Anatomical and functional studies of vestibular neuroepithelia from patients with Ménière's disease.

Surgical removal of vestibular end organs is a final treatment option for people with intractable Ménière's disease (MD). Here, we used surgically excised vestibular neuroepithelium from patients with MD for (1) anatomical investigation of hair cell and nerve fibre markers using immunohistochemistry, and (2) functional studies using electrophysiological recordings of voltage-activated currents. Our data show considerable reduction in and disorganisation of vestibular hair cells in the cristae ampullares. Nerve fibres maintain contact with remaining sensory receptors but appear thin in regions in which hair cells are absent. Electrophysiological recordings of voltage-activated potassium currents from surviving hair cells demonstrated normal activity in both type I and type II vestibular hair cells. Current-voltage plots from type I vestibular hair cells are consistent with the presence of a surrounding calyx afferent terminal. These data indicate that the surviving hair cells that were sampled in patients with MD remain functional and capable of transmitting sensory information to the central nervous system. Determining functionality of vestibular receptors and nerves is critical for vestibular implant research to restore balance in people with MD.