12 Vestibular System

• head turn to left, eyes stay focus on object

• 3 loops: semicircular canal
• filled with endolymph fluid

• otolith stones on top of hair cells move forward/backward with motion

Vestibular Dysfunction

• vertigo: motion when there's no movement

• 2 CN 8 pushing eye toward middle of head, keep eye centered.
• If one nerve is gone, other slowly pushes eye towards one side. When brain detects the error, it quickly jerks the eye in the opposite direction

• peripheral: vestibular apparatus dysfunction in inner ear
• central: brain stem lesions, strokes

Central Vs Peripheral

• BPV common cause of peripheral

• changing direction: when look left may have upbeat nystagmus, look right downbeat
• lower pt down will get immediate nystagmus
• skew deviation: one eye higher than other

• lie down on table: delayed

Dix-Hallpike

Benign Positional Vertigo

• debris moves hair cells when they shouldn't be moved

Vestibular Neuronitis

• usually after cold

Meniere's Disease