Neurodiagnostic Testing (EMG)
Electromyography (EMG and Nerve conduction studies) is a type of testing that is used to study nerve and muscle function. This test can assess information about the extent of nerve and/or muscle injury, determine the exact location of injury and give some indication whether the damage is acute or chronic.
There are two parts to EMG testing: a nerve conduction study and a needle exam. Both may result in some discomfort, but are usually well tolerated. The needle exam involves inserting fine needle electrodes into several muscles to measure normal and abnormal electrical signals given off by the muscle. Usually the orthopaedic surgeon will perform both parts of the procedure, but there are situations where only the nerve conduction or EMG testing is performed.
What are nerve conduction studies (NCS)?
Nerve conduction studies are non invasive electrical tests –to assess nerve physiology and function. The nerve conduction study involves stimulating nerves at different points with small electric shocks to measure function. They are used for suspected conditions of nerve entrapment, radiculopathy, plexopathy and primary muscle problems.
Nerve conduction studies help identify whether a nerve or a group of nerves are injured. Nerve conduction studies can explain the cause of acute or chronic nerve pain. The test is performed by placing electrodes over the specific area to be studied and briefly electrically stimulating nerves. The latency, amplitude and velocity of the nerve is measured and interpreted.
An EMG, or electromyography, uses a needle to evaluate the electrical activity of muscle fibers. It can provide information about the function and integrity of your individual muscle fibers. Problems with the nerves supplying the muscle and or problems with the muscle themselves can be identified. The test involves inserting a small needle electode into the muscle. Normal and damaged muscle produces specific characteristics.