Teaching video neuroimages: see-saw nystagmus.

A 43-year-old woman experienced a worsening of her usual headache. As a right hemifacial hypoesthesia had appeared, the patient underwent a brain MRI that revealed a giant cavernoma localized at the left meso-diencephalic region (figure, A and B). After the operation, an involuntary ocular oscillation known as see-saw nystagmus developed (video on the Neurology® Web site at www.neurology.org). See-saw nystagmus consists of alternating phases of intorsion of the elevating eye and extorsion of the descending eye.(1) The patient displayed a right head tilt with left hypertropia referred to as "ocular tilt reaction" (figure, C)-a phenomenon related to the imbalance in the graviceptive pathways between vestibular nuclei and the interstitial nucleus of Cajal (figure, D).(2.)