Amygdalar Asymmetry in Temporal Lobe Epilepsy: MRI-SEEG Study
Abstract number :
2.454
Submission category :
4. Clinical Epilepsy / 4A. Classification and Syndromes
Year :
2023
Submission ID :
1341
Source :
www.aesnet.org
Presentation date :
12/3/2023 12:00:00 AM
Published date :
Authors :
Presenting Author: Subeikshanan Venkatesan, MBBS – University of Florida
Abbas Babajani-Feremi, PhD – University of Florida; Giridhar Kalamagalam, MD, DPhil – University of Florida
Rationale: The amygdala may be enlarged in 12-60% of temporal lobe epilepsy (TLE) patients (Beh SJ et.al. 2016; Epilepsy Behav 1:60:33). Eight of 11 patients with nonlesional TLE had amygdalar enlargement and/or asymmetry (AE/AA) concordant with seizure lateralization (Bower SP et.al. 2003; J Neurol Neurosurg Psych 74:1245). AE has also been described ipsilaterally, contralaterally or bilaterally in TLE (Reyes A et. al. 2017; Epilepsy Res 132:34). Case series of SEEG in TLE with AE report large volumes ipsilateral to seizure onsets and amygdalar epileptiform activity in all patients (Suzuki H et. al., Epileptic Disord 2019; 21(3):252; Makhalova J et. al. 2022; Clin Neurophysiol 133:94). Here, the largest SEEG study of the amygdala in TLE to date, we sought to address the above inconsistencies by (i) determining the incidence of AE/AA in a surgical TLE cohort, (ii) examining the predictive value of AE/AA vis-à-vis SEEG-identified TLE lateralization, and (ii) discovering correlations between AE/AA and amygdalar epileptiform activity.
Methods: We reviewed 20 pharmacoresistant TLE patients undergoing SEEG (12 females) with one (14) or both (6) amygdalae sampled. We computed an amygdalar volume asymmetry index (AAI) from Freesurfer-extracted segmentation (Fischl et al 2002; Neuron 33: 341) of pre-operative structural MRIs (Fig 1), formulated as 200*(Rvol-Lvol)/(Rvol+Lvol). Normative amygdalar volumetric data were obtained from the ENIGMA database (Dima D et al. 2002; Hum Brain Mapp 43:452). We classified patients as having right-, left-, or bilateral independent SEEG ictal onsets.
Results: Right amygdalar volumes of patients (mean (SD): 1883 (301)) were significantly higher than of controls (mean [SD]: 1621 [32.5]) (p< 0.001). For the left side, the numbers were mean (SD): 1674 [294]) and mean (SD): 1560 (38.8) (p< 0.05). AAI in patients (-19.5%-31.4%; mean 12%, SD 11.1) was significantly different from normals (3.1-5.3%; mean 3.9%, SD 0.68) (p < 0.
Clinical Epilepsy