Impact of laterality on seizure duration in mesial temporal lobe epilepsy with hippocampal sclerosis

• Right-sided MTLE-HS shows significantly longer seizures, reflected in increased longest and mean seizure durations. • Prolonged seizures without bilateral tonic-clonic progression occur more frequently in right-sided MTLE-HS, indicating a lateralized vulnerability to sustained ictal activity. • Findings reveal a lateralization effect in MTLE-HS, suggesting that seizure duration characteristics differ between dominant and non-dominant mesial temporal epilepsies. This study aims to evaluate differences in seizure durations in mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) based on laterality, along with other related findings. This retrospective trial (2009–2023) at Istanbul University-Cerrahpasa’s VEM Unit reviewed patients diagnosed with MTLE-HS via MRI and/or postoperative histopathology. Demographic data, epilepsy duration, and MTLE laterality were recorded. Seizure durations (excluding bilateral tonic-clonic periods) were analyzed, including the shortest, longest, and average seizure durations per admission. The occurrence of prolonged seizures without progression to bilateral tonic-clonic seizures (PS) was also documented. The study included 82 participants, with 58.5% (n = 48) left-sided and 41.5% (n = 34) right-sided MTLE-HS cases. The shortest recorded seizure duration showed no significant difference between sides (p > 0.05), but the longest seizure was significantly longer in right-sided MTLE-HS (p = 0.014). The mean seizure duration per patient was also significantly longer in the right-sided group (p = 0.035). PS occurred in 17.1% (n = 14) of participants, with a significantly higher incidence in right-sided MTLE-HS (p = 0.002). This study suggests that seizure durations may be longer in right-sided (non-dominant) MTLE-HS compared to left-sided (dominant) cases, contributing new insights into the lateralization of MTLE-HS.