A nerve conduction velocity (NCV) test measures how quickly electrical impulses move through a nerve.
This test is used to detect nerve damage and is done while you stay in the hospital or undergo outpatient treatment.
During the test, recording electrodes are placed over the muscle that corresponds to a suspect nerve and the nerve is stimulated with a mild electrical impulse. The nerve conduction velocity (speed) is then calculated by measuring the distance between electrodes and the time it takes for electrical impulses to travel between electrodes. This process is repeated for each nerve that’s being tested.
The NCV test can be used to evaluate several conditions or diseases:
- Guillain-Barré syndrome
- carpal tunnel syndrome
- Charcot-Marie-Tooth disease
- herniated disc disease
- chronic inflammatory polyneuropathy and neuropathy
- sciatic nerve problems
- pinched nerves
- peripheral nerve injuries
Your doctor may also order a nerve conduction study to identify the cause of some symptoms you may be experiencing, such as numbness, tingling and continuous pain. The NCV test can be used to evaluate several conditions such as herniated disc disease, chronic inflammatory polyneuropathy and neuropathy to carpal tunnel syndrome. Both procedures are typically performed at the same time and help detect the presence, location and extent of diseases that damage the nerves and muscles.
How to Prep for your NCV Test
Prior to your test, eat a normal breakfast and/or lunch. Don’t apply any lotions or oils as this could keep the electrodes from connecting properly to your skin.
An EMG is a related procedure that measures the electrical activity in your muscles. During this test, a small needle electrode is inserted into your muscle. The electrical activity it detects is displayed on a monitor as waves, and an audio-amplifier allows the technician to hear the activity.
Electrical activity will be measured when your muscle is at rest, when it’s slightly contracted and when it’s fully contracted. Muscles do not produce electrical activity when they are at rest.
This test is often performed at the same time as an NCV test. Both procedures help to detect the presence, location and extent of diseases that damage the nerves and muscles.