Durable Medical Equipment Section - Threshold Electrical Stimulation as a Treatment of Motor Disorders

IMPORTANT REMINDER

This Medical Policy has been developed through consideration of medical necessity, generally accepted standards of medical practice, and review of medical literature and government approval status.

Benefit determinations should be based in all cases on the applicable contract language. To the extent there are any conflicts between these guidelines and the contract language, the contract language will control.

The purpose of medical policy is to provide a guide to coverage. Medical Policy is not intended to dictate to providers how to practice medicine. Providers are expected to exercise their medical judgment in providing the most appropriate care.

Description

Threshold electrical stimulation is described as the delivery of low intensity electrical stimulation to target spastic muscles during sleep at home. The stimulation is not intended to cause muscle contraction. Although the mechanism of action is not understood, it is thought that low intensity stimulation may increase muscle strength and joint mobility leading to improved voluntary motor function. The technique has been used most extensively in children with spastic diplegia related to cerebral palsy, but also in those with other motor disorders, such as spina bifida.

Devices used for threshold electrical stimulation are classified as “powered muscle stimulators.” As a class, the U.S. Food and Drug Administration (FDA) describes these devices as “an electronically powered device intended for medical purposes that repeatedly contracts muscles by passing electrical currents through electrodes contacting the affected body area.”

Policy/Criteria

Threshold electrical stimulation as a treatment of motor disorders, including but not limited to cerebral palsy, is considered investigational.

Scientific Background

Validation of therapeutic electrical stimulation requires controlled, randomized studies that can isolate the contribution of the electrical stimulation from other components of therapy. Physical therapy is an important component of the treatment of cerebral palsy and other motor disorders. Therefore, trials of threshold electrical stimulation ideally should include standardized regimens of physical therapy. Randomized studies using sham devices are preferred to control for any possible placebo effect.

Steinbok and colleagues report one randomized trial of threshold electrical stimulation. (2) The study included 44 patients with spastic cerebral palsy who had undergone a selective posterior lumbosacral rhizotomy at least one year previously. All patients had impeding motor function, but some form of upright ambulation. Patients were randomized to receive a 12-month period of 8 to 12 hours of nightly electrical stimulation or no therapy. The principal outcome measure was the change from baseline to 12 months in the Gross Motor Function Measure (GMFM), as assessed by therapists blinded to the treatment. The patients and their parents were not blinded; the authors stated that the active device produced a tingling sensation that precluded a double blind design. Patients were encouraged to maintain whatever ongoing therapy they were participating in. The type of physical therapy in either the control or treatment group was not described.

After one year the mean change in the GMFM was 5.5% in the treated group, compared to 1.9% in the control group, a statistically significant difference. The authors state that this 3.6% absolute difference is clinically significant. For example, a child who was previously only able to rise and stand while pushing on the floor, could now do so without using hands. While these results point to a modest benefit, the lack of control for associated physical therapy limits the interpretation.

Dali and colleagues published the results of a double blind placebo control trial that randomized 57 children with cerebral palsy to receive either threshold electrical stimulation or a sham device for a 12-month period. (3) Visual and subjective assessments showed a trend in favor of the treatment group; however, there was no significant effect of therapeutic electrical stimulation in terms of motor function, range of motion, or muscle size. The authors concluded that therapeutic electrical stimulation was not shown to be effective in this study.

Two smaller randomized controlled studies found no improvement in muscle strength with electrical stimulation as a treatment of motor disorders. Van der Linden and colleagues found no clinically or statistically significant differences in twenty-two children with cerebral palsy who were randomized to either electrical stimulation to the gluteus maximus over a period of eight weeks to improve gait or no electrical stimulation or additional treatment. (4) Fehlings and colleagues also found no evidence of improved strength in thirteen children with types II/III spinal muscular atrophy who were randomized to either receive electrical stimulation or a placebo stimulator over a twelve month period. (5) More recently, a study of 24 patients with cerebral palsy demonstrated positive results for the subset that received stimulation combined with dynamic bracing; however, the effect did not last after discontinuing treatment. (6) Finally, Kerr and colleagues compared the efficacy of neuromuscular electrical stimulation (NMES), threshold electrical stimulation (TES) and placebo in strengthening the quadriceps muscles in children with cerebral palsy. (7) Sixty children were randomized to receive sixteen weeks of therapy with NMES (n=18), TES (n=20) or placebo (n=22). At six-week follow-up, no statistically significant between-group differences were found for strength or function. For impact of disability the only statistically significant difference was between TES and placebo. The authors concluded that further evidence will be required to determine whether NMES and/or TES may be useful to these children. Compliance in the threshold electrical stimulation group was 38%; compliance in the placebo group was not reported. Retrospective analysis indicated that the study would require 110 to 190 subjects to achieve 80% power for measures of strength and function. Evidence remains insufficient to determine if threshold electrical stimulation improves health outcomes in children with cerebral palsy.

A search of the MEDLINE database through September 4, 2008 failed to identify any published literature that alter the above conclusions.

References

1. BlueCross and BlueShield Association Medical Policy Reference Manual, Policy No. 1.01.19
2. Steinbok P, Reiner A, Kestle JRW et al. Threshold electrical stimulation (ThresholdES) following selective posterior rhizotomy in children with spastic diplegia due to cerebral palsy: A randomized clinical trial. Dev Med Child Neurol 1997;39:515-20
3. Dali C, Hansen FJ, Pedersen SA et al. Threshold electrical stimulation (TES) in ambulant children with CP: a randomized double-blind placebo-controlled clinical trial. Dev Med Child Neurol 2002;44(6):364-9
4. Van der Linden ML, Hazelwood ME, Aitchison AM et al. Electrical stimulation of gluteus maximus in children with cerebral palsy: Effects of gait characteristics and muscle strength. Dev Med Child Neurol 2003;45(6):385-90
5. Fehlings DL, Kirsch S, McComas A, et al. Evaluation of therapeutic electrical stimulation to improve muscle strength and function in children with types II/III spinal muscular atrophy. Dev Med Child Neuro 2002;44(11):741-4
6. Ozer K, Chesher SP, Scheker LR. Neuromuscular electrical stimulation and dynamic bracing for the management of upper-extremity spasticity in children with cerebral palsy. Dev Med Child Neurol 2006;48(7):559-63
7. Kerr C, McDowell B, Cosgrove A, et al. Electrical stimulation in cerebral palsy: a randomized controlled trial. Dev Med Child Neurol 2006;48(11):870-6

Cross References

Electrical Stimulation Devices for Home Use, Regence Medical Policy Manual, DME, Policy No. 11

Sympathetic Therapy for the Treatment of Pain, Regence Medical Policy Manual, DME Policy No. 65

Interferential Stimulation, Regence Medical Policy Manual, DME Policy No. 66

DME Section Table of Contents