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Functional Electrical Stimulation (FES) applies small electrical pulses to paralyzed muscles to restore or improve their function. FES is commonly used for exercise, but also to assist with breathing, grasping, transferring, standing and walking. FES can help some to improve bladder and bowel function. There's evidence that FES helps reduce the frequency of pressure sores.
FES made a splash in 1983 when Nan Davis, a paraplegic student at Wright State University, got out of her wheelchair and "walked" to get her diploma. She was powered by an FES system and inspired a TV movie called "First Steps."
The Wright State technology soon emerged commercially in the form of a stationary bicycle (ergometer) called the Regys; users pedaled the bike using FES-stimulated leg muscles. Researchers soon noted that this form of FES provides real aerobic exercise in people who otherwise can't move on their own; it boosts heart and lung function, improves strength and circulation, builds muscle mass, even in people with high quadriplegia.
Two companies make FES bikes in the U.S. Therapeutic Alliances, Inc., which originated the Regys 25 years ago, makes the Ergys 2 (www.musclepower.com). Restorative Therapies, Inc. offers the RT300-S which is operated from the wheelchair without the need for a transfer (www.restorative-therapies.com). RTI was started by Dr. John McDonald, the physician who got Christopher Reeve on an FES bike and who has claimed that FES helped Reeve get significant function back seven years after his C1 injury. According to McDonald, the FES bike can be more useful than just exercise. "We propose to use them for a totally different reason -- to promote regeneration and recovery of function." There is to date no support in the medical literature that FES affects recovery.
A doctor's prescription is needed for FES biking; each individual is given a program customized for run times, resistance, etc. The bikes cost in the range of $15,000. The manufacturers have yet to convince Medicare to pay for the devices. Some private insurance companies have reimbursed for them but many people access FES exercise in community settings, at health clubs and rehab clinics.
There are some risks associated with FES. Fracture of leg bones is possible due to loss of bone mineral density. Also, FES can trigger autonomic dysreflexia in upper-level injuries. People with severe spasticity, contractures, or osteoporosis are not good candidates.
Bladder or bowel FES:
Sacral stimulators are surgically implanted FES systems for on-demand control of the paralyzed bladder and bowel; these have been implanted in more than 1,500 paralyzed people, mostly in Europe. The stimulator, called the Finetech-Brindley device, has a strong track record for improving bladder and bowel control in the vast majority of users.
In 1999 a company called NeuroControl licensed the Brindley system and got FDA approval as the Vocare system. A company called NDI Medical more recently obtained the marketing rights to Vocare in the United States. See www.ndimedical.com.
Upper extremity:
About 15 years ago the FDA also approved an FES implant system to restores some hand and arm function to quads. The FreeHand system was well liked by the quads who used it; they gained significant function in grip, writing, eating, computer work, etc. Alas, NeuroControl dropped this from the market.
Walking:
There is a commercially available device called Parastep that is FDA approved for some paraplegics (T4 to T12 ) for "ambulation." Parastep, which has been approved by Medicare for reimbursement, facilitates gait by firing leg muscles; a front-wheeled walker fitted with a control pad is used. Contact www.sigmedics.com.
The future:
Brain-wave communication, it's the next big leap in neuroprosthetics and it's nearly here: in clinical trials, people area already controlling computer cursors and opening email with just their thoughts. Monkeys can precisely move robotic arms using only brain waves.
BrainGate is an investigational brain implant system from a biotech company called Cyberkinetics that places a computer chip into the brain; this monitors brain activity and converts the intention of the user into computer commands. The company is currently recruiting people with spinal cord injury, stroke or muscular dystrophy conditions for pilot clinical trials in Boston, Chicago and Rhode Island. Call the company for more: 508-549-9981.
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