Neurophysiological localization of epileptic nystagmus

Epileptic nystagmus (EN) consists of rapid, repetitive eye movements, caused by epileptic activity. Proposed neurophysiological mechanisms have largely been based on clinical observations. In the awake patient, there is epileptic activation of a cotical saccade region, generating quick eye- movement phases, contraversive to the seizure focus. Localization of this epileptic focus has previously been demonstrated using electroencephalography. This paper presents a patient with localization of activitation obtained from single photon emission tomography (SPECT) with congruent data from EEG. These data confirm the anatomic localization of EN to the contralateral temporo-parieto-occipital junction in an awake patient.