Updated: Aug 1, 2022
Increases in walking speed seen with the use of Functional Electrical Stimulation (FES) are substantial and range from a low value of a 15% change at 3 months 17 to a high of a 47% change at 1 year
Several studies have even demonstrated that FES can have a significant therapeutic effect, noting continued improvement in walking speed even with FES device turned off.
Walking speed is an essential indicator of overall functional mobility and has shown to be a good discriminate measure of physiological and functional recovery for patients post CVA.11 The support in the literature for changes in walking speed with the use of FES is very strong. A great deal of the research regarding the efficacy of FES has investigated changes in walking speed; these studies have consistently demonstrated statistically significant improvements. The increases in walking speed noted with FES have been demonstrated in RCTs both with therapeutic and neuroprosthetic FES applications. The evidence demonstrates that significant changes with FES are noted after both short term (2 to 5 months) and long term (6 to 12 months) applications.
FES utilization has the capacity to effect significant changes in gait speed in a short amount of time, as evidenced in one study by an initial 17% change seen post fitting of the device and, in one of the most significant increases noted in the literature, a 37% change seen after only 8 weeks.13
The lowest reported percent change in PCI was 10%18 and the highest 31%.20
The evidence shows that the use of FES has a significant and positive impact on the effort required to ambulate. All but one of the studies utilized the Physiologic Cost Index (PCI) as a measure of the effort involved in gait. PCI is a measure that combines changes in heart rate and respiratory rate, with a decrease in PCI indicating a lower energy cost. The studies, ranging in duration from 0 to 12 months, all found that gait required significantly less effort with the utilization of FES. The lowest reported percent change in PCI was 10% and the highest 31%. The study reporting the most significant findings was also the shortest at 4.5 months and one of the only studies to show a significant therapeutic effect for PCI, with a 19% decrease in PCI noted when the FES device was turned off. Another study investigated subjects with chronic stroke who had utilized FES for 2 years. The results demonstrated a decreased energy cost using the measure of total work. This study showed that the total work of walking was significantly less for the subjects with a CVA, both when the FES was turned on and off, than it was for normal controls.
Gait/Walking Pattern Symmetry:
FES has been shown to significantly improve gait symmetry as measured by the Gait Asymmetry Index, a marker of inter limb coordination associated with balance status and fall risk
Many studies have investigated the effect of FES on symmetry and quality of gait. FES has been shown to significantly improve gait symmetry as measured by the Gait Asymmetry Index, a marker of inter limb coordination associated with balance status and fall risk. Studies have also demonstrated that the use of FES can improve gait quality by decreasing the variability of gait. Swing time and stride time variability, measures associated with gait stability and fall risk, have been noted to improve with the use of FES. One case report demonstrated improvement in hip and knee flexion angles and symmetry of hip and knee motion during gait. These improvements, accompanied by an improved push off at terminal stance, combined to demonstrate a restoration of gait symmetry to near normal. These results indicate that FES not only improves ankle dorsiflexion and symmetry of swing, but the entire lower extremity flexor pattern as well. Another study showed that the use of FES resulted in improvements in the Rivermead Visual Gait Analysis, a tool that assesses the degree of asymmetry in the trunk, pelvis, hip, knee and ankle. The improvements shown in all these studies demonstrate that utilization of FES can significantly impact gait quality and symmetry. Spasticity: FES can positively affect spasticity levels as well. Three studies have investigated the effect of FES on extensor spasticity, measuring the level of spasticity found in the antagonist gastroc-soleus muscle. Two studies found improvement in spasticity scores (the Modified Ashworth Scale and the Composite Spasticity Score), and one noted increased inhibition of the affected side gastroc-soleus muscle spasticity when PN FES was utilized to activate the affected side anterior tibialis muscle.
Perhaps the most valuable outcomes noted with the use of FES come from studies demonstrating positive neuroplastic changes in cortical activity and motor control.
Two studies looked at cortical activity, measured by changes in Motor Evoked Potentials (MEP), and found improved MEPs with the use of FES. Plasticity of motor control was demonstrated in 4 studies whose results noted an increase in voluntary muscle activity and maximum voluntary contractions (MVC) of the anterior tibialis. These increases in cortical activation and muscle activity were attributed to central nervous system changes and not to training or isolated strengthening of the affected side anterior tibialis muscle. Neuroplastic changes in motor control can also be measured by improvements in gait speed that occur even when the FES device has been turned off. Several studies have found therapeutic effects of FES on gait speed, noting increases in gait speed that remain without FES stimulation and range from a 14% to a 31% change.
Quality of Life (QOL) and patient preference: The evidence supports that the use of FES can have a positive effect on QOL. In 3 RCTs, a significant number of subjects preferred FES to an AFO.
The evidence cites other study results demonstrating that patients feel safer when using FES, report fewer falls and have a decreased fear of falling. In one study of patients with chronic stroke and their caregivers, both groups recognized FES as having a positive impact on disability post CVA and overall QOL.
Recent RCT evidence: Four recent RCTs trials comparing FES to the usual standard of care present evidence that FES is at least equivalent to the AFO for treating drop foot post CVA. All of these studies show FES to be as effective in improving gait speed and as safe as an AFO for long-term use. In one study the FES group also showed significant improvements on the Berg Balance Scale, 6-Minute Walk Test9 and Modified Emory Functional Ambulation Profile tasks that were not seen in the AFO group. Studies have also noted that FES, when used as a neuroprosthesis or as part of a rehabilitation program, is cost effective, decreases time to complete rehabilitation, improves rehabilitation outcomes and increases the number of patients discharged to home. These studies support that FES is at least an equivalent alternative to bracing and may perform better than an AFO on some measures of function and balance. Given the efficacy of FES and the positive impact of FES use on the course of rehabilitation, FES should be an assessable option for patients with drop foot after CVA especially for those patients who are not successfully treated with an AFO.
Bibliography 1. Burridge J, Taylor P, Hagan S, Wood D & Swain I. The effects of common peroneal nerve stimulation on the effort and speed of walking: a randomized controlled clinical trial with chronic hemiplegic patients. Clin Rehab 1997;11:201-10. 2. Yan TB, Hui-Chan CW, Li LS. Effects of functional electrical stimulation on the improvement of motor function of patients with acute stroke: a randomized controlled trial. Zhonghua Yi Xue Za Zhi. 2006 Oct 10;86(37):2627-31. 3. Morone G, Fusco A, Di Capua P, Coiro P, Pratesi L. Walking Training with Foot Drop Stimulator Controlled by a Tilt Sensor to Improve Walking Outcomes: A Randomized Controlled Pilot Study in Patients with Stroke in Subacute Phase. Stroke Res Treat Volume 2012, Article ID 523564, 5 pages. 4. Sheffler LR, Taylor PN, Gunzler DD, Buurke JH, Ijzerman MJ, Chae J. Randomized controlled trial of surface peroneal nerve stimulation for motor relearning in lower limb hemiparesis. Arch Phys Med Rehabil. 2013;94:1007-14. 5. Wilkinson IA, Burridge J, Strike P, Taylor P. A randomised controlled trial of integrated electrical stimulation and physiotherapy to improve mobility for people less than 6 months post stroke. Disabil Rehabil Assist Technol. 2014 May 14:1-7. [Epub ahead of print] 6. Kottink AI, Hermens HJ, Nene AV, Tenningo MJ, Groothuis-Oudshoorn CG, Ijzerman MJ. Therapeutic effects of an implantable Peroneal nerve stimulator in subjects with chronic stroke and footdrop: A randomized clinical trial. Phys Ther 2008;88(4): 437-448. 7. Everaert DG, Stein RB, Abrams GM, et al. Effect of a foot-drop stimulator and ankle-foot orthosis on walking performance after stroke: a multicenter randomized controlled trial. Neurorehabil Neural Repair 2013;27:579-591. 8. Kluding PM, Dunning K, O’Dell MW et al. Foot drop stimulation versus ankle foot orthosis after stroke: 30-week outcomes. Stroke 2013;44:1660-69. 9. Bethoux F, Rogers HL, Nolan KJ et al. The effects of peroneal nerve functional electrical stimulation versus ankle-foot orthosis in patients with chronic stroke: a randomized controlled trial. Neurorehabil Neural Repair. 2014 Sep;28(7):688- 697. 10. Bethoux F, Rogers HL, Nolan KJ et al. Long-term Follow-up to a Randomized Controlled Trial Comparing Peroneal Nerve Functional Electrical Stimulation to an Ankle Foot Orthosis for Patients with Chronic Stroke. Neurorehabilitation and Neural Repair. 2015, Feb 5. [e-pub ahead of print]. 11. Harris JE, Eng JJ, Marigold DS, et al. Relationship of balance and mobility to fall incidence in people with chronic stroke. Phys Ther. 2005;85:150–8. 12. Burridge JH, Elessi K, Pickering RM, Taylor PN. Walking on an uneven surface: The effect of common peroneal stimulation on gait parameters and relationship between perceived and measured benefits in a sample of participants with a drop-foot. Neuromodulation: Technologies at the Neural Interface 2007;10(1):59-67. 13. Hausdorff JM and 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. 14. Johnson CA, Burridge JH, Strike PW, Wood DE, Swain ID. The effect of combined use of botulinum toxin type A and functional electrical stimulation in the treatment of spastic drop foot after stroke: a preliminary investigation. Arch Phys Med Rehabil 2004;85(6) 902-9. 15. Laufer Y, Ring H, Sprecher E, Hausdorff JM. Gait in Individuals with Chronic Hemiparesis: One-Year follow-up of the effects of a neuroprosthesis that ameliorates foot drop. J of Neuro PT 2009;33:104-110. 16. Laufer Y, Hausdorf JM, Ring H. Effects of a foot drop neuroprosthesis on functional abilities, social participation, and gait velocity. Am J Phys Med Rehabil 2009;88:14-20. 17. Stein RB, Chong SL, Everaert DG, Rolf R, Thompson AK, Whittaker M, Robertson J, Fung J, Preuss R, Momose K, Ihashi K. A muliticenter trial of a footdrop stimulator controlled by a tilt sensor. Neurorehabil Neural Repair 2006;20(3):371-79. 18. Stein RB, Everaert D, Chong SL, Thompson AK. Using FES for foot drop strengthens Cortioc-Spinal Connections. 12th Conference of the International FES Society, 2007. 19. Stein RB, Everaert DG, Thompson AK, Chong SL, Whittaker M, Robertson J, Kuether G. Long term therapeutic and orthotic effects of a foot drop stimulator on walking performance in progressive and nonprogressive neurological disorders. Neurorehabil Neural Repair 2010;24(2):152-167. 20. Taylor PN, Burridge JH, Dunkerley AL, Wood DE, Norton JA, Singleton C & Swain ID. Clinical use of the Foot Drop Stimulator: its effect on the speed and effort of walking. Arch Phys Med Rehab 1999;80:1577-1583. 21. Wieler M, Stein RB, Ladouceur M, Whittaker M, Smith AW, Naaman S, Barbeau H, Bugaresti J, Aimone E. Multicenter evaluation of electrical stimulation systems for walking. Arch Phys Med Rehab 1999;80:495-500. 22. Voigt M, Sinkjaer T. Kinematic and kinetic analysis of the walking pattern in hemiplegic patients with foot-drop using a peroneal nerve stimulator. Clin Biomech 2000;15(5):340-51. 23. van Swigchem R, Weerdesteyn V, van Duijnhoven HJ, den Boer J, Beems T, Geurts AC. Near-Normal gait pattern with peroneal electrical stimulation as a neuroprosthesis in the chronic phase of stroke: A Case Report. Phys Med Rehabil 2011;92:320-24. 24. Ring H, Treger I, Gruendlinger L, Hausdorf JM. Neuroprosthesis for footdrop compared with Ankle-Foot orthosis: Effects on postural control during walking. J Stroke Cerebrovasc Dis 2009;18(1):41-47. 25. Sheffler LR, Hennessey MT, Naples GG, Chae J. Peroneal Nerve Stimulation versus an Ankle Foot Orthosis for Correction of Footdrop in Stroke: Impact on Functional Ambulation. Neurorehabil Neural Repair 2006;20(3):355-360. 26. Wilkie KM, Shiels JE, Bulley C, Salisbury LG. “Functional electrical stimulation (FES) impacted on important aspects of my life”: a qualitative exploration of chronic stroke patients’ and carers’ perceptions of FES in the management of dropped foot. Physiother Theory Pract 2012;28(1):1-9. 27. Robertson JA, Eng JJ, Hung C. The Effect of Functional Electrical Stimulation on Balance Function and Balance Confidence in Community-Dwelling Individuals with Stroke. Physiother Can. 2010;62:114–19. 28. Burridge JH and McLellan DL. Relation between abnormal patterns of muscle activation and response to common peroneal nerve stimulation in hemiplegia. J Neurol Neurosurg Psychiatry 2000;69:353-361. 29. 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. 30. Taylor P, Humphreys L, Swain I. The long-term cost-effectiveness of the use of Functional Electrical Stimulation for the correction of dropped foot due to upper motor neuron lesion. J Rehabil Med 2013;45(2):154-160. 31. Tanovic E. Effects of functional electrical stimulation in rehabilitation with hemiparesis patients. Bosn J Basic Med Sci. 2009 Feb;9(1):49-53. 32. Taylor PN, Burridge JH, Dunkerley AL, Lamb A, Wood DE, Norton JA, Swain ID. Patients’ perceptions of Dropped Foot Stimulator. Clin Rehabil. 1999 Oct;13(5):439-46. 33. Perera S, Mody SH, Woodman RC, Studenski SA. Meaningful change and responsiveness in common physical performance measures in older adults. J Am Geriatr Soc. 2006;54:743-49. 34. Tilson JK, Sullivan KJ, Cen SY, et al. Meaningful gait speed improvement during the first 60 days poststroke: minimal clinically important difference. Phys Ther. 2010;90:196-208.