Neuroprosthetics are electrical stimulation technologies that replace or assist damaged or malfunctioning neuromuscular organ systems and attempt to restore normal body processes, create or improve function, and/or reduce pain. These systems are either implanted or worn externally on the body.
In 1986 I was introduced to a fascinating technology that clearly was way ahead of its time. I had just completed my orthotic and prosthetic residency as I visited a research center of the Cleveland, Ohio, Veterans Medical Center called the FES (Functional Electrical Stimulation) Gait Lab. This is where I first heard the word "neuroprosthetics." It was not a familiar term to me nor was it a part of the curriculum at the University of Washington's O&P program, but in this rather unknown, futuristic venue, the paraplegics were not braced. Instead, to my amazement, muscles were energized by a portable microprocessor which coordinated them to mimic the characteristics of normal gait.
Each paraplegic subject in this study seemed to transcend his neurological loss. Muscles that were once atrophied and easily fatigued were now toned, well-defined, and had sufficient strength to power patients out of their wheelchairs and propel them down the hallway. Seeing their renewed gait, their improved bodies, and their health radically transformed, I quickly signed up as a research orthotist to learn and contribute as much as possible.
This was the beginning of a long and evolving discovery of how electrical stimulation can augment the rehabilitation process. After the early days in research, I went on to develop an electrode suit that patients use to don and align surface electrodes. My original intention was to help paraplegics use muscle stimulation in the home rather than under the guidance of a physical therapy center. That would help lower the cost of receiving muscle therapy and advance the technology by reducing the complexity of setting up as many as 18-20 electrodes on the body. It seemed to me that an improved electrode interface would increase patient compliance and medical outcomes.
Christopher Reeve Used System
Christopher Reeve was among the first users of this new system. It's what kept his muscles strong and his body in good shape for many years. He was a vehement proponent of muscle stimulation technology because it imparted better health, and it prepared his body for when medical science is able to repair cord injuries. Though Mr. Reeve's paralysis was complete, the Bioflex Wearable Therapy System furnished improved circulation, cardiopulmonary exercise, reduced spasticity, more range of motion for his joints, along with added protection against undue pressure and skin breakdown.
Muscle stimulation acts as a prosthesis by replacing aspects of an incapacitated nervous system. In patients with upper motor neuron damage (spinal cord injury, stroke, cerebral palsy, multiple sclerosis, head injury), it bypasses the impaired part of the brain or cord and stimulates the motor nerves directly. This makes the muscles contract. The stimulator's microprocessor and controller execute and coordinate commands to each muscle, instructing which ones to contract and which ones to relax at any given moment. A muscle stimulator's level of sophistication determines the complexity of movement it imparts to the body as well as what level of muscle force and firing sequence to emulate.
Strengthening Muscles, Reducing Spasticity
Muscle stimulation can be used in patients with incomplete spinal cord injury to strengthen muscles and reduce spasticity, so that the body operates more efficiently and effectively. For example, many persons with incomplete injuries having voluntary control over the quadriceps can stand and walk longer and more effectively when the quadricep muscles are strengthened. This means less reliance on wheelchairs and orthoses or at least minimizing their magnitude. Muscle stimulation is advantageous because it improves the body's physiology while build- ing muscle and reducing spasticity. In patients who ambulate and who are looking for improved functional outcomes, this is a huge psychological victory, because it shows patients that their bodies are still operable and restorable.
Implementation of neuroprosthetics in stroke patients having foot drop is another example of its utility because it restores movement in a more physiological way. Stroke patients can be fi tted with a sleeve that positions and holds electrodes over the dorsifl exors and a heel switch for the shoe that triggers the muscles at each step. The advantage is that the ankle remains free to dorsifl ex and plantarfl ex without restriction, and spasticity in the plantarfl exors is greatly reduced. This means more normal walking and a minimization (often elimination) of torsional forces by the spastic muscles causing the foot to supinate.
Reducing Pain
Another area I found electrical stimulation to be immensely helpful is the reduction of chronic pain. While most clinicians are familiar with TENS, few are aware that muscle stimulation can be used as well. The difference is that muscle stimulation is a stronger stimulus and is capable of contracting and relaxing muscles in a cyclic manner. My clinical experience shows that muscle stimulation is better at blocking pain than TENS. One theory is that it reverses the vicious cycle of pain, spasm, and muscle tightness, and that by reducing muscle tightness, you remove a signifi cant component of the pain. I have observed both TENS and muscle stimulation preventing pain from rising when increases in patient activity occur. This is helping patients to be more mobile and is helping them to return to work. It is not uncommon for pain to be reduced 50-90 percent with these technologies.
Electrode Garment
The neuroprosthetics I create and employ in my practice typically entail an electrode garment. The purpose of the garment is to help align and hold electrodes in place. The material comprising the body of the garment is a flexible spandex. The electrodes are made of silver cloth and are highly conductive. I make the garments in such a way that wires do not interfere with or restrict body movement. The garment fitting is a three to five stage process which varies, depending on the complexity of the case. Patients doing therapy can don the garment, then remove it after a few hours, or if being used for pain relief, it can be worn under clothes throughout the day, sometimes even at night when the patient sleeps. Because the garment is worn directly on the skin and is worn for extensive periods of time, it must fit just right. Otherwise, skin irritation and breakdown might occur.
The way in which we treat patients changes and evolves all the time. Neuroprosthetics will certainly become more commonplace with time. They have distinct advantages over traditional medicine and orthotics because of the powerful ability to transform the body and to integrate with nerve and muscle.
Technology for Orthotists, Prosthetists
Physical therapy is not the only venue for electrical stimulation and neuroprosthetics. Orthotists and prosthetists must assimilate the technology if we are to advance our profession. The neuroprosthetics I employ entail extensive evaluations, fittings, and modifications to ensure delivery of an effective and safe medical device to my patients--the same qualifications and standards of practice that make a successful orthotist and prosthetist. Embracing neuroprosthetics will open up greater possibilities for the patients we work with and ensure we are part of this growing trend.
Philip Muccio, CPO, is owner and director of Bioflex Inc., Columbus, Ohio. He can be contacted at 800.552.3539; philipmuccio@earthlink.net; www.mypainmanager.com