More than 4,000 children in China who have received cochlear implants and other devices will soon benefit from a speech perception test offered in Mandarin.

More than three decades ago, scientists pursued the then-radical idea of implanting tiny electronic hearing devices in the inner ear to help profoundly deaf people. An even bolder alternative that promised superior results - implanting a device directly in the auditory nerve - was set aside as too difficult, given the technology of the day.