Optimal Surgical Extent for Memory and Seizure Outcome in Temporal Lobe Epilepsy

Abstract

Objective: Postoperative memory decline is an important consequence of anterior temporal lobe resection (ATLR) for temporal lobe epilepsy (TLE), and the extent of resection may be a modifiable factor. This study aimed to define optimal resection margins for cognitive outcome while maintaining a high rate of postoperative seizure freedom. Methods: This cohort study evaluated the resection extent on postoperative structural MRI using automated voxelbased methods and manual measurements in 142 consecutive patients with unilateral drug refractory TLE (74 left, 68 right TLE) who underwent standard ATLR. Results: Voxel-wise analyses revealed that postsurgical verbal memory decline correlated with resections of the posterior hippocampus and inferior temporal gyrus, whereas larger resections of the fusiform gyrus were associated with worsening of visual memory in left TLE. Limiting the posterior extent of left hippocampal resection to 55% reduced the odds of significant postoperative verbal memory decline by a factor of 8.1 (95% CI 1.5-44.4, p = 0.02). Seizure freedom was not related to posterior resection extent, but to the piriform cortex removal after left ATLR. In right TLE, variability of the posterior extent of resection was not associated with verbal and visual memory decline or seizures after surgery. Interpretation: The extent of surgical resection is an independent and modifiable risk factor for cognitive decline and seizures after left ATLR. Adapting the posterior extent of left ATLR might optimize postoperative outcome, with reduced risk of memory impairment while maintaining comparable seizure-freedom rates. The current, more lenient, approach might be appropriate for right ATLR.

Structure and function of language networks in temporal lobe epilepsy

“…However, TLE research suggests involvement in semantic processing. Research using voxel‐lesion symptom mapping found that resection of a small area of the STG correlated with naming decline following ATLR 56 . DES research did not find significant differences in naming sites in the STG between those with lesional and nonlesional TLE 51 .…”

Serum neurofilament light and MRI predictors of cognitive decline in patients with secondary progressive multiple sclerosis: Analysis from the MS-STAT randomised controlled trial

“…39,40 The BIRT memory battery has also been validated against the histological severity of hippocampal sclerosis in temporal lobe epilepsy and is sensitive to decline following anterior temporal lobe resection. 41,42 While the WASI and BIRT are not commonly used in MS research, previous work has found that lower WASI Full Scale IQ was associated with slower walking speed and higher risk of falls in a cohort of 78 pwMS and baseline WASI performance has been reported in a randomised controlled trial of cognitive rehabilitation for pwMS. 43,44 In summary, we felt that the requirement for more comprehensive cognitive outcome measures was warranted given the aim and hypotheses of the original MS-STAT interventional trial.…”

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

“…Lesional mesial temporal lobe epilepsy usually include hippocampal sclerosis, focal cortical dysplasia, or local neurodevelopmental tumors [53,54]. Due to their limited focal damages, standard anterior temporal lobectomy offers comparatively favorable outcomes (50-80% seizure-free rate) [55,56]. However, if combined with an extended frontal or thalamic 18 F-FDG metabolic disturbance, actual lesions associated with epileptogenesis or seizure related networks in MTLE may be larger than they appear on structural imaging.…”