What is an EEG?
“EEG” is an abbreviation for electroencephalogram. It is a test in which electrodes are attached to the scalp, in order to record electrical brain wave activity. This is an important test to help diagnose conditions such as epilepsy, but there can be other reasons why it is requested. Sometimes people may have had an unwitnessed fall or an episode of loss of consciousness, and it is not clear what the cause was. Having a normal EEG can be important in ruling out a seizure as the cause. Sometimes, a routine (20 minute) EEG may be normal, as it is a snapshot in time of the electrical activity of the brain. If there is a high suspicion of epilepsy, even if the routine EEG is normal, a sleep deprived or prolonged EEG is often requested to try to get more information.
Types of EEGs
We currently offer routine (20 minute), sleep deprived (1 hour) and prolonged sleep deprived (3 hour) EEGs on site at Brisbane Neurology. We are able to offer EEGs to children and adults.
In general, if an EEG is abnormal one of our neurologists will see a patient to explain the results and depending on who has referred, will either liaise with their referring neurologist regarding treatment, or will organise an initial treatment plan.
Our routine EEG days are Tuesdays and Wednesdays but we are able to organise urgent EEGs outside of these days if it is clinically indicated. We are happy to discuss these requests with referring doctors.
Just as with all our appointments, we require a referral from a medical practitioner or nurse practitioner with a provider number in order to book the EEG.
Preparing for an EEG
You will receive more information from us when your test is booked in, however there are some things you should do to prepare for EEG:
- Don’t eat or drink anything with caffeine for 8 hours before the test
- You may be given instructions on how much to sleep the night before the test – if you are booked in for a sleep deprived EEG and haven’t received instructions, please contact us
- Bring a list of your current medications and any over the counter medications or supplements
- Wash your hair the night before – do not use any styling products such as gel or mousse afterwards
- Do not drive to the appointment – ensure you have safe transport home especially if you are having a sleep-deprived test
What happens in an EEG test?
The EEG scientist will apply multiple electrodes to the scalp with paste. This is not invasive. The electrodes record brain wave activity in all the areas of the brain on a monitor. You will be asked to sit or lie on a bed. At various times you will be asked to open and close your eyes. In some tests it will be expected that you fall asleep. Sometimes you will be asked to hyperventilate (breathe in and out deeply) or flashing lights (photic stimulation) will be shown to you. After the test, the electrodes will be removed with a special solution. You will usually still need to wash your hair properly when you get home.
If you have any queries about EEGs we are happy to talk to you before your test.
For queries please contact: reception@brisbaneneurology.com.au
Clearance to Drive
Having had a seizure or an unexplained loss of consciousness can be a highly distressing experience. On top of that, a person will have been told that they are not allowed to drive, until a cause is determined, in case it happens again. Sometimes, it can be reasonably determined that the cause was a faint – for instance, it occurred while having a blood test. However, if it was unwitnessed, or unclear, then testing needs to be done. It is worth knowing that if a person has had an episode of loss of consciousness that is unexplained, a normal EEG will not guarantee that they can return to driving straight away. There is a minimum non-driving period determined by law, with the default being six months. It can be very upsetting for people to realise that they may not be able to drive straight away even with a normal EEG.
An abnormal EEG usually predicts whether or not a person needs to be on anti-epileptic medication, however does not completely rule out a diagnosis of epilepsy – but if there are no further episodes in the next six months it is thought that having epilepsy is unlikely. The rules regarding driving and medical conditions are set out in a document called the Austroads Guidelines and are Australian Law. There have been changes to the rules over the past few years, and now any seizure or unexplained loss of consciousness (even if proven to be not epilepsy e.g. dissociative seizures) is included in the six-month non-driving period. The standards for driving are also different for commercial license holders.
We will not be able to clear you to drive at your EEG appointment.
