Motor Stimulation

Paralysis and paretic extremities impact a growing population due to diseases such as stroke, spinal cord injury, and multiple sclerosis. For more than 50 years, physicians and engineers have worked together to develop technology that can be used to stimulate healthy nervous tissue, leading to contraction of the innervated muscles. Termed functional electrical stimulation, this technique has been used as an assistive tool and as a therapeutic intervention to improve recovery and pain intensity in formerly paretic extremities. The mechanisms are still not completely understood, but are likely a combination of motor output maintaining the bulk and function of innervated muscles as well as enhancing recovery through neuroplastic changes of the sensorimotor cortex. Devices have grown in complexity over the years to address greater disease burden. More complex systems have also been developed to facilitate ease of use by implanting under the skin or using automated triggering devices to achieve a more physiologic movement profile. Devices can be placed using simple electrodes with adhesive on the surface of the skin or surgically implanted around the target peripheral nerve. Serious complications are rare but include the typical complications of peripheral nerve stimulation. Less serious side effects include skin irritation and early muscle fatigue.