Sleep-Deprived EEG in Sydney
A higher-yield brain wave test when routine EEG was normal but epilepsy is still suspected.
Why Sleep-Deprived EEG Has a Higher Yield
Two things make sleep-deprived EEG more sensitive than routine EEG: sleep deprivation itself, and the natural sleep captured during the recording.
Sleep deprivation provokes discharges
A short night of sleep lowers the brain's seizure threshold. Epileptiform discharges that were absent on a well-rested routine EEG often appear after sleep deprivation.
Natural sleep is captured
Drowsiness and the early stages of sleep are the periods when epileptiform discharges are most likely to be seen. By having you fall asleep during the recording, we capture exactly the windows where the diagnosis is most likely to be made.
How to Prepare
Preparation is what makes the test work. Please follow these instructions carefully.
Stay awake most of the night before
Adults typically sleep no more than 3 to 4 hours. If your test is in the morning, go to bed late and get up very early. If you have any safety concerns about being awake (such as driving, looking after children alone overnight, or operating machinery), discuss with us first.
Avoid caffeine on the morning of the test
No coffee, tea, energy drinks or caffeinated soft drinks on the morning of your appointment. Caffeine prevents the natural sleep we are trying to capture.
Wash your hair the night before
Use shampoo only — no conditioner, oils, leave-in treatments, gels, sprays or styling products. These all interfere with how well the electrodes adhere to your scalp.
Take your usual medications
Unless we have specifically told you otherwise, take all of your usual medications as normal — including any anti-seizure medications. We are not trying to provoke a seizure.
Arrange a lift home
You should not drive after the test — you will be sleep-deprived. Bring a support person, arrange a lift, or plan to use a taxi, rideshare, or public transport.
What Happens During the Test
Painless, non-invasive, and finished in about an hour.
Electrode placement
23 small gold-plated electrodes are placed on your scalp using conductive paste. Painless and non-invasive. The electrodes only detect signals — they don't send any electricity into your brain.
Natural sleep recording
You lie back, dim the lights, close your eyes and allow yourself to drift off. The recording captures awake, drowsy and natural sleep stages — the windows where epilepsy is most likely to show itself.
Activation procedures
We may include hyperventilation (deep breathing) and photic stimulation (flashing lights). Both are standard, safe ways to bring out epileptiform discharges that would otherwise stay hidden.
Frequently Asked Questions
Why is a sleep-deprived EEG better than a routine EEG?
Sleep deprivation and natural sleep during the recording both make epileptiform discharges more likely to appear. The combination of a longer recording and capturing drowsiness and sleep significantly raises the chance of detecting epilepsy compared with a 30-minute routine EEG.
How do I prepare for a sleep-deprived EEG?
Stay awake most of the night before (typically no more than 3 to 4 hours sleep). Avoid caffeine on the morning of the test. Wash your hair the night before with shampoo only — no conditioner, oils, or styling products. Arrange a lift home — you should not drive after the test.
How long does a sleep-deprived EEG take?
Allow about an hour. The recording itself is longer than a routine EEG to give you time to fall asleep naturally during the test, which is when epileptiform discharges are most likely to appear.
Can I drive home after a sleep-deprived EEG?
No. You will be sleep-deprived. Arrange a lift, a taxi, or public transport.
When would I need a sleep-deprived EEG?
Most commonly when routine EEG was normal but clinical suspicion of epilepsy is still significant, when investigating juvenile myoclonic epilepsy or other generalised epilepsies, or when investigating sleep-related events. Your neurologist will explain the specific reason in your case.