Risk of Developing Seizures in Children With Abnormal EEG Findings During Polysomnography.

BACKGROUND: Polysomnography (PSG) utilizes abbreviated electroencephalogram (EEG) to stage sleep. The aim of this study was to determine whether epileptiform abnormalities on this limited EEG coverage correlated with abnormalities on routine EEG (rEEG) and an increased risk for seizures in children without a prior diagnosis of epilepsy. METHODS: A six-year retrospective chart review was performed assessing children with abnormalities on EEG during PSG. Children who underwent subsequent rEEG were included; children with a prior diagnosis of seizures were excluded. The main outcome measures were rEEG results and subsequent diagnosis of epilepsy. RESULTS: A total of 67 children met inclusion criteria. Average age was six years, and 43 (64%) were male. rEEG was normal in 16 (24%). Epileptiform abnormalities were focal in 36 (54%), generalized in eight (12%), and mixed in five (8%). An additional two (3%) had slow background rhythm without epileptiform discharges. Thirty-one patients had neurology clinic follow-up with an average duration of 31 months (range 4 to 65 months). Of these, nine (29%) developed seizures, including all three with generalized epileptiform discharges, four of 19 (21%) with focal epileptiform discharges, and two of five (40%) with mixed epileptiform discharges or background slowing. None of the four patients with a normal rEEG had seizures. Eight of the nine patients with seizures were treated with antiepileptic drugs. CONCLUSIONS: Children with no history of seizures found to have abnormal EEG during PSG are likely to have an abnormal rEEG. Additionally, they have an increased risk for developing seizures