Abstracts

It is not known if neuropsychological functioning differs based on magnetic resonance imaging (MRI) abnormalities and electroencephalography (EEG) patterns. This study explored these differences in a study of children with new-onset seizures.
Through a prospective, observational project, 6 to 14 year-old children who had experienced their first recognized seizure within the preceding 3 months were enrolled. Participants were excluded if they had an acute provoked seizure, a chronic illness affecting their activities of daily living, significant failure to meet developmental milestones, or prior IQ testing less than 70. MRI abnormalities were subdivided into four groups denoted as cortical lesions, white matter lesions, asymmetric lateral ventricles, and an unclassified group including abnormalities such as cerebellar lesions and venous anomalies. EEG data were grouped into four classes: normal, focal epileptiform, generalized epileptiform, and abnormal slowing. Neuropsychological testing included the Kaufman Brief Intelligence Test (K-BIT) and subtests of the Wide Range Assessment of Memory and Learning (WRAML).
All patients with MRI, EEG, and the specified neuropsychological testing results (n = 104) were analyzed. Within this group, 39 patients (37.5%) had abnormal MRI findings and 71 patients (68.3%) had abnormal EEG results. Of those with an abnormal MRI, 24 patients (61.5%) also had an abnormal EEG. Forty-seven (72.3%) patients with normal MRI results had abnormal EEG patterns. All 5 patients with focal cortical MRI findings and an abnormal EEG, had lesions ipsilateral to focal epileptic discharges. One of 6 patients with cortical MRI findings had a normal EEG. Patients had similar cognitive test scores whether the MRI result was normal or abnormal (K-BIT mean composite: 103 vs 102; F = 0.013, NS). They also had similar cognitive test scores despite different EEG findings. Subjects with abnormal MRI results and unilateral focal epileptiform discharges (5 left, 4 right) had similar composite cognitive testing. In this group of nine, patients with right-sided epileptiform abnormalities had lower K-BIT matrices scores (mean R 92.5 vs L 112) though this trend was not subjected to statistical testing due to the small size of this subsample.
This preliminary analysis shows similar initial neuropsychological testing despite different MRI and EEG results in healthy six to fourteen-year-old children with new-onset seizures. MRI abnormalities included 6 (5.8%) cortical lesions likely relevant to seizure etiology. Future testing of these individuals and the relation of additional seizure episodes may show deviations from initial cognitive function.
[Supported by: National Institutes of Health - NS22416 (PI J. Austin)]