-- The surprise on 3-year-old Grayson Clamp's face in the video is priceless. His mouth opens wide as he points to the person in front of him speaking.
It was the first time Grayson had heard sound. He was born without a cochlear nerve, which connects the brain stem to audio waves in the outside world. His parents had him fitted for a cochlear implant at a young age, but the device didn't help.
Last month, Grayson became the first child in the United States to receive an auditory brain stem implant.