Impact of side of lesion, seizure outcome and interictal epileptiform discharges on attention and memory after surgery in temporal lobe epilepsy

Purpose. To determine the impact of side of surgery, seizure outcome and interictal epileptiform discharges (IEDs) on attention and memory in a cohort of patients with temporal lobe epilepsy who had undergone unilateral mesial temporal lobe resection. Material and methods. Ninety-four patients were investigated pre- and postoperatively by means of a standardised neuropsychological battery measuring subcomponents of attention, as well as short-term, working and long-term memory. The side of epilepsy surgery, seizure outcome and the presence of postoperative IEDs, as well as their possible relationship to the neuropsychological changes, were assessed. Statistical data were analysed using a repeated measures MANOVA. Results. The absence of seizures following surgery had a positive effect on short-term memory and attentional control. The occurrence of IEDs was found in patients with impaired figural learning. In terms of attentional control and working memory, patients who continued to present IEDs had also scored lower in these domains prior to surgery. Conclusion. IEDs had an effect independent of seizure presence, but were found to have a "supplementary negative effect" when the two variables were combined.