tissue in a deaf person become atrophied and our conclusions is that there was a mistake. that science had misunderstood the function of this tissue. reporter: the research also showed early exposure to a visual language like american sign language did not undermine a baby s ability to learn spoken language. in fact, petitto says, it s just the opposite. early exposure to sign language is by far the most healthy thing we can do for the human brain because the brain, the research shows us that the brain doesn t care about modality. it doesn t care if you give it the hands or the tongue. reporter: no matter how it s expressed, communication is really what language is all about. a little boy and his family were fully prepared for a life spent communicating through sign language. but a clinical trial is offering a second chance for deaf
i m proud of him for just sticking to it. reporter: hearing is a gift, along with our other senses, an incredible function of our bodies. that doesn t mean deafness is a curse. just ask super bowl champion derrick coleman. or the ph.d. students in dr. petitto s lab whose research is changing how we understand learning and development. like dr. petitto says, people might discriminate between sign language and the spoken language, but the brain does not. for vital signs, i m dr. sanjay gupta.
in her lab petitto and her graduate students work with a special machine petitto helped design. it s called the f nerves, a faster, quieter, and more portable version of an mri machine. if petitto was going to study the brains of infants she needed a way to look at them. this is quite an extraordinary new microscope into the brain. it also allows the baby to engage in more naturalistic behaviors. they can look, they can turn their head, they can move their hands. and this was very exciting. reporter: remember that baby babbling in sign language? well, petitto found that babies exposed to sign language hit the same developmental milestones as babies exposed to speech. for example, the first word and first sign both come around 12 months. that meant something was happening in the brain, unique to language.