NMES

Neuromuscular electrical stimulation (NMES) is a technique that uses electrical impulses to evoke contractions in skeletal muscles by stimulating peripheral nerves. It is delivered through surface electrodes placed on the skin or, less commonly, via implanted leads. NMES differs from transcutaneous electrical nerve stimulation (TENS), which is usually used for pain relief rather than muscle activation.

NMES is applied in rehabilitation to improve strength, endurance, and motor control after neurological injuries (such as stroke or spinal cord injury) or orthopedic conditions, and to counteract muscle atrophy due to immobilization. A related approach, functional electrical stimulation (FES), uses NMES to produce purposeful movements to restore functional tasks like grasp or walking with assistive devices.

Technique and protocols typically involve pulsed electrical currents that are biphasic and symmetrical. Frequencies commonly range from about 20 to 60 Hz to produce a tetanic muscle contraction. Parameters such as pulse width, intensity, and on/off cycling are adjusted to generate a visible, comfortable contraction while allowing rest. Electrode placement targets the motor points of the involved muscles, and distal and proximal sites may be used to recruit larger muscle groups.

Safety and practicality are important considerations. NMES is usually administered under professional supervision, with session durations commonly in the range of 10 to 60 minutes, several times per week as part of a broader therapy plan. Potential adverse effects include skin irritation or burns at electrode sites and transient muscle soreness. Contraindications include implanted electronic devices (e.g., pacemakers/defibrillators), active infections or dermatitis at the electrode site, and certain medical conditions in which electrical stimulation is inappropriate.

Overall, NMES serves as an adjunct tool in rehabilitation, with outcomes varying across individuals and conditions.