electromyograph

An electromyograph is a medical device used to assess the health of muscles and the nerve cells that control them. These nerve cells, called motor neurons, transmit electrical signals that cause muscles to contract. Electromyography, often abbreviated as EMG, is the process of using an electromyograph to record these signals.

The procedure typically involves placing small electrodes on the skin over the muscle being tested or, in some cases, inserting thin needle electrodes directly into the muscle. These electrodes detect the electrical activity produced by muscle fibers when they are stimulated. A more specialized test called nerve conduction studies (NCS) can be performed alongside EMG to measure how quickly and effectively electrical signals travel along nerves.

An electromyograph works by amplifying the tiny electrical signals generated by muscle activity and displaying them on a screen as waveforms. A healthcare professional, usually a neurologist or physiatrist, analyzes these waveforms to identify abnormalities. These abnormalities can indicate conditions such as nerve damage, muscle disease, or disorders affecting the connection between nerves and muscles, like myasthenia gravis.

EMG is a diagnostic tool used to help diagnose a wide range of neuromuscular disorders. It can help pinpoint the location and severity of nerve or muscle problems, aiding in the diagnosis and management of conditions like carpal tunnel syndrome, herniated discs, amyotrophic lateral sclerosis (ALS), and peripheral neuropathy. The information gathered from an EMG can guide treatment decisions and help predict prognosis.