The MUSC Neurophysiology Lab offers both EMG (electromyography) and NCS (nerve conduction studies) by board certified electrodiagnostic physicians and certified nerve conduction study technologists. These are special tests used to detect neuromuscular disorders (nerve and muscle problems).
These tests assist in the diagnosis and treatment of:
- ALS/Motor Neuron Disease
- Myasthenia Gravis
- Inflammatory and other Myopathies
- Muscular Dystrophies
- Focal nerve lesions (carpal tunnel syndrome, foot drop, tarsal tunnel syndrome)
- Brachial or lumbosacral plexopathy
- Facial nerve disorders (Bell’s Palsy)
EMG (electromyography) studies the peripheral nervous system by evaluating the passive and active electrical discharges of the muscles. Each muscle of the body is innervated by a specific nerve and nerve root. By testing muscles of each nerve root of interest, the physician may isolate the area of the spine, plexus, and/or distal nerve that has been damaged. EMG is performed by inserting a needle electrode into the muscle and recording motor unit action potentials during contraction and normal quiet baseline or abnormal positive sharp waves, fibrillations, and occasionally fasciculations during rest.
NCS (nerve conduction study) evaluate the peripheral nervous system by testing the function of individual nerves. This is done by stimulating the nerve at a specific point and recording a response from a specific location. The latency, amplitude and conduction velocity of the response are measured and compared to the lab’s established normal values to determine whether there is a problem in the physiological function of the nerve. Both motor and sensory components of the nerve can be tested. The stimulation starts off with no current and is gradually increased until the best response is obtained.
The EMG combined with the nerve conduction study will give a clear picture of the amount and location of peripheral nervous system damage.