Electromyogram (EMG): Test, Definition, Results, Machine

Definition: what is an electromyogram?

An electromyogram (EMG) is a medical exam that can detect electrical activity in the nerves and muscles and can also evaluate nerve damage. It is used in cases of nerve problems such as peripheral neuropathy.

How to carry out an electromyogram

An electromyogram is carried out by a neurologist and is done in two stages. Initially, needle-shaped electrodes are inserted into the skin and then the muscle, in the area to be examined (arm, leg, foot…). These then measure the electrical activity in the muscle whilst the patient relaxes and contracts the muscle. This is the detection test. A healthy muscle produces no electrical activity when resting, however it does when the muscle contracts.

The EMG can also be used for a stimulation test which is when a mild and brief electrical current is sent along the nerves in order to stimulate muscle activity. This is used to evaluate nerve conduction speed.

It is a relatively long test and the duration of an electromyogram lasts between half an hour and an hour.

Complications of an electromyogram

An electromyogram is a non-risky procedure; there are nearly no complications or secondary effects. In some cases however, the patient can end up with a hematoma.