Electromyography (EMG) and nerve conduction studies (NCS)

This page from Great Ormond Street Hospital (GOSH) explains the procedure for EMG and nerve conduction studies and what to expect when your child has these tests.

Electromyography, or EMG, is used to test the electrical activity of nerves and muscles. Nerve conduction studies test how nerves transmit electrical activity through the body. EMG and nerve conduction studies are used to diagnose conditions that may be affecting them and causing weakness.

Why EMG tests or a nerve conduction study are needed

Our brain controls how our muscles move by sending an electrical signal down a series of nerve cells. These signals tell our muscles when to contract and when to relax. In some medical conditions, the electrical activity in the muscles or nerves is not working normally, which can lead to muscle weakness. EMG and nerve conduction studies are used to look at whether the weakness is being caused by problems with the muscles, or by the nerve supply to those muscles.

The EMG test

An EMG test uses sticky pads (electrodes) placed on the skin or a fine needle in the muscle to record muscle activity.

Nerve conduction study (NCS)

A nerve conduction study uses small electrical pulses to stimulate the nerves and measure how fast the pulse moves along the nerve. This can cause mild tingling. The pulse is very quick, and lasts less than a hundredth of a second.

How it feels

With the nerve conduction study, your child may experience mild tingling and discomfort, which may feel a little unpleasant. Keep in mind that each electrical pulse is very quick and will last less than a hundredth of a second.

Your child may feel a small amount of discomfort during the EMG when the wire goes in, but the wires are very small. The team will use distraction therapy to help your child cope.

Contact information

If you require more information about the test or have any questions, please contact the Department of Clinical Neurophysiology between Monday and Friday, between 9am and 5pm.

Telephone: 0207 813 8471