The electro-neurodiagnostic exam usually takes 45- 60 minutes to perform and involves two parts: (1) nerve conduction studies and (2) the needle exam. Your doctor has recommended that you undergo nerve testing because you have numbness, tingling, pain, weakness, or muscle cramping.
If you have a pace-maker or any other implanted electrical device(s) let the doctor who performs the test know before the testing begins.
The doctor will take standard measurements on your arms and/or legs (both arms or both legs are usually done to compare side to side) and surface electrodes are placed over different body parts. The nerves are then stimulated with a low level of electricity. This is often reported as feeling like small shocks similar to touching a doorknob and getting a jolt.
In the needle exam a small disposable needle electrode is used to sample multiple muscles (usually 5-10) in each of the affected extremities. The needle electrode picks up the electrical signals of the muscles. The diameter of the needle electrode is much smaller than most needles used to draw blood and therefore usually causes only minimal discomfort.
Frequently Asked Questions:
Do I need to do anything special prior to my EMG test?
It is recommended that you do not use moisturizing cream on your arms, hands, legs and feet (the adhesive on the surface electrodes is affected by moisture). The use of moisturizing cream may prolong your test or even make it impossible to complete. If your discomfort is in your upper extremities (arms/hands) or neck please wear a T-shirt or garment that allows easy access to the arms and neck. If your discomfort is in your lower extremities (legs/feet) please wear shorts or garments that allow easy access to your legs / lower back.
Do I need to stop any medications prior to the EMG test?
You may continue taking all medication prescribed by your physicians except for blood thinners Warfarin (Coumadine), Plavix (Clopidogrel), Aggrenox. If you are on these medications please check with your physician as to the risks and benefits of coming off these medications so that the EMG can be performed. If you show up on test day and have recently taken these medications only the nerve conduction studies may be done.
If you are currently taking anti-inflammatory medications such as Ibuprofen, Celebrex, Naprosyn, or pain medication such as Tylenol, Vicoden or Darvocet continue to take as directed by your physician.
Do I need a ride home from after the test?
No. Unless you are under the influence of medication that interferes with your ability to drive, you can drive yourself to and from the test. You do not need to bring a friend or relative to the test.
Risks of the Procedure
Parts of this test are contraindicated in persons with a pace-maker or any other implanted electrical device(s). If you have a pace-maker or any other implanted electrical device(s) or bleeding disorder, if you are on blood thinners please let the doctor who performs the test know before the testing begins. All your medical information as always will remain confidential in accordance to the HIPPA privacy laws.
Some discomfort, similar to the feeling of an injection or an acupuncture needle, may be felt when the needle electrodes are inserted into the muscle. Afterwards, the muscle may feel sore for a few days and a bruise may appear at the needle-stick site.
No known contraindications exist from performing needle EMG and nerve conduction studies on pregnant patients. In addition, no complications from these procedures have been reported in the literature.
The risks of this test include bruising, bleeding and infection due to needle placement. These risks are no greater than getting an immunization or IV placed. This is why your skin will be cleaned with alcohol wipes and we only use disposable needles which are thrown away after each patient.
EMG is usually contraindicated in persons receiving anticoagulant therapy (blood thinning medication such as Coumadin) because the needle electrodes may cause bleeding within the muscle. EMG may also be contraindicated in persons with extensive skin infections due to the risk of spreading infection from the skin to the muscle.
Certain factors or conditions may interfere with EMG test results. Swelling, bleeding, or obesity may interfere with the transmission of electrical waves to the electrodes, and thereby alter the EMG results.