The most useful role of an EEG is when someone already has epilepsy, and then it helps give a clue to the underlying cause (for example an abnormality in one part of the brain on EEG can suggest an abnormality is a possibility in that area on a brain scan). Using the results of an EEG test can be harmful if the EEG test information is incorrectly interpreted, for example it can result in over-diagnosis of epilepsy (when a person does not have epilepsy), treatment with anti-seizure medications (when these are not required) or even just health anxiety over what the EEG findings mean. There is such a variation in the EEG findings in normal children that defining ‘abnormal’ is not always easy. The recording can appear abnormal, but this can be caused by artefact (for example interference from electrical devices, chewing/sucking, patting, or even from picking up the child’s or nearby parents heart-beat or breathing).
An EEG is not a precise test, it simply measures small electrical signals recorded from the surface of the brain, and the recording only indicates what is happening at the time of the test but may not reflect what is happening all of the time.
