Basic Science Review

Hearing and balance disorders caused by the lossof inner ear hair cells isa.common problem encountered in otolaryngology-head and neck surgery. The postembryc:mlc production of hair cells in cold·blooded vertebrates has been known for several decades, and recent studies in the avian inner ear after ototoxic drug and noise damage have demonstrated a remarkable capacity for both anatomic and functional recovery. The regeneration of sensory hair cells has been shown to be integral to this repair process. Current work is focusing on the cellular progenitor source of new hc:lircells and the trigger mechanism responsible for inducing hair cell regeneration. Preliminary studies suggest that reparative proliferation may also occur, in the mammalian inner ear. Work in this field is moving at a rapid pace. The results thus far have yielded optimism that direct stimulation of hair cell production or transplantation of IMng hair cells may eventually become treatment modalities for the damaged human Inner ear. These proposals wouid have been considered unrealistic less than 10 years ago, but they now have caught the full attention of both clinician and researcher. (OTOlARYNGOl HEAD NECK SURG