Electromyography (EMG) is a technique for evaluating and measuring the response of muscles and nerves to electrical activity. It’s used to help determine muscle conditions that might be causing muscle weakness, including muscular dystrophy and nerve disorders.
In some medical conditions the electrical activity of the muscles or nerves is not normal. Finding and describing these electrical properties in the muscle or nerve helps to diagnose conditions.
Electromyography helps to diagnose three different kinds of diseases that can interfere with normal muscle contraction:
- Diseases of the muscle itself (such as muscular dystrophy).
- Diseases of the neuromuscular junction (such as myasthenia gravis).
- Diseases in nerves and nerve roots (such as sciatica).
Muscles are stimulated by signals from nerve cells called motor neurons. This stimulation causes electrical activity in the muscle, which in turn causes the muscle to contract or tighten. The muscle contraction itself produces electrical signals.
To perform EMG, a needle electrode is inserted into the muscle (the insertion of the needle might feel similar to an injection). The signal from the muscle is then transmitted from the needle electrode through a wire to a receiver/amplifier, which is connected to a device that displays a readout, which is observed by a trained professional (neurologist, physiatrist, or physical therapist).
When intramuscular Electromyography is deemed too invasive, an EMG may also be performed without skin penetration, using a surface electrode. Surface EMG monitors the general picture of muscle activation, as opposed to intramuscular EMG, which focuses on the activity of only a few muscle fibers.
About Alpana Gowda, MD
EMGs are performed by our staff Physiatrist, Alpana Gowda, MD.
Physiatry is the branch of medicine emphasizing the prevention, diagnosis, and treatment of disorders – particularly related to the nerves, muscles, bones and brain – that may produce temporary or permanent impairment.
Dr. Gowda is a board certified in Physical Medicine & Rehabilitation and Pain Medicine. She specializes in treating back and joint pain, utilizing minimally invasive techniques such as EMG to diagnose and treat pain.
Appointments with Alpana Gowda, MD may be scheduled through our clinic by calling 408-370-6300 or by submitting the form below.