- Reference Number: HEY-662/2015
- Departments: Neurophysiology
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What is an Ambulatory EEG?
An ambulatory EEG is very similar to the routine EEG which you or your child may have already had done. The electrodes will be placed onto the scalp as before but on this occasion will be further secured with a special glue and the ‘brain waves’ will be recorded onto a special box placed in a bag, which is carried over you/your child’s shoulder. The recording will usually be undertaken for a period of 48 hours. The procedure is not painful but electrode removal may at times be a little uncomfortable. You do not have to stay but can go home with the electrodes attached.
Why do I need an Ambulatory EEG?
An ambulatory EEG is usually done in an attempt to capture some of the seizures/episodes that you/your child have been experiencing. The test is most useful on people who are having at least 2-3 seizures per week, giving us the best chance of capturing the seizures.
If your seizure frequency becomes much less than this, please advise the Neurophysiology department so we can decide whether the investigation is still appropriate for you.
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. The electrode cables running from the head to the recorder can become entangled if not worn under items of clothing or taped along your back. Staff will discuss how to minimise these risks with you.
How do I prepare for the Ambulatory EEG?
Please read the information leaflet. You may want to share the information it contains with your partner and family 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.
- It will not be possible to bathe or shower whilst the equipment is attached. Therefore, please take a bath or shower and wash you/your child’s hair the night before, or the morning of your appointment. Do not apply any hair styling products and ensure the hair is dried thoroughly. The electrodes attach best to clean, dry hair.
- You/your child will need to wear something that buttons up the front in order that clothing can be removed and changed without the need for going over the head and risk dislodging the electrodes. We are sometimes able to manage with a very loose/baggy necked item of clothing if need be. Please wear skirts or trousers and not dresses.
- You/your child may wish to bring a hat or wear a hooded, zipped jacket for travelling to and from the hospital but please remove this as soon as you are at home.
- Continue taking all medication as usual.
- Continue to eat and drink as normal.
- The purpose of the ambulatory EEG is to document one of you/your child’s habitual seizures. For this reason, if you are unaware of your seizures you must arrange for someone to be with you for the period of the recording who will be able to identify them, log them in the event diary and press the button that marks the recording. If you are not able to arrange this, please contact the Neurophysiology department and let them know.
- If the ambulatory is being done on your child, they will need to be observed closely day and night to ensure that no seizures are missed. Again if you do not think you will be able to manage this, please let the Neurophysiology department know.
This investigation takes a long time both to record and to review. If you are unable to attend for your appointment, please let us know as soon as possible so we can offer your appointment to someone else.
What will happen?
- Please attend the Neurophysiology Department on Gladstone Street (map enclosed).
- On arrival, a physiologist will take you/your child through to the room where the equipment will be attached.
- A detailed history will be taken to confirm the procedure will still be of benefit to you/your child.
- The physiologist will discuss what will happen to you your child, obtain your verbal consent for the procedure and answer any questions you may have.
- The physiologist will then measure you/your child’s head and attach 25 small electrodes to the head to record brainwaves and two electrodes on the chest to record the heartbeat.
- The electrodes are connected to the recorder and the physiologist will check all the equipment is working properly and record a short period of EEG, during which you/your child will be asked to briefly close your eyes.
- You will be shown how to replace any electrodes should they become dislodged whilst you are at home and provided with glue and tape to do this.
- The physiologist will show you/your child’s the event diary you will need to keep during the recording and explain how this needs to be completed.
- The physiologist will demonstrate the button used to mark the recording and explain when you/your child should use it.
Failure to complete the diary and press the event marker will directly affect the usefulness of the investigation and the value of the information we are able to give to your referring doctor.
- Once the physiologist is satisfied the equipment is working correctly and has answered all your questions you/your child will be able to go home and return the same time the next day.
- Once at home, we ask that you/your child try and carry on with normal activities as much as possible. However it is not possible to bathe or shower with the ambulatory EEG in place and avoid things that may cause a lot of movement, for example fitness classes/sporting activities etc.
- Please avoid chewing gum.
- Adults may go to work if they wish however the electrodes will be visible. Please discuss with your child’s school the feasibility of them attending school with the electrodes in place.
- An ambulatory EEG will usually be worn for up to 48 hours initially but you/your child will have to return to the department after 24 hours to have the batteries replaced, the brainwaves downloaded and the electrodes checked over. If you/your child have a seizure on the first day, it may be possible to remove the electrodes earlier. If not, they will be removed on the final day and the glue removed from the hair. You/your child’s hair will then need a good wash and we advise combing conditioner through the hair after washing to help remove any small particles of glue that may have inadvertently been left in the hair.
What if my child does not have a seizure?
The aim of the recording is to try and capture one of you/your child’s habitual attacks. However, occasionally we are unsuccessful. This does not mean that the investigation has been a waste of time. Recording someone’s EEG for a prolonged period of time can still be very useful. On rare occasions, your doctor may refer you back for a repeat study.
What happens afterwards?
Once you have left the department the recording will be reviewed by the physiologist and then by a member of the medical team who will send a report to the doctor who referred you for the ambulatory 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 on: (01482) 675339 or (01482) 675388
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 Confidential Information about You
If you or your carer needs information about your health and well-being 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.