This document addresses uses of functional electrical stimulation (FES) and threshold electrical stimulation (TES).  Functional electrical stimulation (FES) is used to improve functional activity in neurologically impaired individuals, including those with spinal cord injury and stroke.

Threshold (or therapeutic) electrical stimulation (TES), which involves the delivery of low intensity electrical stimulation (typically at night), has been investigated as a treatment of scoliosis. 

Note: FES has been used to treat or prevent muscle disuse atrophy in individuals with neurologic impairment.  However, the use of electrical stimulation for the same indication in individuals without neurologic injury (typically in the postoperative setting) is addressed in the following document:

• CG-DME-03 Neuromuscular Stimulation in the Treatment of Muscle Atrophy

Investigational and Not Medically Necessary:

Functional electrical stimulation (FES), when used to prevent or reverse muscular atrophy (wasting) and bone demineralization (loss), by stimulating paralyzed limbs for the performance of stationary exercise, or to correct gait disorders, is considered investigational and not medically necessary.This includes, but is not limited to, functional electrical stimulation ergometer devices (e.g. ERGYS^® and ERGYS^® 2). 

Functional electrical stimulation (FES), when used to promote ambulation (e.g., Parastep^® I System), is considered investigational and not medically necessary.

Functional electrical stimulation (FES), when used to activate muscles of the upper limb or lower limb to produce functional movement patterns is considered investigational and not medically necessary for all indications. This includes, but is not limited to, the Handmaster™, NESS H200^® Hand Rehabilitation System, NESS L300™ Foot Drop System, ODFS Dropped Foot Stimulator, and the WalkAide^® System. 

Threshold electrical stimulation (TES) as a treatment of motor disorders, including, but not limited to, cerebral palsy or scoliosis, is considered investigational and not medically necessary.

General Considerations: Functional Electrical Stimulation 

By definition, functional electrical stimulation (FES) is designed to stimulate muscles and thus improve the function of the extremities. FES has primarily been investigated in individuals with neurologic impairment, most prominently following spinal cord injury, stroke or multiple sclerosis. The stimulation can directly improve function utilizing devices intended to restore ambulation in the lower extremity or dexterity and function in the upper extremity; or devices to indirectly improve function, such as exercise devices adapted to FES that are designed to prevent or treat muscle disuse atrophy. The majority of these devices use surface electrodes, but intramuscular electrodes have also been used. Standard therapy in individuals with neurologic impairment includes active and passive physiotherapy and the use of various braces and orthoses. Therefore, studies were reviewed that investigate the outcomes of FES compared to these standard therapies.

Functional Electrical Stimulation to Prevent Muscular Atrophy and Bone Demineralization

A variety of devices use electrical muscle stimulation technology as a means of physical therapy and exercise for individuals with spinal cord injury, stroke or other neurological disorders. These devices may be referred to as functional neuromuscular exercisers or powered muscle stimulators. For treatment of the lower extremities, FES has been incorporated into an exercycle. For example, the legs are wrapped in fabric strips that contain electrodes to stimulate the muscles, thus permitting the individual to pedal. The resulting exercise is designed to prevent muscular atrophy and bone demineralization. The key outcome in the evaluation of these devices is whether the use of electrical stimulation permitting active exercise provides clinically significant incremental improvements compared to passive devices used for the same purpose.

Janssen and colleagues (2008) randomized 12 post-stroke individuals to receive cycling exercise with and without FES. Outcome measures included aerobic capacity, functional performance and lower limb strength. There was no significant difference reported between the two groups. Other studies of FES-equipped exercycles consist of small case series where the exercycle is used for a limited time as part of a rehabilitation program. No randomized controlled studies were identified that reported the outcomes of long term use of the FES-equipped exercycle in the home.

In a two-year longitudinal prospective study, Kern and colleagues (2010) attempted to confirm the results of the European Project RISE study. Muscle mass, force, and structure were determined before and after use of a home-based FES (h-bFES) using computed tomography, measurements of knee torque during stimulation, and muscle biopsy analysis in individuals (n=25) with complete conus and cauda equina spinal cord lesions. Five of the original 25 participants dropped out from the final study results. A cross-sectional increase in area of the quadriceps muscle from 28.2 plus/minus 8.1 to 38.1 plus/minus 12.7 cm² (p<0.001), a 75% increase in the mean diameter of muscle fibers from 16.6 plus/minus 14.3 to 29.1 plus/minus 23.3 µm (p<0.001), and an increase in force output during electrical stimulation (p<0.001) was reported. However, limited "measurable" knee torque changes in h-bFES trained muscles were evident. Complete lower extremity denervation remained before initiation, during and after the two years of training with the h-bFES. 

Functional Electrical Stimulation to Restore Ambulation

The clinical impact of the FES devices to provide ambulation rests on identification of clinically important outcomes. For example, the primary outcome of the Parastep device (Sidmedics, Inc., Fairborn, Ohio), and the main purpose of its design, is to provide a degree of ambulation that improves the individual's ability to complete the activities of daily living, seek employment, or positively affect the individual's quality of life. Physiologic outcomes (i.e., conditioning, oxygen uptake, etc.) have also been reported, but these are intermediate, short-term outcomes, and it is not known whether similar or improved results could be attained with other training methods. In addition, the results are reported for mean peak values, which may or may not be a consistent result over time. The effect of the Parastep on physical self-concept and depression are secondary outcomes and similar to the physiologic outcomes; interpretation is limited due to lack of comparison with other forms of training.

The largest study of the Parastep device was conducted by Chaplin and colleagues (1996) who reported on the ambulation outcomes using the Parastep I in 91 individuals. Of these 91 individuals, 84 (92%) were able to take steps and 31 (34%) were able to eventually ambulate without assistance from another person. Duration of use was not reported. Other studies of the Parastep device include a series of five studies from the same group of investigators, which focused on different outcomes in the same group of 13 to 15 individuals. For example, Jacobs and colleagues (1997) reported on physiologic responses related to use of the Parastep device. There was a 25% increase in time to fatigue and a 15% increase in peak values of oxygen uptake, consistent with an exercise training effect. There were no significant effects on arm strength. Needham-Shropshire and colleagues (1997) reported no relationship between use of the Parastep device and bone mineral density, although the time interval between measurements (12 weeks) and the precision of the testing device may have limited the ability to detect a difference. Nash and colleagues (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. Finally, Guest and colleagues (1997) reported on the ambulation performance of 13 men and three women with thoracic motor complete spinal injury. All individuals underwent 32 training sessions prior to measuring ambulation. The group's mean peak distance walked was 334 meters, but there was wide variability, as evidenced by a standard deviation of 402 meters. The mean peak duration of walking was 56 minutes, again with wide variability, evidenced by a standard deviation of 46 minutes. It should be noted that peak measures reflect the best outcome over the period evaluated; peak measures may be an inconsistent, one-time occurrence for the specific individual. The participants also underwent anthropomorphic measurements of various anatomic locations. Increases in thigh and calf girth, thigh cross-sectional area, and calculated lean tissue were all statistically significant. The authors emphasize that the device is not intended to be an alternative to a wheelchair, and thus other factors such as improved physical and mental well-being should be considered when deciding whether or not to use the system. The same limitations were noted in a review article by Graupe and Kohn (1998), who state that the goal for ambulation is for individuals to get out of the wheelchair at will, stretch, and take a few steps every day.

Finally, it should be noted that evaluations of the Parastep device were performed immediately following initial training or during limited study period durations. There is limited data regarding whether individuals remain compliant and committed with long-term use. Brissot and colleagues (2000) reported independent ambulation was achieved in 13 of 15 individuals, with two individuals withdrawing from the study. In the home setting, five of the 13 individuals continued using the device for physical fitness, but none used it for ambulation.

In summary, studies of the Parastep FES device used for ambulation demonstrate the device is associated with improvements in the intermediate outcomes of a variety of physiologic outcomes. However, there is inadequate data to show that these benefits exceed those offered by non-functional (passive) stimulation approaches. While device users can stand and walk short distances, there is inadequate data to show whether this results in clinically significant improvements in activities of daily living, and inadequate results to demonstrate that individuals consistently use the device over the long term. In addition, FES can expose the subject to significant risks such as falls, sprains and bone fractures.

Reciprocating gait orthoses consist of a rather cumbersome hip-knee-ankle-foot device linked together with a cable at the hip joint. These orthoses have been used in conjunction with FES as a hybrid device to reduce the energy requirement of walking. The literature includes a number of studies; one compared use of the orthosis with and without FES (Sykes, 1996). The study included only five subjects and concluded that there was no significant difference in energy requirement between the two devices. Solomonow and colleagues (1997) published two case series of 70 individuals which studied ambulation performance (Part I) and physiological outcomes (Part II). Of the 70 individuals who completed an initial 14 week training period, 41 continued to use the orthosis at home on a long term basis. Eighty percent of these reported that they were regular users of the device. The authors concluded that the device could restore standing and limited walking in carefully selected paraplegics. This study has not been followed by any additional studies, and it appears that reciprocating gait orthoses have not been widely accepted.

FES has also been investigated using intramuscular electrodes. For example, Johnston and colleagues (2003) investigated intramuscular electrodes placed to stimulate hip and knee extension, and hip abduction and adduction, which were used in conjunction with various orthoses. The technique was investigated in seven children with spinal cord injury. The individuals reported improvements in time to complete tasks and level of independence.  The authors concluded that the use of intramuscular electrodes was feasible. Other reports of this technique similarly consist of small case series.

Seifart and colleagues (2009) conducted a systematic review of the literature (three case reports, one single subject and one crossover design study were eligible for review of the 37 available citations) to "assess and synthesize the existing evidence regarding the use of functional electrical stimulation in children and adolescents with CP (cerebral palsy) when applied to the lower limb." FES application to either the triceps sura muscle alone or in combination with the tibialis anterior muscle was favorable. Although the studies suggested that FES had a positive effect on gait and function, the review concluded the analysis was difficult due to the wide variety of application methods, stimulation protocol, and outcome measures.

Other Applications of Functional Electrical Stimulation

Elbow, Hand, and Shoulder

FES of the shoulder has been incorporated into post-rehabilitation primarily as a technique to reduce shoulder pain that is commonly associated with hemi- or paraplegia secondary to stroke or spinal cord injury. The effectiveness of FES has also been investigated with bilateral activities training on upper limb function in individuals with chronic stroke. Similar to the shoulder, key outcomes focus on a comparison of function of those treated with physiotherapy with and without FES. In a double-blind randomized controlled trial, Chan and colleagues (2009) evaluated 20 individuals, six months after the onset of stroke to receive 15 training sessions of stretching activities, FES with bilateral tasks, and occupational therapy treatment. The outcome measures included Functional Test for the Hemiplegic Upper Extremity (FTHUE), Fugl-Meyer Assessment (FMA), grip power, forward reaching distance, active range of motion of wrist extension, Functional Independence Measure, and Modified Ashworth Scale. At baseline comparison, there was no significant difference in both groups. After 15 training sessions, the FES group had significant improvement in FMA (p=.039), FTHUE (p=.001), and active range of motion of wrist extension (p=.020) when compared with the control group. The authors concluded that bilateral upper limb training with FES could be an effective method for upper limb rehabilitation of post-stroke individuals after 15 training sessions. This trial is limited in its application by the small sample size, short duration of treatment, and lack of long-term outcome measures.

Ring and Rosenthal (2005) reported on a case series of 22 individuals with moderate to severe limb paresis three to six months following stroke. Participants were categorized into those with or without active finger movements and then randomized to receive either FES (Handmaster™, NESS Neuromuscular Electrical Stimulation Systems Ltd., Raanana, Israel) or standard physiotherapy. The FES group had greater improvements in spasticity, active range of motion and functional hand scores. Interpretation of this study is limited by its small size. The largest study identified consisted of a historical cohort study of 110 individuals with chronic stroke (Meijer, 2009). Participants were evaluated before and after a six week "try-out" period of the Handmaster device, and then again after a four week "withhold" period to determine the durability of any initial response. A prescription for long term use was based on positive responses (primarily a reduction in hypertonia) during the initial trial period followed by relapse in the "withhold" period. Individuals prescribed a device for long term use were sent a questionnaire investigating the actual use of the device. Users were defined as those using the device for at least 15 minutes on a daily basis. Everyone else was categorized as a non-user. Of the 147 potential participants, 110 met the criteria and agreed to participate; 86 (76%) were categorized as users. Given the high percentage of continued use, the authors concluded that the initial short term benefit used as participant selection criterion predicted long term use. Interpretation of this study is limited by the retrospective study design, including the lack of a controlled group or comparison to standard physical therapy.

Other studies consisted of small case series; no study had more than 20 participants (Alon, 2003; Hendricks, 2001; Santos, 2006; Snoek, 2000; Sullivan, 2007; Weingarden, 1998).  

Lower Extremity

Foot drop is weakness of the foot and ankle that causes reduced dorsiflexion and difficulty with ambulation. It can have various causes such as stroke or nerve injury. Treatment typically consists of an ankle foot orthosis or another type of limb brace. These devices are designed to provide stability. In contrast, FES devices are designed to improve function by enabling the foot to be raised during the swing phase of ambulation.  

In a small comparative study, Ring and colleagues (2009) compared the effects of a radio frequency-controlled neuroprosthesis on gait stability and symmetry to the effects obtained with a standard ankle-foot orthosis (AFO) in 15 individuals with prior chronic hemiparesis resulting from stroke or traumatic brain injury whose walking was impaired by foot drop and regularly used an AFO. After a four-week adaptation period, there were no differences between walking with the neuroprosthesis and walking with the AFO (p>.05). After eight weeks, there was no significant difference in gait speed, whereas stride time improved from 1.48 seconds (plus or minus 0.21 seconds) with the AFO to 1.41 seconds (plus or minus 0.16 seconds) with the neuroprosthesis (p<.02). Swing time variability decreased from 5.3% (plus or minus 1.6%) with the AFO to 4.3% (plus or minus 4%) with the neuroprosthesis (p=.01). A gait asymmetry index improved by 15%, from 0.20 (plus or minus 0.09) with the AFO to 0.17 (plus or minus 0.08) with the neuroprosthesis (p<.05). The authors concluded that compared with AFO, the studied neuroprosthesis appears to enhance balance control during walking and, thus, more effectively managed foot drop. Additional study is required involving larger sample populations that measure long-term outcomes.

Hausdorff and Ring (2008) studied 24 individuals with hemiparesis whose ambulation was impaired due to foot drop. Subjects walked for six minutes with and without an FES device using surface electrodes. Additional assessments while using the FES device were conducted at four and eight weeks. A gait asymmetry index significantly improved at initial evaluation (i.e. with the six minute walk test and after eight weeks). Walking speed and stride time also significantly improved at the two time periods. This study is limited by a small number of participants.  

Kottink and colleagues (2007) reported on a trial of 29 individuals with stroke who were randomized to receive either an implantable peroneal nerve stimulator or usual care group consisting of either an orthoses or no specific therapy. The primary outcome measure was walking speed assessed by a six minute walk test, which improved by 23% in the FES group. Interpretation of this study is limited by its small size. The second study included 32 post-stroke individuals who were randomized to FES or a control group receiving physiotherapy (Daly, 2006). There was no significant difference in walking distance between the two groups.

The largest case series was reported by Taylor and colleagues (1999) who retrospectively evaluated 151 individuals who had used the OdStock Dropped Foot Stimulator (ODFS) device (Odstock Medical Limited, Salisbury, Wiltshire, UK; NDI Medical, Cleveland, OH) for a minimum of 4.5 months. There was a 12% increase in walking speed and a decrease in effort by 12%. Pomeroy and colleagues (2006) completed a systematic review and meta-analysis of electrical stimulation in the post stroke setting. The review included randomized controlled trials of electrostimulation delivered to the peripheral neuromuscular system which was designed to improve voluntary movement control, functional motor ability and activities of daily living. A total of 24 trials were reviewed. The authors concluded that "at present, there are insufficient robust data to inform clinical use of electrostimulation for neuromuscular re-training. Research is needed to address specific questions about the type of electrostimulation that might be most effective, in what dose and at what time after stroke."

In a small randomized crossover trial conducted in an outpatient rehabilitation clinic setting, Embrey and colleagues (2010) attempted to evaluate whether FES timed to activate the dorsiflexors and plantar flexors during gait improved the walking of adults with hemiplegia. Twenty-eight adults with hemiplegia completed three months of intervention "A" (wearing the FES system for a specified time during walking) or "B" (walking without the FES system). Crossover occurred at three months, with the A-B group continuing to walk but without receiving FES. Outcomes were measured without electrical stimulation at pretreatment, three months, and six months. In phase one, participants who received treatment A (A-B group) showed improvement compared with participants who received treatment B (B-A group) on a six-minute walk test (p=0.02), Emory Functional Ambulatory Profile (p=0.08), and Stroke Impact Scale (p=0.03). In phase two, the A-B group maintained improvement in all three primary outcomes even without FES; however, the carryover improvements were not statistically different from their performance at crossover. Both groups improved significantly on all primary outcome measures when initial measurements were compared to measurements at six-months (p≤0.05). This study however, is limited in drawing conclusions due to the small number of participants, crossover at three months, and short-term follow-up.

Additional small randomized controlled and comparative trials have evaluated the use of FES to reduce ankle spasticity or improve muscle strength, walking ability and metabolic responses in the management of drop foot in individuals with post-stroke hemiparesis (Cheng 2010; Sabut, 2010a; Sabut, 2010b). Limitations of these studies include small participant populations, lack of blinding to treatment, and short-term follow-up.

Barrett and colleagues (2009) investigated the effects of FES and therapeutic exercise on walking performance in a  two-group randomized trial (n=44) assessing the effects of single channel common peroneal nerve stimulation on objective aspects of gait relative to exercise therapy for persons with secondary progressive multiple sclerosis (SPMS) and unilateral foot drop. Twenty individuals were randomly allocated to a group receiving FES and the remaining 24 to a group receiving a physiotherapy home exercise program for a period of 18 weeks. The exercise group showed a statistically significant increase in walking speed and distance walked in three minutes, relative to the FES group who showed no significant change in walking performance without stimulation. At each stage of the trial, the FES group performed to a significantly higher level with FES than without for the same outcome measures. The investigators concluded that exercise may provide a greater training effect on walking speed and endurance than FES for persons with SPMS. FES may provide an orthotic benefit when outcome is measured using the same parameters. However, more research is required to investigate the combined therapeutic effects of FES and exercise for this particular group of individuals.

A small randomized controlled trial (n=24) investigated the use of FES in multiple sclerosis (Paul, 2008). Although the results of this study suggested that FES had a beneficial effect, the authors agreed that additional, larger trials were needed to support the outcomes. Esnouf and colleagues (2010) measured participant satisfaction and improvement in activities of daily living in a small randomized controlled trial of 64 people with multiple sclerosis with unilateral dropped foot. The authors concluded that highest gains in satisfaction scores were recorded with improvements in being able to walk further while using the ODFS device, however, there was no training effect recorded over the period of the intervention, and "the long-term training benefit recorded by the exercise group may not have impacted on the activities of daily living to the same extent as the more immediate assistance provided by the ODFS." Limitations of this study include the small number of subjects reporting similar problems in each performance measure category (i.e. tripping, climbing stairs, balance, walking distance, and steps and curbs) and a 17% participant drop-out rate. 

Stein and colleagues (2010) compared the orthotic and therapeutic effects of the WalkAide (Innovative Neurotronics, Austin, TX) stimulator on walking performance of subjects with chronic nonprogressive (n=41, with stroke, spinal cord injury, head injury, or cerebral palsy) and progressive (n=32, with secondary progressive multiple sclerosis or familial spastic paraparesis) disorders resulting in foot drop. After three months of FES use, the nonprogressive and progressive groups had a similar, significant orthotic effect (5.0% and 5.7%, respectively, p<0.003; percentage change in mean values) and therapeutic effect with FES off (17.8% and 9.1%, respectively, p<0.005) on figure-8 walking speed. The therapeutic effect on figure-8 speed diverged later between both groups to 28.0% (p< 0.001) and 7.9% at 11 months. While the nonprogressive group continued to increase speed with and without stimulation, a plateau of gait speed with a tendency to a decline in speed occurred in the progressive group as a whole. The authors suggested that the decrease in walking speed may have resulted from weakening of other muscle groups that were not being stimulated. There was a significant difference in the use of the WalkAide by the progressive group compared to the nonprogressive group (p=0.037). The study limitations include the small heterogeneous participant population, lack of randomization and a control group, and short-term follow-up.

Following the Stein (2010) study, Everaert and colleagues (2010) conducted a small study on a subgroup (n=36) of the participant population to determine the effect of long-term use of the WalkAide on "residual corticospinal connections in those with central nervous system disorders." Ten participants with nonprogressive disorders (e.g. stroke) and 26 with progressive disorders (e.g. multiple sclerosis) used the WalkAide for three to 12 months. Significant improvement was reported in walking speed with the WalkAide stimulator off in both the nonprogressive group (24%) and the progressive group (7%) (p= 0.008 and p=0.014, respectively). The authors concluded that increases in maximum voluntary contraction (MVC) and motor-evoked potential (MEP) suggest that regular use of the WalkAide may explain the improved voluntary control over the tibialis anterior muscle and a therapeutic effect on walking speed.

In 2009, the National Institute for Health and Clinical Excellence (NICE) published an overview and guidance document for FES specifically for foot drop. This review included the three randomized trials discussed above and three additional case series. The authors commented that protocols, outcomes and participant selection criteria varied across the studies. Additionally, improvements in physiologic outcome may be poor predictors of functional improvement. 

Finally, there is limited evidence about quality of life and impact of the procedure on disability. A search of the clinical trials database identified several ongoing controlled studies of FES for foot drop. A large study of 170 individuals with hemiparesis and foot drop were randomized to the ODFS FES device or usual care for 12 weeks (NICHD, 2010). The focus of this trial is to determine if a limited period of FES can facilitate motor relearning and improve the mobility and quality of life of stroke survivors.

Threshold Electrical Stimulation

Threshold electrical stimulation (TES) as a treatment of scoliosis was widely investigated and enjoyed some popularity in the 1980s. However, retrospective studies suggested that the outcomes associated with electrical stimulation were not significantly different than the natural history of scoliosis. In 1995, Nachemson and Peterson published the results of a prospective study comparing the outcomes of bracing and electrical stimulation to those of untreated individuals. While those treated with bracing reported improved results, those treated with electrical stimulation did not. Since that time many scoliosis experts have abandoned electrical stimulation.

Studies conflict as to whether TES shows net benefit as a treatment for cerebral palsy (CP) and other motor disorders. One randomized controlled trial of individuals with CP, who had previously undergone selective rhizotomy, appeared to depict a net improvement in motor function from TES (Steinbock, 1997); however, other randomized controlled trials using TES in individuals with CP failed to show any objective clinical benefit (Kerr, 2006; Steinbock, 1997). Cauraugh and colleagues (2010) conducted a recent systematic review and meta-analysis using the International Classification of Functioning to determine the summary effect of electrical stimulation on impairment and activity limitations relevant to gait problems of children with cerebral palsy. The authors cited reservation about recommending electrical stimulation as an efficacious intervention for individuals with cerebral palsy. Outside of the laboratory-testing experiments, "no quantitative, functional immediate or longitudinal effects beyond the testing situations were reported in the studies. Thus, long-term effects of various types of electrical stimulation on gait challenges in children with cerebral palsy would advance our understanding."

General Background: Functional Electrical Stimulation (FES)

Functional electrical stimulation attempts to replace stimuli from destroyed nerve pathways with computer-controlled sequential electrical stimulation of muscles to enable individuals with spinal cord injury or stroke to function independently, or at least maintain healthy muscle tone and strength. This is in contrast to the use of neuromuscular stimulation for disuse atrophy when the nerve supply to the muscle is intact.

Functional Electrical Stimulation: Devices Used to Prevent or Treatment Muscle Atrophy and Bone Demineralization

The ERGYS (Therapeutic Alliances Inc., Fairborn, Ohio) is a medical device categorized as a powered muscle stimulator by the FDA. Computer generated, low-level electrical pulses transmitted through surface electrodes cause coordinated contractions of the large muscles of the legs. Sensors located in the ERGYS provide continuous feedback to a computer which controls the sequence of muscle contractions as well as the resistance to pedaling.

Functional Electrical Stimulation: Devices Used for Ambulation

The Parastep Ambulation System (Parastep I) is an ambulation FES device approved by the U.S. Food and Drug Administration (FDA) in 1994. The premarket approval (PMA) document states the Parastep-I device "enables appropriately selected skeletally mature spinal cord injured individuals (level C6-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." According to the device manufacturer, the system is designed to provide up to six channels of stimulation, stimulating up to three muscle groups on the side of each leg. Some individuals may require only four channels of stimulation to stand and ambulate, where electrical stimulation is directed to four electrodes on each lower extremity. Stimulation of the quadriceps muscles results in knee extension, enabling the user to stand. Stimulation of the peroneal nerve in the lower extremity initiates a triple-flexion reflex response, resulting in contraction of muscles to flex the hip, knee, and ankle, which lifts the foot off the floor. Subsequent quadriceps stimulation extends the knee in preparation for heel-strike and weight bearing. When six channels of stimulation are used, electrical stimulation is directed to the previously mentioned sites and to two additional electrodes on each hip. Stimulation of gluteal muscles extends the hips, contributing to stability while standing and taking steps. In addition, the individual uses a walker or elbow-support crutches for further support. The electrical impulses are controlled by a computer microchip attached to the individual's belt that synchronizes and distributes the signals. Finally, there is a finger-controlled switch that permits activation of the stepping device by the individual.

Other devices include a reciprocating gait orthosis (RGO) with electrical stimulation. The orthosis used is a rather cumbersome hip-knee-ankle-foot device linked together with a cable at the hip joint. FES has been adapted to use with the RGO as a hybrid device.

Functional Electrical Stimulation: Devices Used for Other Indications

Devices used to treat foot drop include the WalkAide, the NESS L300 Foot Drop System (Bioness Ltd, Valencia, CA), and the ODFS Dropped Foot Stimulator. The devices consist of a gait sensor, leg cuff and hand held control. When the heel lifts, signals from the gait sensor are sent to the stimulation unit in the leg cuff that stimulates the common peroneal nerve that innervates the tibialis anterior muscles, which in turn lifts the foot while walking. The WalkAide device first received 510(k) marketing clearance from the FDA in the 1990s with subsequent upgrades to the system. The Bioness NESS L300 received 510(k) marketing clearance in July 2006. The ODFS Dropped Foot Stimulator received 510(k) marketing clearance on July 15, 2005. The FDA summaries for these devices state that they are intended for use in individuals with drop foot by assisting with ankle dorsiflexion during the swing phase of gait.

There are multiple FDA 510K approvals for functional neuromuscular stimulators for use on the hand and forearm. These include the NESS Neuromuscular Electrical Stimulation Systems Handmaster (K010837, K012823, K031900). The FDA has also approved the NESS System Powered Muscle Stimulator (K022776) for use at sites on the limbs other than the hand. The NESS Systems are portable, one-channel electrical neuromuscular stimulators. The stimulators are powered by rechargeable batteries. Surface electrodes are held on to the limb by a splint. Electrical stimulation is delivered to the muscles through the surface electrodes. The NESS H200 Hand Rehabilitation System (Bioness Ltd, Valencia, CA) (device formerly known as the Handmaster) is designed to stimulate the extensor and flexor muscle of the forearm as well as the ulnar muscle of the hand. The stimulation is intended to provide hand active range of motion and hand function for individuals with upper limb paralysis due to C5 spinal cord injury or hemiplegia due to stroke.

Threshold Electrical Stimulation

Threshold (or therapeutic) electrical stimulation involves the delivery of low intensity electrical stimulation (typically at night) and has been investigated as a treatment of scoliosis. Stimulation is applied to the convex side of the curvature in order to evoke muscle contractions causing curvature correction. Electrical stimulation may be one component of an overall non-surgical treatment program for scoliosis. For example, the Scoliosis Treatment Recovery System, which includes the Copes Scoliosis Dynamic Brace, also includes electrical stimulation as part of the treatment program. For individuals with cerebral palsy, threshold electrical stimulation is designed to increase muscle strength and joint mobility leading to improved voluntary motor function.

Cerebral palsy: A persistent qualitative motor disorder appearing before the age of three years due to non-progressive damage to the brain.

Disuse atrophy: A wasting or loss of size of a part of the body because of disease or other influences.

Functional electrical stimulation (FES): A rehabilitation technique where a low-level electrical current is applied to muscles of a neurologically impaired individual in an attempt to replace stimuli from destroyed nerve pathways and enhance that person's ability to maintain healthy muscle tone and strength to function independently.

Scoliosis: A congenital lateral curvature of the spine.

Threshold (or therapeutic) electrical stimulation (TES): A form of low-intensity electrical stimulation that attempts to strengthen muscles weakened by non-use.

The following codes for treatments and procedures applicable to this document are included below for informational purposes.  Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy.  Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member. 

Functional Electrical Stimulators
When services are Investigational and Not Medically Necessary: 

Threshold Electrical Stimulators
When services are Investigational and Not Medically Necessary:

Future ICD-10 coding (effective 10/01/2013)
A draft of ICD-10 Coding related to this document, as it might look today, is available for reference and comments at: Appendix 1: Future ICD-10 coding

Peer Reviewed Publications:

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9. Daly, JJ, Roenigk K, Holcomb J, et al. A randomized controlled trial of functional neuromuscular stimulation in chronic stroke subjects. Stroke. 2006; 37(1):172-178.
10. Embrey DG, Holtz SL, Alon G, et al. Functional electrical stimulation to dorsiflexors and plantar flexors during gait to improve walking in adults with chronic hemiplegia. Arch Phys Med Rehabil. 2010; 91(5):687-696.
11. Esnouf JE, Taylor PN, Mann GE, Barrett CL. Impact on activities of daily living using a functional electrical stimulation device to improve dropped foot in people with multiple sclerosis, measured by the Canadian Occupational Performance Measure. Mult Scler. 2010; 16(9):1141-1147.
12. Everaert DG, Thompson AK, Chong SL, Stein RB. Does functional electrical stimulation for foot drop strengthen corticospinal connections? Neurorehabil Neural Repair. 2010; 24(2):168-177.
13. Graupe D, Kohn KH. Functional neuromuscular stimulator for short-distance ambulation by certain thoracic-level spinal-cord-injured paraplegics. Surg Neurol. 1998; 50(3):202-207.
14. Guest RS, Klose J, Needham-Shropshire BM, et al. Evaluation of a training program for persons with SCI paraplegia using the Parastep^®1 Ambulation System: part 4. Arch Phys Med Rehabil. 1997; 78(8):804-807.
15. Hausdorff JM, Ring H. Effects of a new radio frequency-controlled neuroprosthesis on gait symmetry and rhythmicity in patients with chronic hemiparesis. Am J Phys Med Rehabil. 2008; 87(1):4-13.
16. Hendricks HT, IJzerman MJ, de Kroon JR, et al. Functional electrical stimulation by means of the 'Ness Handmaster Orthosis' in chronic stroke patients: an exploratory study. Clin Rehabil. 2001; 15(2):217-220.
17. Jacobs PL, Nash MS, Klose KJ, et al. Evaluation of a training program for persons with SCI paraplegia using the Parastep 1 ambulation system: part 2. Effects on physiologic responses to peak arm ergonometry. Arch Phys Med Rehabil. 1997; 78(8):794-798.
18. Janssen TW, Beltman JM, Elich P, et al. Effects of electric stimulation-assisted cycling training in people with chronic stroke. Arch Phys Med Rehabil. 2008; 89(3):463-469.
19. Johnston TE, Betz RR, Smith BT, Mulcahey MJ. Implanted functional electrical stimulation: an alternative for standing and walking in pediatric spinal cord injury. Spinal Cord. 2003; 41(3):144-152.
20. Kern H, Carraro U, Adami N, et al. Home-based functional electrical stimulation rescues permanently denervated muscles in paraplegic patients with complete lower motor neuron lesion. Neurorehabil Neural Repair. 2010; 24(8):709-721.
21. Kerr C, McDowell B, Cosgrove A, et al. Electrical stimulation in cerebral palsy: a randomized controlled trial. Dev Med Child Neurol. 2006; 48(11):870-876.
22. Kottink AI, Hermens HJ, Nene AV, et al. A randomized controlled trial of an implantable 2-channel peroneal nerve stimulator on walking speed and activity in poststroke hemiplegia. Arch Phys Med Rehabil. 2007; 88(8):971-978.
23. Meijer JW, Voerman GE, Santegoets KM, Geurts AC. Short-term effects and long-term use of hybrid orthosis for neuromuscular electrical stimulation of the upper extremity in patients after chronic stroke. J Rehabil Med. 2009; 41:157-161.
24. Nash MS, Jacobs PL, Montalvo BM, et al. Evaluation of a training program for persons with SCI paraplegia using the Parastep^®1 Ambulation System: part 5. Arch Phys Med Rehabil. 1997; 78(8):808-814.
25. Needham-Shropshire BM, Broton JG, Klose KJ, et al. Evaluation of a training program for persons with SCI paraplegia using the Parastep^®1 Ambulation System: Part 3. Arch Phys Med Rehabil. 1997; 78(8):799-803.
26. Paul L, Rafferty D, Young S, et al. The effect of functional electrical stimulation on the physiologic cost of gait in people with multiple sclerosis. Multiple Sclerosis. 2008; 14: 954-961.
27. Ring H, Rosenthal N. Controlled study of neuroprosthetic functional electrical stimulation in sub-acute post-stroke rehabilitation. J Rehabil Med. 2005; 37(1):32-36.
28. Ring H, Treger I, Gruendlinger L, Hausdorff JM. Neuroprosthesis for footdrop compared with an ankle-foot orthosis: effects on postural control during walking. J Stroke Cerebrovasc Dis. 2009; 18(1):41-47.
29. Sabut SK, Lenka PK, Kumar R, Mahadevappa M. Effect of functional electrical stimulation on the effort and walking speed, surface electromyography activity, and metabolic responses in stroke subjects. J Electromyogr Kinesiol. 2010a; 20(6):1170-1177.
30. Sabut SK, Sikdar C, Mondal R, Kumar R, Mahadevappa M. Restoration of gait and  motor recovery by functional electrical stimulation therapy in persons with stroke. Disabil Rehabil. 2010b; 32(19):1594-1603.
31. Santos M, Zahner LH, McKiernan BJ, et al. Neuromuscular electrical stimulation improves severe hand dysfunction for individuals with chronic stroke: a pilot study. J Neurol Phys Ther. 2006; 30(4):175-183.
32. Seifart A, Unger M, Burger, et al. The effect of lower limb functional electrical stimulation on gait of children with cerebral palsy. Pediatr Phys Ther. 2009; 21(1):23-30.
33. Snoek GJ, IJzerman MJ, Groen FA, et al. Use of the NESS Handmaster to restore hand function in tetraplegia: clinical experiences in ten patients. Spinal Cord. 2000; 38(4):244-249.
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Government Agency, Medical Society, and Other Authoritative Publications:

1. Centers for Medicare and Medicaid Services (CMS). National Coverage Determinations. Available at: http://www.cms.hhs.gov/mcd/index_list.asp?list_type=ncd. Accessed on March 22, 2011.
   • Neuromuscular Electrical Stimulation (NMES). NCD #160.12. Effective October 1, 2006.
   • Treatment of Motor Function Disorders with Electric Nerve Stimulation. NCD #160.2. Effective 1, 2003.
2. Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD); MetroHealth Medical Center, Case Western Reserve University. Functional electrical stimulation for footdrop in hemiparesis. NLM Identifier: NCT00148343. Last updated on May 12, 2010. Available at: http://www.clinicaltrials.gov/ct2/show/NCT00148343?term=functional+electrical+stimulation+and+ambulation&rank=1. Accessed on March 22, 2011.
3. National Institute for Health and Clinical Excellence (NICE). Interventional procedure overview of functional electrical stimulation for drop foot of central neurological origin. April 2008. Available at: http://www.nice.org.uk/nicemedia/pdf/657_FES_overview_post%20IPAC%20II%20190109.pdf. Accessed on March 22, 2011.
4. National Institute for Health and Clinical Excellence (NICE). IBG278 Functional electrical stimulation for drop foot of central neurological origin: guidance. January 28, 2009. Available at: http://www.nice.org.uk/guidance/index.jsp?action=download&o=42902. Accessed on March 22, 2011.
5. Pomeroy VM, King L, Pollock A, et al. Electrostimulation for promoting recovery of movement or functional ability after stroke. Cochrane Database Syst Rev. 2006; (2):CD00324.

1. National Institute of Health (NIH): National Institute of Neurological Disorders and Stroke (NINDS). Spinal cord injury: emerging concepts. Available at: http://www.ninds.nih.gov/health_and_medical/pubs/sci_report.htm#Summary. Accessed on March 22, 2011.

EMG-Triggered Neuromuscular Stimulation
EMPI Portable Stimulator
ERGYS
FES
FES-CE Cycle Ergometry
Functional Electrical Stimulator
Handmaster
NESS H200 System
NESS L300 System
ODFS-Odstock Dropped Foot Stimulator
Parastep
TES
Threshold Electrical Stimulation
WalkAide

The use of specific product names is illustrative only.  It is not intended to be a recommendation of one product over another, and is not intended to represent a complete listing of all products available.