Before your test
EEG Test Preparation: Hair, Sleep & Medicines
The three things people get wrong before an EEG, and what actually matters on the day.
An EEG records the brain's own electrical activity through electrodes resting on the scalp. Nothing is passed into you and nothing hurts. Almost all the preparation is about one thing: making sure the electrodes can hear clearly.
Hair: wash it, leave everything else off
Wash your hair the night before or that morning, and let it dry. Do not use oil, gel, cream, serum or hairspray afterwards — a film of oil sits between the electrode and the scalp and weakens the signal the test exists to record. Come with hair loose rather than in a tight plait or bun, and leave clips, extensions and pins at home.
This is the single most common reason a recording has to be repeated, and it is entirely avoidable.
Sleep: only if you were told to
A routine EEG needs no change to your sleep. Some studies are deliberately sleep-deprived — you are asked to sleep much less than usual the night before, because drowsiness brings out changes a fully alert recording may miss.
That instruction comes from your doctor for your study. If nobody has told you to stay awake, sleep normally; arriving exhausted for a routine EEG does not improve it. If you were told to, ask whether someone should travel with you, because you should not drive afterwards.
Medicines: keep taking them
Continue your regular medicines unless your doctor has specifically told you otherwise. This matters most for anti-seizure medicines — stopping them to "show something on the test" is dangerous and is never the right thing to do on your own. Bring the list, or the strips, so the technologist can note what you are on.
Avoid tea, coffee and energy drinks on the morning of the test unless told otherwise, and eat normally: arriving hungry can itself change the recording.
On the day
Allow about 30–45 minutes for a routine recording. You sit or lie comfortably while electrodes are placed with a paste that washes out. You may be asked to breathe deeply for a period, or to look at a flashing light — both are standard parts of the test. Afterwards you can go straight back to your normal day.
Bring previous reports, scans and prescriptions, and your referral letter if you have one. Patient resources has the full list.
Children, and tests at home
For a child, bring a favourite toy or blanket and, for a younger child, plan around their usual nap — a settled child gives a better recording than a rushed one. See paediatric neurodiagnostics.
Where a patient cannot travel, an EEG can sometimes be recorded at home or at the bedside — see home & bedside services, and home EEG in Agartala for how that is arranged.
Anything you are unsure about, ask when you book — it is a shorter conversation than a repeated test.