What is EMG?
EMG/Nerve Conduction Study is a diagnostic procedure that assesses the health of muscles and the nerve cells that control them (motor neurons). Motor neurons transmit electrical signals that cause muscles to contract. An EMG translates these signals so that a specialist can interpret them. EMG results can reveal nerve dysfunction, muscle dysfunction or problems with nerve-to-muscle signal transmission.
Why is it Done?
Your doctor may order an EMG if you may have a nerve or muscles disorder. Indicating symptoms may include:
- Tingling or numbness
- Muscle weakness
- Muscle pain or cramping
- Certain types of limb pain
EMG results can help diagnose or rule out such conditions as:
- Muscles disorders, such as muscular dystrophy or polymyositis
- Diseases affecting the connection between the nerve and the muscle, such as myasthenia gravis
- Disorders of nerves outside the spinal cord (peripheral nerves), such as carpal tunnel syndrome or peripheral neuropathies
- Disorders that affect the motor neurons in the brain or spinal cord, such as amyotrophic lateral sclerosis or polio
- Disorders that affect the nerve root, such as a herniated disk in the spine
How is it Done?
During a needle NCS, a needle electrode inserted directly into a muscle records the electrical activity in that muscle. The needle electrode may cause some minor discomfort or pain that should end shortly after the needle is removed.
A nerve conduction study, uses electrodes taped to the skin (surface electrodes) to measure the speed and strength of signals traveling between two or more points.
How can I prepare for an EMG?
Take a shower or bath shortly before your exam to remove oils from your skin. Don't apply any lotions or creams before the exam. Please let our team know if you have a pacemaker or other electrical medical device, if you take blood-thinning medications, or if you have hemophilia.
We'll give you more detailed instructions when you schedule your appointment.