What is a nerve conduction study?
A nerve conduction study (NCS), is a measurement of the speed of conduction of an electrical impulse through a nerve. It may also be called a nerve conduction velocity (NCV) test. This test is used to determine nerve damage and destruction.
Why are nerve conduction studies performed?
Nerve conduction velocity is often used along with an EMG to differentiate a nerve disorder from a muscle disorder. NCS detects a problem with the nerve whereas an EMG detects whether the muscle is functioning properly in response to the nerve's stimulus.
There are several diseases or conditions that may be evaluated with NCS. These include, but are not limited to, conditions such as:
Guillain-Barré syndrome - Condition in which the immune system attacks part of the peripheral nervous system. Initial symptoms may include weakness or tingling sensations in the legs.
Carpal tunnel syndrome - Condition in which the median nerve, which runs from the forearm into the hand, becomes pressed or squeezed at the wrist by enlarged tendons or ligaments. This results in pain and numbness in the fingers.
Charcot-Marie-Tooth disease - Hereditary neurological condition affecting both motor and sensory nerves. One characteristic is weakness of foot and lower leg muscles.
Herniated disk disease
Chronic inflammatory polyneuropathy and neuropathy. These are conditions resulting from diabetes or alcoholism.
Sciatic nerve problems
Peripheral nerve injury
Nerve conduction studies may also be recommended by your doctor to identify the cause of symptoms such as numbness, tingling, and continuous pain, or for various other reasons.
How does a nerve conduction study work?
During this test, usually surface electrode patches are attached to the skin to stimulate a nerve. Two electrodes are placed on the skin over the nerve. One electrode stimulates the nerve with a very mild electrical impulse and the other electrode records it. The resulting electrical activity is recorded by another electrode. This is repeated for each nerve that is being tested.
The nerve conduction velocity (speed) is then calculated. This is done by measuring the distance between electrodes and the time it takes the electrical impulses to travel between them.
An electromyography (EMG) is a related procedure that may be performed in addition to a nerve conduction study. An EMG measures the electrical activity in muscles. It is often performed at the same time as NCS. Both procedures help to detect the presence, location, and extent of diseases that damage the nerves and muscles.
For more information about nerve conduction studies or other safe and effective treatment options for conditions of the hand, elbow, and upper extremities, call Dr. Sagini's office at (239) 337-2003.