Labyrinthitis and Vestibular Neuritis

Acute inflammation of the eighth cranial nerve divides into two clinical entities. In vestibular neuritis, the inflammatory process is confined to the vestibular division; the cochlear branch remains intact, so hearing stays normal. In labyrinthitis, the same inflammatory cascade spreads to the cochlear portion, damaging hair cells and producing sudden sensorineural hearing loss or tinnitus. The inflammation creates an imbalance in afferent firing: the affected ear fires less than the intact ear. The brain interprets this asymmetry as rotation toward the healthy side, generating the classic spinning sensation and a corrective nystagmus that beats away from the lesion.