Cognitive and seizure outcomes for anterior temporal lobectomy versus laser ablation in temporal lobe epilepsy

Introduction: Anterior temporal lobectomy with amygdalohippocampectomy (ATL+AH) is an effective surgical approach for temporal lobe epilepsy (TLE) that has established costs to language and memory functions. MRI-guided laser ablation (LITT) offers a less-invasive alternative to ATL+AH, with potential for preserving cognitive functions by reducing damage to surrounding non-epileptogenic functional tissue. Few studies have directly compared these functions and seizure outcomes across both approaches. We investigated language, memory, and seizure outcomes from individuals who underwent ATL+AH or LITT by a single surgeon from a single institution.

Methods: 151 patients (18-73 years old) with pre- and post-operative neuropsychological testing underwent ATL+AH (n=97) and selective amygdalohippocampal LITT (n=54). Domain-level changes in language, verbal memory (VM), and non-verbal memory (NVM) and changes in individual tests were assessed as a function of surgery type and hemisphere. Multivariate voxel-based lesion-symptom mapping analysis (VLSM) was used to correlate surgical lesions with cognitive changes. Seizure outcomes (ILAE) were collected at post-operative neuropsychological testing.

Results: We found a significant effect of surgery type and hemispheric dominance for language (p=0.0071) with larger declines following ATL+AH versus LITT in the dominant hemisphere only. For dominant hemisphere surgeries, visual confrontation naming raw scores declined by 4.867.74 points following ATL+AH (p < 0.001) and 2.145.20 points following LITT (p=0.0145). At post-op neuropsychological testing, 54% of ATL+AH patients and 69% of LITT patients were seizure free (ILAE class I). VLSM localized language ability to the dominant ventral temporal lobe, VM to the dominant mesial temporal lobe, and NVM to the non-dominant mesial temporal lobe.

Conclusion : Patients with dominant hemisphere LITT showed attenuated declines in language compared to dominant ATL+AH, indicating that these functions are better preserved following LITT in the dominant hemisphere. Seizure outcomes were similar across both surgical approaches. These results provide strong evidence for the use of LITT in patients with dominant TLE to mitigate cognitive decline.