Hemispheric differences in the duration of focal onset seizures

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.

Automated summary

The study revealed significantly longer seizure durations in cases of left-hemispheric seizure onset, especially in temporal lobe seizures. Seizures starting in the left hemisphere also showed prolonged duration when commencing during waking state, but not during sleep. Gender differences were observed, with a similar hemispheric difference in seizure duration found in female patients, but not in men.