Electrodiagnostic Medicine (EMG / Nerve Conduction Studies)
Electrodiagnostic medicine tests the peripheral nervous system for a variety of conditions, some common, some uncommon. Two medical specialties receive training in conducting the test, Physiatrists (Physical Medicine and Rehabilitation) and Neurologists.
The testing consists of two portions: an electromyogram (EMG), and a nerve conduction study (NCV). During the electromyogram the physician uses a small, sterile, single use needle electrode to study the individual muscles. When done properly, there is some minimal discomfort, but generally no more than that experienced with the insertion of a needle during an acupuncture treatment. The EMG test is able to evaluate for primary disorders of the muscles (myopathy) as well as damage to the muscle as a result of a pinched nerve (radiculopathy). During the nerve conduction study the physician uses a small (milliampere) current to test the peripheral nerves for disorders such as diabetic neuropathy and carpal tunnel syndrome.
The test typically takes about 30-60 minutes to perform.
Some common disorders that EMG/NCV are able to diagnose:
1) Carpal tunnel syndrome: This is an entrapment of one of the nerves in the hand (median nerve). The symptoms are typically numbness in the first three to four fingers of the hand, often worse at night, and often alleviated by shaking the hand (the “wake and shake” sign).
2) Radiculopathy aka “pinched nerve”: This is an entrapment of the spinal nerve as it exits the spinal cord on its way through the vertebra and intervertebral disc. Symptoms may include tingling and numbness of the hand or foot, weakness, and or muscle atrophy.
3) Peripheral neuropathy: A diffuse term indication that the nerves in the arms and legs are not functioning properly. The most common causes of this condition are diabetes and alcoholism. While most people know if they are alcoholics, many persons may not know they have diabetes, and a properly performed EMG/NCV can be the first test that confirms a physician’s suspicion of the condition.
Some important, but less common conditions that EMG/NCV is used to diagnose include:
1) ALS (amyotrophic lateral sclerosis or “Lou Gerig’s disease”). This is a primary disorder of the spinal cord itself, and the EMG/NCV test is crucial in making the diagnosis. Symptoms of this disorder vary, and typically include patchy but widespread weakness, without any numbness or sensory loss
2) Myasthenia gravis. In this disorder, the body produces antibodies that affect the ability of the muscles to function properly. The symptoms may include drooping of the eyelids, and other muscle weakness, with normal sensation.
What do you need to do on the day of your test?
1) Do not use any lotion on your skin. The lotion will block the electric impulses along the skin and significantly alter the results of the test.
2) Please do take any pain medications that you typically take. The EMG/NCV and in fact no test, can determine how much pain an individual is having. Pain medication will not alter the results of the test.
Will my medical insurance pay for the testing?
Yes, almost all medical insurance covers the cost of the test. You may need preauthorization before the test is performed. Our staff at West County Integrative Medicine will contact your insurance carrier prior to the date of your examination.