Search "cochlear implant" on YouTube and the first result that fills in is "hearing for the first time." You'll get 54,000 results for that phrase, with a variety of videos of children, teens and adults sitting in a doctors office, listening to their loved one talk, with shocked expressions on their faces. The latest viral sensation added to that club is of three-year-old Grayson Clamp, who is the first child get an auditory brain stem implant to help his hearing.
An auditory brain stem implant is different than the more commonly known cochlear implant, which uses electronic pulses to stimulate the cochlear nerve which carries sound from the ear to the brain. Instead, a stem implant stimulates just the brain stem, bypassing the nerves. Because they require getting actual brain surgery, these implants have previously only been available for adults. Grayson received a stem implant because his parents tried a cochlear implant and it didn't work, something that's quite common.