Normal head thrust test to the left (A and B), abnormal to the right (C–E). Large arrow denotes direction the head will be thrust. (A) Initial starting position places subject's head into cervical flexion; eyes are focused on the target. (B) Upon stopping the head thrust, the eyes are still on target and no corrective saccade is observed. In photographs A and B, the subject's eyes stay fixed on the examiner's nose throughout the test. (C) Initial starting position places subject's head into cervical flexion; eyes are focused on the target. (D) As the head is thrust rapidly to the right, the eyes fall off the target and move with the head. (E) The subject must make a corrective saccade (small arrows) to bring the eyes back to the target of interest.