Sydney Paediatric Neurology

What is an EEG (electroencephalogram)?
An EEG is a medical test used to measure the electrical activity of the brain. This test records brain wave patterns and is useful in assisting in the diagnosis of epilepsy (seizure disorders) and excluding mimics of seizures such as sleep and movement disorders.

Types of EEG:

Standard (Routine) EEG tests
Usually, a standard EEG test will be done at the clinic room. The appointment is scheduled for 40 minutes although in younger infants this may take slightly longer to set-up. This study is normally performed in the awake patient.

Sleep-deprived EEG tests
A sleep-deprived EEG test is done when a child has had less sleep than usual, the night before the study (‘sleep deprived’). When patients are sleep deprived, there is a higher chance that abnormal electrical activity (if present) will be detected. Before a sleep-deprived EEG test, school aged children (>5 years) will be asked to stay up as late as possible (3 hours past the normal bedtime) and to wake up at least 2 hours earlier than normal. Care should be taken and discussion with your doctor should occur if your sleep deprivation is a trigger for your child’s seizure. In that case, it may be possible just to wake your child up earlier than usual on the day of the EEG test.

Overnight video-EEG study
This study is reserved for selected individuals with private health insurance coverage (criteria under overnight video-EEG checklist). This study requires admission to Norwest Private Hospital and the video EEG recording occurs overnight.  This study is similar to a standard EEG expect that it records for more than 12 hours with the ability to capture sleep EEG features and record and sleep related events suspicious of a seizure.

Why does my child need an EEG?
The most common reason an EEG is performed is to assist in diagnosing epilepsy. It is useful also to exclude unusual movements in the awake and sleep state.

Is the EEG safe for my child?
The EEG test is painless and safe, without side effects. The electrodes only pick up the electrical signals that are present and do not affect the child’s brain or cause a seizure.

Younger children can be sensitive to having their head touched and bandaged (to keep the leads in place). Distraction and comfort from parents is helpful. Booking the study during a day nap of the child is helpful.

How do we prepare before EEG?
Wash your child’s hair the night before the EEG without applying any hair products. Please keep your child’s hair clean and dry on the day. If there are active head lice, please rebook the appointment once it has been fully treated.

Please consult with your doctor if your child should stop taking any medications before the test.

Your doctor may have requested a sleep deprived EEG, so please attempt the guide discussed above. If a sleep deprived EEG is essential, then working out how much sleep deprivation is needed could be trialed on a weekend prior to the test.

What if my child has autism or developmental delay and needs an EEG?
Children with autism or developmental delay suspected of having seizures can have the test. If some children are sensitive to touching of the scalp, role play and modeling could help prepare the child for the procedure. Pictures of what the leads look like attached to the head can be viewed on this website.

The EEG service provides no sedation for patients with autism or developmental delay with challenging behaviors. One option to obtain an EEG for such children is to trial a single dose of Melatonin 30-45 minutes prior to the procedure. Melatonin is a naturally occurring substance in the body that helps to initiate sleep. This should ideally be trialed once or twice prior to the actual EEG appointment to ensure that it does help settle the child and allow sleep onset.

What happens on the day?
Parents stay with the child during the test. Your child will be asked to lie on a bed or sit in a chair. Infants are held by their parent on a chair and can be fed during the process or given a favorite toy to calm or help with distraction.

The EEG neuroscientist will attach small metal discs (electrodes) with thin wires on different locations using adhesive paste. Generally about 20 electrodes will be applied to child’s scalp. Each electrode is connected to an amplifier and EEG recording machine. The leads are bandaged to prevent accidental removal and artefacts for moving leads.

Your child will be asked to lie or sit still because movement can alter the recording.

During the study, bright flashing lights will be directed to your child in bursts of 10 seconds with a 5 second rest between sets of flashes. If this causes you (parent) or child to be uncomfortable, please inform the neuroscientist. Older children will be asked to hyperventilate by taking in deep breaths, slowly for 3-5 minutes.

Once the test is complete, the electrodes will be removed and the paste is wiped off the scalp with wet wipes. The hair can be washed more thoroughly when the child returns home. All gel and paste used for the test, is water soluble and easily removed with soap & warm water. The child is allowed to go to school following the test unless tired or sleepy from the sleep deprivation the night before.

The EEG result will be faxed to your referring doctor within 24 hours.

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