New strategies for the restoration of hearing loss: challenges and opportunities.

INTRODUCTION: For most types of hearing impairments, a definitive therapy would rest on the ability to restore hair cells and the spiral ganglion neurons. The only established technique to treat deafness is based on the functional replacement of hair cells with a cochlear implant, but this still has important limitations. SOURCES OF DATA: A systematic revision of the relevant literature is presented. AREAS OF AGREEMENT: New curative strategies, ranging from stem cells to gene and molecular therapy, are under development. AREAS OF CONTROVERSY: Although still experimental, they have delivered some initial promissory results that allow us to look at them with cautious optimism. GROWING POINTS: The isolation of human auditory cells, the generation of protocols to control their differentiation into sensory lineages, their promising application in vivo and the identification of key genes to target molecularly offer an exciting landscape. AREAS TIMELY FOR DEVELOPING RESEARCH: In this chapter, I discuss the latest advances in the field and how they are being translated into a clinical application.