What are EMG tests?
The Iowa Clinic offers a range of advanced diagnostic procedures to help diagnose and treat various health conditions. One such procedure is Nerve Conduction Studies (NCS) coupled with Electromyography (EMG), collectively known as EMG tests.
Who needs an EMG test?
A nerve conduction study (NCS) is a test that measures the speed and strength of electrical signals traveling through your nerves. EMG tests are typically ordered for patients experiencing signs or symptoms that may indicate a nerve or muscle disorder. These symptoms may include:
- Numbness of a certain part of the body
- Weakness of muscles
- Tingling sensation
- Muscle or limb pain
It is used to diagnose a variety of nerve and muscle disorders, including:
- Carpal tunnel syndrome
- Peripheral neuropathies
- Muscular dystrophy
- Polymyositis
- Amyotrophic lateral sclerosis
- Polio
- Neuromuscular diseases such as myasthenia gravis
- Nerve root disorders such as a herniated disk in the spine
How does an EMG and NCS test work?
An EMG tests muscles and nerves for abnormal patterns of electrical activity. This test only measures muscle activity, so it is often done along with an NCS test – a study that goes beyond observation and stimulates your nerves with small bursts of energy. An EMG test can detect peripheral nerve damage and can tell if a muscle is truly weak or if you just aren’t using it because of pain.
What should I expect during an EMG test?
If you are having an NCS, then small pads will be taped along the path of the nerve. These pads deliver light electric “shocks” that are too mild to be harmful; they feel a bit like the shock you get when you first rub your feet on carpet then touch a doorknob. One end of your nerve is stimulated with the electricity, and if your nerve is functioning properly, then the pads along the nerve will capture the signal as it passes. The signal moves faster or slower depending on how healthy your nerve is.
During an EMG, thin needles will be inserted into the muscles being tested. The needles are thinner than those used to draw blood, but you may still feel some discomfort. Each needle contains an electrode attached to a wire. The wire transmits signs from the electrode in your muscle to a machine called an oscilloscope. The oscilloscope displays the signals as an electrical waveform on a screen. You may be asked to slowly contract your muscle.
The EMG test takes about 30 to 60 minutes, depending on how many muscles are being tested.
What are the risks of EMG test and NCS?
The needles won’t cause bleeding, and the shocks are too mild to cause any damage to your muscles. Your muscles may be sore for a day or two following the test.
If you are experiencing symptoms like numbness, tingling, muscle weakness, or pain, The Iowa Clinic can perform EMG tests to assist in your diagnosis and develop an appropriate treatment plan. Our team of skilled providers provides you with accurate results and exceptional care, ensuring your journey toward optimal health.