Inner ear symptoms and disease: pathophysiological understanding and therapeutic options

Abstract

In recent years, huge advances have taken place in understanding of inner ear pathophysiology causing sensorineural hearing loss, tinnitus, and vertigo. Advances in understanding comprise biochemical and physiological research of stimulus perception and conduction, inner ear homeostasis, and hereditary diseases with underlying genetics. This review describes and tabulates the various causes of inner ear disease and defines inner ear and non-inner ear causes of hearing loss, tinnitus, and vertigo. The aim of this review was to comprehensively breakdown this field of otorhinolaryngology for specialists and non-specialists and to discuss current therapeutic options in distinct diseases and promising research for future therapies, especially pharmaceutic, genetic, or stem cell therapy.

Figure 1

Schematic illustration of the human ear. (A) The ear consists of the outer, middle, and inner ear. (B) A section through the cochlear duct illustrates the fluid-filled compartments of the inner ear. (C) The organ of Corti resides in the scala media, with sensory hair cells surrounded by supporting cells that include Deiters’, Hensen, and pillar cells. (D) Immunohistochemistry with the inner ear hair cell marker myosin VI, marking the cytoplasm of inner and outer hair cells, and4,6-diamidino-2-phenylindole (DAPI), marking the nuclei. (E) Scanning electron microscopy image of the top view of the sensory epithelium reveals the precise arrangement of 1 row of inner hair cells and 3 rows of outer hair cells, separated by the pillar cells. (with permission from Dror AA, Avraham KB. Hearing loss: Mechanisms revealed by genetics and cell biology. Annu Rev Genet, 2009; 43: 411–37. Copyright © 2009, Annual Reviews. All rights reserved).