ABSTRACT
PURPOSE: This study aims to determine the clinical significance of epileptic nystagmus in patients with acute neurological symptoms. METHOD: The clinical findings of patients with documented epileptic nystagmus, their original video and EEG data, and cranial imaging and laboratory tests were analyzed retrospectively. RESULTS: 20 patients were included in the study and 21 epileptic nystagmus attacks were determined from patients' clinical and video-EEG recordings. All recorded seizures with epileptic nystagmus were focal onset in nature. The ictal discharge pattern was rhythmic fast activity with a mean frequency of 15 Hz. The ictal discharges originated from the parieto-occipital (n = 8), temporo-occipital (n = 7), parieto-occipito-temporal (n = 3), temporal (n = 2), occipital (n = 1), and centroparietal (n = 1) areas. In the fast phase, the nystagmus was beating away from the side of ictal discharges. The origin of the ictal discharges on EEG images was compatible with the lesion localization at cranial MRI in all patients. Etiologies were epilepsy in seven patients, non-ketotic hyperglycemia in four, ketotic hyperglycemia in one, PRES in three, acute stroke in three, HSV encephalitis in one, and MELAS in one. CONCLUSIONS: Epileptic nystagmus represents a guide to the lateralization and localization of the lesion in cases presenting with acute neurological symptoms. In these patients, the lesion is frequently in the posterior regions of the hemispheres. Although various diseases affect these regions in terms of etiology, such cases should be evaluated in terms of the presence of hyperglycemia.