Peripheral nerve conduction velocity (sensory and motor)

What This Test Measures

Nerve conduction velocity (NCV) tests evaluate how fast electrical impulses travel through your nerves. Sensory NCV measures responses from sensory nerves (e.g., those in your arms or legs), while motor NCV measures responses from motor nerves (e.g., those controlling muscles). These tests often use small electrical stimuli to trigger nerve impulses and measure the time it takes for signals to reach a muscle or skin surface.

Why It’s Done

Your doctor may order this test if you have symptoms like tingling, numbness, weakness, or pain—common signs of nerve damage. It’s also used to diagnose conditions like diabetic neuropathy, multiple sclerosis, carpal tunnel syndrome, or peripheral neuropathy.

How It’s Performed

You’ll lie on an exam table while electrodes are placed on your skin (or on a needle inserted into muscles for motor testing). A mild electrical stimulus is applied to trigger nerve signals, and the time it takes for the signal to travel is recorded. The process is quick and painless, though you may feel a slight tingling or muscle twitch.

Preparation

No special preparation is needed, but avoid caffeine or nicotine 24 hours before testing, as they can affect nerve responses. Wear loose clothing and avoid lotions or oils on the test areas.