This page explains about telemetry monitoring and what to expect when your child comes to Great Ormond Street Hospital (GOSH) to have this procedure.
Telemetry monitoring is a test that looks at the function of the brain. The brain works by a series of nerve impulses, which cause electrical signals within the brain. These signals (also called brainwaves) can be recorded through the scalp.
Telemetry monitoring is similar to an electroencephalogram (EEG) test in that it records the brainwaves but over a much longer period of time, sometimes taking up to five days to get the information needed. A digital video recording will be made during the test. This enables the doctors to compare your child’s brainwaves with his or her movement and/or behaviour at the time.
Telemetry monitoring is a safe method of recording your brain’s function without the need for sedation or an anaesthetic. This makes it a good way to get an overall view of the function of the brain and can indicate stages of development. It may be done to obtain a complete night’s sleep recording, to record seizures or tell the difference between seizures and other types of ‘attack’. It can also be used to pinpoint if one or more particular areas of the brain are causing the seizures.
What happens before the test?
Telemetry monitoring is carried out on Koala Ward. The telemetry monitoring rooms are larger than usual hospital rooms, so your child will be able to move about during the test. The ward play specialist will be able to provide things for your child to do during the day, but you can also bring in any favourite games, toys or videos/DVDs.
It is helpful if you could make sure that your child’s hair is clean before the test, with no mousse, gel, oil or hairspray. If your child is taking medicines, you should continue to give them as normal. Your child will only be able to change clothes during the test if they fasten up the back or front, so it will help if you can bring in a zip or button front top with you for your child to wear.
The doctor will explain about the test in more detail, discuss any worries you may have and ask you to give permission for both the telemetry monitoring and video recording by signing a consent form. For this test, both are needed to analyse the results.
What does the test involve?
The clinical physiologist will attach small silver discs (electrodes) to certain points on your child’s scalp using a special glue. Sometimes, he or she will measure your child’s head beforehand and mark the points with a soft pencil before attaching the electrodes. As each electrode is attached, he or she will clean the area of the scalp with a cotton bud and some cream. This does not hurt but some children do not like it. While all the electrodes are applied, your child can sit on a chair, the bed or your lap, and can play with toys.
The electrodes are attached by wires to a ‘headbox’ and then to the recording machine. The clinical physiologist will record your child’s brainwaves on to the recording machine connected to a computer and monitor them on a screen.
Depending on the information the doctors gain from the results, the test may continue for five days. In some cases, a few hours or an overnight stay is long enough to get the results needed. The doctors may need to reduce or stop your child’s anti-epilepsy medicines for the test, but they will discuss this with you in more detail before the test starts.
The video camera in your child’s room will record his or her seizures or other disorder events during the test. Your child can move around the room as long as he or she stays in range of the camera. You are welcome to stay with your child for the test, as parents are often best placed to identify a typical event or seizure should they occur. Your child will need an adult present during this admission to hospital. Nursing staff are available to look after your child when you need a break. If you are unable to stay with your child, please telephone the epilepsy service coordinator on 020 7405 9200 ext 5789 to rearrange the admission.
Your child will be able to eat and drink as normal during the test. We will provide food and drink for your child but parents need to bring in food or buy it from one of the eating places in the hospital. There is a kitchen with a kettle and microwave you can use to make drinks and heat up food.
Are there any risks?
If the doctors decide to reduce or stop your child’s anti-epilepsy medicines for the test, they will decide this when you come to the hospital. If your child has had a number of seizures recently, he or she may be able to continue taking them during the test. There is always a risk in reducing or stopping your child’s medicines suddenly for the test. This can cause your child to have a longer or more intense seizure than usual. However, the doctors and nurses will monitor your child closely to stop this happening.
What happens after the test?
The clinical physiologist will remove the electrodes from your child’s scalp. This will not hurt as a liquid is applied to the glue to soften it before an electrode is removed. He or she will also clean your child’s hair but it may feel a bit sticky to the touch until you wash it.
If your child’s anti-epilepsy medicines have been reduced or stopped for the test, they will be started again at the normal dose. You will be able to take your child home once he or she has had two doses of anti-epilepsy medicines and the frequency of his or her seizures is back to normal.
How long until we get the results?
You will not be given the results during your stay. The doctors in the EEG department will write a detailed report of the test results and send it to your child’s doctor. The results will usually be ready in time for your child’s next appointment.
Last reviewed by Great Ormond Street Hospital: December 2009
Ref: 2009F0251 © GOSH Trust December 2009
Compiled by the Epilepsy Surgery Team in collaboration with the Child and Family Information Group.
This information does not constitute health or medical advice and will not necessarily reflect treatment at other hospitals. If you have any questions, please ask your doctor. No liability can be taken as a result of using this information.