Epileptic nystagmus: A case study video‐EEG correlation

Abstract

Epileptic nystagmus (EN) is an uncommon phenomenon characterized by repetitive and rapid saccades, in association with epileptic discharges. We present a critical video‐EEG recording in a patient with occipital seizures that appeared clinically as EN. The subject, male, 70 years‐old, was examined because of generalized tonic‐clonic seizures, preceded by left cephalic version. These were controlled using i.v. PHT, but partial seizures persisted, which we recorded using video‐EEG. Clinically, we observed episodes of left conjugate deviation of the eyes, accompanied by horizontal nystagmoid movements, with a rapid leftward component and visual hallucinations. The patient did not lose consciousness. Ictal EEG: spike rhythm in the posterior right occipito‐temporal region extending to adjacent and contralateral regions, followed by post‐discharge of slow waves. The video‐EEG was interpreted as partial oculo‐clonic status epilepticus of right temporo‐occipital origin. Cranial MRI: old, bilateral hemorrhaging occipital contusions associated with previous cranial injury. The picture persisted for two days, and disappeared with administration of CBZ 600 mg/d. Our patient's nystagmus seemed to be related to the critical activity recorded in the right occipito‐temporal region. The co‐existence of visual hallucinations and the video‐EEG correlation support this possibility. This phenomenon is probably due to epileptic activation of the cortical center of saccadic movements, with a rapid phase of nystagmus, contralateral to the focus, and a slow ipsilateral phase in association with a defect in the gaze‐fixing system (“leaky neural integrator”) [published with videosequences].