Head Impulse Test in Unilateral Vestibular Loss
Video demonstrates overt versus covert corrective saccades. In some patients, corrective saccades are easily visualized by the examiner (ie, overt saccades) whereas in other patients they may be difficult to observe or may even be imperceptible to the examiner (ie, covert saccades). This video shows examples of overt and covert corrective saccades after the head-impulse test in two patients with unilateral vestibular loss.
Reproduced with permission from Weber KP, Aw ST, Todd MJ, et al. Head impulse tests in unilateral vestibular loss: vestibulo-ocular reflex and catch-saccades. Neurology 2008;70(6): 454Y463.
CONTINUUM: Lifelong Learning in Neurology. 18(5, Neuro-otology):1041-1059, October 2012