Test Overview
An electromyogram (EMG) measures the electrical impulses of muscles at rest and during contraction. Nerve conduction studies, which measure nerve conduction velocity, determine how well individual nerves can transmit electrical signals. Nerves control the muscles in the body using electrical impulses, and these impulses make the muscles react in specific ways. Nerve and muscle disorders cause the muscles to react in abnormal ways.

An electromyogram (EMG) is done to:

• Diagnose conditions that damage muscle tissue, nerves, or the junctions between nerve and muscle (neuromuscular junctions), for example, a herniated disc.
• Evaluate the cause of weakness, paralysis, involuntary muscle twitching, or other symptoms. Problems in a muscle, the nerves supplying a muscle, the spinal cord, or the area of the brain that controls a muscle can all cause these kinds of symptoms.

• Detect and evaluate damage to the peripheral nervous system, which includes all the nerves that lead away from the brain and spinal cord and the smaller nerves that branch out from those nerves. Nerve conduction studies are often used to help diagnose nerve disorders, such as carpal tunnel syndrome.
• Identify the location of abnormal sensations, such as numbness, tingling, or pain

EMG /NCV testing should be considered when:

1. There is no response to care, but symptoms continue
2. Subjective complaints are evident, but objective findings are not supportive.
3. X-rays, CT, MRI, or EMG are negative, yet symptoms persist.
4. There is non-resolving radicular pain.
5. A determination of nerve irritation or damage needs to be made.
6. The need for further care is to be evaluated and substantiated.
7. Real vs. imagined pain is questioned.