Skip to main content



Nerve Conduction Velocity Study (NCV/EMG)

Electroencephalography (EEG)

Ambulatory EEG

Evoked Potentials

Transcranial Doppler (TCD)

Carotid Ultrasound

Nerve Conduction Velocity Study (NCS/EMG)

Nerve Conduction Studies and Electromyography are two separate tests that are usually done one after the other.

Preparation for this procedure:

  • No children please.
  • Please be on time. If you are more than 10 minutes late, your test may be rescheduled.
  • You may eat, drink, and keep your normal schedule until the test.
  • If you smoke, please refrain from doing so until after the test.
  • Please notify your doctor if you are on blood thinner medications such as Coumadin. Your dosage may need to be adjusted, or the doctor may take you off the medication a few days before the test.

What can I expect?

The technician may ask you to remove your clothes and give you an appropriate robe. This test is a two-part test beginning with the NCS portion. During this time, the technician places some electrodes on the area to be tested. With an instrument, the tech sends a series of electrical shocks through to test the nerves in the area. This usually does not hurt, though it can be uncomfortable. The computer registers how long it takes for electricity to pass between electrodes. This is done to evaluate the nerves.

The second portion of the test is EMG. The doctor does this portion of the test, which involves the insertion of some very fine needles into the muscle to check electrical activity within the muscle. The doctor will ask you to move in different positions to evaluate the muscle. This portion of the test can be painful, but it is usually done very quickly. The NCS and EMG may take from 45-60 minutes. You may resume your daily activities as usual. Please make a follow-up appointment with the doctor to get the results of the test. Results are usually available within a week.

Electroencephalography (EEG)

An electroencephalogram (EEG) is a test that measures and records the electrical activity of your brain. Special sensors (electrodes) are attached to your head and hooked by wires to a computer. The computer records your brain’s electrical activity on the screen or on a paper as wavy lines. Certain conditions, such as seizures, can be seen by the changes in the normal pattern of the brain’s electrical activity. The duration of the test is 45 minutes to an hour.

Preparation Instructions:

It will help us to get an accurate EEG test result if you follow a few instructions before coming in for your EEG test.

  • Try to get NO MORE than six (6) hours of sleep the night before your EEG test. It will help if you are sleep deprived.
  • You may have a small meal. Before your test, no caffeine (coffee, tea, coke). No natural stimulants like orange juice.
  • Take your medications as prescribed but no sedation medications (like Valium or Ativan) are allowed before the test.
  • We will be working with your head so come with clean hair; no sprays, gels, or oils in the hair.
  • You will need to shampoo afterwards. Hats are suggested.

Ambulatory EEG

Ambulatory EEG (Electroencephalogram) enables the interpreting neurologist to actually look at events along with associated electroencephalographic discharges. The patient then typically goes home with the equipment and goes about usual activities. Any specific events are recorded and then reviewed in detail after the patient is unhooked. Typically, this test is done in patients who are having unrecognized seizures, frequent seizures, or pseudoseizures.

Evoked Potentials

Evoked Potentials, sometimes called Evoked Responses, are tests that record the brain’s response to sounds, touch, and light. These tests help to evaluate a number of neurological conditions.

  • Brainstem Auditory Evoked Potential (BAER) checks the pathway from the ear to the brain. The BAEP test may help uncover the cause of hearing balance problems, and other symptoms.
  • Somatosensory Evoked Potential (SSEP) checks the pathway from the nerves in the limbs to the brain. It is the way to study the function of the nerves, the spinal cord, and brain.
  • Visual Evoked Potential (VEP) checks the pathway from the eyes to the brain and may help find the cause of certain vision problems and other conditions.


  • No children please.
  • Please be on time. If you are more than 10 minutes late, your test may be rescheduled.
  • You may eat, drink, and keep your normal schedule until the test.
  • The evening before or morning of your appointment, wash and dry your hair but do not apply any spray, oil, mousse, or cream.
  • Please do not wear perfume or apply lotions or oils to your skin.
  • If you have contact lenses, glasses, or a hearing aid, please wear them for this test.

What can I expect?

For each of these tests, a technologist will use toothpaste-like gel to position and apply small electrodes to your scalp (in some cases, on your earlobes, shoulders, neck, and back). The electrodes will be attached to equipment that records your brain’s responses to certain stimuli. Each test takes approximately 45 to 60 minutes to perform and is painless, safe, and performed with little to no discomfort.

After care:

You may resume your normal activities immediately after testing. You must schedule a follow-up appointment for these results approximately a week after the test ism performed.

Transcranial Doppler (TCD)

A TCD uses ultrasound waves to measure blood flow rate and direction in the main cerebral arteries of the brain. It helps detect blockages, narrowing, or spasms of the arteries. TCD is non-invasive and has no risks.

No special precautions are necessary. No special preparation is needed. There are no diet or activity restrictions before the test. The patient may remove their contact lenses and may wish to avoid use of make up, since the gel is likely to smear it.


The test does not involve the use of needles or injections. TCD is done with either one or two probes placed against the skin. The examiner spreads a clear gel on the areas of the head where the probe will be placed:

  • On each side of your head.
  • Under your chin.
  • Over your closed eyelid.
  • At the back of your neck.

In these places there is the least amount of thick protective bone so the sound waves can penetrate the best. The examiner adjusts the probe position and orientation to direct the sound waves toward the blood vessels of interest. Finding the best approach may take some time. A compression test may be performed during the exam. In this test, the main artery in the neck (carotid artery) is briefly compressed, and changes in blood flow patterns are observed. A full TCD exam may last 30-45 minutes, and often longer in patients with disease.

After care:

The gel is washed off with soap and water. No other after care is needed.

Carotid Ultrasound

Carotid Ultrasound is a painless and harmless test that uses a high frequency sound wave to create pictures of the insides of the two large arteries in your neck. These arteries, called the carotid arteries, supply your brain with oxygen rich blood. You have one carotid artery on each side of your neck.

There is no special preparation for a carotid ultrasound.

The carotid examination procedure can take up to 20 minutes.


Neurology Center of Las Vegas
2480 Professional Court
Las Vegas, NV 89128
Phone: 702-936-3309
Fax: 702-405-3017

Office Hours

Get in touch