Hemispheric differences in the duration of focal onset seizures

Abstract

Objective: To assess hemispheric differences in the duration of focal onset seizures and its association with clinical and demographic factors.

Methods: A retrospective analysis was performed on adult patients with drug-resistant unifocal epilepsy, who underwent intracranial EEG recording between 01/2006 and 06/2016. Seizure duration was determined based on the subdural and/or stereo-EEG (sEEG) recordings. Hemispheric differences in seizure duration were statistically evaluated with regard to clinical and demographic data.

Results: In total, 69 patients and 654 focal onset seizures were included. The duration of seizures with left-hemispheric onset (n = 297) was by trend longer (91.88 ± 93.92 s) than of right-hemispheric seizures (n = 357; 71.03 ± 68.53 s; p = .193). Significant hemispheric differences in seizures duration were found in temporal lobe seizures (n = 225; p = .013), especially those with automotor manifestation (n = 156; p = .045). A prolonged duration was also found for left-hemispheric onset seizures with secondary generalized commencing during waking state (n = 225; p = .034), but not during sleep. A similar hemispheric difference in seizure duration was found in female patients (p = .040), but not in men.

Conclusions: Hemispheric differences in seizure duration were revealed with significantly longer durations in case of left-hemispheric seizure onset. The observed differences in seizure duration might result from brain asymmetry and add new aspects to the understanding of seizure propagation and termination.

Keywords: focal epilepsy; intracranial EEG recording; lateralization; sEEG; seizure termination; semiology.