Authors :
Alena Stasenko, PhD – University of California, San Diego; Erik Kaestner, PhD – UCSD; Donatello Arienzo, PhD – UCSD; Adam Schadler, M.A – UCSD; Anny Reyes, PhD – UCSD; Monika Polczynska, PhD – UCLA; Carrie McDonald, PhD – UCSD
This abstract has been invited to present during the Basic Science Poster Highlights poster sessionRationale: Bilingualism has been suggested to induce neuroplasticity and modulate network efficiency, with evidence of increased resistance to neurological disease. However, bilingualism’s effect on epilepsy is un-investigated at a network level. Given that epilepsy is a network disorder, we tested whether bilingualism improves whole-brain structural network organization in temporal lobe epilepsy (TLE).
Methods: Eighty-eight monolinguals and 29 bilinguals with TLE, and 81 healthy controls (HC) completed diffusion-weighted MRI. Whole-brain connectomes were generated via diffusion tractography and analyzed using graph theory. Analyses compared the area under the curve (AUC) across network densities
of path length (i.e., network integration) and transitivity (i.e., network specialization) in TLE versus HC and in a 2 (L vs R-TLE) x 2 (bilingual vs monolingual) MANOVA. A follow-up analysis compared mean local efficiency in a-priori defined frontal-executive and perisylvian subnetworks, due to previous literature suggesting these networks as modulated by bilingualism._x000D_
Results: A significant interaction between language status and side of seizure onset revealed higher network efficiency for bilinguals compared to monolinguals but only in left TLE. In addition, bilinguals with L-TLE showed higher efficiency in frontal-executive networks, with no difference in perisylvian networks compared to monolinguals. Network specialization positively correlated with neuropsychological tests of executive function in bilingual L-TLE.
Conclusions: Higher structural network efficiency in bilinguals with L-TLE is suggestive of a neuroprotective effect of bilingualism on whole-brain white matter connectivity in epilepsy. This may reflect attenuation or repair of epilepsy-related dysfunction of the left hemisphere, and/or a potential compensatory increased efficiency of frontal networks underlying executive function due to their hypothesized involvement in dual-language control. These findings highlight a role of bilingualism as a protective factor in epilepsy and supports testing interventions aimed at increasing bilingual language use in TLE._x000D_
Funding: Supported by NIH/NINDS R01 NS124585 (CRM); F32 NS119285-02 (AS); T32 MH018399 (EK); F31 NS111883-01 (AR)