Introduction
Functional electrical stimulation (FES), also called functional neuromuscular stimulation (FNS), is a technique used to replace or assist a voluntary muscle contraction during a functional task by applying low-level electrical current to the nerves that control muscles or directly over the motor end-plate of the muscle (just like a pacemaker makes a heart beat).
The term “FES” is commonly used to describe electrical stimulation used as a treatment modality for loss of shoulder function, pain, spasticity and subluxation following stroke. The U.S. AHCPR Post Stroke Rehabilitation Guidelines defines FES as “bursts of electrical stimulation applied to the nerves or muscles affected by the stroke, with the goal of strengthening muscle contraction and improving motor control.”
Neuromuscular electrical stimulation, or simply “electrical stimulation” (ES), is a modality used for strengthening muscles. ES may be considered a FES when a muscle contraction is facilitated during a functional task. Despite the use of all three terms in the literature (FES, FNS and ES) the applications to the hemiplegic shoulder all focus on the stimulation of the supraspinatus and deltoid muscles. Therefore, this module includes the modalities that elicit muscular contraction of the rotator cuff muscles. TENS and other therapeutic electrical stimulation that do not elicit muscular contraction are reviewed in other modules.
Theoretically, FES should help to compensate or facilitate flaccid shoulder muscles, which in turn should reduce the risk of shoulder subluxation, by involuntary muscle contractions. The effectiveness of FES in improving function, tone, EMG activity and in reducing pain and subluxation has been reported.
Patient/Family Information
Author: Marc-André Roy, MSc.
What is functional electrical stimulation (FES)?
The term FES is used to describe a technique used to make a muscle move using electrical current. While this may seem bizarre or unnatural to some, we should point out that the body naturally uses electrical current to make muscles move! To do this, the brain sends these currents through our nerves. The nerves relay the message to the muscle and then the muscle shortens.
FES works in a very similar way. Current is applied to either the skin over the nerve or over the muscle belly to cause a muscle contraction (muscle shortening). So people paralyzed by injuries to their necks or backs may be able to move their muscles and maybe even do things such as walking thanks to FES.
However, this module will look at FES used for a different purpose. Strokes often result in loss of function, pain, spasticity (stiffness) and subluxation (joint out of socket) in the shoulder. This module of StrokEngine reviews the use of FES for reducing or reversing these effects of the stroke in the shoulder.
There are also types of electrical stimulation that do not cause muscle contraction. These are described elsewhere (see TENS).
Are there different kinds?
Despite the use of different terms (functional electrical stimulation, functional neuromuscular stimulation and electrical stimulation), these all have the same goal: to make the shoulder muscles contract in order to increase function and decrease pain, spasticity (stiffness) and subluxation (joint out of socket). Different terms are often used to describe the same technique.
Why use FES applied to the shoulder after stroke?
Loss of shoulder function, pain, spasticity, subluxation and shoulder pain after stroke are common and can profoundly affect quality of life. FES is used for increasing shoulder function and for preventing pain and dysfunction in hemiplegic stroke patients.
Does it work for stroke?
Research has studied how FES can help stroke patients with a hemiplegic shoulder:
- Muscle function: There is limited evidence that FES in combination with regular physical therapy can improve muscle function. There is moderate evidence that FES treatment does not prevent the loss of shoulder function after a stroke.
- Shoulder Subluxation: There is limited evidence that FES improves and prevents shoulder subluxation after stroke. There is conflicting evidence as to whether there is a lasting effect after the treatment is stopped.
- Shoulder Pain: There is moderate evidence that FES does reduce shoulder pain post-stroke when there is shoulder subluxation.
- Shoulder Muscle Tone: There is limited evidence that FES treatment, in combination with conventional physical therapy, can improve tone in the shoulder of post-stroke patients.
- Shoulder EMG Activity: There is limited evidence that FES treatment, in combination with conventional physical therapy, can improve EMG activity in the shoulder of post-stroke patients.
What can I expect?
Small square stickers (electrodes) are placed over the centre of the muscle belly. Wires connect the electrodes to a stimulator, a small machine that produces the current. The stimulation is usually started at a very low level causing a tingling “pins & needles” feeling on the skin. The current will then slowly be increased after each stimulation until it is strong enough to make the muscle contract. This level (the smallest current necessary to make the muscle contract) will be used for the treatment. Although some people find it uncomfortable, it is usually well tolerated. Treatment times may vary. However, the time is usually divided into 3 to 5 sessions per day ranging in duration from 45 minutes to 2 hours, 5 to 7 days per week.
Side effects/risks?
The electrodes can irritate the skin, but this is not common. Using hypoallergenic electrodes or changing the type of stimulation used can often solve this problem. After the treatment, there may be pink marks on the skin under the electrodes. Usually the pink marks fade out within an hour. Although very rare, this type of therapy can increase spasticity (muscle tightness).
Some people should not use FES. These include people with: epilepsy, poor skin condition, hypersensitivity to the electrical stimulation, cancer, cardiac pacemakers.
Who provides the treatment?
Physical therapists will usually provide the FES treatment. However, due to the long duration of the stimulation it is possible for the treatment to be done at home after discharge from the hospital. This will require having a stimulator at home.
How many treatments?
Some patients continue to use FES for many years. To maximize the benefits after stroke, it should be used for at least 6 weeks.
How much does it cost? Does Insurance Pay For It?
Although the cost of an FES machine varies, some systems are relatively inexpensive. Rental or lease options bring the cost down to the equivalent of 1 or 2 clinical visits per month.
Is FES for me?
While there haven’t been many high quality studies of FES for treating the hemiplegic shoulder, most of the studies have reported good results from its use. More specifically, FES has been reported to improve function, reduce subluxation, reduce pain, reduce tone and increase EMG activity.
Clinician Information
Note: When reviewing the findings, it is important to note that they are always made according to randomized clinical trial (RCT) criteria – specifically as compared to a control group. To clarify, if a treatment is “effective” it implies that it is more effective than the control treatment to which it was compared. Non-randomized studies are no longer included when there is sufficient research to indicate strong evidence (level 1a) for an outcome.
Five studies (two high quality RCTs and three fair quality RCTs) have explored the use of Functional electrical stimulation (FES) applied to the shoulder in patients with stroke. These studies have reported significant improvement in muscle tone, EMG activity and a reduction in shoulder subluxation and pain.
Results Table
View results table
Outcomes
Global health status
Not effective
1b
One high quality RCT (Church et al., 2006) has investigated the use of FES for improving global health status in patients with acute stroke.
The high quality RCT (Church et al., 2006) investigated the use of FES applied to the hemiplegic shoulder to improve global health status (Nottingham E-ADL Index, Nottingham Health Profile) in 176 patients with acute stroke. Those randomized to the FES group received 4 weeks (3 times daily for an hour each) of FES applied to the shoulder, while the control group received sham stimulation. Both groups also received standard stroke unit care. No significant between group difference on global health status was seen at 3 months.
Conclusion: There is moderate evidence (Level 1b) from one high quality RCT that FES in addition to standard stroke unit care is not more effective than sham stimulation in addition to standard stroke unit care for improving global health status in patients with acute stroke.
Preventative measure for shoulder function
Not effective
1B
One high quality RCTs (Linn et al. 1999) investigated the use of electrical stimulation (FES) as a preventative measure for shoulder function loss in 40 subjects with no preexisting shoulder subluxation. No difference was reported in motor function for those receiving FES and conventional therapy versus conventional therapy alone, as assessed using the upper arm section of the Motor Assessment Scale.
Conclusion: There is moderate evidence (Level 1b) based on one high quality RCT, that FES treatment does not prevent the loss of shoulder function after a stroke.
Preventative measure for shoulder subluxation
Effective
1B
One high quality RCT (Linn et al., 1999) has investigated the use of FES for preventing shoulder subluxation in patients with acute stroke.
The high quality RCT (Linn et al., 1999) investigated the use of FES for preventing shoulder subluxation (measured by X-ray) in 40 patients with acute stroke. Those randomized to the FES group received stimulation 4 times per day for 4 weeks, while the control group received no treatment. Both groups also received conventional occupational therapy and physical therapy. Immediately after treatment, the FES group had significantly less subluxation and pain compared to the control group, however, no significant between group differences in subluxation were reported at follow-up (8 weeks and 3 months).
Conclusion: There is moderate evidence (Level 1b) from one high quality RCT that FES in addition to conventional therapy is more effective than conventional therapy alone for preventing shoulder subluxation in patients with acute stroke, however, the gains were not maintained at follow-up.
Shoulder EMG activity
Effective
2A
One fair quality RCT reported in two publications (Faghri et al., 1994, Faghri and Rodgers, 1997) investigated the use of FES for improving electromyographic (EMG) activity of the shoulder in patients with acute stroke.
The fair quality RCT (Faghri et al., 1994, Faghri and Rodgers, 1997), investigated the use of FES for improving EMG activity of the shoulder in 26 patients with acute stroke. Those randomized to the FES group received 1.5 to 6 hours of stimulation daily for 6 weeks while the control group received sham stimulation. Both groups also received standard physical therapy. At 5 weeks during treatment and at post- intervention, there was a significant difference in favor of the experimental group in EMG activity of the shoulder. This difference was not maintained at the 6 week follow-up, however, the significant difference in favour of the experimental group re-emerged at the 12 week follow-up (Faghri and Rodgers, 1997).
Conclusion: There is limited evidence (Level 2a) from one fair quality RCT that FES in combination with conventional physiotherapy is more effective than sham stimulation in combination with conventional physiotherapy for improving shoulder EMG activity in patients with acute stroke.
Shoulder impairment
Not effective
1b
One high quality RCT (Church et al., 2006) investigated the use of FES for improving shoulder impairment in patients with acute stroke.
The high quality RCT (Church et al., 2006) investigated the use of FES applied to the hemiplegic shoulder to improve shoulder impairment (Frenchay Arm Test, arm section of the Motricity Index) in 176 patients with acute stroke. Those randomized to the FES group received 4 weeks (3 times daily for an hour each) of FES applied to the shoulder, while the control group received sham stimulation. Both groups also received standard stroke unit care. Following the 4-week intervention, there were no significant differences between the groups on shoulder impairment on both measures, however, at 3 months, there was a significant difference in favor of the control group, where they experienced a greater reduction in shoulder impairment than the FES group.
Conclusion: There is moderate evidence (Level 1b) from one high quality RCT that FES in combination with conventional therapy is not more effective than sham stimulation in combination with conventional therapy for improving shoulder impairment in patients with acute stroke.
Shoulder muscle tone
Effective
2a
One fair quality RCT reported in two publications (Faghri et al., 1994, Faghri and Rodgers, 1997) has investigated the use of FES for improving shoulder muscle tone in patients with acute stroke.
The fair quality RCT (Faghri et al., 1994, Faghri and Rodgers, 1997) investigated the use of FES for improving shoulder muscle tone (Modified Gross Clinical Scales and the Modified Ashworth Clinical Scale) in 26 patients with acute stroke. Those randomized to the FES group received 1.5 to 6 hours of stimulation daily for 6 weeks while the control group received sham stimulation. Both groups also received 6 weeks of standard physical therapy. At 2-4 weeks during treatment and at post-treatment there was a significant difference in favour of the experimental group in shoulder muscle tone compared to the control group. This difference was not maintained at 6 week follow-up, however, the significant difference in favor of the experimental group re-emerged at the 12 week follow-up (Faghri and Rodgers, 1997).
Conclusion: There is limited evidence (Level 2a) from one fair quality RCT that FES in combination with conventional therapy is more effective than sham stimulation in combination with conventional therapy for improving shoulder muscle tone in patients with acute stroke.
Shoulder pain (with subluxation)
Effective
2A
One fair quality RCT reported in two publications (Faghri et al., 1994, Faghri and Rodgers, 1997) and an additional fair quality RCT (Chantraine et al., 1999) have investigated the use of FES for improving shoulder pain associated with shoulder subluxation in patients with acute stroke.
The first fair quality RCT (Faghri et al., 1994, Faghri and Rodgers, 1997) investigated the use of FES for improving shoulder pain (measured with a goniometer) in 26 patients with acute stroke. Those randomized to the FES group received 1.5 to 6 hours of stimulation daily for 6 weeks while the control group received sham stimulation. Both groups also received standard physical therapy. After the 6 week intervention, there was a significant difference in favor of the experimental group in shoulder pain (a reduction) compared to the control group, which was maintained at the 6 and 12 week follow-up (Faghri and Rodgers, 1997).
The second fair quality RCT (Chantraine et al., 1999) investigated the use of FES for improving shoulder pain (measured by a 10-cm visual analog scale) associated with subluxation (measured by X-ray) in 120 patients with acute stroke. Those assigned to the FES group received stimulation applied to the affected limb for 130 minutes per session in the first week, and increased by five minutes each week for 5 weeks, while the control group received no treatment. Both groups also received conventional Bobath therapy. At 3, 6, 12, and 24 months post-intervention, the FES group had significantly less shoulder pain compared to the control group.
Conclusion: There is limited (Level 2a) evidence from two fair quality RCTs that FES in combination with conventional therapy is more effective than conventional therapy (alone or in combination with sham stimulation) for decreasing pain associated with shoulder subluxation in patients with acute stroke.
Shoulder pain (without subluxation)
Not effective
1a
Two high quality RCTs (Linn et al., 1999, Church et al., 2006) have investigated the use of FES for improving shoulder pain in patients without subluxation in acute stroke.
The first high quality RCT (Linn et al., 1999) investigated the use of FES for improving shoulder pain (five-point pain scale) without subluxation in 40 patients with acute stroke. Those randomized to the FES group received stimulation 4 times per day for 4 weeks, while the control group received no treatment. Both groups received conventional occupational and physical therapy. At 4 weeks (immediately post-intervention) 8 weeks, and 3 month follow-up, there were no significant between group differences on the five-point pain scale.
The second high quality RCT (Church et al., 2006) investigated the use of FES applied to the hemiplegic shoulder to improve shoulder pain (upper limb pain assessed by a visual analogue scale – VAS) in 176 patients with acute stroke without subluxation. Those randomized to the FES group received 4 weeks (3 times daily for an hour each) of FES applied to the shoulder, while the control group received sham stimulation. Both groups also received standard stroke unit care. Following the 4-week intervention and at 3 months, there were no significant differences between the groups in upper limb pain.
Conclusion: There is strong evidence (Level 1a) from two high quality RCTs that FES in combination with conventional therapy is not more effective than conventional therapy (alone or in combination with sham stimulation) for improving shoulder pain in those without subluxation in acute stroke.
Shoulder subluxation in hemiplegic shoulder
Effective
1B
One high quality RCT (Linn et al. 1999) investigated the use of FES for preventing shoulder subluxation in subjects with no preexisting shoulder subluxation. The treatment group received electrical stimulation 4 times per day for 4 weeks in addition to conventional occupational and physical therapy. The control group received conventional occupational and physical therapy only. The treatment group had significantly less subluxation and pain after the treatment period. However, no significant differences between groups were reported at follow-up (8 weeks).
Conclusion: Based on the findings of one high quality RCT, there is moderate evidence (Level 1b) that FES helps prevent shoulder subluxation after stroke. However, there is no evidence of a lasting effect.
Treatment for shoulder subluxation
Effective
2A
Three fair quality RCTs (Faghri et al., 1994, Chantraine et al., 1999, Wang et al., 2000) have investigated the effectiveness of FES for reducing shoulder subluxation in patients with acute or chronic stroke.
The first fair quality RCT (Faghri et al., 1994) investigated the use of FES for reducing shoulder subluxation (measured by X-ray) in 26 patients with acute stroke. Those randomized to the FES group received 1.5 to 6 hours of stimulation daily for 6 weeks while the control group received sham stimulation. Both groups also received 6 weeks of standard physical therapy. At post-treatment, there was a significantly different reduction in subluxation in favor of the experimental group compared to the control group. This difference was not maintained at the 6 week follow-up.
The second fair quality RCT (Chantraine et al., 1999) investigated the use of FES for improving shoulder subluxation (measured by X-ray) in 120 patients with acute stroke. Those assigned to the FES group received stimulation applied to the affected limb for 130 minutes per session in the first week, and increased by five minutes each week for 5 weeks, while the control group received no treatment. Both groups also received conventional Bobath therapy. At 6 weeks, and 12 and 24 months post-intervention a significant reduction in shoulder subluxation was found in the experimental group compared to the control group.
The third fair quality RCT (Wang et al., 2000) investigated the use of FES for reducing shoulder subluxation (measured by X-ray) in 32 patients with acute (called short duration) and chronic (called long duration) post-stroke hemiplegia. Participants in the acute and chronic phase were further randomly assigned to either an experimental group that received FES 5 times a week for 6 weeks, followed by 6 weeks of standard rehabilitation, followed by an additional 6 weeks of FES, or to a control group that received no stimulation. After the first 6 weeks, significantly reduced shoulder subluxation was found in the FES group versus the control group but only for those in the acute phase: not for those in the chronic phase. These results were maintained after the second 6 weeks of FES treatment.
Conclusion: There is limited evidence (Level 2a) from three fair quality RCTs that FES in combination with conventional therapy is more effective than conventional therapy (alone or in combination with sham stimulation) for reducing shoulder subluxation in patients with acute stroke.
Treatment of shoulder function
Not effective
1A
Two high quality RCTs (Church et al., 2006, Linn et al., 1999), one fair quality RCT reported in two publications (Faghri et al., 1994, Faghri and Rodgers, 1997) and an additional fair quality RCT (Chantraine et al., 1999) have investigated the use of FES for improving shoulder function in patients with acute stroke.
The first high quality RCT (Church et al., 2006) investigated the use of FES applied to the hemiplegic shoulder to improve shoulder functioning (Action Research Arm Test- ARAT) in 176 patients with acute stroke. Those randomized to the FES group received 4 weeks (3 times daily for an hour each) of FES applied to the shoulder, while the control group received sham stimulation. Both groups also received standard stroke unit care. Following the 4-week intervention, no significant differences were observed between the two groups on the ARAT. However, at 3 months, the control group performed significantly better than the intervention group on the ARAT – grasp and gross movement sections.
The second high quality RCT (Linn et al., 1999) investigated the use of FES for improving shoulder function (Pain-free range of passive lateral rotation assessment and the Motor Assessment Scale- MAS) in 40 patients with acute stroke. Those randomized to the FES group received stimulation 4 times per day for 4 weeks, while the control group received no treatment. Both groups also received conventional occupational and physical therapy. At post-treatment and at 8 week and 3 month follow-up, there were no significant between group differences on the pain-free range of passive lateral rotation assessment, or on the upper arm section of the MAS.
The first fair quality RCT (Faghri et al., 1994, Faghri and Rodgers, 1997) investigated the use of FES for improving shoulder function (Modified Bobath Assessment Chart) in 26 patients with acute stroke. Those randomized to the FES group received 1.5 to 6 hours of stimulation daily for 6 weeks while the control group received sham stimulation. Both groups also received standard physical therapy. At weeks 4 and 5 during treatment and at post-treatment (6 weeks) there was a significant difference in favor of the experimental group in shoulder function compared to the control group. This was not maintained at the 6 week follow-up, however, the significant difference re-emerged at the 12 week follow-up (Faghri and Rodgers, 1997).
The second fair quality RCT (Chantraine et al., 1999) investigated the use of FES for improving shoulder function (range of motion) in 120 patients with acute stroke. Those assigned to the FES group received stimulation applied to the affected limb for 130 minutes per session in the first week, and increased by five minutes each week for 5 weeks, while the control group received no treatment. Both groups also received conventional Bobath therapy. At 6 weeks, 12, and 24 months post-intervention, the intervention group showed significantly better range of motion in the shoulder compared to the control group.
Conclusion: There is strong evidence (Level 1a) from two high quality RCTs that FES in combination with conventional therapy is not more effective than conventional therapy (alone or in combination with sham stimulation) for improving shoulder function in patients with acute stroke.
Note: However, two fair quality RCTs found a significant difference in favor of the experimental group in shoulder function compared to the control group but this was not maintained at the 6 week follow-up in one of the RCT.
Upper arm girth
Not effective
1B
One high quality RCT (Linn et al., 1999) and one fair quality RCT (Faghri et al., 1994) have investigated the use of FES for maintaining upper arm girth in patients with acute stroke.
The high quality RCT (Linn et al., 1999) investigated the use of FES for maintaining upper arm girth in 40 patients with acute stroke. Those randomized to the FES group received stimulation 4 times per day for 4 weeks, while the control group received no treatment. Both groups also received conventional occupational therapy and physical therapy. At post-treatment and at 8 week and 3 month follow-up, there were no significant between group differences on the measurement of upper arm girth.
The fair quality RCT (Faghri et al., 1994) investigated the use of FES for improving upper arm girth in 26 patients with acute stroke. Those randomized to the FES group received 1.5 to 6 hours of stimulation daily for 6 weeks while the control group received sham stimulation. Both groups also received standard physical therapy. After the 6 week intervention and at the 6 week follow-up, there was no significant difference between the groups on upper arm girth.
Conclusion: There is moderate evidence (Level 1b) from one high quality RCT that FES in combination with conventional therapy is not more effective than conventional therapy (alone or in combination with sham stimulation) for maintaining upper arm girth in patients with acute stroke.
References
Chantraine A., Baribeault A., Uebelhart D., & Gremion, G. (1999). Shoulder pain and dysfunction in hemiplegiaComplete paralysis of the arm, leg, and trunk on one side of the body that results from damage to the parts of the brain that control muscle movements. Hemiplegia is not a progressive condition, nor is it a disease.: effects of functional electrical stimulation. Arch Phys Med Rehabil, 80(3), 328-331.
Church C., Price C., Pandyan A., Huntley S., Curless R., Rodgers H. (2006). Randomized controlled trial to evaluate the effect of surface neuromuscular electrical stimulation to the shoulder after acute strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain.. StrokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain., 37(12), 2995-3001.
Faghri P. D., Rodgers M. M., Glaser R. M., Bors J. G., Ho C., & Akuthota, P. (1994). The effects of functional electrical stimulation on shoulder subluxation, arm function recovery, and shoulder pain in hemiplegic strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain. patients. Arch Phys Med Rehabil, 75(1), 73-79.
Faghri PD, Rodgers MM. (1997) The effects of functional electrical stimulation – augmented physical therapy program in the functional recovery of hemiplegic arm in strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain. patients, J Clin Kinesiol, 51, 9-15.
Linn S. L., Granat M. H., & Lees, K. R. (1999). Prevention of shoulder subluxation after strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain. with electrical stimulation. StrokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain., 30(5), 963-968.
Wang R. Y., Chan R. C., & Tsai, M. W. (2000). Functional electrical stimulation on chronic and acute hemiplegic shoulder subluxation.Am J Phys Med Rehabil, 79(4), 385-390; quiz 391-384.
