Motor | knowyourphysio

ESTIM for Motor

Electrical stimulation for motor control stimulates motor nerves to elicit a contraction within the muscle(s) they innervate. The pulse duration curve shows that to get this desired response, the pulse duration needs to be set between 100 and 600 msec. This stimulation of the motor neurons can have many clinical benefits to include:

Restoration of force generation
Reduced muscle inhibition
Maintaining muscle health in peripheral nerve injuries
Treatment of Bell's Palsy
Management of Osteoarthritis and Rheumatoid arthritis
Reduction/Prevention of shoulder subluxation
Improved functional ability in patients after CVA
Improved bladder control
Improved muscular endurance

Russian and Biphasic are the usual settings for motor ESTIM. They can produce a strong contraction. Keep in mind, however, that electrically stimulated contractions have a ripid, jerky onset and will be less comfortable compared to our usual physiological contractions.

Contraindications

Synchronous, demand-type cardiac pacemakers
Over the carotid sinus
Venous or arterial thrombosis or thrombophlebitis
Pelvis, abdomin, trunk, and low back during pregnancy

Precautions

Cardiac disease
Impaired mentation
Impaired sensation
Malignant tumors
Skin irritation or open wounds

Setting up ESTIM

Identify the muscle to be treated and inspect the overlying skin. The skin surface should be clean and excess hair may need to be removed for the electrode to stick and to reduce impedence. Position the patient in a comfortable position that exposes the target tissue and will allow them to contract the muscle. Determine the maximum voluntary isometric contraction (MVIC) of the target muscle, using a dynamometer if possible. Place 2 pads on the target tissue. Ideally, one pad should be over the muscle belly and the other pad on a more proximal portion of the muscle. Secure these with the patient's body weight or a compression wrap if necessary to improve contact. Set the parameters for the desired effect of strength or endurance, as outlined in the charts below. Strength settings should use a frequency of 50 Hz for a smooth tetanic contraction and the amplitude should be increased so that the patient expereiences a strong, tolerable muscle contraction. This may or may not be visible to the therapist. Palpation may be necessary to ensure muscle activation. Endurance settings should use a requency closer to 35 Hz because the goal here is not to fatigue the muscle. With both strength and endurance settings, the patient should be instructed to actively contract the muscle as the machine provides and electrical contraction. The patient should rest when the machine rests. Treatment can range from 5-20 minutes. At the end of treatment, reassess strength and check the area of the electrodes for any adverse effects or skin irritation.

This is not meant to be a passive intervention

Take into Consideration

Decreasing the size of the electrodes increases the density. If the patient is experiencing pain with the treatment, try increasing the electrode pad size for improved comfort.
Another method of reducing pain and increasing patient comfort is by increasing the ramp so the contraction is brought on a little slower.
The reflex arc of the current is more superficial with the closer the electrodes are to one another and goes deeper with the further the electrodes are from one another.
Electrodes need to be at least 1/2 diameter apart from one another.
Sweep mode should be on to prevent attenuation.
Attenuation may happen to some degree anyway so it is important to check in with the patient and monitor the intensity.