In head impulse testing and VOR assessment, which pattern suggests peripheral vestibular pathology?

• A. Reduced VOR gain with corrective saccades and unidirectional nystagmus.
• B. Normal VOR gain with no corrective saccades.
• C. Direction-changing, vertical or pure torsional nystagmus without corrective saccades.
• D. Bilateral symmetrical nystagmus that fatigues with fixation.

Answer: (A)

In head impulse testing and VOR assessment, peripheral vestibular pathology is suggested when the eyes struggle to stay fixed on the target during a rapid head movement on the side of the lesion. The VOR gain drops because the damaged peripheral organ can’t drive the eyes as effectively, so the eyes drift off target during the head impulse. The brain then generates a corrective, or catch-up, saccade to bring the gaze back to the target. This combination—reduced VOR gain with a corrective saccade—along with a unidirectional nystagmus (fast phase beating away from the lesioned side) is characteristic of a peripheral vestibular deficit.

If the VOR gain were normal and no corrective saccade occurred, that would argue against a peripheral deficit. Direction-changing, vertical, or torsional nystagmus without corrective saccades points more toward central pathology. Bilateral symmetrical nystagmus that fatigues with fixation can reflect bilateral vestibular loss rather than a unilateral peripheral issue.