LINKING MEMORY IMPAIRMENT TO STRUCTURAL CONNECTIVITY IN TEMPORAL LOBE EPILEPSY SURGERY
Poster No:
1769
Submission Type:
Abstract Submission
Authors:
Niels Alexander Foit1, Alexander Rau2, Horst Urbach2, Juergen Beck2, Andreas Schulze-Bonhage2, Christopher Nimsky3
Institutions:
1McGill University, Montreal, QC, 2University Medical Center, Freiburg, Germany, 3Uniklinik Marburg, Marburg, Germany
First Author:
Co-Author(s):
Introduction:
Temporal lobe epilepsy (TLE) is the most common drug-refractory seizure syndrome worldwide. TLE originates from extrahippocampal lesions in 25% of surgical candidates, necessitating tailored approaches (1). Despite high rates of seizure control, concern persists regarding postoperative memory decline. Here, we investigated associations between structural connectivity and postoperative memory performance in neocortical TLE.
Methods:
Fifty-four patients with neocortical TLE undergoing hippocampal sparing surgery were evaluated. All participants underwent standardized neuropsychological evaluation of verbal memory and figural learning. Utilizing hand-drawn, 3T-derived , T1-weighted volumetric lesion volumes intersected with HCP-derived ultra-high resolution tractography data (3), structural connectivity was assessed by means of voxel-based and connectome-informed lesion-symptom mapping, identifying cortical and white matter structures driving cognitive phenotypes. Permutation testing with 5000 permutations for general linear models and one-tailed tests at FWE-corrected thresholds of p<0.05 were utilized to assess relationships between markers of structural impairment and neurocognitive scores. Only disconnections present in n>3 patients were considered relevant.
Results:
Widespread structural disconnections of ipsi- and contralateral white matter pathways were found postoperatively, which correlated with verbal and visual memory decline. Importantly, alterations involved structures which were explicitly spared or distant to the surgical site, likely reflecting upstream white matter degeneration (Figure 1). Disconnections of major WM tracts include the anterior commissure (AC), bilateral uncinate fascicle (UF), bilateral inferior longitudinal fasciculus (ILF), posterior portion of the corpus callosum (CCposterior) and left arcuate fasciculus (AF). Disconnections were mostly located within the ipsilateral temporal lobe, orbitofrontal, limbic and visual areas, but also extending to the contralateral hemisphere.
Conclusions:
Our study highlights the role of structural connectivity alterations in postoperative memory decline in extrahippocampal TLE surgery. Personalized surgical approaches should be considered to minimize cognitive decline, with future research being directed at exploring potential of connectome informed, minimally invasive approaches to protect neurocognitive function.
Learning and Memory:
Neural Plasticity and Recovery of Function 2
Neuroanatomy, Physiology, Metabolism and Neurotransmission:
White Matter Anatomy, Fiber Pathways and Connectivity 1
Keywords:
Atlasing
Computational Neuroscience
Epilepsy
Memory
1|2Indicates the priority used for review
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2. Wagner K, Gau K, Metternich B, et al. Effects of hippocampus-sparing resections in the temporal lobe: Hippocampal atrophy is associated with a decline in memory performance. Epilepsia. 2020;61:725–734.
3. Griffis JC, Metcalf NV, Corbetta M, Shulman GL. Lesion Quantification Toolkit: A MATLAB software tool for estimating grey matter damage and white matter disconnections in patients with focal brain lesions. NeuroImage Clin. Epub 2021 Mar 22.:102639.
4. Griffis JC, Metcalf NV, Corbetta M, Shulman GL. Structural Disconnections Explain Brain Network Dysfunction after Stroke. Cell Rep. 2019;28:2527-2540.e9.