What is a NCV Test?

A nerve conduction velocity (NCV) test measures the degree of damage in large nerve fibers, revealing whether symptoms are caused by degeneration of the myelin sheath or the axon. The myelin covering is responsible for the very fast speed of nerve conduction. During this test, a probe electrically stimulates a nerve fiber, which responds by generating its own electrical impulse. An electrode placed further along the nerve’s pathway measures the speed of impulse transmission along the axon. Slow transmission rates and impulse blockage tend to indicate damage to the myelin sheath, while a reduction in the strength of impulses at normal speeds is a sign of axonal degeneration.

This test is done by a Neurologists in their office or a trained technician.

Electromyography (EMG) involves inserting a fine needle into a muscle to record electrical activity when muscles are at rest and when they contract. EMG tests detect abnormal electrical activity in motor neuropathy and can help differentiate between muscle and nerve disorders.

There is limited value of performing EMG test on a patient with suspected neuropathy.