An EMG (or Electromyogram) helps determine the level of electrical activity the muscles engage in while the body is at rest. Nerve conduction studies (abbreviated NCS) determine the level of efficiency and speed with which electrical signals are sent by the nerves. In addition to bones, blood vessels, tissues, and veins, the body is also partly composed of muscles. They are in turn controlled by nerves which send to the muscles, electrical signals known as impulses. These pulses help dictate muscle reactions. Any issues that may arise within the muscles or nerves, may result in the muscles reacting in unusual ways. EMG/NCS studies are undertaken when the patient experiences pain or numbness in the legs and to also evaluate the performance level of the spinal nerves and and the nerves operating in the legs and arms.
EMG/NCS studies serve two different purposes. An EMG identifies diseases that may have contributed to the damaging of muscle tissues, nerves, or even possibly the joint between the muscle and nerves. Conditions that may play a role include herniated discs, myasthenia gravis, or amyotrophic lateral sclerosis (ALS). An EMG also helps to determine the underlying factors contributing to muscle weakness, twitching, or paralysis. A Nerve conduction study is done to locate the damage done to the peripheral nervous system. Nerve problems such as Guillain-Barre syndrome and carpal tunnel syndrome are identified through this procedure.
The electromyogram is a procedure that is usually done at the doctor’s office but can also be undertaken at a clinic or a hospital. Patients undergoing the procedure may be requested to either lie down on a bed or table or rest on a reclining chair. This is done to help the muscles relax. Electrodes will be attached to the skin for monitoring purposes, so it is important that the skin is clean and free of any oils, lotions or creams. The skin is first cleaned with alcohol and antiseptic solution, then a small electrode needle that is attached to a recording machine, is inserted into the muscle being examined. This is done in order to record the electrical activity being produced by the muscle. The patient may have to tighten and contract the muscle repeatedly in a slow and calm manner in order to record electrical activity.
The procedure can last anywhere between 30 and 60 minutes. Once the procedure is done, the electrodes will be removed and the area where the needle was inserted will be cleansed.
For the nerve conduction studies, metal disc electrodes that are flat, will attached to the body and held in place with either tape or paste. The nerve to be examined will have a shock-emitting electrode placed over it while the muscles impacted by the specific nerve will be monitored with a recording electrode. Electrical pulses will be emitted to the nerve and the electrode will record the time it takes for the muscle to contract. This procedure may be done for other nerves throughout the body. If the patient is undergoing both an EMG and a NCS, the NCS will be done prior to the EMG. A typical NCS procedure may take anywhere between 15 minutes to an hour depending the amount of nerves being evaluated.
Both procedures have little to no risks and patients undergoing an EMG may experience some bruising or swelling at the site where the needle was inserted. A full report detailing the results of the procedure may take between 2-3 days to appear but the results may be provided to the patient right after the procedure as either normal or abnormal.