NMES.pptx................................

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1. NMES (NEUROMUSCULAR ELECTRICAL STIMULATION) K. GEETHA REDDY ASST. PROF

2. INTRODUCTION Neuromuscular electrical stimulation (NMES) is a non-invasive electrotherapeutic modality that consists of the application of electric current through electrodes, leading to motor neuron depolarization, thus eliciting a muscle contraction. NMES is most commonly used for increasing strength, endurance and retard atrophy of muscle. DEFINITION NMES is defined as the application of electrical stimulation using surface electrodes placed over the skeletal muscles to produce visible muscle contraction through stimulation of the intact peripheral nerve.

3. NMES INSTRUMENTATION Selection of appropriate electrical stimulator: High voltage pulsed current stimulator (HVPCS). Interferential therapy (IFT). Russian current stimulator. Biphasic pulsed currents and other types of stimulators. Current type: (a) The Amplitude Modulated Alternating Current. (b) The Burst Modulated Alternating Current.

4. Waveforms used in NMES (a) A rectangular, balanced, symmetric, biphasic pulsed current. Symmetrical pulses are less painful over a large muscle mass because there is an equal amount of stimulation under both electrodes. (b) A rectangular, balanced, asymmetric, biphasic pulsed current. Force of contraction: The effectiveness of waveforms in eliciting contraction force depends on amplitude, frequency and waveform. Both pulsed and alternating currents are used in NMES devices. The currents used by the soviet researchers were 2500 Hz, sinusoidal, symmetric alternating current, burst modulated every 10 ms to provide 50 bursts per second. This form of stimulation has been promoted commercially as Russian stimulation.

5. PARAMETERS FOR TYPICAL STIMULATOR DESIGNED FOR NMES APPLICATIONS Waveform: Patient comfort (Any waveform). Pulse amplitude: 0-100 mA. Pulse duration: 0-500 µs, may require longer duration for electrical muscle Stimulator. Frequency controls: 0-100 pps . On time/off time controls : 0-60 for both on & off time. Ramp modulation controls : 0-5 sec. Treatment duration timer: 0-60 minutes. Number of output channels : 2.Electrodes considerations in NMES for Strengthening muscle : Motor points: In general, the motor point of the muscle is located over the belly of the muscle at (or) near the point at which the motor nerve enters the muscle.

6. PHYSIOLOGICAL EFFECTS & THERAPEUTIC EFFECTS: Physiological effects Effect on sensory nerve Stimulation of motor nerve Effects on skeletal muscle Local rise in metabolism Effect on peripheral blood flow of limb. Effect on edema control Effect on muscle tone

7. THERAPEUTIC USES OF NMES NMES is mainly used for strengthening or maintaining muscle mass during or following prolonged periods of immobilization. NMES is used for increasing the endurance of the muscle. Retarding of disuse muscle atrophy, Temporary reduction of spasticity. Denervated muscle stimulation. Stress incontinence. Reeducation/retraining of muscle following surgery or injury. Control of oedema . Maintenance of range of motion and to reduce/prevention of contracture.

8. NMES for Strengthening of Muscle Neuromuscular electrical stimulation (High intensity, moderate repetition for short period) ↓ Depolarization of motor nerve fibers ↓ Selective augmentation of Type II a & b muscle fibers (Fast twitched, Oxidative glycolytic & fast twitched Glycolytic, fatigue resistant) ↓ The strength of the muscle is increased.

9. 2. NMES for Improving Endurance of Muscle Neuromuscular electrical stimulation(Moderate intensity, low repetition for long period) ↓ Depolarization of motor nerve fibers ↓ Selective augmentation of Type I muscle fibers (Slow oxidative, fatigue resistant) ↓ The endurance of the muscle is increased. 3. Facilitation of Muscle Contraction When voluntary contraction of muscle is inhibited by pain or injury, stimulation may be of assistance in establishing voluntary contraction. For example: stimulation of Achilles tendon in chronic and post-surgical cases of Achilles tendon injury.

10. 4. Re-education of Muscle Action Inability to contract a muscle voluntarily may be the result of prolonged disuse of the muscle, which loses its ability to contract. So NMES is applied to facilitate muscle contraction. Example, in intrinsic foot muscles with a longstanding flat foot, or of incorrect use as with the abductor hallicius in hallux valgus. 5. Improve Venous and Lymphatic Drainage The muscle milking action: Rhythmic muscle contraction mechanically compresses the adjacent soft walled venous and lymphatic vessels to increase the centripetal flow of their content. The consequent reduction of interstitial pressure is considered to be effective venous and lymphatic return reduces oedema .

11. 6. Maintenance of ROM Neuromuscular electrical stimulation is very useful in increasing range of motion → Stimulation of antagonist muscle → Repetitive movement of stiff joint → Range of motion is maintained. 7. Stress Incontinence NMES is effective in the treatment of stress incontinence. Primarily by stimulating the pelvic floor muscles. 8. Temporary Reduction of Spasticity NMES is recommended to temporarily reduce the spasticity. Electrodes Placement Sites for the Control of Spasticity: Over the antagonist(s) to the spastic muscle. Over the spastic muscle itself. Dermatome associated with the same level as the motor nerve to the spastic muscle.

12. Nerve trunk innervating antagonist of spastic muscle. Para spinal stimulation. Over the dorsal column.

13. INDICATIONS FOR NMES. To increase strength of muscle. To increase endurance of muscle, Disuse atrophy after prolonged immobilization. Spasticity control. Denervated muscle stimulation. Stress incontinence. Reeducation/retraining of muscle following surgery or injury. Control of oedema . Maintenance of range of motion and to reduce/prevention of contracture. Knee osteoarthritis. Central nervous system disorders.

14. Stroke. Cerebral palsy Spinal cord injury. Multiple sclerosis Venous stasis Swallowing CONTRAINDICATIONS FOR NMES Over the carotid sinus. Over the cardiac pacemaker. Impaired circulation. Haemorrhagic conditions.

15. The patients who are unable to provide clear feedback regarding level of stimulationfor example: Infants, mentally disordered individual. Over the pelvis, abdomen and low back area of the pregnant women. Over the thoracic region because current may interfere with the function of the vital internal organs, including the heart. In regions of the phrenic nerve, urinary bladder stimulators because current may interfere with the normal operations of these devices. In hypersensitive or hypertensive patients, because autonomic responses may adversely affect control of the blood pressure. Peripheral vascular diseases-Venous thrombosis, thrombophlebitis.Tumor . Infection. Over the reproductive organs. Over the eyes & Recent surgery, bone fracture and osteoporosis.

16. PRECAUTIONS FOR NMES Impaired cognition/ communication. Skin disease (e.g., eczema). Regenerating nerves. Active epiphysis. NMES in close proximity to diathermy devices because of the potential for the loss of stimulation parameters. Obese patients. Lack of sensation.