Pseudo-reversed catch-up saccades during head impulses: a new cerebellar sign.

These corrective saccades were only noticeable during the bedside HITs and had been interpreted as back-up saccades. Herein, we describe overt back-up saccades during HITs due to hypermetric covert saccades in a patient with an acute circumscribed lesion involving the cerebellum, which were misinterpreted as reversed corrective saccades due to the hyperactive VOR during bedside examination. When these corrective saccades are hypermetric due to cerebellar dysfunction, the eyes would overshoot the target with corrective saccades in the opposite direction. (MP4 15487 KB) Graph: Supplementary file3 Video-head impulse tests show hypermetric covert corrective (red arrowhead) and overt back-up saccades (red arrow) during stimulation of the left horizontal semicircular canal and covert corrective saccades (blue arrowhead) during stimulation of the right horizontal canal. [Extracted from the article]