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Invasive Telemetry

Your consultant would like you to have an invasive electrode video telemetry recording.

What is an invasive electrode video telemetry recording? 

You are having this investigation as your consultant requires more information following surface EEG recordings. Invasive electrodes are inserted into or directly on to the brain under general anaesthetic in the operating theatre. We will then record continuous EEG until sufficient information is obtained which can take up to 2 weeks in duration. On the ward for your safety you will be monitored by a member of staff via live video. You will be in a single private room with television and private bathroom. Once the investigation starts you will be unable to leave the room until the test is finished. You may need to go back to the operating theatre to have the electrodes removed. 

What should I do before the test?

Take your medication as normal unless otherwise directed by your doctor. Hair should be washed and avoid any hair products. If you have extensive hair extensions/weave these will need to be  removed prior to your EEG. It would be helpful if you could wear loose comfortable clothing - for example pyjamas or shirts and skirts or trousers. You are welcome to bring a friend or relative to accompany you to your appointment. You will be asked to press a button when you hear a sound.

What will happen during the test?

You will be admitted to the ward the day  before the recording is due to take place so that any necessary pre-operation checks can be performed. On the day of electrode placement you will be taken to the operating theatre and given a general anaesthetic after which the invasive electrodes will be implanted. Some areas of your head hair may need to be shaved.

Once the electrodes are in place and you have recovered from the anaesthetic you will  return to your room on the ward. When you wake up you will have a bandage on your head - please try not to touch this. Generally within the next 24 hours a Clinical Physiologist will connected the electrodes to a small box on a belt that you will wear around your waist. A cable then goes from this to a computer in the corner of your room. The belt needs to remain in place for the whole recording time. You will not be able to wash or comb your hair or have a bath/shower  during the investigation time. Your medication may be reduced prior to or during admission . This was be decided by the doctor looking after you. Continuous EEG and video recording will be undertaken - your consent will be requested for the video recording.

How will the results assist my Consultant?

Hopefully we will be able to record at least 2 or 3 of your typical events. This will give the consultant more information on how best to treat your condition  and/or change your medication.

Are there any risks? 

These will have been discussed with you at one of your clinic visits by the Neurosurgeon. There is a 2-4% chance of developing an infection during the recording. There is a 1-2% chance of a brain haemorrhage during the operation . This could result in temporary or permanent incapacity, such as a stroke. There is a small chance that during your attacks you may fall and hurt yourself—staff on the ward will do their best to reduce this risk.

Is the invasive electrode monitoring painful?

Your head will feel sore after the operation but painkillers will be available.

How long will the test take?

The test can take been 5-14 days.

What happens after the test?

Once the doctors have enough information, the invasive electrodes will be removed—this may involve another visit to the operating theatre. If you have had your medication reduced or stopped during the test it will quickly be returned to normal. You may be required to stay on the ward for a few days after the test has finished. A written report is compiled and sent to your consultant within 2-3 weeks. The consultant will discuss the results with you at your next out-patient appointment. 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.


If for any reason you are unable to make this  appointment or have any questions (before or after your investigation) please ring 0151 556 3416

Further information about EEG is available from numerous organisations including:




  • Last Updated:
    01 October 2022
  • Review Date:
    01 October 2024
  • Author:
    Beverley Haworth/Natalie Gore Neurophysiology Department
  • Summary:

    You are having this investigation as your consultant requires more information following surface EEG recordings. 

  • Related Service:

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