Vertical saccades during horizontal head impulses: a sign of posterior semicircular canal hypofunction.

Objective: We describe an uncharacteristic vestibular-ocular reflex (VOR) pattern, studied by video head impulse tests (VHIT) in patients suffering from unilateral isolated posterior semicircular canal (PSC) hypofunction. In these patients, we found an upward sliding of the eyes, followed by an oblique downward catch-up saccade during horizontal head impulse to the healthy side.

Methods: We present a retrospective study of all VHIT exams presenting isolated PSC hypofunction between May 2020 and November 2022.