After three years of silence, a 3-year-old boy is able to hear the world for the first time due to an auditory brainstem implant.
"He likes sound," Grayon's mom, Nicole Clamp, told WBTV in Charlotte, N.C. "He enjoys the stimulus, the input. He's curious, and he definitely enjoys it."
"Enjoys" might be an understatement, as seen in the video in which Grayson hears his father speak for the first time and, overwhelmed, doesn't seem to know what to do with himself.
Born without cochlear nerves or the auditory nerve that carries the sound signal from the cochlea in the inner ear to the brain, his parents first tried a cochlear implant, but it failed.
They then chose to enroll their son in a research trial at University of North Carolina Hospitals in Chapel Hill, N.C. Three weeks ago, he became the first child in the United States to receive an auditory brainstem implant, which involves placing a microchip on the brainstem where it stimulates electrodes on the brain's cochlear nucleus.
As Dr. Craig Buchman, Grayson's head and neck surgeon, told CBSNews.com, the devices were made only a handful of years ago for adults with tumors in their cochlear nerves, but was never approved for children in the United States. And while the implants were able to give the adults some of their hearing back, they were not as effective as cochlear implants.
However, Buchman harbored a theory that, through Grayson, he is finally going to be able to test, which is that, due to children's brain plasticity, the boy may be able to adapt better to the device, ultimately interpreting sounds better than adults fitted with it.
At this point, it's not clear what Grayson is hearing, though it's obvious he's hearing something, those around him say.
"He's sound aware, but we don't know what exactly he hears," Buchman told CNN.
Going forward, Buchman says his team has evaluated 10 other children with similar problems with missing nerves. Should the implants prove to be successfully, they are hoping that they may one day prove helpful in giving a voice to older children who never learned how to speak because of hearing problems.