Parents and caregivers often wonder whether their child needs an electroencephalogram (EEG) test if they are exhibiting challenging behaviour, or have been diagnosed with Autism Spectrum Disorder (ASD). Children with these conditions can have episodic odd behaviours, fluctuations in levels of engagement in non-preferred activities, or staring. In many instances, these are not epileptic. In most instances, figuring out if these events are epileptic or not can only be done through clinical assessment*, and an EEG test is not needed to arrive at a correct diagnosis.
What is an EEG?
An EEG test is where metal discs (called electrodes) are placed on the head, held in place by a head bandage, and these are used to record signals from the brain, with a video recorded of the child at the same time. Having the test is not painful, the scalp is rubbed clean under each electrode and some children can find this uncomfortable. The child has to sit still and comply with instructions, keeping the bandage and electrodes on their head for the duration of the test, otherwise the test is not successful. Children with behaviour challenges or autism can find it hard to comply with sitting still and some children with anxiety can find it distressing.
In general, an EEG test cannot diagnose or exclude epilepsy, unless the actual event that is of concern for epileptic seizure happens while the EEG is recording. This is because an abnormal EEG can occur without a person having epilepsy, and his happens more frequently in children with developmental, behavioural and mental health disorders. While around 2-4% of the general healthy population may have an abnormal EEG, around 50% (range 30-80%) of children with autism have an abnormal EEG. An abnormal EEG alone, therefore, cannot tell you if your child has epilepsy or not. An EEG is mostly used to find a clue to the cause of the epilepsy in children where there is no known cause. It is less helpful in working out whether children with challenging behaviours or autism have epilepsy.
How do I find out if my child with challenging behaviour or ASD has epilepsy?
Epilepsy can occur at a higher rate in children with autism than in children in the general population, therefore it is important to check if there are events that might be epileptic seizures. The diagnosis of epilepsy is always based on clinical assessment* of the events of concern, aided significantly these days by video of the events. Good clinical assessment, which can be supported by clinical opinion from Neurologists if needed, is often all that is needed to establish whether events are epileptic or not.
My child is already booked for an EEG, what should I do?
If you are worried your child will be distressed and not tolerate the procedure, please contact us and we can discuss how we might manage this, we can put special procedures in place to help your child through the procedure and we can help develop an alternative plan if the EEG test is not possible.
Can an EEG be done under sedation?
While in theory, children who will not tolerate an EEG can be sedated for the test to be done, the sedating medications change the EEG findings and do not reflect the normal background EEG recording. It is therefore not considered helpful to consider sedation or general anaesthesia for EEG tests.
What if I have more questions?
If you have more questions about EEG tests in a child with challenging behaviour or autism, contact your child’s treating specialist paediatrician or neurologist who can discuss these with you further. Your specialist paediatrician can also discuss your child’s specific case with a neurologist if assistance with clinical diagnostic support is required.
** Clinical assessment involves the assessment of the detail of the manifestations of the events, scrutinizing these for positive signs consistent with epileptic seizure or known imitators. Video of events can be crucial for correct diagnosis. Clinicians can obtain support, if required, in the form of an clinical opinion from Neurology services.
Department of Neurosciences
Queensland Children’s Hospital
501 Stanley Street, South Brisbane
t: 07 3068 1111 (general enquiries)
In an emergency, always call 000.
If it’s not an emergency but you have any concerns, contact 13 Health (13 43 2584). Qualified staff will give you advice on who to talk to and how quickly you should do it. You can phone 24 hours a day, seven days a week.