An EMG is a diagnostic study focusing on evaluating neuromuscular conditions. The purpose of the study is to determine if there is any dysfunction involving the cervical or lumbar nerve roots, plexus and peripheral nerve roots as well is evaluating the muscles they supply. Common symptoms you will be referred for this study include numbness and tingling in the extremities, burning in the feet, cervical and lumbar pain with radiation down the extremities, muscle weakness or muscular pain. Common conditions that are evaluated with EMG studies include carpal tunnel syndrome, sciatica, cervical or lumbar disc herniations causing sciatica or radiculopathy, peripheral neuropathy, tarsal tunnel syndrome and brachial plexopathies to name a few.
The study involves nerve conduction testing as well as needle EMG testing. The nerve conduction testing is performed by applying a small electrical current over the nerve and measuring the latency of response, the strength of the response and conduction velocity of the response. The patient will feel a very slight electrical impulse over the arm or leg which is brief and usually well tolerated. Several nerves will be studied per extremity. The second part of the study is the needle EMG. A very thin monopolar needle is inserted just under the skin within the muscle and studied with the computer for areas of abnormalities. The patient also will be asked to contract the muscle briefly to assess the muscles response to activation. Several muscles will be studied per extremity as well. This also is usually well tolerated, even for those with fear of needles.
The usual timeframe for the study is 30 min., typically 10 minutes for office consultation and examination followed by 20 min. of actual study time. It is best to wear loose fitting clothing, short sleeve shirts if we are studying the upper extremity and neck region and shorts or elastic pants if we are studying the lower extremity/lumbar region. It is not necessary to have someone give you a ride back and forth and it is not necessary to withhold pain medications prior. Having pain medications prior to the study will not alter the results of the study. You may wish to take your own pain medications beforehand but it is also not necessary.
Dr. Agana is Board Certified through the American Board of Electrodiagnostic Medicine, 1998.