(1001) Cognitive impairment and higher rates of seizure recurrence correlates with spread of epilepsy

Surgery for temporal lobe epilepsy (TLE) results is curative in only 66% of medically refractory cases. Understanding of network-level disruptions may improve response rates of surgery and minimize cognitive morbidity. Here, we applied a novel network modeling algorithm and correlated measures of global network and epilepsy network connectivity patterns with surgical outcomes and neuropsychological performance.

Methods:

Twenty-two patients were prospectively included, and relevant demographic information was attained. Resting-state functional MRI and EEG data were recorded and pre-processed. Using our novel algorithm, patient-specific epileptic networks were mapped pre-operatively and geographic spread was quantified. Global functional connectivity was also determined using a volumetric functional atlas. Neuropsychological pre- and post-surgical raw and standardized scores obtained blinded to epileptic network status. Key demographic data and features of epileptic networks were then correlated with surgical outcomes using Pearson’s product-moment correlation.

Results:

Pre-operatively, increased connectivity in the hemisphere contralateral to the seizure onset correlated with impairment in executive functioning and in both short- and long-term measures of verbal memory. Epilepsy networks were generated using a non-invasive methodology and spread of the epilepsy network correlated with lower scores in neuropsychological tests measuring verbal learning and short-term memory. Seizure freedom rates were also correlated with the spread of the epilepsy network to the bitemporal lobes.

Conclusions: It was shown that aberrant synchronicity contralateral to seizure onset and widespread involvement of the epilepsy network correlated with impairment of executive functioning and verbal memory. Furthermore, widespread epilepsy networks were also associated with higher rates of seizure recurrence. This preliminary work shows the promise of a non-invasive method to image clinically-relevant networks in patients pre-operatively that relate to cognitive dysfunction and worse surgical outcomes. Future work aims to understand how the epilepsy network becomes more widespread over time and how targeted surgical interventions may better assess or disrupt this network.

Funding: Please list any funding that was received in support of this abstract.: No funding