Scientists have discovered a key mechanism behind age-related hearing loss, and they say a common oral medication could delay its progression.In a study of crab-eating macaques, the team from China and the United States found that a gradual deficiency in a protein vital to receptor cells in the ear was a characteristic of cochlear ageing in primates.The researchers also found that it was possible to slow down age-related hearing loss in the monkeys by using a common diabetes medication called...