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Electroencephalogram (EEG)

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An electroencephalogram (EEG) is a diagnostic test for measuring the electrical activity of the brain. The brain works non-stop, even while sleeping, by sending electrical impulses to other organs of the body.


Why is EEG done?


EEG is done to check several conditions associated with the brain. They are:

  • Epilepsy, different types of seizure
  • Brain injury, brain tumour or any kind of brain disorder or infection
  • Loss of memory- dementia, Alzheimer’s disease
  • Whether the individual in coma is brain dead
  • Nervous system and spinal cord injury
  • Mental disorder- psychosis
  • Sleep disorder- narcolepsy
  • Response of brain during surgery and post anaesthesia  


How is EEG done?


The activity of the brain is measured with the help of electrodes which are nothing but flat metal discs with an adhesive. The technician figures out the spots where the electrodes should be placed. Around 17-21 electrodes are attached on the scalp.

Electrodes caps are also available, which come along with the electrodes, thereby eliminating the need to fix them directly on the scalp.

The electrodes pick the electrical signals from the brain and send them to the amplifier via the wires. The amplifier is connected with a computer for the purpose of recording and measuring the data of the brain.

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How to prepare for EEG?

You need to tell your doctor about the medicines you take. Pills that might interfere with the electrical activity of the brain would be stopped.
You cannot eat caffeinated foods (chocolates) or drinks (tea, coffee, cola) 12 hours before the test

You will be asked to rinse your hair with a shampoo if the electrodes need to be placed on the scalp. Do not apply conditioner, gel, oil or any other cosmetic on your hair after washing.

You may be given a sedative before the test depending upon your sleep pattern and medical condition. Generally, your doctor will suggest you to have a sound sleep the night before the test.

 

What happens during the test?

You be lying down still on your back over a table or may be asked to sit on a comfortable chair, keeping your eyes closed. A gel is usually applied on the scalp to withhold the electrodes properly.

EEG is a painless technique. During the test, you may be asked to breathe deeply and rapidly for 2-3 minutes, read something, to open and close your eyes and look at bright light. You may be given a sedative as well if the brain impulse requires to be recorded while sleeping.

EEG lasts typically from 30 minutes to 2 hours.

 

What to expect after the test?

The electrodes will be removed from your head after the test is over. Your scalp me be washed to remove the gel.
You might feel dizzy or lightheaded for sometime due to heavy breathing.

The effect of sedative might linger for some time, so it’s advised that someone escorts you to home. Avoid driving for that day.

 

Are there any risks of the procedure?

There are no potential risks. However, if you have a pre-existing medical condition like seizures, then activities like looking at bright light, hyperventilation, etc. can trigger seizures.

However, your doctor will evaluate your medical history and take necessary precautions during the test.

 

Interpreting the results of EEG

The results will indicate the activity of your brain during various levels of consciousness. It will be predicted by the technician and your doctor will explain them to you.

Normal results typically indicate alpha rhythm when you are still with your eyes closed. They tend to disappear when you open your eyes. Otherwise, an underlying complication can be interpreted with abnormal readings.

Your doctor will assess the results and then move forward with the probable treatment options.


Written by: healthplus24.com
Date last modified: Feburary 02, 2014