Figure 1.

Examples of horizontal head impulse tests in a healthy subject (A) and a patient two weeks (B) and two months (C) after a sudden vestibular asymmetry. If the vestibulo-ocular reflex (VOR) were perfectly compensatory, traces would be parallel to the abscissa (head-in-space axis); if the vestibulo-ocular reflex were absent, traces would move on a 45° slope. G_R: median gain value for head impulses to the right; G_L: median gain value for head impulses to the left. Traces are clipped beyond 10° eccentricity of head-in-space. Dashed vertical lines indicate intervals used to determine the gains (see Methods).