Epileptic nystagmus in infancy.

Epileptic nystagmus (EN) is a rare form of nystagmus that occurs only during epileptic seizures. We report an infantile case in which EN was first noted at 10 days of age. Electronystagmography showed a right-beating nystagmus with predominantly linear slow phases that traversed the midline. Neuro-imaging revealed dysplasia of the left middle temporal gyrus extending posteriorly into the parieto-occipital cortex. The right hemisphere and subcortical structures appeared normal. Perfusion studies demonstrated interictal hypoperfusion with ictal hyperperfusion in the left temporal lobe. Electrocorticography demonstrated spiking over the left temporal-parieto-occipital region. Following extensive surgical resection of this area and weaning of anti-convulsants, the child has remained seizure-free without nystagmus. This case demonstrates the cortical origin of EN, and shows that infant cortex has functioning efferent connections to brainstem oculomotor centres from 10 days of age.