What is Electromyography (EMG)?
Electromyography or EMG is a test a doctor will order in order to determine abnormal electrical activity of the muscles. It can help to detect tarsal tunnel syndrome, inflamed muscles, and pinched nerves. This is done by inserting a small needle into the muscle belly of the foot and ankle. Five or more needles may be used and their may be slight pain with this insertion. The needle then transmits data to a computer to log the electrical activity of the muscle. Based on the readings the doctor will determine whether or not improper muscle function is present. A neurologist or trained technologist will locate the nerves to be studied.
What is a Nerve Conduction Velocity test?
A nerve conduction velocity test or NCV can determine how healthy the nerves are by testing the ability of a nerve to transmit an electrical signal. The doctor will place electrodes on the skin, over the spine, and stimulator will be used to send out a small electrical charge along the nerve. The measured time between stimulation and response is then recorded.
Both of these tests are used in combination to diagnose tarsal tunnel syndrome, peripheral neuropathy, nerve palsy, and other neuromuscular disorders. A neurologist will also be involved in order to perform a thorough neurological workup for the patient. Both of these tests can typically take thirty to forty five minutes and do not cause too much discomfort. Based on the results proper intervention can be initiated.
The risks of the procedure are minimal but the electrodes can cause irritation to the muscle and nerves. Some factors may interfere with the results of the tests such as spinal cord damage, severe pain, and body temperature. If the patient has a defibrillator or pacemaker precautions will need to be taken.
After the procedure the electrodes are removed from the skin. The patient can return to previous activities as tolerated unless instructed otherwise. Some patients need to avoid strenuous activities for at least twenty four hours after the procedure.