Nerve Conduction Study (NCS)

A Nerve Conduction Study (NCS) is a diagnostic test used to evaluate the function and health of your peripheral nerves (the nerves outside your brain and spinal cord). It measures how fast and how strong an electrical impulse travels through a specific nerve, helping to identify areas of nerve damage or compression.

While both are electrodiagnostic studies often done during the same appointment, they measure different things. An NCS tests how well the nerves are conducting electrical signals. An EMG tests how well the muscles are receiving those signals and responding to them.

Your doctor will recommend an NCS if you have symptoms of nerve damage, such as continuous tingling, burning pain, or loss of sensation in your extremities. It is the gold standard for diagnosing conditions like Carpal Tunnel Syndrome, Herniated Discs (sciatica), and peripheral neuropathy often caused by diabetes.

The doctor will place small, flat electrode patches on your skin over the nerve being tested. A very mild, brief electrical pulse is delivered through one electrode to stimulate the nerve, while another electrode records the response. The computer calculates the speed of the signal based on the distance between electrodes.

Preparation is very simple. You should shower and wear loose, comfortable clothing. The most important rule is to avoid applying any lotions, creams, oils, or perfumes to your skin on the day of the test, as these can interfere with the electrode pads and affect the accuracy of the results.