When Sasha was adopted at age six, her new parents were warned that she was profoundly deaf. Three years later, Sasha runs around the house like any nine-year-old, and she can hear her parents, thanks to a cochlear implant under the skin behind her ear. An external microphone and processor pick up sound, convert it to electric impulses, and transmit it to the implant, which activates 16 electrodes that stimulate the auditory nerve. The brain then processes the signals as sound. More than 100 000 people worldwide have been fitted with such implants since the 1980s. New advances promise to make implants safer to install and more sensitive to sound.
A traditional implant consists of a bunch of wires encased in silicon, “a bit like a thick strand of spaghetti,” says Soli Sigfrid, an expert on hearing at the House Ear Institute in Los Angeles. The most exciting areas of...
