A test used to assess damage or dysfunction of the peripheral nerves — the nerves outside the brain and spinal cord. To function normally, the nerve needs to have a healthy myelin sheath, the tissue that insulates it. A nerve that is functioning normally, with its myelin sheath intact, transmits stronger and faster electrical signals than one that is damaged.
To perform the test, the doctor places two electrodes on the patient’s skin over the nerve — one that sends out a mild electrical signal and one that records it. The doctor then uses a brief, mild electrical shock to stimulate the nerve. Nerve conduction velocity is calculated as the distance between the electrodes divided by the time it takes the electrical signals to travel between them.
A nerve conduction velocity test can be used to detect and evaluate several different conditions, including carpal tunnel syndrome, diabetic neuropathy (diabetes-related nerve disease), herniated disk disease, sciatic nerve problems, and pinched nerves.