Fig. 1.

Representative illustration of five head impulses (HIT, 1-5) after a left earth-vertical-axis rotation at 200deg/s. Horizontal eye velocity is shown in (a) with the higher-velocity, downward spikes indicating the occurrence of quick phases and the lower-velocity, flatter portion of the traces reflecting the slow phases of the post-rotatory nystagmus (PRN) plus the additional dynamic VOR response stimulated by the superimposed head impulse. Head velocity is shown in b. Eye position traces are shown in c. The first head impulse (HIT1) with the slow phase of PRN directed oppositely to the slow phase of the HIT induced VOR (b) and the second impulse with slow phases in the same direction, are magnified and shown in the insets.