Research Fellow The Hospital for Sick Children Toronto, Ontario, Canada
Rationale: Aspects of executive functioning, which are considered to rely on frontal lobes, are found to be impaired in children with frontal lobe epilepsy (FLE) and temporal lobe epilepsy (TLE; Longo et al., 2013, Epilepsy Behav, 26, 102-108). Similarly, aspects of memory, which have been linked to temporal lobe functioning, are found to be impaired in children with FLE and TLE (Kibby et al., 2019, Epilepsy Behav, 99). These results have led to the intriguing possibility that cognitive abnormalities extend beyond the seizure foci and result in overlapping cognitive symptoms in children with FLE and TLE (Smith., 2016, Epilepsy Behav, 64, 313-317). Critically, other areas of cognitive functioning have not been directly compared across both groups of patients.To date, few studies have compared cognitive outcomes following resective epilepsy surgery in youth with FLE and TLE. Furthermore, these studies have been limited to assessing aspects of executive and memory functioning only. Given these limitations, the objective of this study was to assess multiple aspects of intellectual function pre-operatively and following epilepsy surgery in youth with FLE vs. TLE, as compared to a non-surgical epilepsy control group. Methods: Participants included children who completed a comprehensive neuropsychological evaluation to determine their candidacy for epilepsy surgery. Children were included in the study if they had undergone a frontal or temporal lobe resection and completed a post-operative cognitive assessment. A non-surgical epilepsy control group, comprised of children who did not undergo surgery, was also included. Pre-operative and post-operative measures of intelligence included Full Scale intelligent quotient (IQ) and Verbal IQ, Performance IQ, Processing Speed Index and Working Memory index. Outcomes were examined over time and across the groups using repeated-measures analysis of variance Results: A total of 146 patients: 26 patients had undergone a frontal lobe resection, 74 patients had undergone a temporal lobe resection, and 46 were non-surgical controls. All patients completed neuropsychological assessments prior to and on average 1.9 years following baseline evaluation. Mean differences in scores were small, but all patients exhibited better performance on Verbal IQ pre-operatively relative to the follow-up assessment (p = 0.004, ηp2=0.07). Patients with temporal lobe resections performed better compared to patients with frontal lobe resections and non-surgical epilepsy group on Performance IQ (p =0.005, ηp2=0.09) and the Working Memory index (p = 0.036, ηp2=0.08). Conclusions: The current study extends the extant literature by examining multiple aspects of intellectual abilities and including a non-surgical comparison group to delineate the effects of epilepsy surgery on cognition. These preliminary results suggest different patterns of cognitive dysfunction based on the site of seizure focus. Future work will examine other aspects of neuropsychological performances to delineate a comprehensive evaluation across the epilepsy groups pre-operatively and following epilepsy surgery. Funding: Please list any funding that was received in support of this abstract.: Funding for TT provided by The Hospital for Sick Children Foundation
