Overview Introduction Vestibular system angular acceleration of the head is detected by the semicircular canals this is secondary to endolymph movement via the ampulla the hair cells will then send excitatory input into the primary sensory neuron which have their cell bodies in the vestibular ganglia (of Scarpa) which send axons via the vestibular nerve which runs in the internal acoustic meatus linear acceleration of the head and head tilt is detected by maculae (which is contained within the utricle and saccule) maculae contain otolith (calcified crystals) otolith may be pulled with linear acceleration and activate hair cells which excites primary sensory neurons → vestibular ganglia → vestibular nerve vestibular nerve runs synapses to the vestibular nuclei which then relays to other structures within the central nervous system such as medial longitudinal fasciculus which mediates the vestibulo-ocular reflex spinal cord cerebellum (e.g., flocculonodular lobes and vermis) cerebral cortex via the thalamic ventral posterior nucleus Clinical correlate caloric testing a test that stimulates the vestibulo-ocular reflex via warm or cold water infusion into the ear normal findings warm water nystagmus with the fast phase towards the side of infused water cold water nystagmus with the fast phases towards the opposite side of infused water mnemonic COWS (Cold Opposite, Warm Same) nystagmus describes rhythmic movements of the eye which can result from an asymmetric vestibular inputs vertigo Summary of Peripheral Vs. Central Vertigo Vertigo Type Etiology Differential Symptoms Peripheral vertigo Lesion affecting the vestibular apparatus (in the inner ear) cranial nerve VIII Benign paroxysmal positional vertigo (BPPV) Vestibular neuritis Meniere's disease Acoustic neuroma Aminoglycoside toxicity Semicircular canal dehiscence syndrome Perilymphatic fistula Herpes zoster oticus (Ramsay Hunt syndrome) Intermittent and positional vertigo Can be associated with tinnitus as well as hearing loss postural unsteadiness Nyastagmus is delayed in onset rotatory or horizontal prominent if vertigo is present adaptive Vertigo stops with visual fixation Central vertigo Lesion affecting the brainstem nuclei cerebellum Vestibular migraine Brainstem stroke Multiple sclerosis Ischemic or hemorrhagic damage to the cerebellum Non-positional vertigo May accompany other cranial nerve injuries such as facial droop dysarthria Nystagmus is immediate or delayed in onset rotatory, horizontal, or vertical not adaptive Vertigo does not stop with visual fixation