, Development and Evaluation method.

Table 14. Comparison of Studies Included in Systematic Reviews and Meta-Analyses

Table 15. Systematic Review and Meta-Analysis Characteristics

FES: functional electrical stimulation; NMES: neuromuscular electrical stimulation; NR: not reported; RCT: randomized controlled trial.

Section Summary: Functional Electrical Stimulation for Chronic Foot Drop
For chronic poststroke foot drop, a meta-analysis and 2 RCTs comparing FES with a standard AFO showed no significant differences between groups in objective measures such as walking, but the RCTs indicated some improved patient satisfaction with FES. A longitudinal cohort study assessed patients’ ability to avoid obstacles while walking on a treadmill using FES versus AFO. Although the FES group averaged a 4.7% higher rate of avoidance, the individual results between devices ranged widely. One RCT with 53 subjects examining neuromuscular stimulation for foot drop in patients with multiple sclerosis showed a reduction in falls and improved patient satisfaction compared with an exercise program but did not demonstrate a clinically significant benefit in walking speed. Another RCT showed that at 12 months, both FES and AFO had improved walking speed, but the difference in improvement between the 2 devices was not significant. A reduction in falls is an important health outcome. However, it was not a primary study outcome and should be confirmed in a larger number of patients. The literature on FES in children with cerebral palsy includes 3 systematic reviews of small studies with within-subject designs. All included studies only measure short-term results; it is unclear what the long-term effects of FES may be in this population.Further study in a larger number of subjects for a longer duration of study is needed.

Ambulation in Patients With Spinal Cord Injury
Clinical Context and Therapy Purpose
Another application of FES is to provide patients with SCI the ability to stand and walk. Using percutaneous stimulation, the device delivers trains of electrical pulses to trigger action potentials at selected nerves at the quadriceps (for knee extension), the common peroneal nerve (for hip flexion), and the paraspinals and gluteals (for trunk stability). Patients use a walker or elbow-support crutches for further support. The electric impulses are controlled by a computer microchip attached to the patient’s belt, which synchronizes and distributes the signals. In addition, there is a finger-controlled switch that permits patient activation of the stepping.

Other devices include a reciprocating gait orthosis with electrical stimulation. The orthosis used is a cumbersome hip-knee-ankle-foot device linked together with a cable at the hip joint. The use of this device may be limited by the difficulties in donning and doffing the device.

The purpose of FES for ambulation in patients who have SCI is to provide a treatment option that is an alternative to or an improvement on existing therapies.

The following PICO was used to select literature to inform this review.

Populations
The relevant population of interest is patients with SCI at segments T4 to T12.

Generally, only SCI patients with lesions from T4 to T12 are considered candidates for ambulation systems. Lesions at T1 to T3 are associated with poor trunk stability, while lumbar lesions imply lower-extremity nerve damage.

Interventions
The therapy being considered is FES.

To date, the Parastep Ambulation System (Sigmedics) is the only noninvasive functional walking neuromuscular stimulation device to receive premarket approval from the U.S. Food and Drug Administration (FDA). The Parastep device is approved to “enable appropriately selected skeletally mature spinal cord injured patients (level C6 to T12) to stand and attain limited ambulation and/or take steps, with assistance if required, following a prescribed period of physical therapy training in conjunction with rehabilitation management of spinal cord injury.”¹

Comparators
The following therapies are currently being used to make decisions about FES for ambulation: standard of care.

Outcomes
The general outcomes of interest are functional outcomes and quality of life. The clinical impact of the Parastep device rests on the identification of clinically important outcomes. The primary purpose of this device is to provide a degree of ambulation that improves patient ability to complete the ADLs or positively affect the patient’s quality of life. Physiologic outcomes (ie, conditioning, oxygen uptake) have also been reported, but they are intermediate, short-term outcomes.

Based on available literature, longer-term outcomes would require follow-up of at least 18 months.

Study Selection Criteria
Methodologically credible studies were selected using the following principles:

• To assess efficacy outcomes, comparative controlled prospective trials were sought, with a preference for RCTs.
• In the absence of such trials, comparative observational studies were sought, with a preference for prospective studies.
• To assess long-term outcomes and adverse events, single-arm studies that capture longer periods of follow-up and/or larger populations were sought.
• Studies with duplicative or overlapping populations were excluded.

Review of Evidence
The evidence on FES for ambulation is shown in Table 16.

Chaplin (1996) reported on the largest study, which was on ambulation outcomes using the Parastep 1 and included 91 patients.²⁴ Of these 91 patients, 84 (92%) were able to take steps, and 31 (34%) were able eventually to ambulate without assistance from another person. Duration of use was not reported. Other studies on the Parastep device include a series from the same group of investigators, which focused on different outcomes in the same group of 13 to 16 patients.^{25,26,27,28,29}

Guest et al. (1997) reported on the ambulation performance of 13 men and 3 women with thoracic motor complete spinal injury.²⁸ The group’s mean peak distance walked was 334 meters, but individual studies varied widely. The mean peak duration of walking was 56 minutes, again with wide variability. Anthropomorphic measurements were taken at various anatomic locations. Increases in thigh and calf girth, thigh cross-sectional area, and calculated lean tissue were all statistically significant. The authors emphasized that the device was not intended as an alternative to a wheelchair, and thus other factors such as improved physical and mental well-being should be considered when deciding whether to use the system. Graupe and Kohn (1998) noted the same point in a review article.³⁰

Brissot et al. (2000) found that 13 of 15 patients evaluated in a case series achieved independent ambulation.³¹ Five of the 13 patients continued using the device for physical fitness at home, but none used it for ambulation. Sykes et al. (1996) found low use of a reciprocating gait orthosis device with or without stimulation over an 18-month period,³² and Davis et al. (2001) found mixed usability/preference scale results for ambulation, standing, and transfers with a surgically implanted neuroprosthesis in 12 patients followed for 12 months.³³ The effects of a surgically implanted neuroprosthesis on exercise, standing, transfers, and quality of life were also reported in 2012.^34,35 The device used in both studies was not commercially available at that time.

Several publications reported on physiologic responses to use of the Parastep device. Jacobs et al. (1997) found a 25% increase in time to fatigue and a 15% increase in peak oxygen uptake, consistent with an exercise training effect.²⁶ Needham-Shropshire et al. (1997) reported no relation between use of the Parastep device and bone mineral density, although the interval between measurements (12 weeks) and the precision of the testing device might have limited the ability to detect a difference.²⁷ Nash et al. (1997) reported that use of the Parastep device was associated with an increase in arterial inflow volume to the common femoral artery, perhaps related to the overall conditioning response to the Parastep.²⁹

Table 16. Key Case Series

SCI: spinal cord injury.

Section Summary: Ambulation in Patients With Spinal Cord Injury
The evidence on functional FES for standing and walking in patients with SCI consists of case series. Case series are considered adequate for this condition because there is no chance for ambulation in patients with SCI between segments T4 to T12. As stated by various authors, these systems are not designed as alternatives to a wheelchair and offer, at best, limited, short-term ambulation. Some studies have reported improvements in intermediate outcomes, but improvement in health outcomes (e.g., ability to perform ADLs) have not been demonstrated. Finally, evaluations of these devices were performed immediately after initial training or during limited study period durations. There are no data in which patients remained compliant and committed with long-term use.

Functional Electrical Stimulation Exercise Equipment for Spinal Cord Injuries
Clinical Context and Therapy Purpose
The U.S. Department of Health and Human Services Office of Disease Prevention and Health Promotion recommends 2 days per week of muscle strengthening for both healthy adults and adults with disabilities, and at least 150 minutes to 300 minutes (5 hours) of moderate-intensity aerobic activity per week or 75 minutes to 150 minutes of vigorous aerobic activity.³⁶ In patients with SCI, inactivity due to injury or barriers to exercise can lead to multiple degenerative changes that include muscle atrophy, bone mass loss and osteoporosis, and reduction in cardiopulmonary function. Other adverse effects of inactivity that are common with SCI include muscle spasms and weight gain, which may predispose individuals to metabolic syndrome, Type 2 diabetes, and their associated health problems.

Functional electrical stimulation cycle ergometers are available in rehabilitation facilities. An ergometer is a device that measures work performed by exercising. When the term "ergometer" is used in the context of FES, it refers to exercise equipment that measures both position and speed and stimulates muscles in a prescribed sequence to provide coordinated movement (e.g., cycling) of the paralyzed limb. The devices can provide increasing resistance as work capacity increases, and reduce stimulation when fatigue is detected (eg, a speed of cycling below 35 rpm). Some models of FES cycle ergometers have been designed for home exercise in individuals with SCI and are the focus of this evidence review.

The proposed benefit of FES exercise equipment is to counteract the health consequences of paralyzed limbs and include:

• Prevention of muscle atrophy.
• Reduction of muscle spasms.
• Improvement of circulation.
• Improvement in range of motion.
• Improvement in cardiopulmonary function.
• Reduction in pressure sore frequency.
• Improvements in bowel and bladder function.
• Decreased incidence of urinary tract infections.

Hunt et al. (2012) conducted a systematic review of the efficiency of FES cycling.³⁷ They recommended that future work address factors that limited cycling performance including the crude recruitment of muscle groups, non-optimal timing of muscle activation, lack of synergistic and antagonistic joint control, and non-physiologic recruitment of muscle fibers. The purpose of FES exercise equipment for patients who have SCI and lower extremity paresis is to provide a treatment option that is an alternative to or an improvement on existing therapies.

Three specific issues will be addressed in this evidence review:

1. Are there demonstrated health benefits of FES cycle ergometers in patients with SCI?
2. Do the different devices provide similar health benefits?
3. What levels of compliance are needed to obtain a health benefit?

The following PICO was used to select literature to inform this review.

Populations
The relevant population of interest is patients with SCI.

Interventions
The therapy being considered is FES exercise equipment.

The majority of home FES devices are cycle ergometers for the lower limbs of patients with lower extremity paresis, although some devices may also include upper arm exercise. All of the devices have evolved over the past 3 decades. Some have internet capability and can be programmed remotely.

• The REGYS and ERGYS series ergometers are manufactured by Therapeutic Alliances. These devices are the largest, include a computer console, and require transfer to an integrated seat. The ERGYS3 is a fourth generation device; earlier models continue to be utilized.
• There are several models of the RT300 by Restorative Therapies, Inc (RTI). The RT300-S includes both leg and arm cycles. This device is used with the patient's own wheelchair and does not require a transfer.
• The Myocycle Home by Myolyn is designed for home use and is the simplest of the cycle ergometers.
• The StimMaster Orion was manufactured by Electrologic. Electrologic ceased business operations in 2005.

Comparators
The following therapy is currently being used to make decisions about cycle ergometers: standard of care without home exercise equipment.

Outcomes
The general outcomes of interest are symptoms, functional outcomes, and quality of life. Specific outcomes of interest include reduction in muscle atrophy and muscle spasms, reversal of bone mass loss, improvement in circulation and cardiopulmonary function, and quality of life. These should be measured after at least 3 months of exercise in a home environment with self-directed activity, although supervised training protocols may provide useful information regarding the potential health benefits of cycle ergometers.

Study Selection Criteria
Methodologically credible studies were selected using the following principles:

• To assess efficacy outcomes, comparative controlled prospective trials were sought, with a preference for RCTs.
• In the absence of such trials, comparative observational studies were sought, with a preference for prospective studies.
• To assess long-term outcomes and adverse events, single-arm studies that capture longer periods of follow-up and/or larger populations were sought.
• Studies with duplicative or overlapping populations were excluded.

Review of Evidence
Four within-subject comparisons of health benefits of the RT300 are described in Table 17. Ralson et al. (2013) reported on the short-term effects (2 weeks) of the cycle ergometer and found no significant benefit on urine output, lower limb swelling, and spasticity compared with standard rehabilitation.³⁸ Dolbow et al. (2013) reported an improvement in quality of life on 2 of 4 domains.³⁹ However, only 11 of the original 17 participants who remained in the study after the first 8 weeks were included in this report, and this detail was not reported in the second publication.^40,39 It is notable that the incentive to remain in the study in the first 8 weeks was strong because the Veterans Affairs Medical Center purchased the devices for participants who met exercise requirements over the first 8 weeks of device rental. In the third study, Johnston et al. (2009) conducted an RCT to evaluate the health benefits of home FES cycling in children with a pediatric RT300.⁴¹ The 3 groups in this study were FES cycling, passive cycling, and electrical stimulation controls. There was no significant difference in health measures across the groups, although the FES group had a greater within-subject improvement in 1 of 4 health measures. Compliance was supervised by parents, who filled out activity logs and had regular contact with study personnel. Because this study was conducted over a decade ago, it is uncertain if newer models of the RT300 would show greater health benefits. Dolbow et al. (2021) evaluated the efficacy of FES cycling (RT300) along with nutrition counseling for 8 weeks in 10 obese adults with SCI.⁴² The participants were treated with either FES cycling plus nutrition counseling (n = 5) or nutrition counseling alone (n = 5). The cycling group completed high intensity interval cycling for 30 minutes 3 times weekly. The cycling group improved body fat and lean leg mass to a greater extent than those who received nutrition counseling alone.

Table 17. Summary of Studies on the RT300

FES: functional electrical stimulation; RCT: randomized controlled trial; SCI: spinal cord injury.

Sadowsky et al. (2013) evaluated motor and sensory recovery with long-term use of the ERGYS2.⁴³ Individuals with SCI who were treated with FES had positive outcomes on motor and sensory scores compared with individuals who did not receive FES, but the retrospective study was limited by potential for selection bias. The within-subject comparisons in Table 18 uniformly show an improvement in aerobic capacity and metabolism with training. Griffin et al. (2009) showed in their prospective study that cycling for 30 minutes, 2 to 3 times per week, for 10 weeks on the ERGYS2 resulted in improvements in a number of physiological measures of health (lean muscle mass, work capacity, glucose tolerance, insulin levels, inflammatory markers) along with an improvement in motor and sensory function.⁴⁴ These positive results are notable for the relatively short training period. A reduction in bone mass and osteoporosis is common in individuals with SCI, but no studies have demonstrated an improvement in bone mineral density. Farkas et al. (2021) compared FES leg cycling (ERGYS2) with arm cycling in 13 patients with SCI.⁴⁵ Patients exercised 5 times weekly for 16 weeks with greater improvement in exercise energy expenditure and cardiorespiratory fitness in patients exercising with arm cycling than in patients exercising with FES leg cycling. A major limitation in relevance of the studies for the present evidence review is that they do not appear to have been conducted in the home environment. The REGYS and ERGYS cycle ergometers have a bulky integrated seat and require transfer from a wheelchair, which may be a significant limitation to home use. Sustained motivation to exercise for 2 to 3 times per week outside of the investigational setting is uncertain. (See Table 18 for more study details.)

Table 18. Summary of Studies on the ERGYS2

ASIA: American Spinal Injury Association (neurological classification of SCI test battery); FES: functional electrical stimulation; SCI: spinal cord injury.

Kressler et al. (2014) conducted an analysis of data usage patterns and energy expenditure of 314 individuals over 20,183 home activity sessions with Restorative Therapies FES cycle ergometers (e.g., RT300; see Tables 19 and 20 ).^46, With use categorized into low (< 2 days/week), medium (2 to 5 days/week) and high use (at least 5 days/week), 71% of individuals with SCI were considered low users with an average of 0.9 days and 34 minutes of cycling per week. Seven of the 314 individuals were high users (2%) and 83 were medium users (27%). Kressler et al. (2014) noted that none of the users met the recommended 1000 kcals/week, with maximal weekly expenditure of 43 kcals.

Table 19. Characteristics of Studies on Home Use of Restorative Therapies Cycle Ergometers

FES: functional electrical stimulation; NR: not reported; SCI: spinal cord injury.

Table 20. Results on Home Use of Restorative Therapies Cycle Ergometers

SD: standard deviation.

Dolbow et al. (2012) assessed factors affecting compliance with recommended levels of activity on a home cycle ergometer.⁴⁰ Seventeen veterans with SCI were provided a rental RT300 and instructed to cycle continuously for 40 to 60 minutes, 3 times per week. If the participants achieved the recommended level of exercise, the Veterans Affairs Medical Center would purchase the device. Thus, there was a strong incentive to achieve the recommended level of exercise. Participants were monitored for another 8 weeks after purchase to determine if compliance remained high without the incentive, although participation in a study was also known to improve adherence. Adherence rates were 71.7% for the first 8 weeks and 62.9% for the second 8-week period (not statistically different). The odds of adhering to the exercise program in the first 8 weeks were higher in younger participants (odds ratio [OR], 4.86; p = .02), in participants who were active prior to the study (OR, 4.59; p = .02) and in participants with non-FES pain (OR, 2.22; p = .01). Level of injury, time since injury, and history of depression were not significant factors in adherence. Five older participants dropped out of the study before the second 8-week period began. The remaining participants were included in a subsequent report of the effect of the exercise on quality of life over the 8 weeks of the study.³⁹

Section Summary: Functional Electrical Stimulation Exercise Equipment for Spinal Cord Injuries
The evidence on FES exercise equipment consists primarily of within-subject, pretreatment to posttreatment comparisons. Evidence was identified on 2 commercially available FES cycle ergometer models for the home, the RT300 series and the REGYS/ERGYS series. There is a limited amount of evidence on the RT300 series. None of the within-subject studies showed an improvement in health benefits; however, improvement in body fat with RT300 was found in a small group of patients when FES high intensity interval cycling was added to nutrition counseling compared to nutritional counseling alone. One analysis of use for 314 individuals over 20,000 activity sessions with a Restorative Therapies device showed that a majority of users used the device for 34 minutes per week. Two percent of individuals with SCI used the device for an average of 6 days per week, but caloric expenditure remained low. Compliance was shown in 1 study to be affected by the age of participants and level of activity prior to the study. Studies on the REGYS/ERGYS series have more uniformly shown an improvement in physiologic measures of health and in sensory and motor function; however, a small comparative study found arm cycling to improve exercise energy expenditure and cardiorespiratory fitness to a greater extent than FES leg cycling. A limitation of these studies is that they all appear to have been conducted in supervised research centers. No studies were identified on long-term home use of ERGYS cycle ergometers. The feasibility and long-term health benefits of using this device in the home is uncertain.

The purpose of the following information is to provide reference material. Inclusion does not imply endorsement or alignment with the evidence review conclusions.

Practice Guidelines and Position Statements
Guidelines or position statements will be considered for inclusion in Supplemental Information if they were issued by, or jointly by, a U.S. professional society, an international society with U.S. representation, or National Institute for Health and Care Excellence (NICE). Priority will be given to guidelines that are informed by a systematic review, include strength of evidence ratings, and include a description of management of conflict of interest.

National Institute for Health and Care Excellence
In 2009, NICE published guidance stating that the evidence on functional electrical stimulation for foot drop of neurologic origin appeared adequate to support its use.⁴⁷ The Institute noted that patient selection should involve a multidisciplinary team. The Institute advised that further publication on the efficacy of functional electrical stimulation would be useful, specifically including patient-reported outcomes (e.g., quality of life, activities of daily living [ADL]) and these outcomes should be examined in different ethnic and socioeconomic groups.

U.S. Preventive Services Task Force Recommendations
Not applicable

Ongoing and Unpublished Clinical Trials
Some currently unpublished trials that might influence this review are listed in Table 21.

Table 21. Summary of Key Trials

NCT: national clinical trial.

References:    

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31. Brissot R, Gallien P, Le Bot MP, et al. Clinical experience with functional electrical stimulation-assisted gait with Parastep in spinal cord-injured patients. Spine (Phila Pa 1976). Feb 15 2000; 25(4): 501-8. PMID 10707398
32. Sykes L, Ross ER, Powell ES, et al. Objective measurement of use of the reciprocating gait orthosis (RGO) and the electrically augmented RGO in adult patients with spinal cord lesions. Prosthet Orthot Int. Dec 1996; 20(3): 182-90. PMID 8985998
33. Davis JA, Triolo RJ, Uhlir J, et al. Preliminary performance of a surgically implanted neuroprosthesis for standing and transfers--where do we stand?. J Rehabil Res Dev. 2001; 38(6): 609-17. PMID 11767968
34. Rohde LM, Bonder BR, Triolo RJ. Exploratory study of perceived quality of life with implanted standing neuroprostheses. J Rehabil Res Dev. 2012; 49(2): 265-78. PMID 22773528
35. Triolo RJ, Bailey SN, Miller ME, et al. Longitudinal performance of a surgically implanted neuroprosthesis for lower-extremity exercise, standing, and transfers after spinal cord injury. Arch Phys Med Rehabil. May 2012; 93(5): 896-904. PMID 22541312
36. U.S. Department of Health and Human Services Office of Disease Prevention and Health Promotion. Physical activity guidelines, second edition. https://health.gov/paguidelines/second-edition/. Accessed February 6, 2023.
37. Hunt KJ, Fang J, Saengsuwan J, et al. On the efficiency of FES cycling: a framework and systematic review. Technol Health Care. 2012; 20(5): 395-422. PMID 23079945
38. Ralston KE, Harvey L, Batty J, et al. Functional electrical stimulation cycling has no clear effect on urine output, lower limb swelling, and spasticity in people with spinal cord injury: a randomised cross-over trial. J Physiother. Dec 2013; 59(4): 237-43. PMID 24287217
39. Dolbow DR, Gorgey AS, Ketchum JM, et al. Home-based functional electrical stimulation cycling enhances quality of life in individuals with spinal cord injury. Top Spinal Cord Inj Rehabil. 2013; 19(4): 324-9. PMID 24244097
40. Dolbow DR, Gorgey AS, Ketchum JM, et al. Exercise adherence during home-based functional electrical stimulation cycling by individuals with spinal cord injury. Am J Phys Med Rehabil. Nov 2012; 91(11): 922-30. PMID 23085704
41. Johnston TE, Smith BT, Mulcahey MJ, et al. A randomized controlled trial on the effects of cycling with and without electrical stimulation on cardiorespiratory and vascular health in children with spinal cord injury. Arch Phys Med Rehabil. Aug 2009; 90(8): 1379-88. PMID 19651272
42. Dolbow DR, Credeur DP, Lemacks JL, et al. Electrically induced cycling and nutritional counseling for counteracting obesity after spinal cord injury: A pilot study. J Spinal Cord Med. Jul 2021; 44(4): 533-540. PMID 31971487
43. Sadowsky CL, Hammond ER, Strohl AB, et al. Lower extremity functional electrical stimulation cycling promotes physical and functional recovery in chronic spinal cord injury. J Spinal Cord Med. Nov 2013; 36(6): 623-31. PMID 24094120
44. Griffin L, Decker MJ, Hwang JY, et al. Functional electrical stimulation cycling improves body composition, metabolic and neural factors in persons with spinal cord injury. J Electromyogr Kinesiol. Aug 2009; 19(4): 614-22. PMID 18440241
45. Farkas GJ, Gorgey AS, Dolbow DR, et al. Energy Expenditure, Cardiorespiratory Fitness, and Body Composition Following Arm Cycling or Functional Electrical Stimulation Exercises in Spinal Cord Injury: A 16-Week Randomized Controlled Trial. Top Spinal Cord Inj Rehabil. 2021; 27(1): 121-134. PMID 33814890
46. Kressler J, Ghersin H, Nash MS. Use of functional electrical stimulation cycle ergometers by individuals with spinal cord injury. Top Spinal Cord Inj Rehabil. 2014; 20(2): 123-6. PMID 25477734
47. National Institute for Health and Care Excellence (NICE). Functional electrical stimulation for drop foot of central neurological origin [IPG278]. 2009; http://www.nice.org.uk/nicemedia/pdf/IPG278Guidance.pdf. Accessed February 6, 2023.
48. Centers for Medicare & Medicaid Services. National Coverage Determination (NCD) for Neuromuscular Electrical Stimulaton (NMES) (160.12). 2006; https://www.cms.gov/medicare-coverage-database/details/ncd- details.aspx?NCDId = 175&ncdver = 2&DocID = 160.12&SearchType = Advanced&bc = IAAAABAAAAAA&. Accessed February 5, 2023.

Coding Section 

Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each policy. They may not be all-inclusive. 

This medical policy was developed through consideration of peer-reviewed medical literature generally recognized by the relevant medical community, U.S. FDA approval status, nationally accepted standards of medical practice and accepted standards of medical practice in this community, Blue Cross Blue Shield Association technology assessment program (TEC) and other nonaffiliated technology evaluation centers, reference to federal regulations, other plan medical policies, and accredited national guidelines.

"Current Procedural Terminology © American Medical Association. All Rights Reserved" 

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