The Presence or Absence of Hippocampal Atrophy Differently Disrupts Graph Theory Properties of Cerebral Functional Connectivity in Temporal Lobe Epilepsy. (S30.004)

Abstract

<h3>Objective:</h3> To investigate brain connectivity and network properties with graph theory methods in TLE patients according to the presence or absence of HA. <h3>Background:</h3> Although temporal lobe epilepsy (TLE) with unilateral hippocampal atrophy (HA) has been extensively investigated, the impact of bilateral HA and the absence of HA on brain connectivity and networks’ efficiency remains unknown. <h3>Design/Methods:</h3> We analyzed 216 3T-MRI resting-state images of TLE patients (median age: 48 years; 122 women): 92 LEFT-HA, 70 RIGHT-HA, 25 BILATERAL-HA, 29 NEGATIVE-TLE, and 216 healthy controls. We used the CONN connectivity_toolbox/MATLAB2019 to extract graph theory measures (global efficiency (Global-eff), average path length (PATH), degree/cost (DEGREE), betweenness centrality (BC), local efficiency (Local-eff), and clustering coefficient (CC). We considered a cost of 0.15 (including only the 15% more statistically significant results) and reported p-values&lt;0.05. <h3>Results:</h3> The LEFT-HA and RIGHT-HA presented a trend to higher measures of global connectivity (Global-Con), local connectivity (Local-Con), and centrality in the brain (higher Global-eff, DEGREE, BC, Local-eff, CC, and lower PATH) and a trend to lower Global-Con, Local-Con, and centrality in the cerebellum. The LEFT-HA and RIGHT-HA presented higher DEGREE in the ipsilateral hippocampus and higher Local-eff /CC in the contralateral hippocampus. The NEGATIVE-TLE group showed a trend to lower Global-eff and higher average PATH, DEGREE and CC in the brain. The BILATERAL-HA presented a trend to higher Local-eff /CC in the brain. <h3>Conclusions:</h3> Overall, there was a trend for higher local connectivity to the detriment of the Global-eff. Our data indicate more severe alterations in the unilateral groups, as the presence of unilateral HA disturbs hemispheric connectivity, which may disrupt global connections. While the unilateral groups showed higher connectivity levels in the brain (with higher ipsilateral hippocampal Global-Con and probable compensatory higher contralateral hippocampal Local-Con), the NEGATIVE-TLE presented concordantly higher Local-Con and lower Global-Con in the brain. <b>Disclosure:</b> Lucas Silva has nothing to disclose. Dr. Karmann Aventurato has received research support from Coordenadoria de Aperfeiçoamento de Pessoal de Ensino Superior (CAPES). Raphael Casseb has nothing to disclose. The institution of Brunno de Campos has received research support from São Paulo Research Fundation. Dr. Cendes has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for UCB Pharma. Dr. Cendes has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for UCB Biopharma. Dr. Cendes has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for United Medical – Brazil. Dr. Cendes has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Zodiac Pharma . Dr. Cendes has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Eurofarma – Brazil . Dr. Cendes has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Epilepsia. Dr. Cendes has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Frontiers in Neurology - Epilepsy. The institution of Dr. Cendes has received research support from São Paulo Research Foundation - FAPESP. The institution of Dr. Cendes has received research support from Conselho Nacional de Desenvolvimento Científico e Tecnológico - Brazil . The institution of Dr. Cendes has received research support from NIH. Clarissa Yasuda has nothing to disclose.