Neurological Associates

Electromyogram (EMG) and Nerve Conduction Studies (NCS): An explanation of the procedure

The EMG/NCS are tests used to detect nerve and muscle problems. An electromyogram measures the electrical activity of muscles, whereas the nerve conduction study measures the speed and intensity of electrical signals as they travel along the nerves.

How these tests work

Nerve and muscle cells produce tiny amounts of electricity. Our nerves send electrical signals to the muscles while our muscles produce electrical activity during motion. When nerves and muscles are affected by injury or disease, their electrical activity can be altered.

EMG/NCS equipment can detect changes in electrical activity. Electrodes record electrical activity of the nerves or muscles and a computer analyzes, stores, and prints this data. A monitor will display the electrical activity in wave patterns while a speaker allows the electrical activity to be heard by the technician or physician.

What will happen during the test

During an EMG, you will lie flat in a comfortable and relaxed position. Certain areas of your skin may be cleaned. A small, thin needle electrode is inserted into the muscle- you may feel pressure or a dull ache. Other electrodes will be attached to the skin.

During an NCS, you will lie in a comfortable and relaxed position. The areas of your body being tested will be cleaned and gel will be applied. Three small, flat electrodes will be taped to your skin. Stimulating electrodes are held against your skin. You will feel a shocking sensation each time the nerve is stimulated.

Allow approximately 60 minutes for the two-part test:

• Part 1- Nerve Conduction (30minutes)
• Part 2- Electromyogram (30 minutes)

You may feel tenderness or soreness in the tested muscles for a few hours after your test. To relieve discomfort, apply ice wrapped in a cloth or a cold pack to the affected area. You may also take an over-the-counter pain medication such as acetaminophen or Ibuprofen.

Test preparation

• You may bathe or shower on the day of your test. Please do not use bath oils, lotions, or creams.
• Eat meals according to your usual daily schedule.
• Be sure to tell the physician or technician about any medications you are currently taking (especially Coumadin), if you bruise easily, have hemophilia, diabetes, a pacemaker, or a skin infection.
• If you are taking Coumadin, you MUST have blood work drawn 2 to 3 days prior to testing (INR levels and protime). Please bring your lab results with you the day of your test.
• Allow plenty of time to avoid feeling rushed. Please arrive 20 minutes prior to your appointment in order to complete check in and have any additional questions answered.
• Please do not bring your children to your appointment due the equipment and limited space. Family must remain in the waiting room.
• If you are taking Mestinon (Pyridostigmine), please let us know at the time of scheduling for further instructions.

Frequently asked questions

• Does the Electromyogram hurt?
  Most patients feel temporary pain or discomfort during the EMG. However, most are able to tolerate this minor level or pain quite well. Anesthesia or sedation is not needed.
• Does the Nerve Conduction study hurt?
  Most patients feel an unusual tingling sensation during the study. Some may also experience slight, temporary pain.
• Are there any associated risks?
  Risks are usually very minor for EMG and nerve conduction studies. Patients with certain medical conditions may have increased risks. As with any procedure, be sure to discuss with your doctor all risks and benefits.
• Why do I have to undergo this test?
  Both an EMG and nerve conduction study can be quite effective in helping your physician make an accurate diagnosis and develop an effective care plan for you.
• How soon will I receive the results?
  Test results are faxed to your ordering physician as soon as they are available, usually 5-7 business days after your test. Please contact your physician’s office if you have not received your test results after one week.

Locations we offer testing

Your visit will be at one of the following testing sites. Please arrive 20 minutes prior to your appointment time.

Brain and Spine Center
1011 Johnston Willis Dr., Suite 200
Richmond, VA 23235
Phone: (804) 272-9146
Fax: (804) 288-9053
Provider: Robert White, MD

Sarah Cannon Cancer Institute
7607 Forest Ave., Suite 300
Henrico, VA 23229
Phone: (804) 288-2742
Fax: (804) 288-9053
Provider: Mary Beth Ramsey, MD

What is MRI-guided focused ultrasound?

MRI-guided focused ultrasound is a minimally invasive procedure for the treatment of essential tremor and Parkinson’s disease related tremors. It uses high-intensity ultrasound energy, guided by magnetic resonance imaging (MRI) to heat an exceedingly small, targeted area of the brain treating the tremor. This procedure does not involve any significant radiation.

Prior to the procedure

• A video or in-person consultation will be arranged with the neurosurgeon. Patients are educated about the procedure by the nurse practitioner. During this session, patients and family members have the opportunity to ask questions.
• A computerized tomography (CT) scan and MRI of the brain will be ordered.
• Instructions will be given to discontinue essential tremor medications the night before the procedure, except for Propranolol which should not be discontinued.
• If you are on a blood thinner, you will be advised to stop taking it two days before the procedure with approval of your prescribing doctor.
• Patients are advised not to eat or drink anything after midnight before the procedure.

Day of the procedure

• This is an outpatient procedure. You will be assigned a private suite and a very experienced nurse will be with you throughout the procedure. Your family member will be updated throughout the day of treatment.
• An IV will be placed, and you will receive an antibiotic, nausea medication, and any other necessary medications.
• Your head will be shaved by your nurse. This allows the ultrasound to work properly.
• Numbing medication will be applied to your scalp and a head frame will be secured. The frame remains in position during the procedure. An anesthesiologist will be present to administer medications if needed. This procedure does not require general anesthesia. You will not be put to sleep.
• After the completion of the frame placement, patients are taken to the MRI suite. There, a silicon membrane is placed on your head that will circulate cool water. This minimizes potential heating near the scalp.
• You will lie flat on your back on a dedicated bed in the MRI suite. If you have difficulty lying flat, please inform your neurosurgeon during the initial consultation.
• You must be awake during the process and be able to communicate with the treatment team. The procedure will be guided by the neurosurgeon and his team working together outside the MRI room where you are being closely monitored by the entire team. Your nurse will be with you throughout the procedure, monitoring your blood pressure, heart rate, and well-being and providing you with warm blankets since the room can get quite cold. The MRI imaging enables the neurosurgeon to locate and fine-tune the area that needs to be treated. Small doses of ultrasound energy will be given as a test to help confirm the proper location.
• The treatment team will be in and out of the MRI suite monitoring and testing you on several occasions. They will ask you questions and have you perform simple tasks such as speaking, writing, or to pretend you are drinking from a bottle of water. They may also ask you to do other tasks which may provoke your tremors.
• Once the neurosurgeon and the team are confident of the location, the focused ultrasound energy will be increased to make further improvement in your tremor. In most cases, immediate results are noticeable.
• When the procedure is complete, you will leave the MRI treatment area and return to your suite. The head frame will be removed, and pain medication will be given if needed. You will be able to have something to eat and drink at this point.
• An MRI scan is done upon completion of the treatment.
• Patients are discharged from the hospital same day after the treatment. A responsible adult must be available to drive the patient home.
• Discharge instructions are reviewed.

Procedure completion

• A follow-up visit is arranged with the neurosurgeon about two weeks after the procedure.
• An MRI would be ordered four months after the procedure. This MRI can be done at a center close to your home if you do not reside in Richmond, Virginia. You may request a video consult or an office visit after the MRI to discuss the results. Occasionally, some patients may have trouble with balance, dizziness, numbness, or tingling. These effects usually are transient and improve with time. Always stay in touch with your neurosurgeon’s office.

Questions or concerns?

If you have questions or concerns prior to your procedure, contact our Navigator, Denise Laine, at (804) 483-5711 or via email.