Quantification of Ipsilateral and Contralateral Head Movements during Seizures in Patients with Temporal Lobe Epilepsy

We have attempted to evaluate quantitatively the lateralizing significance of ipsilateral and contralateral head movements during seizures in patients with temporal lobe epilepsy. We included only EEG and video recorded seizures of patients with temporal lobe epilepsy, for whom the camera position was perpendicular to the head facing the camera in an upright position and bilateral head movements were recorded. Head turning in a reaction to outside stimuli was excluded. A total of 12 seizures in 10 patients, in whom both contralateral and ipsilateral head movements were recorded with high quality video were investigated. Nine patients have unilateral temporal lobe epilepsy. One patient has bilateral temporal lobe epilepsy with ictal EEGs of the two seizures showing independent seizure onset from either side. Ipsi- and contralateral head versions were defined according to the side of ictal EEG seizure patterns. Head movements were quantified for speed analysis on the videos by selecting the movement of the nose in relation to a defined point on the trunk (25/s) in the inner 90° angle facing the camera. The analysis of the duration was independent of the camera angle. The angle, the duration, and the angular speed of the ipsilateral and contralateral head movements were computed. Inter- and intrasubject analysis was performed (Mann-Whitney test). The positive predicting value was 100% for both the ipsi- and contralateral head movement with regards to the ictal EEG pattern. Ipsiversion always preceded contraversion. The duration of the contralateral head version was significantly longer than that of the ipsiversion (7.4±3.2s vs. 4.6±2.9s, p<0.036). The angular speed of the contralateral head version was similar to the ipsilateral version (11.5±7.8 vs. 11.1±8.6 deg/s). Ictal head versions have a high lateralizing significance in temporal lobe epilepsy. The quantitative analysis of ipsilateral and contralateral head versions shows that the duration of head version and the occurrence in the seizure evolution is important for the correct lateralization.