Functional electrical stimulation
Functional electrical stimulation (FES) is a technique that uses electrical currents to activate nerves innervating extremities affected by paralysis resulting from spinal cord injury (SCI), head injury, stroke and other neurological disorders. FES is primarily used to restore function in people with disabilities. It is sometimes referred to as Neuromuscular electrical stimulation (NMES).
FES was initially referred to as Functional Electrotherapy by Liberson, and it wasn't until 1967 that the term Functional Electrical Stimulation was coined by Moe and Post, and used in a patent entitled, "Electrical stimulation of muscle deprived of nervous control with a view of providing muscular contraction and producing a functionally useful moment". Offner's patent described a system used to treat foot drop.
The first commercially available FES devices treated foot drop by stimulating the peroneal nerve during gait. In this case, a switch, located in the heel end of a user's shoe, would activate a stimulator worn by the user.
Common Applications 
Spinal Cord Injury 
Injuries to the spinal cord interfere with electrical signals between the brain and the muscles, resulting in paralysis below the level of injury. Restoration of limb function as well as regulation of organ function are the main application of FES, although FES is also used for treatment of pain, pressure, sore prevention, etc.
Some examples of FES applications involve the use of Neuroprostheses that allow people with paraplegia to walk, stand, restore hand grasp function in people with quadriplegia, or restore bowel and bladder function.
FES is commonly used in foot drop neuroprosthetic devices.
In the acute stage of stroke recovery, the use of cyclic electrical stimulation has been seen to increase the isometric strength of wrist extensors. In order to increase strength of wrist extensors, there must be a degree of motor function at the wrist spared following the stroke and have significant hemiplegia. Patients who will elicit benefits of cyclic electrical stimulation of the wrist extensors must be highly motivated to follow through with treatment, After 8 weeks of electrical stimulation, an increase in grip strength can be apparent. Many scales, which assess the level of disability of the upper extremities following a stroke, use grip strength as a common item. Therefore, increasing strength of wrist extensors will decrease the level of upper extremity disability.
Patients with hemiplegia following a stroke commonly experience shoulder pain and subluxation; both of which will interfere with the rehabilitation process. Functional electrical stimulation has been found to be effective for the management of pain and reduction of shoulder subluxation, as well as accelerating the degree and rate of motor recovery. Furthermore, the benefits of FES are maintained over time; research has demonstrated that the benefits are maintained for at least 24 months.
Electrical stimulation for the purpose of helping persons with paralysis of the arms or legs mainly focuses on the neuromuscular transmission peripherally. E-stim can also be used for central nervous system stimulation to hasten awakening from coma or the vegetative state. There is a long history of neurosurgeons who have implanted electrodes into the brain and spinal cord, especially in Japan, for increasing cerebral blood flow and certain neurotransmitters in persons in long term coma states.
Beginning in 1991 in Greenville, North Carolina (East Carolina University) and shortly after that in Charlottesville, Virginia (University of Virginia), the right median nerve has been used as a portal to help awaken injured human brains. Trains of differentiated square electrical pulses at 40 Hz (a frequency for upregulation of the thalamus), 20 seconds on and 40 seconds off, have been applied to the palmar side of the right wrist for transdermal stimulation of the right median nerve at low amplitudes, enough to produce contraction of the thumb. Battery powered FDA approved electrical neuromuscular stimulators have been used in these research projects connected by wires to the pair of right wrist electrodes embedded in a custom made plastic orthosis to localize the stimulation target. The right median nerve was selected as the electrical portal as there is large cortical representation of that nerve in the dominant left cerebral hemisphere. By subcortical connections, the transmitted signals go to Broca's motor/speech planning area (whether the person is right or left-handed, the majority are left hemisphere dominant). Awakening from deep coma from motor vehicle crashes with closed head injury in the Glasgow Coma Scale range of 4-6 can be expected to respond in half of the treated cases after two to four weeks of 8 hours/day electrical treatment,if started within one to two weeks of the severe brain trauma. The advantage of the shorter than expected period of unconsciousness is a quicker start into a neurorehabilitation program to encourage ambulation and talking.
Over the last decade, this RMNS project has spread from the USA East Coast to Central Japan, parts of Europe, and most recently in 2005 to Shanghai, China.
Functional electrical stimulation (FES) of paraplegics allows paraplegics with complete paralysis due to spinal cord injury at the thoracic level of their spinal cord to walk distances that average 450 meters per walk under some training procedures and 110 meters per walk when undergoing less demanding training, when using the noninvasive Parastep FES system that received the USA FDA approval in 1994. Certain such patients can walk one mile (1.6 km) using that same system. FES for ambulation also shows improvements in blood flow to lower extremities and in other medical and physiological parameters including bone density.
Functional electrical stimulation (FES) offers a variety of health benefits. Like any exercise FES improves fitness, prevents obesity and helps to protect against cardiovascular disease. FES cycling however provides some other extra benefits:
- An increase in bone density, decreasing the risk of fractures.
- Improved circulation, decreasing the likelihood of thrombosis.
- Prevents or reverses muscle atrophy.
- Reduction of muscle spasms.
See also 
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- M. Claudia et al.,(2000), Artificial Grasping System for the Paralyzed Hand, International Society for Artificial Organs, Vol 24 No.3 pp:185-188
- Liberson, W. T.; Holmquest, H. J.; Scot, D.; Dow, M. (1961). "Functional electrotherapy: Stimulation of the peroneal nerve synchronized with the swing phase of the gait of hemiplegic patients". Archives of physical medicine and rehabilitation 42: 101–105. PMID 13761879.
- Moe and Post, 1967
- Offner et al. (1965), Patent 3,344,792
- Powell, Joanna; David Pandyan, Malcolm Granat, Margart Cameron, David Stott (1999). "Electrical Stimulation of Wrist Extensors in Poststroke Hemiplegia". Stroke: Journal of the American Heart Association 30 (7): 1384–1389. Retrieved 11 May 2011.
- Chantraine, Alex; Baribeault, Alain; Uebelhart, Daniel; Gremion, Gerald (1999). "Shoulder Pain and Dysfunction in Hemiplegia: Effects of Functional Electrical Stimulation". Archives of Physical Medicine and Rehabilitation 80: 328–331.
- London's Global University - Department of Medical Physics and Bioengineering. "Why do FES Cycling?". Retrieved 16/04/2013.
- Cyclone Mobility. "FES Benefits". Retrieved 16/04/2013.
Further reading 
- Chudler, Eric H. "Neuroscience For Kids - Cells of the Nervous System." UW Faculty Web Server. Eric H. Chudler, 1 June 2011. Web. 7 June 2011.<http://faculty.washington.edu/chudler/cells.html>.
- Cooper E.B., Scherder E.J.A., Cooper J.B (2005) "Electrical treatment of reduced consciousness: experience with coma and Alzheimer's disease," Neuropsyh Rehab (UK).Vol. 15,389-405.
- Cooper E.B,& Cooper J.B. (2003) "Electrical treatment of coma via the median nerve," Acta Neurochirurg Supp, Vol. 87, 7-10.
- "FEScenter.org » Cleveland FES Center." FEScenter.org » Home. Cleveland VA Medical Center, Case Western Reserve University, MetroHealth Medical Center, 3 June 2011. Web. 8 June 2011. <http://fescenter.org/index.php?option=com_content>
- Graupe D (2002). "An overview of the state of the art of noninvasive FES for independent ambulation by thoracic level paraplegics". Neurological Research 24: 431–442.
- Graupe D, Cerrel-Bazo H, Kern H, Carraro U (2008). "Walking Performance, Medical Outcomes and Patient Training in FES of Innervated Muscles for Ambulation by Thoracic-Level Complete Paraplegics". Neurol. Research 31: 123–130.
- Johnston, Laurance. "FES." Human Spinal Chord Injury: New & Emerging Therapies. Institute of Spinal Cord Injury, Iceland. Web. 7 June 2011. <http://www.sci-therapies.info/FES.htm>.
- Lichy A., Libin A., Ljunberg I., Groach L., (2007) " Preserving bone health after acute spinal cord injury: Differential responses to a neuromuscular electrical stimulation intervention", Proc. 12th Annual Conf. of the International FES Soc., Philadelphia, PA, Session 2, Paper 205.
- Liu, Yi-Liang, Qi-Dan Ling, En-Tang Kang, Koon-Gee Neoh, Der-Jang Liaw, Kun-Li Wang, Wun-Tai Liou, Chun-Xiang Zhu, and Daniel Siu-Hung Chan. "Volatile Electrical Switching in a Functional Polyimide Containing Electron-donor and -acceptor Moieties." Journal of Applied Physics 105 (2009): 1-9. Print.
- Nolte, John, and John Sundsten. The Human Brain: an Introduction to Its Functional Anatomy. 5th ed. St. Louis: Mosby, 2002. Print.
- Reeve, Christopher, and Dana Dana Reeve. "Functional Electrical Stimulation." Christopher & Dana Reeve Foundation. Reeve Foundation. Web. 7 June 2011. <http://www.christopherreeve.org/site/c.mtKZKgMWKwG/b.4453425/k.27A5/Functional_Electrical_Stimulation.htm#>.
- Rosenzweig, Mark R., Arnold L. Leiman, and S. Marc. Breedlove. Biological Psychology. Sunderland: Sinauer Associates, 2003. Print.
- Wilkenfeld, Ari J., Musa L. Audu, and Ronald J. Triolo. "Feasibility of Functional Electrical Stimulation for Control of Seated Posture after Spinal Cord Injury: A Simulation Study." The Journal of Rehabilitation Research and Development 43.2 (2006): 139-43. Print.
- Yuan, Wang, Zhang Ming, Netra Rana, Liu Hai, Jin Chen-wang, and Ma Shao-hui. "A Functional Magnetic Resonance Imaging Study of Human Brain in Pain-related Areas Induced by Electrical Stimulation with Different Intensities." Neurology India58.6 (2010): 922-27. Print.
- "How Can FES Help after a Stroke and What Is a Stroke/TIA/mini-stroke? Pain Rehab Solutions." Surviving Major Illness Such as Stroke | Pain and Rehab Solutions. PARS. Web. 14 June 2011. <http://www.pain-rehab.co.uk/stroke-about.htm>.