Nerve conduction velocity

How the Test is Performed:
The nerve is stimulated, usually with surface electrodes, which are patch-like electrodes (similar to those used for ECG ) placed on the skin over the nerve at various locations. One electrode stimulates the nerve with a very mild electrical impulse. The resulting electrical activity is recorded by the other electrodes. The distance between electrodes and the time it takes for electrical impulses to travel between electrodes are used to calculate the nerve conduction velocity.

Electromyography is often done at the same time as the nerve conduction velocity (NCV) test.

How to Prepare:
Normal body temperature must be maintained (low body temperature slows nerve conduction).

Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:



How it Feels:
There is no discomfort. The electrical stimulus is so small that it is usually not perceived by the person.

Risks:
There are essentially no risks.

Why this Test is Performed:
This test is used to diagnose nerve damage or destruction.

Normal Values:
NCV is related to the diameter of the nerve and the normal degree of myelination (the presence of a myelin sheath on the axon) of the nerve (tables of normal values are used). Newborn infants have values that are approximately one-half that of adults, and adult values are normally reached by age 3 to 4.

Abnormal Results:
Most often, abnormal results are caused by some sort of neuropathy (nerve damage or destruction) including:

Some of the associated diseases or conditions include:

Any peripheral neuropathy can cause abnormal results, as can damage to the spinal cord and disc herniation ( herniated nucleus pulposus ) with nerve root compression.

Cost:
The estimated cost is $500.

Special Considerations:
A NCV test reflects the status of the "best" surviving nerve fibers and may remain normal if even a few fibers are unaffected by a disease process. A normal NCV test result can occur despite extensive nerve damage.