A 12-year-old female, with normal birth and development, presented with multiple daily seizures since eight months of age. Her baseline extraocular eye movements were normal. She had focal seizures with semiology of epileptic nystagmus with a fast component to the right. MRI showed a large left parieto-temporo-occipital dysplasia with significant PET hypometabolism. She became seizure-free after parieto-temporo-occipital disconnection (figures 1, 2).
Epileptic nystagmus or occuloclonia originates from cortical regions contralateral to the fast component (Lee et al., 2014). Occuloclonia originating from saccadic areas results in contralesional ocular deviation with decreasing slow-phase velocity (SPV) and does not cross the midline (Tusa et al., 1990). In contrast, Occuloclonia originating from smooth pursuit areas results in ipsilesional ocular deviation with linear SPV and a reflex quick phase crossing the midline towards contralesional side (Tusa et al., 1990).
None of the authors have any conflict of interest to declare.