Feline Vestibular Disease Study Guide

Overview and Clinical Importance

Vestibular disease is one of the most dramatic neurological presentations encountered in feline medicine. The vestibular system maintains balance, posture, and coordinates eye and head movements relative to gravity. When dysfunction occurs, cats develop acute onset of head tilt, nystagmus, ataxia, and falling or rolling toward the affected side. Understanding the distinction between peripheral (inner ear/CN VIII) and central (brainstem/cerebellum) vestibular disease is critical for the NAVLE, as this differentiation guides diagnostics, treatment, and prognosis.

Anatomy of the Feline Vestibular System

Peripheral Vestibular System

The peripheral vestibular system is located within the inner ear (labyrinth) and includes the vestibular portion of the vestibulocochlear nerve (CN VIII). Key structures include:

• Semicircular canals (3): Anterior, posterior, and horizontal canals detect angular (rotational) acceleration of the head
• Otolith organs (utricle and saccule): Detect linear acceleration and head position relative to gravity
• Vestibular ganglion (Scarpa's ganglion): Contains bipolar sensory neurons that relay information from hair cells to the brainstem
• Vestibulocochlear nerve (CN VIII): Vestibular division transmits balance information; cochlear division transmits auditory information

Central Vestibular System

The central vestibular system includes the vestibular nuclei in the brainstem (medulla) and the flocculonodular lobe of the cerebellum. The vestibular nuclei (superior, inferior, medial, lateral) receive input from the peripheral system and project to: