Bilateral internuclear ophthalmoplegia in progressive supranuclear palsy with an overriding oculocephalic maneuver.

We present a patient with progressive supranuclear palsy (PSP) who had a bilateral internuclear ophthalmoplegia (INO) that could be fully overcome by the oculocephalic maneuver. In addition to being an unusual finding in the clinical setting of PSP, this phenomenon has interesting implications for the functional control of conjugate horizontal gaze.