Abstracts

Rationale: Ictal automatism with preserved responsiveness (APR) refers to the ability of patients to respond verbally or follow motor commands during a seizure. Impaired consciousness during temporal lobe seizures results from focal abnormal ictal activity in the temporal and subcortical networks, leading to widespread dysfunction in connected cortical or subcortical regions. While previous studies on SPECT perfusion changes in APR have underscored its diagnostic value, the complexity of the technique limits its widespread use. This study aims to compare and analyze the topographic glucose metabolic differences between patients with APR (APR+) and those without APR (APR-) using 18F-Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) imaging.

Methods: We retrospectively evaluated patients with right temporal lobe epilepsy (TLE) who underwent video-EEG monitoring and PET imaging between March 2003 and March 2017 at Samsung Medical Center in Seoul, South Korea. The epilepsy classification of each patient was based on meticulous phase I presurgical evaluation modalities. The scans revealed abnormal glucose metabolism. Variables included in this study were: 1) presence of FDG-PET hypometabolism, 2) lateralization of hypometabolism (right, left, bilateral), 3) localization within the temporal lobe (anterior vs. posterior; lateral, basal, and mesial regions), and 4) visual grading of hypometabolism (none, mild, severe) across each brain topographic region. We analyzed the relationship between APR presence and hypometabolism on PET using linear-by-linear association. The degree of hypometabolism in 16 ipsilateral and contralateral brain regions was compared using Bonferroni correction, with significance set at p < 0.0016 for multiple comparisons.