Telemetry: long-term electro-encephalogram (EEG) monitoring

Telemetry is an electro-encephalogram (EEG) test which looks at the function of the brain. The brain’s activity can be detected from electrical signals which we record using scalp electrodes.

Telemetry is an EEG test that records for a longer period of time. It can last for up to five days. Recording for a longer period allows us to capture your child’s brain activity in different states such as wakefulness and sleep. A video recording is made at the same time as the EEG – this is helpful for the doctor to see any changes in behaviour or movements that could help interpreting the activity of the brain.

Most importantly, we will hopefully record your child’s seizures, which will provide useful information for your doctor. Telemetry can be used to record different seizure types and potentially identify which parts of the brain are causing the seizures.

Telemetry usually takes between one to five days. This means your child will need to stay in hospital whilst they are having telemetry.

Your child will need an adult present with them while they are in 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 call the epilepsy service coordinator before your child’s admission.

If you are unable to make your appointment, please call us as soon as possible. Our services are very busy and cancelling early can allow the appointment to be given to another child on our waiting list.

Please make sure that your child’s hair is clean. Do not apply mousse, gel, oil, or hairspray to your child’s head. If your child is taking medicines, they should continue to take them as normal.

Your child will be able to change clothes during the test, but for the setup it is helpful if they wear a zip or button front top.

Your child will have their telemetry in Koala Ward, which is on Level 5 of the Morgan Stanley Clinical Building.

The person bringing your child to their appointment should ideally have ‘Parental Responsibility’ for them. Parental Responsibility refers to the individual who has legal rights, responsibilities, duties, power, and authority to make decisions for a child. This is because the person will need to give consent for your child to have the test. If you are unable to attend with your child but we still need you to give consent, we might need to contact you by phone during the test.

Check in with reception on Koala ward and you will be taken to your room. Your child’s room will be spacious and contain a bed and space to play. There will also be a fold-out bed for a parent to sleep in and an ensuite toilet. We recommend that you bring in any favourite games, toys, or a tablet to keep your child entertained during their stay. The play team can also provide toys and activities to help your child settle in.

One of the neurology doctors and the clinical physiologist will explain the test in more detail and discuss any concerns or questions you may have. The doctor will ask for your written consent for the video recording. Consent is required before the test begins. The doctor may also discuss reducing or stopping any anti-seizure medicine your child is taking. There is a separate section on drug reduction in this leaflet.

We might also ask you to give permission for any additional procedures such as looking at flashing lights or taking lots of deep breaths (also known as hyperventilation or over-breathing). If you want a copy of the consent form, please ask us.

As we are a teaching hospital, on occasion, we might ask you if you would agree for a trainee to perform the test under supervision. Sometimes other healthcare professionals or students might ask to observe the test as well. Saying ‘no’ to this will not affect your child’s treatment.

The clinical physiologist will measure your child’s head and mark locations with a soft pencil. Small silver discs (electrodes) will be attached over the pencil marks using a soft paste. Additional, electrodes will be applied to the shoulders to record your child’s heart rate and the upper arms to monitor muscle activity. Sometimes the doctors will attach extra electrodes and/or sensors to your child to monitor certain muscles or things like oxygen levels. This will be discussed with you and your child.

To attach each electrode, the physiologist will clean the area of the scalp with a cotton bud and some gel. This does not hurt but some children do not like it. The electrode will be positioned on top of some conductive paste which is like Vaseline. A hypoallergenic sticker will be placed on top of each electrode to keep it in place. After all the electrodes are attached, the physiologist will bandage your child’s head. A hat may also be used to help secure the bandage and electrodes.

The setup takes around 45 to 60 minutes but may take longer in children who struggle with sitting still or have sensory issues. While the electrodes are being applied, your child can sit on a chair, the bed, or your lap, and they are allowed to play with toys. A play specialist is usually available to help if needed.

The electrodes are attached by wires to a small device which your child will carry around in a bag. The device is connected to a recording machine via a long cable which will allow free movement around the room and the toilet.

The clinical physiologist will record the signals from your child’s brain on a computer. Your child will not feel anything during the telemetry recording. At the same time, a video recording of your child will be made – this is helpful for the doctor to see any changes in behaviour or movements that could be linked to seizure activity. The cameras in the room are remotely monitored and moved by staff to make sure that your child is in view of the camera.

In the event of a seizure, you will be asked to press a button. We will show you this during the setup. When the button is pressed the time and date will be documented and an alarm will sound. The nurse will respond to the alarm and assess your child.

Your child will be able to eat and drink as normal during the test. We will provide food and drink for your child, but we are unable to provide food for parents/carers. There is a kitchen with a kettle and microwave you can use to make drinks and heat up food. Your child will not be able to bathe or shower while the electrodes are in place because the system is not waterproof. They will need to stay in their room for the duration of the test.

At some point during your stay, the physiologist may ask your child to do some tasks such as opening and closing their eyes, taking fast deep breaths (also known as hyperventilation or ‘over-breathing’), or looking at flashing lights. This is to see how their brain responds to these tasks. The physiologist will monitor your child throughout. The doctors may also need to ask you to keep your child up past their normal bedtime during their stay.

Depending on the information needed, the test may continue for up to five days, but in some cases, an overnight stay is long enough. Please be aware that there may be a decision by the doctors to either shorten or prolong your stay. This is dependent on the amount and quality of information collected during the recording.

Please ensure you bring your child’s anti-seizure medicines as well as all other regular and non-regular medications in with you for the duration of the stay.

The doctors may need to temporarily reduce or stop your child’s anti-seizure medicines for the test. This will be discussed with you in more detail before the test starts.

If the doctors decide to reduce or stop your child’s anti-seizure medicines for the test, this can cause your child to have prolonged or increased seizures. Any reduction of drugs requires your consent, and a seizure rescue plan will be created. In addition, your child will have a cannula inserted for the rapid delivery of rescue medications.

If your child’s anti-seizure medicines are reduced or stopped for the test, we will need them to be on their normal dose of medication for 24 hours before they are allowed home. They will need to have two normal doses of anti-seizure medicines and their seizures will need to be happening at their normal rate.

There are doctors on the ward and there is always a nurse outside the room who will attend and assess your child.

When a seizure occurs, please press the button which marks the time on the recording. We will also ask you to describe out loud what is happening. This description is especially useful when your child is off camera.

There is also an emergency alarm which can be used to alert all staff. You will be shown this on your arrival.

The physiologist or nurse will remove the electrodes and stickers from your child’s head. This will not hurt as the paste stays soft and is easy to remove. They will also clean your child’s hair, but it may feel a bit sticky to the touch until you wash it.

We might be able to let you know small amounts of information about what the telemetry is showing during your stay. The team will look at the results and write a detailed report. This will be sent to your child’s neurology consultant in time for their next appointment.

If you require more information about the test or have any questions, please call the Department of Clinical Neurophysiology.

Telephone: 020 7813 8471

We are open Monday to Friday, 9am to 5pm.

If you are unable to make your appointment, please call us as soon as possible as we may be able to offer the appointment to another child on the waiting list.

Please use the Morgan Stanley Clinical Building entrance on Guildford Street.

Go to the main reception on level 2 of the Morgan Stanley Clinical Building and then go to Level 5 where you will find Koala ward.

Find out more information about travelling to GOSH.