Metabolic profiles and correlation with surgical outcomes in mesial versus neocortical temporal lobe epilepsy

Objective: The ictalHarmonicpattern (Hpattern), produced by the non-linear characteristics of EEG waveforms, may hold significant potential for localizing the epileptogenic zone (EZ) in focal epilepsy. However, further validation is needed to establish theHpattern′s effectiveness as a biomarker for measuring the EZ. Methods: We retrospectively enrolled 131 patients diagnosed with drug-resistant focal epilepsy, all of whom had complete stereo-electroencephalographic (SEEG) data. From this cohort, we selected 85 patients for outcome analysis. We analyzed the morphological and time-frequency (TF) features of the H pattern using TF plots. A third quartile (Q3) threshold was applied to classify channels expressing either dominant (ChanneldH pattern) or non-dominant H patterns (Channelnon-dH pattern). We then examined associations between the morphological features of theHpattern and patients′ clinical characteristics, as well as the correlations between the extent of channel removal and seizure outcomes. Results: We found no significant correlations between the morphological features of the ictalHpattern and clinical factors, including lesional MRI findings, epileptic onset patterns, epilepsy type, pathology, or surgical outcomes. The non-localizableHpattern appeared exclusively in patients with non-focal onset patterns. Notably, the proportion ofChanneldH patternwas higher in the seizure-onset zone (SOZ) compared to the early propagation zone. The seizure-free group demonstrated significantly higher removal proportions ofChanneldH pattern, both within and outside the SOZ (p= 0.014;p= 0.036), with AUCs of 0.606 and 0.660, respectively, in a seizure freedom prediction model. Survival analysis confirmed that complete removal of these regions correlated with long-term seizure freedom (p= 0.008;p= 0.028). Further subgroup analysis showed a significant correlation in neocortical epilepsy (p= 0.0004;p= 0.011), but not in mesial temporal lobe epilepsy. Additionally, multivariate analysis identified the complete removal ofChanneldH patternas the only independent predictor for seizure freedom (p= 0.022; OR 6.035, 95% CI 1.291-28.211). Conclusions: Our study supports the notion that the dominance of the ictalHpattern, regardless of its morphology, serves as a novel biomarker for the EZ in focal epilepsy. The non-linearity in EEG waveforms provides new insights into understanding ictal spreading propagation and offers potential improvements for surgical planning in neocortical epilepsy.

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Metabolic profiles and correlation with surgical outcomes in mesial versus neocortical temporal lobe epilepsy

Zhu

Tang

Xiao

et al. 2023

CNS Neurosci Ther

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Aims Differentiating mesial temporal lobe epilepsy (MTLE) and neocortical temporal lobe epilepsy (NTLE) remains challenging. Our study characterized the metabolic profiles between MTLE and NTLE and their correlation with surgical prognosis using 18F‐FDG‐PET. Methods A total of 137 patients with intractable temporal lobe epilepsy (TLE) and 40 age‐matched healthy controls were recruited. Patients were divided into the MTLE group (N = 91) and the NTLE group (N = 46). 18F‐FDG‐PET was used to measure the metabolism of regional cerebra, which was analyzed using statistical parametric mapping. The volume of abnormal metabolism in cerebral regions and their relationship with surgical prognosis were calculated for each surgical patient. Results The cerebral hypometabolism of MTLE was limited to the ipsilateral temporal and insular lobes (p < 0.001, uncorrected). The NTLE patients showed hypometabolism in the ipsilateral temporal, frontal, and parietal lobes (p < 0.001, uncorrected). The MTLE patients showed extensive hypermetabolism in cerebral regions (p < 0.001, uncorrected). Hypermetabolism in NTLE was limited to the contralateral temporal lobe and cerebellum, ipsilateral frontal lobe, occipital lobe, and bilateral thalamus (p < 0.001, uncorrected). Among patients who underwent resection of epileptic lesions, 51 (67.1%) patients in the MTLE group and 10 (43.5%) in the NTLE group achieved Engel class IA outcome (p = 0.041). The volumes of metabolic increase for the frontal lobe or thalamus in the MTLE group were larger in non‐Engel class IA patients than Engel class IA patients (p < 0.05). Conclusions The spatial metabolic profile discriminated NTLE from MTLE. Hypermetabolism of the thalamus and frontal lobe in MTLE may facilitate preoperative counseling and surgical planning.

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Metabolic profiles and correlation with surgical outcomes in mesial versus neocortical temporal lobe epilepsy

Cited by 3 publications

References 51 publications

Individual cerebellar metabolic connectome in patients with MTLE and NTLE associated with surgical prognosis

Individual cerebellar metabolic connectome in patients with MTLE and NTLE associated with surgical prognosis

Dominant harmonic pattern as an ictal marker of the epileptogenic zone in focal neocortical epilepsy

Metabolic profiles and correlation with surgical outcomes in mesial versus neocortical temporal lobe epilepsy

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