Jerky hemi-seesaw nystagmus and head tilt reaction combined with internuclear ophthalmoplegia from a pontine infarction.

Internuclear ophthalmoplegia (INO) is a complex ocular motility disorder caused by damage to the medial longitudinal fasciculus. The occurrence of hemi-seesaw nystagmus in an INO patient has been reported rarely. This nystagmus may be caused by damage to the pathway from the contralateral vertical semicircular canal. The ocular tilt reaction is characterized by ipsilateral head and neck tilt, skew deviation, and ocular torsion. We report a patient who presented with hemi-seesaw nystagmus, ocular tilt reaction, and limb ataxia combined with an INO from a right focal pontine infarction. INO may be accompanied by a variety of ocular findings associated with the disruption of the medial longitudinal fasciculus.