Background: Many children with ADHD develop epilepsy, and approximately 20% of children with epilepsy also have ADHD. In this article we discuss the use of EEG in connection with ADHD in children, with emphasis on the diagnosis of comorbid epilepsy.
Method: The article is based on a literature search in PubMed, personal literature archives and the authors' own experience with the use of EEG, treatment of epilepsy and the diagnosis and treatment of ADHD in children and adolescents.
Results: A moderately elevated prevalence of epileptiform EEG activity is described in children with ADHD without epilepsy compared with healthy children, during both wakefulness and sleep. Selected material and a lack of controlled blinded studies probably explain much of this difference. The significance of epileptiform EEG activity in children with ADHD without seizures is uncertain. Evaluating the extent to which EEG findings may explain the symptoms and whether anti-epileptic drugs should be tried is a specialist task. In many studies, spectral analysis of the frequency content of the EEG (QEEG) has shown higher slow theta activity and a higher theta/beta ratio in children with ADHD.
Interpretation: Seizure symptoms, disturbed sleep quality, significant changes in behaviour or regression of cognitive ability in children with ADHD should lead to paediatric neurological assessment with EEG and possibly a 24-hour EEG. In our view, the QEEG variables are artifact-prone and biologically unspecific. We therefore do not recommend the use of QEEG as a stand-alone diagnostic marker.