Nerve Conduction and Electromyography
What is EMG Testing?
An electromyogram (EMG) is a test used to detect abnormal electrical activity of muscles that can occur in many diseases and conditions.
Why is an EMG test done?
An EMG test is often performed when patients suffer from sciatica, radicular pain, tingling, numbness and muscle weakness. The test also helps to distinguish between problems with muscles or nerves. It is also used to isolate the level of nerve irritation or injury.
Part I – Nerve Conduction Testing (NCV):
A nerve conduction velocity test is done by stimulating the nerve with a stimulator device and recording the electrical response 'down-stream' from the site of stimulation. The time taken by the electrical impulse to travel between electrodes is referred to as nerve conduction velocity.
The NCV test can be used to detect nerve disorders such as neuropathy or compression of the nerve as in Carpal Tunnel Syndrome.
Part II – Needle Examination:
A fine needle is inserted into the muscle to record the electrical activity.
The presence, size, and shape of the waveform (called the action potential) visualized on the computer screen provides information on the muscle function
The EMG test is used to detect muscle disorders like myopathy and also to test the neuromuscular junction where the nerve and the muscle meet.
How to come prepared for the EMG test?
Come wearing loose clothing like shorts and a T-shirt with no skin lotion applied to the arms and legs.
Does an EMG test hurt?
An experienced physician can keep any minor discomfort to a minimum.