Network Adequacy and Reserve: White Matter Asymmetry Predicts Post-Operative Memory in Epilepsy
Abstract number :
3.097
Submission category :
2. Translational Research / 2C. Biomarkers
Year :
2021
Submission ID :
1825759
Source :
www.aesnet.org
Presentation date :
12/6/2021 12:00:00 PM
Published date :
Nov 22, 2021, 06:50 AM
Authors :
Alena Stasenko, PhD - University of California, San Diego; Erik Kaestner, PhD - UCSD; Anny Reyes, M.S. - UCSD; Sanam Lalani, PhD - UCSD; Brianna Paul, PhD - UCSF; Manu Hegde, MD - UCSF; Sharona Ben-Haim, MD - UCSD; Carrie McDonald, PhD - UCSD
Rationale: Anterior temporal lobectomy (ATL) is an effective treatment for drug-resistant temporal lobe epilepsy (TLE) but leads to memory impairment in up to 60% of patients, decreasing quality of life and functional outcomes. To understand the neuroanatomical correlates associated with cognitive outcomes, studies assessed both the pre-operative integrity of the ipsilateral hippocampus (functional adequacy) and presumed “functionality” of the contralateral hippocampus (hippocampal reserve). However, whether the concepts of adequacy and reserve also apply to white matter (WM) integrity of the medial temporal lobe (MTL), and whether this predicts memory decline following ATL is unknown. To that end, we investigated whether microstructural asymmetry of deep and superficial WM networks within the MTL predicts memory decline after ATL independently of hippocampal volume and baseline memory score.
Methods: Forty-two patients with TLE (19 left, 23 right) completed pre-operative T1 and diffusion-weighted MRI and pre- and post-operative neuropsychological testing. Fractional anisotropy (FA) of the WM directly beneath the neocortex (i.e., superficial WM; SWM) and of deep WM tracts associated with memory were calculated. Asymmetry was calculated for hippocampal volume (HCV) and FA of each WM tract or region and examined in regressions.
Results: Leftward FA asymmetry of the entorhinal SWM was associated with decline on prose and associative recall in left TLE, whereas leftward FA asymmetry of the uncinate fasciculus was associated with greater decline on prose recall only. After controlling for baseline clinical variables and HCV, leftward asymmetry of the uncinate and entorhinal FA uniquely contributed to decline in prose recall, and the contribution of asymmetry of entorhinal FA to decline in associative recall approached significance. Logistic regression with HCV and asymmetry of entorhinal FA correctly classified memory outcomes in 79% and 81% of patients for prose and associative recall, respectively, with both models revealing that WM asymmetry was the strongest predictor.
Conclusions: Asymmetry of deep and SWM integrity within the MTL reflects both ipsilateral MTL network adequacy and contralateral reserve and is related to post-operative memory outcomes in TLE. This suggests that surgical decision-making may benefit from considering individual patient WM network adequacy and reserve in addition to hippocampal integrity.
Funding: Please list any funding that was received in support of this abstract.: Supported by NIH/NINDS R01 NS065838 (CRM) and R21 NS107739 (CRM; LB); 1F31NS111883-01 (AR).
Translational Research