Epileptic nystagmus: description of a pediatric case with EEG correlation and SPECT findings

Abstract

Epileptic nystagmus (EN) describes repetitive eye movements that result from seizure activity. We describe a patient with EN and vertigo first noted at the age of 4 yr and 10 mo. Brain MRI did not show anomalies. Ictal EEG recordings revealed epileptic activity during three episodes of horizontal, left-beating nystagmus not crossing the midline. Ictal 99mTc-ECD SPECT demonstrated the presence of active foci in multiple cerebral regions including bilateral prefrontal, bilateral parieto-temporo-occipital and the left parieto-insular-vestibular areas. A wide area of hypoperfusion was also evident in the right hemisphere, prevailing in the parieto-occipital regions and the medial prefrontal gyrus. Topiramate was started at a dose of 2 mg/kg/d with complete seizure control after 14 d. EEG and SPECT were repeated after a seizure-free period of 1 mo; disappearance of epileptic activity and modification of cerebral perfusion were evident. This case reaffirms the cortical origin and involvement of temporo-occipital and frontal cortex in the genesis of saccadic epileptic nystagmus. Rapid complete control of clinical events coincided with the normalization of EEG and improvement of the SPECT pattern.