Regeneration of sensory hair cells after acoustic trauma.

Any loss of cochlear hair cells has been presumed to result in a permanent hearing deficit because the production of these cells normally ceases before birth. However, after acoustic trauma, injured sensory cells in the mature cochlea of the chicken are replaced. New cells appear to be produced by mitosis of supporting cells that survive at the lesion site and do not divide in the absence of trauma. This trauma-induced division of normally postmitotic cells may lead to recovery from profound hearing loss.