ABSTRACT
Over the past decades, our understanding of the effects of noise and ototoxic drugs on the mammalian inner, including the human inner ear, has dramatically increased. The identification of free radical formation as a common precursor to cell death inside the cochlea has allowed the identification of free radical scavengers as a category of agents that might have otoprotective benefits. Because of the diverse models in which benefits have been assessed, it is difficult to directly compare or contrast the relative levels of protection achieved. However, the generally positive findings across agents have resulted in significant enthusiasm. The purpose of this chapter is to briefly review the effects of noise and ototoxic drugs on the inner ear and then review the clinical test metrics and paradigms that can be used (or are already being used) for assessment of these otoprotective agents in humans. Many of the drugs being developed now rely on manipulation of the endogenous antioxidant system and current knowledge regarding these systems is reviewed at the end of this chapter. In our companion chapter in this edition, we review the data currently available for a variety of agents that have already been tested in humans.
