EEG video telemetry

What is an EEG?

EEG stands for ‘electroencephalograph’

• Electro – the electrical impulses that are being measured
• Encephalo – the head
• Graph – the way the results of the test are presented

An EEG is a test done in specialist hospitals. The test records the electrical activity that your brain makes whilst sending messages to and from the body. Your child will often have had an EEG before referral for an EEG video-telemetry. EEGs are done on babies and children of all ages and abilities. For more information about EEGs please see our information: What is an EEG?

Will my child need to be admitted to hospital for this test?

Yes, your child will be admitted to a side room on Ward 1 or 3 at Sheffield Children’s Hospital. They will not be able to leave the room for the duration of the test.

A telemetry recording is usually carried out over a period of 1 to 5 days along with a simultaneous video recording. Your doctor will discuss the length of the admission best suited to your child.

How will this test help them?

Recording over a longer period increases the chance of capturing your child’s typical attacks. We can study the electrical activity and the video recorded during the attack. This information is important for us to make an accurate diagnosis and give the correct treatment.

Is it safe?

The test records the ongoing electrical activity that your child’s brain produces naturally, the recording is painless. The aim of the test is to record the attacks and specify the area from which they arise. To increase the chances of capturing an attack, sometimes we may use activation techniques such as deep breathing or partial sleep deprivation (putting a child to bed later and waking them up earlier than usual). Occasionally the doctors may request a reduction in their usual medications.

The risks of these activation techniques is discussed below. Occasionally children have a minor skin irritation due to the products we use.

It is important to keep the telemetry bag on your child at all times, we will tape or feed the wires down their clothing to prevent the wires getting entangled. Your child will need to be supervised at all times.

Please inform the nursing staff if you need to leave your child for example, to get food or have a shower. Food is provided for the child but not the parent.

Is there anything we need to do before my child is admitted?

Yes:

• Bring them clothes and pyjamas that are button through where possible, this will make it easier when they are getting dressed and undressed and we need to reach their shoulders or legs to apply stickers.
• Make sure they have clean, dry, gel-free hair
• Continue to give your child their usual medications unless told otherwise by your hospital doctor
• Explain what will happen and reassure them

Does someone need to stay with them?

This is because they are in a room of their own and they need to be supervised with the equipment. Also it is important that you identify when they are having their typical attacks. If you need to leave for a short period, for example, to collect lunch, please inform the nursing staff.

What happens when we come into the hospital?

You will be in a single room with an en-suite bathroom.

• Play workers on the ward will provide some toys and art materials.
• Free Wi-Fi is available on the wards.
• You may bring your own entertainment with you such as favourite toys, books or tablet device loaded with games or downloaded videos.
• Using your mobile phone is allowed in the room.
• Food will be provided for your child, and parents or carers should use the canteen facilities.
• Sheffield Children’s is a smoke free site.

What preparation is there for the test?

On the day of the test, 2 of our physiologists will visit you and your child to explain the test and what you will need to do. Our physiologists are used to dealing with anxious patients as well as those with sensory or special needs. You may ask any questions you have at this time. They will then set up the equipment and measure your child’s head to mark where the 23 discs need to be placed.

Each site is rubbed with a cotton bud and some abrasive paste and the discs are applied with special glue. Two stickers will be put on your child’s shoulders to record their heart rate. Some additional stickers may be placed on muscles to record movements. Each disc or sticker has a wire plugged in to a small box connected to a computer by a long cable. This box can be carried on a belt around their waist or put in a back pack. This means they can move freely around the room but remain in view of the video camera. The lead will reach into the bathroom on Ward 4. On Ward 5 you can unplug for a short time to visit the bathroom next to your room.

The child will not be able to have a bath whilst wearing the equipment but washing facilities are available.

What happens during the test?

The box will record their brain activity and you and your child will be recorded on video. We will ask you to keep a note of their attacks and activities in a diary we give to you and also to press a button if they have an attack. If possible, it is important not to obstruct the view of the video camera by standing to the side of the bed during a seizure. This is so that we can study what happens in detail. If a seizure occurs during the night it is helpful to pull back the bedcovers so that we can see any movements.

The physiologist will visit daily to check the recording and discuss any attacks that may have occurred. The nursing staff will be available to help with any problems.

If we have not captured an attack we may perform one or more of the following activation procedures:

Hyperventilation

This is taking deep breaths in and out, like blowing a candle out. In the case of young children we do this using a party blower or a windmill. They may feel dizzy or get pins and needles whilst doing this. These are normal side-effects and will go away when they have stopped taking the deep breaths. We will ask about any health problems they have which would make the deep breathing unsafe. The deep breathing causes a change in blood flow which may change their brain waves and give extra information to help make a diagnosis.

Risks of hyperventilation

Hyperventilation (deep breathing) is associated with a risk of triggering:

• any clinical event (less than 3 in 100 patients)
• any type of seizure (2 in 100 patients)
• a generalised tonic-clonic seizure (3 in 10,000 patients)

You will be asked to give consent to this part of the test as there is no alternative way to get the information obtained during hyperventilation.

Photic stimulation

A lamp which flashes on and off at different speeds is placed in front of your child. They will be asked to look at it. In a small percentage of children, the flashing light could trigger a seizure (this is called photosensitivity). If your child has this response the light is turned off quickly and they would not usually go on to have a seizure.

Risks of photic stimulation

The risks are that your child may have:

• any clinical event (less that 2 in 100 patients)
• any type of seizure (7 in 1,000 patients)
• a generalised tonic-clonic seizure is 1 in 10,000 patients

The information from photic stimulation may lead to a definite diagnosis and help the consultant to decide on treatment. You will be asked to give your consent to the procedure as there is no alternative way to get this information.

Sleep Deprivation

Sleep deprivation (going to sleep later and getting up earlier) is said to slightly increase the risk of a seizure.

Risks of sleep deprivation

There are different methods of sleep deprivation in use but the risk of triggering any seizure is small (6 in 100 patients).

Drug reduction

This may be undertaken after discussion with your doctor to increase the chance of capturing a typical attack. You would consent to this happening after talking with the doctor and you should ask them for any additional information on the risks associated with this drug reduction. If your child has a history of frequent seizures or status epilepticus (seizures are prolonged with little or no recovery in between) your doctor may decide not to alter your child’s drugs.

Risks of drug reduction

Reducing or stopping medications can cause frequent seizures or clusters of seizures, which could need additional rescue medications to stop the seizures.

Reduced medication can cause seizure activity to spread further in the brain. If the activity spreads to both sides of the brain then it causes a bilateral tonic-clonic seizure (sometimes called a ‘convulsion’ or ‘grand mal seizure’). There is also a risk of the seizures lasting longer and rarely of seizures that do not stop without emergency treatment (this is called status epilepticus). The risk of this happening is about 15 in every 1,000 patients admitted to a video telemetry unit.

Having epilepsy is associated with a small risk of Sudden Death in Epilepsy (SUDEP), this risk is increased slightly with drug reduction. In adult telemetry units the risk is quoted as 1.2 every 10,000 telemetry monitoring sessions. The risk of SUDEP in children is much smaller than the risk in adults and currently specific figures are unavailable to quote for admissions to children’s telemetry units.

The purpose of this test is to capture seizures or attacks and all of these activation techniques may lead to an increase in the frequency and/or severity of your child’s seizures. This would be managed by the doctors looking after your child on the ward.

What is done with the video of the test?

We routinely video these tests to record any symptoms or seizures that we can re-examine what happened.

Video clips of any symptoms or seizures are kept as part of the record. All remaining video is deleted after the doctor has completed the report. We will ask you for your consent to do this.

We may also ask permission to use the video for teaching purposes and you will be asked to give your consent separately for this purpose.

What happens after the test?

When the test is complete the electrodes are removed using a solution to dissolve the glue. It is unavoidable that a small amount of the glue is left in their hair. This will come out after their hair has been washed and conditioned a few times.

When will I get the results?

You will not get the results of the test during your stay as a large amount of information needs to be interpreted. Once this has been done, the results will be sent to your child’s hospital consultant within 3 weeks. Before your child is discharged from the ward, your consultant will arrange a way to discuss the results with you when they become available.