Neurology and Sleep Medicine Clinic Specializing in Epilepsy and Seizure Disorders.


EEG and Sleep Testing FAQ

How should I prepare for a sleep study?

For a few weeks prior to the scheduled test, try to follow your normal sleep routines. You should arrive for testing neither deprived of sleep nor over-rested.

Do not drink or eat any products containing caffeine (coffee, tea, carbonated beverages, chocolate) for one day before the test.

Take a shower or bath before the test, but do not apply sprays, oils, or gels to your hair.

What should I wear?

Comfortable clothes such as exercise clothes, sweats, t-shirts and shorts, work best.

Should I bring my regular medication?

Yes, unless instructed otherwise by your doctor.

EEG / Sleep Testing Questions

Frequently asked questions: EEG

Please find below answers to questions about electroencephalograms (EEG).

Who performs the test?

A registered technologist with RHD.

A neurologist (someone who specializes in nervous system disorders) interprets the recordings taken from the EEG and then sends the results to your doctor within one to two weeks. Your doctor may schedule an appointment to go over the test results with you.

Electroencephalograms (EEG) tests

Three types of EEG testing may be performed:

  1. Routine EEG
    Allow one hour for this test.
  2. Sleep Deprived EEG
    Allow for 1.5 hours for this test. Awake, drowsy and sleep states will be monitored. Please deprive yourself of sleep by remaining awake the night prior to your test. You may eat and drink but avoid caffeinated beverages. 

    It is strongly recommended that you do not drive to and from this procedure.
  3. Prolonged EEG
    Video monitoring with partial sleep deprivation of four hours. You will be monitored for three hours with digital video during awake, drowsy and sleep states. Allow 3.5 hours for this test. You may eat and drink, but please avoid caffeinated beverages.

What you should do to prepare

  • Continue taking all medications prescribed by your doctor, unless instructed otherwise.
  • Please bring a list of current medications.
  • Wear comfortable clothing. You may be sitting and or lying on a bed during the test.
  • Shampoo your hair the day before your test. DO NOT use any hair gels, hairsprays, conditioners or lotions.
  • Hair extensions, hairpieces or wigs must be removed.

EEG testing is harmless, generally painless, and is a very sensitive technique for detecting neurological abnormalities.

An electroencephalogram (EEG) is a test that detects electrical activity in your brain using small, metal discs (electrodes) attached to your scalp. Your brain cells communicate via electrical impulses and are active all the time, even when you're asleep. This activity shows up as wavy lines on an EEG recording.

An EEG is one of the main diagnostic tests for epilepsy. An EEG can also play a role in diagnosing other brain disorders.

Why it's done

An EEG can determine changes in brain activity that might be useful in diagnosing brain disorders, especially epilepsy or another seizure disorder. An EEG might also be helpful for diagnosing or treating the following disorders:

  • Brain tumor
  • Brain damage from head injury
  • Brain dysfunction that can have a variety of causes (encephalopathy)
  • Inflammation of the brain (encephalitis)
  • Stroke
  • Sleep disorders

An EEG might also be used to confirm brain death in someone in a persistent coma. A continuous EEG is used to help find the right level of anesthesia for someone in a medically induced coma.

EEGs are safe and painless. Sometimes seizures are intentionally triggered in people with epilepsy during the test, but appropriate medical care is provided if needed.

How you prepare

Food and medications

  • Avoid anything with caffeine on the day of the test because it can affect the test results.
  • Take your usual medications unless instructed otherwise.

Other precautions

  • Wash your hair the night before or the day of the test, but don't use conditioners, hair creams, sprays or styling gels. Hair products can make it harder for the sticky patches that hold the electrodes to adhere to your scalp.
  • If you're supposed to sleep during your EEG test, your doctor might ask you to sleep less or avoid sleep the night before your test.

What you can expect

EEG electrodes

You'll feel little or no discomfort during an EEG. The electrodes don't transmit any sensations. They just record your brain waves.

Here are some things you can expect to happen during an EEG:

  • A technician measures your head and marks your scalp with a special pencil to indicate where to attach the electrodes. Those spots on your scalp might be scrubbed with a gritty cream to improve the quality of the recording.
  • A technician attaches discs (electrodes) to your scalp using a special adhesive. Sometimes, an elastic cap fitted with electrodes is used instead. The electrodes are connected with wires to an instrument that amplifies the brain waves and records them on computer equipment.

Once the electrodes are in place, an EEG typically takes up to 60 minutes. Testing for certain conditions requires you to sleep during the test. In that case, the test can be longer.

  • You relax in a comfortable position with your eyes closed during the test. At various times, the technician might ask you to open and close your eyes, perform a few simple calculations, read a paragraph, look at a picture, breathe deeply for a few minutes, or look at a flashing light.
  • Video is routinely recorded during the EEG. Your body motions are captured by a video camera while the EEG records your brain waves. This combined recording can help your doctor diagnose and treat your condition.

Ambulatory EEGs , which allow for longer monitoring outside an office or hospital setting are being utilized. This test can record brain activity over several days, which increases the chances of catching seizure activity.

After the test

The technician removes the electrodes or cap. If you had no sedative, you should feel no side effects after the procedure, and you can return to your normal routine.

If you used a sedative, it will take time for the medication to begin to wear off. Arrange to have someone drive you home. Once home, rest and don't drive for the rest of the day.


Doctors trained to analyze EEGs interpret the recording and send the results to the doctor who ordered the EEG. Your doctor might schedule an office appointment to discuss the results of the test.

If possible, bring along a family member or friend to the appointment to help you remember the information you're given.

How long does a Sleep Study take? When is it finished? Will I have to miss work?

Sleep studies are performed at night. You will be asked to arrive around 8:00 PM, and the studies are completed between 6:00 and 6:30 AM. For your comfort, a light snack is served in the evening, and a continental breakfast is served in the morning.

MSLT studies are performed during the day, and usually take about 6 hours to perform. The office manager will schedule your appointment at a time most convenient to you.

What happens during a sleep study? Will it hurt? Will I be able to go to the bathroom?

Sleep studies are not painful. Several electrodes with wires will be attached to your head, and most people quickly become accustomed to them and have no trouble sleeping. Once a patient is "hooked up," they are still mobile, and go to the bathroom without difficulty. They can also move about, sit in a recliner, and watch TV.

Will I see the Doctor in the morning?

No. The data that is collected during the study must be evaluated, and the reports are sent to your physician within 48 hours.

What about the cost?

Most insurance companies cover services for sleep disorders under medical benefits. Regional Health Diagnostics will verify coverage with your insurance carrier and discuss all financial matters prior to your test.

Where are you located?

Regional Health Diagnostics has multiple Neurodiagnostic, EEG, and Sleep Lab facilities located in multiple states and cities, including:

  • North Carolina (New Bern, Fayetteville, Havelock, Lumberton, Jacksonville, Wilmington, Kenansville, and Kinston)
  • Tennessee (Johnson City, Morristown)
  • Georgia (Columbus)
  • South Carolina (Greenville)
  • Alabama (Montgomery)
  • Florida (Wesley Chapel, Winterhaven).

We also have an international facility in Guatemala City, Guatemala.