Electromyography (EMG) measures muscle response or electrical activity in response to a nerve’s stimulation of the muscle. The test is used to help detect
neuromuscular abnormalities
. During the test, one or more small needles (also called electrodes) are inserted through the skin into the muscle.
What happens if EMG is abnormal?
If your EMG shows abnormal electrical activity when a muscle contracts, then you may have
a herniated disc or a nerve disorder
, such as ALS or carpal tunnel syndrome. Depending on your results, your doctor will talk to you about any additional tests or treatments that might be needed.
What diseases can EMG diagnose?
- Amyotrophic lateral sclerosis (ALS)
- Carpal tunnel syndrome.
- Cervical spondylosis.
- Guillain-Barre syndrome.
- Lambert-Eaton syndrome.
- Muscular dystrophy.
- Myasthenia gravis.
Why would a doctor order an EMG?
EMG results are often necessary to help diagnose or rule out a number of conditions such as:
Muscle disorders
, such as muscular dystrophy or polymyositis. Diseases affecting the connection between the nerve and the muscle, such as myasthenia gravis.
Will an EMG show a pinched nerve?
EMG and NCS are tests that measure the electrical activity of the muscles and nerves of the body, usually to an arm or a leg. The tests can help identify nerve injury or muscle disease such as carpal tunnel syndrome, a pinched spinal nerve, peripheral neuropathy, myositis, or ALS.
Can an EMG make things worse?
Muscle pain
from an EMG test gets worse or you have swelling, tenderness, or pus at any of the needle sites.
Can I drive home after EMG?
You will not be able to drive for about 24 hours if you had sedation
because you will still be drowsy. You will need a ride home from your procedure, and someone should stay with you for the first day. When should I call my doctor? It is important to keep your follow-up appointments after an EMG test.
What is an abnormal EMG?
An abnormal EMG result means
there is a problem in an area of muscle activity
—turning on and off, when it is active, how much it is active, if it is more or less active, and fatigue. This can offer a clue in diagnosing various nerve and muscle conditions. Learn more in 10 Conditions Diagnosed With an EMG.
Why was my EMG so painful?
Pain is commonly associated with EMG,
because the procedure involves the use of needles and electric shock
. Not only friends and relatives who have had a previous EMG experience, but also physicians can sometimes discourage patients from undergoing EMG, believing that the test is very painful and of little benefit (1).
What are the signs of nerve damage?
- Numbness or tingling in the hands and feet.
- Feeling like you’re wearing a tight glove or sock.
- Muscle weakness, especially in your arms or legs.
- Regularly dropping objects that you’re holding.
- Sharp pains in your hands, arms, legs, or feet.
- A buzzing sensation that feels like a mild electrical shock.
What are normal EMG results?
Normal Results from an EMG
Normal EMG results
will appear as no electrical activity while at rest
. It means your muscles are healthy and normal. Your muscles also react normally to stimulation, in a smooth pattern.
How long does it take to get EMG results back?
EMG testing usually takes anywhere from
30 to 90 minutes
, depending on the condition being tested and findings of the study. A report that includes the results and an interpretation will be sent to your doctor.
How does a neurologist check for nerve damage?
By
measuring the electrical activity they
are able to determine if there is nerve damage, the extent of the damage and potentially the cause of the damage. Frequently the neurologist will recommend common, noninvasive neurological evaluations such as electromyography (EMG) and nerve conduction velocity (NCV) testing.
Does nerve damage show up on MRI?
Nerve damage can usually be diagnosed based on a neurological examination
and can be correlated by MRI scan findings. The MRI scan images are obtained with a magnetic field and radio waves. No harmful ionizing radiation is used.
Can an EMG detect a tumor?
You’re likely to have this test along with your EMG . It measures how quickly your nerves carry electrical signals to your muscles. Tumor biopsy. If imaging tests identify a nerve tumor, your doctor may remove and analyze a small sample of cells (biopsy) from your tumor.
How painful is EMG?
Is an EMG painful?
Yes
. There is some discomfort at the time the needle electrodes are inserted. They feel like shots (intramuscular injections), although nothing is injected during an EMG.
