Electrodiagnostic Procedures are commonly known as EMGs. In doing an EMG we find whether or not a person has nerve or muscle damage from a wide range of medical problems, including injuries and disease. To do this, we must give a series of small electric shocks, like static electricity from a door knob or a carpet in the wintertime. That part of the test tells us how much electricity a person's nerve carry and how fast they carry it. In the second part of the test we insert a small needle into several muscles, one muscle at a time. We don't give any shocks with the needles. The needles are hooked to a wire that then goes into the EMG machine and shows us the function of the muscle. As you know, muscles are hooked up to nerves, so that any abnormalities that we see in the muscles may be caused by damage to the nerve that supplies that muscle. By the pattern of abnormality in the nerves and muscles we can assist your doctor in knowing where your nerve damage is; whether in the spinal canal, as from a ruptured disc; in a major nerve near the spinal canal; or farther out the nerve, near the muscle that it supplies. As this is a test of nerve or muscle damage, not of pain, a patient can have a problem that causes him or her a lot of pain, yet have a normal EMG. This is actually good news, as it is never good to have nerve damage. As such, if a patient has a normal study, that should be a source of reassurance for both the patient and his or her doctor.
There are virtually no complications or side effects to Electrodiagnostic Procedures (EMGs). Any muscles that we put a needle in may be sore for a few hours after the procedure. The patient can help this soreness with an over-the-counter pain medication, or rubbing an ice cube over the sore area for a few minutes. We occasionally see a drop of blood while doing the procedure, so we wear gloves to prevent contacting the blood.
At the completion of the procedure, the patient is free to go home. We send the results of the procedure to the patient's doctor within a day or two.
The Electrodiagnostic Laboratory provides testing and evaluation of the peripheral nervous system for inpatients and outpatients. The laboratory is associated with the East Carolina University School of Medicine Department of Physical Medicine and Rehabilitation. It is located at the Vidant Rehabilitation Center.
The laboratory staff includes three full time physicians who perform tests five days a week. If understanding the problem is urgent, we can make same-day appointments for patients.
Indications for Electrodiagnostic Testing
Electrodiagnostic studies are an extension of a patient's history and physical examination and other laboratory studies. They assist in the diagnosis, management, and predicition of the course of neuromuscular disease or nerve injuries.
Services include evaluation of the status of various physiological and anatomic components of the peripheral nervous system:
- motor neurons
- neuromuscular junction
- sensory neurons
- brachial plexus
- lumbar plexus
- nerve root
- selected cranial nerves
The electrodiagnostic test can be helpful in identifying or confirming the following conditions:
- Carpal Tunnel Syndrome
- Cubital Tunnel Syndrome
- Neuropathies from Diabetes and other medical conditions
- Nerve injuries from herniated cervical or lumbar discs
- Nerve Injuries from accidents and other trauma
- Anterior horn cell disease (ALS or Lou Gehrig's Disease)
- Polyneuropathy (axonal versus demyelination, sensory, motor or sensorimotor)
- Mononeuropathy multiplex syndrome
- Radiculopathy or polyradiculopathy
- Guillain-Barre syndrome (polyradiculoneuropathy)
- Neuromuscular junction disorder (like myasthenia gravis)
- Cranial nerve pathology (Bell's Palsy)
- Compression neuropathies (like carpal tunnel syndrome)
Electrodiagnostic testing may involve several components:
- Electromyography (EMG) - placement of thin needle electrode in various muscles to measure inherent electrical activity.
- Nerve Conduction Study (NCS) - measurement of the speed of conduction of electrical impulse as it travels along the nerve.
- The Somatosensory Evoked Potential (SEP) - measurement of an electrical stimulus along peripheral nerves and spinal cord to the cerebral hemispheres. It may provide valuable information in the following conditions:
- differentiating spinal cord versus cauda equina injury
- ruling out spinal cord injury in a patient with minimal responsiveness
- confirming brachial plexus injury
Premedication is generally not needed. Occasionally, a mild sedative or topical anesthetic cream will be used to alleviate discomfort, particularly in children.
The Electrodiagnostic Laboratory can evaluate infants, children and adults. The study requires approximately 1 hour.
A preliminary report will be made in the chart for inpatients, and a final report will be sent to all referring physicians within a day or two.
The lab is accessible to all inpatients and outpatients. A portable machine is available for patients who require testing in their rooms.
Outreach clinics are done at Vidant Edgecombe Hospital and Vidant Chowan Hospital.
If you need more information or wish to refer a patient, call 252-847-6600 or 800-847-4313.