Functional Electrical Stimulation for Post-Stroke

Stroke is currently the leading cause of adult disability in the United States and is the 3rd leading cause of death. Of those who survive a stroke, 2/3 are usually left with some type of physical disability, ranging in severity from mild weakness in an arm or leg to total paralysis of one side of the body. Because of these devastating residual effects, rehabilitation is a key factor in recovery from a stroke. Rehabilitation usually begins immediately in the hospital once a patient is medically stable, and can continue on for months to years depending on the severity of the disability.

Rehabilitation Post-Stroke
One common problem many patients experience post-stroke is the difficulty or inability to walk. Ambulation is typically addressed by conventional physical therapy methods, such as therapeutic exercise, stretching, balance activities, and gait training with an assistive device (i.e. a cane). More advanced methods of rehabilitation include Functional Electrical Stimulation (FES), a technique that uses electrical currents to activate the nerves that innervate the affected muscles in order to obtain a coordinated movement of the otherwise paralyzed limb. Functional Electrical Stimulation (FES) can be performed by a qualified physical therapist in a clinic setting using surface electrodes on the skin. However, the surface placement of these electrodes has its disadvantages, including: poor muscle selectivity, inaccurate placement of the electrodes, inconsistent muscle or nerve stimulation, painful stimulus, and poor electrode longevity.

Functional Electrical Stimulation (FES) Using Intramuscular Electrodes
For more than two decades, research has been performed relative to the use of FES with intramuscular electrodes. These particular electrodes are implanted into the muscles at precise anatomical landmarks referred to as motor points. The specificity of the electrode placement allows for increased effectiveness of FES as a rehabilitation tool. Advantages include: good muscle selectivity, accurate placement of the electrodes, consistent muscle or nerve stimulation, and long electrode longevity. In addition, the implanted electrodes, unlike surface electrodes, bypass the nerve fibers near the surface of the skin. This means a patient will experience less pain during electrical stimulation and will have the ability to tolerate a higher stimulus to achieve a stronger muscle contraction.

FES as a Promising Rehabilitation Tool
The electrodes implanted in various muscles of a lower limb can be programmed in such a way that a patient's leg can be moved through a coordinated movement needed to walk. Having a tool such as this can possibly help with the motor "relearning" of the brain post-stroke. Studies over the years have shown the safety and effectiveness of using intramuscular electrodes, both in the short-term as well as in the long-term. Clinical trials, funded by private and public organizations, are currently being performed at several institutions and hospitals all over the United States. With this ongoing research and the past 20 years of clinical trials, it can be said that Functional Electrical Stimulation is definitely becoming a promising rehabilitation tool for patients post-stroke.