Prognosis of EEG Findings in Infancy

Abstract

To determine how specific early EEG abnormalities correlate with clinical outcome on long-term follow-up for neurological and epilepsy outcomes. Our aim was to revisit how early EEG abnormalities should be weighed for prognosis. This is a retrospective study of 358 infants who had EEGs taken between 3 and 12 months of age and subsequent clinical assessment between 4 to 18 years of age. Of the 358 infants, 215 had unfavorable neurological outcome (UNO), and 234 had epilepsy on follow-up. Breakdown: 117 had major abnormal EEG background of which 86% had UNO and 75% had epilepsy. One hundred had abnormal sleep potentials of which 89% had UNO and 80% had epilepsy. One hundred seventy-five had interictal epileptiform activity of which 80% had UNO and epilepsy. Sixty had ictal epileptiform activity of which 90% had UNO and 86% had epilepsy. One hundred ninety-two had markedly abnormal overall EEG impression of which 80% had UNO and 79% had epilepsy. Occurrence of significant EEG abnormalities in the first year was clearly associated with UNO and epilepsy. Current views that certain EEG abnormalities (e.g., interictal spike) may have little prognostic significance would need to be revisited.