What is a melatonin sleep EEG?

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. EEGs are done on babies and children of all ages and abilities. Staff are used to dealing with children who are anxious or have sensory or special needs.

How does an EEG work?

We produce brain waves all the time and an EEG records these brain waves. If a child has a condition that affects the pattern of these brain waves, an EEG may pick this up.

What is a melatonin sleep EEG?

Your child has been referred for a specific type of EEG recording known called a ‘melatonin sleep EEG’. This means we would like some of the EEG to be recorded whilst your child is asleep.

How will having a melatonin sleep EEG help?

EEG is used to help in the diagnosis in a variety of illnesses. How it will help a child will depend on the clinical problem that they are experiencing such as blackouts or seizures. The EEG may help us to find out the cause of their problem and help us to decide what treatment would work best for them. Falling to sleep will also increase the information we can obtain.

How long will we be at the hospital?

You can expect to be at the hospital for 1 to 2 hours.

Where will the test be done?

The test is performed in a recording room on E Floor, Grey Stair or Lifts, at Sheffield Children’s Hospital, S10 2TH.

The recording room contains a couch, TV with DVD player and EEG equipment. There will be a physiologist present and there is also room for parents or carers. As we are a teaching hospital, with your consent, a trainee physiologist may perform the test under direct or distance supervision or occasionally other healthcare professionals may ask to observe.

Our physiologist are used to dealing with frightened and anxious patients as well as those with sensory issues or special needs.

How do we get to the EEG recording room?

The recording room is on E Floor, Grey Stairs or Lifts, at Sheffield Children’s Hospital, S10 2TH.

The nearest entrance to the department is on Damer Street around the corner from the Emergency Department.

Then follow the signs to grey lifts or stairs and travel to E floor and report to reception. You can also follow the signs for Grey lifts from the Main Entrance.

Public transport is the best way to travel to Sheffield Children’s Hospital. We are well served by bus services (51, 52, 273, 274, 275) and close to the tram route. Find out more on our public transport webpage: www.sheffieldchildrens.nhs.uk/patients-and-parents/public-transport

Please allow plenty of time for delays and roadworks. For up-to-date parking information visit our webpage on parking:
www.sheffieldchildrens.nhs.uk/parking

Is there anything we need to do before having the test?

• You will need to collect your prescribed melatonin from the Pharmacy and bring it with you to the department. Once you have arrived in the department you will be told by the clinical physiologist performing the test when to give the melatonin.
• You should make sure that your child has something to eat before their test. If your appointment is in the morning they should have a good breakfast. If it is in the afternoon, they should have some lunch.
• Make sure their hair is free from hairspray or gel.
• Make sure your child is wears clothes that are comfortable to sleep in.
• Please continue any medication they are currently taking. It is helpful to bring a list of current medications with you.

What happens before the test?

• To prepare your child for the test, their head will be measured and then rubbed with a cotton bud and some abrasive paste.
• A sticky paste is then applied to hold the 23 small discs on their head which will pick up their brain waves.

Getting them ready for the test takes about 15 minutes. If at any time during this preparation you would like to ask us questions about the test please feel free to do so.

What happens during the test?

This part of the test takes about 45 minutes to 1 hour 15 minutes.

Please bring dummies, drinks, snacks and favourite toys or DVDs if you think they will help your child to be comfortable and relaxed.

Your child will not feel anything whilst the EEG is being recorded. Older children find that they are most comfortable lying down. Babies and young children may sit on a parent’s knee to settle to sleep.

Once they are comfortable the discs or pads are connected by leads to a box which records the impulses and sends them to a computer. Two stickers are put on their arms or shoulders to record their heartbeat – this is called an electrocardiogram (ECG).

At the beginning of the test, your child will be left undisturbed to encourage sleep. If they do not sleep after 45 minutes a second dose of melatonin may be given if prescribed by your doctor. A further period of recording will then be performed to encourage sleep after which your child will be asked to perform the following actions:

• Opening and closing their eyes
• Deep breathing (hyperventilation)
• Looking at a flashing light (photic stimulation)

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, 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 of photic stimulation are that you may have:

• Any clinical event – less that 2 in 100 people.
• Any type of seizure – 7 in 1,000 patients.
• A generalised tonic-clonic seizure – 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, there is no alternative way to get this information.

Sleep phase of test

Your child will then be settled into a comfortable position and allowed time to go to sleep. If they do they will be allowed to sleep for 30 minutes and then woken up. It is important that anyone in the room remains quiet during this time so that they are not distracted. It is better to keep the number of family members in the room to a minimum so that your child has a better chance of falling asleep.

What happens after the test?

Once the test is complete we remove the discs from your child’s hair. You may find a small amount of paste left in their hair but this is easily washed out with shampoo. You may wish to bring a hat or cap for them to wear.

When will we get the results?

You will not get the results on the day of the test because it takes time for our doctors to analyse them. The report will be sent to the referring consultant within 5 working days and they will then discuss the results with you.