Print this page

Electroencephalograph (EEG) - Activation Clinic

Your consultant would like you to have an EEG investigation.

What is an EEG?

EEG stands for Electroencephalogram. This is a well established and painless test which will record the electrical activity of the brain. Recording this information will help your consultant in the diagnosis and management of your complaint or condition. An EEG is used to investigate a number of different conditions, most commonly blackouts or seizures.

A Clinical Physiologist will be performing your test, although staff in training may be present during your investigation. This will be explained at the time of your appointment and consent for this will be discussed with you.

The aim of the test is to capture your typical events or attacks, in doing so this will help the Doctors looking after you diagnose your condition and you can receive the correct treatment.

What should I do before the test?

  • Please ensure your hair is clean and do not use any hair products such as gel or hairspray.
  • If you have extensive hair extensions/weave these will need to be removed prior to your EEG.
  • Continue to take your medication as normal and bring along a list of current medication.
  • If possible we request you are accompanied by a relative, friend or next of kin and if possible have observed previous attacks.
  • If you have video footage on a mobile phone of your events we advise you to bring this along to the appointment as this may provide the team with more information
  • If there are any specific triggers to your events please bring them along to the appointment for example certain food/sounds/music/ video games on your mobile phone/tablet etc.

You are welcome to bring a friend or relative to accompany you to your appointment.

What will happen during the test?

The Clinical Physiologist will explain the test, answer any questions you may have and obtain a clinical history from you. The Clinical Physiologist will mark some points on your scalp with a soft pencil. After rubbing these points with a gel, 23 small electrodes will be placed using a sticky paste.

The majority of the test will be performed with your eyes closed. You will not feel anything during the recording. A video will be taken throughout your appointment, this will allow any movements or episodes you may have to be matched up with the EEG recording.

During the test you may be asked to do the following:

  • perform a breathing exercise: This involves taking deep breaths for up to three minutes.
  • look at a flashing light: The physiologist will instruct you to look into a strobe light which will flash on and off at different speeds

These portions of the recording may trigger a typical clinical event or attack. Consent will be discussed at your appointment for this.

In the event of you experiencing a typical attack during the recording we aim to ensure the environment is as safe as possible and a clinical physiologist will remain with you throughout. A Consultant Neurophysiologist will also be available should you require any medical assessment.

The test will take around 1.5 hours in total.

What happens after the test?

After the recording, the electrodes will be taken off with warm water. Your hair will still feel sticky following removal of the electrodes and will require washing when you return home. You will not be told any results following the test. The results will go back to your Consultant in approximately 2-3 weeks.

Are there any risks?

In some people there is a chance that the breathing exercise or the flashing light could result in a seizure or clinical event. These risks are fully explained during the test and your consent is required for these parts. In the event that you do have an epileptic seizure or blackout you would be required to inform the DVLA and your driving licence would be suspended.

If you are unable to attend this appointment, have any specific requirements or questions (before or following your appointment) please ring 0151 556 3416

Patient co-operation is required for the duration of the test; if due to a learning disability you feel more time is needed, please contact the department .In addition we can also provide a visit to the department in advance of the appointment for patients who may require it to familiarize yourself with the surroundings and staff.

Further information about EEG is available from numerous organisations including:

  1. UK Epilepsy Society Helpline: 01494 601 400 or visit 
  2. Epilepsy Action Helpline (Freephone): 0808 800 5050 or visit 
  3. The Brain Charity, Norton Street, Liverpool L3 8LR, 0151 298 2999 or visit 
  • Last Updated:
    01 June 2024
  • Review Date:
    01 June 2028
  • Author:
    Natalie Gore/Sam Owen/Beverley Haworth
  • Summary:

    EEG stands for Electroencephalogram. This is a well established and painless test which will record the electrical activity of the brain. 

  • Related Service:

Related content