What is Electromyography?
Electromyography, sometimes referred to as EMG or Nerve Conduction Testing, is an examination that aids your doctor in the recognition, classification, and treatment of certain conditions associated with the muscles and nerves such as: carpal tunnel syndrome, cervical radiculopathy, lumbar radiculopathy, polyneuropathy, ALS, and many others. The typical electromyographic examination consists of two testing procedures: nerve conduction examination (NCS), and needle examination (EMG). Most EMG examinations take an average of 1-2 hours.
Nerve Conduction Examination (NCS)
A NCS is a test that measures the ability of a specific nerve to conduct an electrical signal. The NCS test is performed by placing small electrodes on the surface of the skin over a specific muscle or nerve. Then, using a nerve stimulator, the nerve is stimulated with a small electrical charge; this charge produces an electrical sensation which is not usually painful. Most people report that it feels similar to the static electrical shock you may get from walking across the carpet. As the nerve is stimulated it conducts an impulse from which various measurements are taken at the recording sites.
Electromographic Needle Examination (EMG)
An EMG is a test that measures the naturally occurring signals your body uses when the nerve communicates with the muscle. This test is performed by inserting a very fine needle (similar in size to an acupuncture needle) just under the skin into a muscle. The needle is moved very slightly within the muscle while it is “at rest” and various measurements are taken. The patient is then asked to gently move the muscle and measurements are taken as it “work”. No external electricity is used. There may be some discomfort with the insertion of the needle. One or more muscles may be tested in this manner.
The muscle may be slightly sore for a day or two after these exams and occassional bruising occurs. There is very minimal risk of infection from this exam.
How to prepare for your test
Please bathe or shower on the day of your appointment. This helps to remove your body’s natural oils and makes the test easier for you and the examiner.
Do not apply oils or lotions to your skin the day or your test. This can interfere with the recording of the neural signals and make testing more difficult for you and the examiner.
Do not wear tight fitting clothes.
If you are having testing on your hands, wrists, or arms, please wear a loose top that will allow the sleeve to be pulled up to the top of your arm. If you forget we will have a gown for your convenience.
If you are having testing on your feet or legs, please wear loose fitting shorts or pants that will allow the pant legs to be pulled up 3 or 4 inches above the knees. If you forget we will have a gown for your convenience.
Please let us know in advance if you have any bleeding problems, take blood thinning medications (including aspirin), or are having any lab tests or biopsies being done in the near future.
Take your routine medications, unless advised not to.
After the examination
After the exam you can resume your normal activities as tolerated. A report of the examination will be sent to the practitioner who ordered the exam and they will discuss the results with you.