Normal Values:

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

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

What abnormal results mean:

Most often, abnormal results are due to some sort of nerve damage or destruction, including:

• Axonopathy (damage to the long portion of the nerve cell)
• Conduction block (the impulse is blocked somewhere along the nerve pathway)
• Demyelination (damage and loss of the fatty insulation surrounding the nerve cell)

The nerve damage or destruction may be due to many different conditions, including:

• Alcoholic neuropathy
• Diabetic neuropathy
• Nerve effects of uremia (from kidney failure)
• Traumatic injury to a nerve
• Guillain-Barre syndrome
• Diphtheria
• Carpal tunnel syndrome
• Brachial plexopathy
• Charcot-Marie-Tooth disease (hereditary)
• Chronic inflammatory polyneuropathy
• Common peroneal nerve dysfunction
• Distal median nerve dysfunction
• Femoral nerve dysfunction
• Friedreich's ataxia
• General paresis
• Mononeuritis multiplex
• Primary amyloidosis
• Radial nerve dysfunction
• Sciatic nerve dysfunction
• Secondary systemic amyloidosis
• Sensorimotor polyneuropathy
• Tibial nerve dysfunction
• Ulnar nerve dysfunction

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