The acute vestibular syndrome with skew deviation, gaze-evoked nystagmus

This is a 60-year-old man with the acute onset of prolonged vertigo and nystagmus, consistent with the acute vestibular syndrome (AVS). HINTS (Head Impulse, Nystagmus, Test of Skew) exam demonstrated a central pattern: 1) Head impulse test (HIT) was abnormal to the right and to the left. An abnormal HIT, indicating vestibular hypofunction on the side that the head is turned (with a compensatory saccade in the opposite direction back to the target) generally suggests a peripheral and usually benign etiology for the AVS. Stroke in the distribution of the AICA is an exception and since the abnormal HIT in this situation often reflects labyrinthine ischemia, it is not a benign cause of the AVS. A bilaterally abnormal HIT (when acute in onset) may be seen in Wernicke’s encephalopathy, trauma or ototoxicity (e.g., gentamicin) for instance. Since the cerebellar flocculus has a role in modulation of the high frequency vestibulo-ocular reflex,