Electroencephalogram (EEG) – Adults

Patient Leaflets Team

  • Reference Number: HEY-662/2019
  • Departments: Neurophysiology
  • Last Updated: 31 May 2019


This leaflet has been produced to give you general information about your test.  Most of your questions should be answered by this leaflet. It is not intended to replace the discussion between you and and the healthcare team, but may act as a starting point for discussion.  If after reading it you have any concerns or require further explanation, please discuss this with a member of the healthcare team.

What is an EEG?

EEG is the abbreviation of electroencephalogram, which is the recording of electrical activity produced by the brain.  It can help to explain fits or seizures and is a tool to help your doctor in making a diagnosis.  The activity is recorded on a computer and a video recording of you is made at the same.

Can there be any complications or risks?

  • Very occasionally people may experience a slight local reaction at the electrode site. This may cause reddening and soreness.  These symptoms resolve quickly on removal of the electrodes.  If you experience these symptoms, please inform the staff attending to you.
  • In some people there is a very small chance that the deep breathing or flashing light could result in a seizure.  In the very unlikely event that you do have an epileptic seizure, your driving licence could be at risk.
  • The clinical physiologist will ask you if you are happy to include the deep breathing and flashing lights as part of the test.

How do I prepare for the EEG?

Please read the information leaflet.  Share the information it contains with your partner and family (if you wish) so that they can be of help and support.  There may be information they need to know, especially if they are taking care of you during/following this examination.

  • Please wash and dry your hair before you come to the hospital and do not use any hair products (gel, hairspray etc).
  • Take your medication as normal unless otherwise directed by your doctor.
  • Eat as normal.
  • Please bring a list of any current medication you are taking.

What will happen?

  • On your arrival in the department we will obtain your consent for the procedure before your investigation begins.
  • The clinical physiologist performing the EEG will explain the test to you and will be happy to answer any questions you may have.
  • You will be asked to sit on a chair and the clinical physiologist will measure your head and mark some points on it with a soft pencil. The psychologist will rub your head with some gritty paste to obtain a good contact with your skin. Then several small electrodes will be placed on your head using sticky paste.
  • You will be asked some questions about the condition leading to your referral for an EEG.
  • Once the electrode application is complete the recording will commence. You will not feel anything during the recording apart from the electrodes resting on your head.
  • The recording will take approximately 30 minutes and during this period there will be times when your eyes are open and times when they are closed.
  • During the test you will be asked to breathe deeply for a short time.
  • For part of the test the physiologist will ask you to watch a flashing light.
  • The entire procedure will take approximately 60 – 75 minutes.

What happens afterwards?

  • The electrodes will be removed and your head cleaned with warm water.  You may wish to bring a brush or comb with you to tidy your hair.  Any residue of paste can be removed by shampooing your hair when you get home.
  • Once you have left the department the recording will be reviewed by the physiologist and then by a member of the medical team or a senior physiologist who will send a report to the doctor who referred you for the EEG.
  • This usually takes up to two weeks.

Should you require further advice on the issues contained in this leaflet, please do not hesitate to contact the Neurophysiology  Department (01482) 675339/675388

General Advice and Consent

Most of your questions should have been answered by this leaflet, but remember that this is only a starting point for discussion with the healthcare team.

Consent to treatment

Before any doctor, nurse or therapist examines or treats you, they must seek your consent or permission. In order to make a decision, you need to have information from health professionals about the treatment or investigation which is being offered to you. You should always ask them more questions if you do not understand or if you want more information.

The information you receive should be about your condition, the alternatives available to you, and whether it carries risks as well as the benefits. What is important is that your consent is genuine or valid. That means:

  • you must be able to give your consent
  • you must be given enough information to enable you to make a decision
  • you must be acting under your own free will and not under the strong influence of another person

Information about you

We collect and use your information to provide you with care and treatment. As part of your care, information about you will be shared between members of a healthcare team, some of whom you may not meet. Your information may also be used to help train staff, to check the quality of our care, to manage and plan the health service, and to help with research. Wherever possible we use anonymous data.

We may pass on relevant information to other health organisations that provide you with care. All information is treated as strictly confidential and is not given to anyone who does not need it. If you have any concerns please ask your doctor, or the person caring for you.

Under the General Data Protection Regulation and the Data Protection Act 2018 we are responsible for maintaining the confidentiality of any information we hold about you. For further information visit the following page: Confidential Information about You.

If you or your carer needs information about your health and wellbeing and about your care and treatment in a different format, such as large print, braille or audio, due to disability, impairment or sensory loss, please advise a member of staff and this can be arranged.

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