Abstracts

RATIONALE: Previous studies have shown EEG abnormalities in 1.7-3.5% of neurologically normal children. In children with psychiatric disease, several studies have shown abnormal EEG findings in 27-60%. We reviewed our EEG database to ascertain the prevalence of EEG abnormalities in children with psychiatric disease. The purpose of this study was to analyze the utility of EEG in children with psychiatric disease and identify clinical risk factors associated with EEG epileptiform abnormalities.
METHODS: EEG records for all individuals 18 years or younger referred from the MCO child psychiatry unit between January 1, 1998 and March 31, 2001 were reviewed. Relevant clinical data obtained by chart review was also analyzed. The research protocol was approved by the MCO IRB. EEGs were reviewed independently by two board certified electroencephalographers (IA and JG) blinded to clinical history; disagreements in interpretation were mutually resolved.
RESULTS: 143 pediatric patients underwent EEG due to a psychiatric diagnosis. Forty (27%) of these were abnormal. Abnormalities included generalized epileptiform activity in 17 (42.5%), focal epileptiform abnormality in 7 (17.5%), generalized slowing of background in 11 (27%)and focal slowing in 5 (12%). Prior to the EEG, seizures were documented in only 2 patients with abnormal EEG, one with a history of epilepsy and the other with febrile seizures. Subsequent epilepsy was diagnosed in one other patient. In those with generalized epileptiform discharges, photoparoxysmal response was noted in 41.1%. Among patients with generalized epileptiform activity, the most common psychiatric diagnoses were Attention Deficit Hyperactivity Disorder (75%) and Oppositional Defiant Disorder (56.2%). In this series, 41 patients had ADHD as one of the primary diagnoses, 22/41 (53%) had an abnormal EEG and 16/22 (72%) had either generalized or focal epileptiform abnormality. There was no significant correlation between EEG findings and other psychiatric diagnosis, family history of epilepsy, gender, type or number of psychotropic or stimulant medications.
CONCLUSIONS: 1- EEG was abnormal in 27% of children with primarily psychiatric disease.
2- The most common abnormality in our series was generalized epileptiform activity.
3- Abnormal EEG was more likely in patients with ADHD.
3- Epileptiform activity did not correlate the history of seizures, or the use of stimulant or psychotropic medications.
4- Epileptiform abnormalities on EEG in children with psychiatric disease may be a marker of neuronal injury associated with psychiatric illness, and may not necessarily be predictive of seizures.