vestibuloocular

Vestibuloocular refers to the interaction between the vestibular system of the inner ear and ocular motor control, a relationship essential for stabilizing gaze during head movement. The most studied example is the vestibulo-ocular reflex (VOR), which generates eye movements that are equal in magnitude and opposite in direction to head movements, helping keep images steadied on the retina.

Anatomy and physiology: The semicircular canals detect angular head motion, while the otolith organs sense linear acceleration. Signals from these sensors project to the brainstem vestibular nuclei, which in turn coordinate eye movements via the oculomotor, trochlear, and abducens nuclei. The resulting gaze-stabilizing response is rapid, and when head movement exceeds the reflex’s capacity, the optokinetic system can supplement it to maintain stable vision.

Plasticity and modulation: The VOR exhibits adaptive plasticity, with the cerebellum (notably the flocculus and vestibulo-cerebellar circuits) adjusting the reflex gain to match changing conditions, such as wearing changing visual inputs or moving between tasks. The VOR can be suppressed during tasks requiring precise fixation on a near target, and recalibration can occur during vestibular rehabilitation or prism adaptation.

Clinical relevance: Impaired vestibuloocular function leads to gaze instability and oscillopsia, affecting balance and spatial orientation. Clinicians assess vestibuloocular function with tests such as the video head impulse test (vHIT), caloric testing, and rotational chair measurements. Conditions that affect the vestibular apparatus or brainstem pathways—such as vestibular neuritis, labyrinthitis, Menière disease, or stroke—can disrupt the vestibuloocular system and reduce gaze stabilization.