Abstracts

Rationale: Half of children with chronic epilepsy exhibit learning disabilities (Fastenau et al., in press), predicted largely by neuropsychological functioning (Fastenau et al., 2004). Based on the transient cognitive impairment model, EEG abnormalities should provide important biomarkers for concurrent and future cognitive comorbidities. Koop, Fastenau, Dunn, and Austin (2004) reported that memory and learning were related to epileptiform discharges and slow wave activity on clinical electroencephalograms (EEGs) in children with chronic epilepsy. Associations were nonsignificant in a group with more recent onset; however, that group was relatively small, and EEGs and neuropsychological testing were obtained 1.5 years apart, on average. The present study reports on a large diverse cohort of children who completed an EEG and neuropsychological testing following their first recognized seizure (FRS). It was hypothesized that abnormalities on EEG at onset would be associated with neuropsychological dysfunction at baseline and 18 and 36 months later.Methods: At baseline, 272 children who had just experienced their first recognized seizure (FRS) completed a clinical EEG (52.9% girls, 88.2% right-handed, 83.1% Caucasian). Age at FRS ranged from 5 to 14 years (M=9.5, SD=2.5), and diverse seizure types were represented. IQ > 55 was required for inclusion (M=103.6, SD=12.9). In addition, at onset (N=272) and again after 18 months (n=214) and 36 months (n=123), children completed neuropsychological testing assessing Language, Processing Speed, Executive/Construction, and Verbal Memory; Byars et al., in press). EEG reports were coded by board-certified child neurologists (DWD, TJD) for presence or absence of electrographic seizures, epileptiform discharges, and slow wave activity. A 2 x 3 (EEG Status x Time) repeated-measures analysis of variance was conducted on each neuropsychological domain to assess the association of the presence of EEG abnormalities with cognitive comorbidity at each time point.Results: Epileptiform discharges were associated with slower Processing Speed at all three time points (p = .02). Slowing was not related to any neuropsychological domain at any time point (p > .10). Electrographic seizures were associated with lower scores in Language (p = .03), Executive/Construction (p = .005), and Verbal Memory (p = .03) at all three time points, but this was based on a very small number of children who exhibited this abnormality. Conclusions: Epileptiform discharges and possibly electrographic seizures on the initial EEG at the onset of seizures, together with MRI abnormalities (Byars et al., in press), provide valuable biomarkers for cognitive comorbidities at the onset of seizures in childhood; children with these findings would benefit from a more complete clinical evaluation and possibly a neuropsychological evaluation for early identification of psychoeducational needs. (Supported by NIH/NINDS #22416 to JKA.)