Kiana Assady Looyeh

Background: Temporal lobe epilepsy is the most common pharmaco-resistant type of epilepsy. The chance of obtaining seizure freedom after resective surgery in pharmaco-resistant mesial temporal lobe patients (mTLE) is significantly higher compared to pharmaceutical treatment (at least 50–60% compared to less than 15%). However, some factors (e.g., craniotomy) may prevent epilepsy patients undergoing surgery. A recent advancement in epilepsy surgery, i.e., magnetic resonance guided laser interstitial thermal therapy (MRgLITT), has become an attractive alternative for performance of selective amygdala-hippo-campectomy, especially because of its minimal invasiveness. Among other medial temporal lobe structures, the hippocampus is particularly important for successful processing of vestibular inputs. Nevertheless, it is still unclear whether mTLE patients who underwent MRgLITT perform worse on vestibular-dependent tests, including balancing, spatial orientation and rotational memory. Methods: Nine patients (Age 40.1 ± 14.5; 2 females) underwent vestibular-dependent assessments before and after MRgLITT using the following test battery: (I) clinical balancing test (CBT), (II) triangle completion test (TCT) and (III) rotational memory test (RM). Results: We found significant improvement from pre- to post-surgery in the vestibular-dependent spatial orientation test, namely in the wheelchair condition of the triangle completion test. Additionally, the obtained effect sizes were medium to large in favor of post-surgery assessment for the majority of conditions in the three tests applied in this study, indicating that the assessment of a larger number of patients could also, potentially, lead to significant results in these cases. Conclusions: This plausibility study is the first to assess vestibular-dependent balancing, spatial orientation and rotational memory functions before and after MRgLITT in mTLE patients. Even with a small sample of nine patients, significant changes and medium to high effect sizes in favor of surgery were observed. Nevertheless, prospective studies with larger sample sizes are necessary for appropriate estimation of MRgLITT effectiveness in these functional domains.

Background: About 65 million people worldwide are affected by epilepsy, with temporal lobe epilepsy being the most common type resistant to drugs and often requiring surgical treatment. Although open surgical approaches, such as temporal lobectomy, have been the method of choice for decades, minimally invasive MRgLITT has demonstrated promising results. However, it remains unknown whether patients who underwent one of these two approaches would show better performance on vestibulo-spatial tasks. Methods: Twenty-seven patients were included in three different groups: (1) MRgLITT (37.0 ± 15.1 years, two females), (2) R-OP (44 ± 15.7 years, five females) and (3) No-OP (43 ± 11.2 years, three females)—with no significant differences in age, disease duration and number of medications. Groups were compared on their performance in three vestibular-dependent tests: (1) clinical balance test (CBT), (2) triangle completion test (TCT) and (3) rotational memory (RM) test. Results: Significantly better performance of MRgLITT patients, in comparison to the other two groups (R-OP and No-OP), was found for the TCT. The other tests revealed no significant differences between the groups. Conclusions: Patients who underwent MRgLITT performed significantly better on the vestibular-dependent spatial orientation task (TCT) compared to those who underwent temporal lobectomy (R-OP) and non-operated patients. Speculations about reasons for such an effect—including minimal invasiveness with less “collateral damage”, influence of operated side, timing of surgery, sample heterogeneity and others—need to be assessed in detail in larger-scale, prospective longitudinal studies.