Example, saccade main sequence, compensation and clinical diagnoses.

<p>A: Top panel shows representative eye (black) and head (gray) velocity traces during head impulse testing (HIT). The covert anti-compensatory quick eye movement (CAQEM) during the head movement has a latency of 96 ms. The CAQEM is compensated for by a saccade (dark gray areas within the CAQEM velocity curve and that of the compensatory saccade match). Middle and bottom panels show eye and head traces for right and left HIT from one subject. CAQEMs on the right side are compensated for by saccades. There is a vestibulo-ocular reflex (VOR) gain deficit on the left side (note how eye velocity does not match head velocity, arrow) with compensatory re-fixation saccades toward the target. B: CAQEM peak velocity as a function of amplitude (area under the curve) for all CAQEMs from all subjects. An exponential fit (black line) shows that CAQEMs follow the saccade main sequence. C. Regression line (black) between the area under the saccades plotted against the area within the corresponding CAQEM indicates that saccades are compensatory (each dot represents the mean of one subject). Inset shows the mean compensation ratio (Ratio_CAQEM and SE) calculated by dividing the area under the compensatory curve by that of the CAQEM. D. Percentage of patients with CAQEMs distributed for the different clinical diagnoses established by neuro-otological experts according to current standards: vestibular migraine (VM), Menière’s disease (MD), unilateral peripheral vestibular deficit (UVD), vestibular paroxysmia (VP), and bilateral vestibulopathy (BV). The percentage of patients with CAQEMs is higher in peripheral vestibular disease (gray), e.g., Menière’s disease, than in vestibular migraine (dark gray). UVDs have the highest percentage of CAQEMs.