Compositions, methods, and devices are provided for inducing or enhancing the growth, proliferation, regeneration of inner ear tissue, particularly inner ear hair cells. In addition, provided are compositions and methods for prophylactic or therapeutic treatment of a mammal afflicted with an inner ear disorder or condition, particularly for hearing impairments involving hair cell damage, loss, or degeneration, by administration of a therapeutically effective amount of IGF-1 or FGF-2, or their agonists, alone or in combination.