Tonight, you're going to mid a toddler who was born into a world of silence and parents who refused to let it stay that way. We followed their journey for over half a year as they took a game Billiel... See More
Tonight, you're going to mid a toddler who was born into a world of silence and parents who refused to let it stay that way. We followed their journey for over half a year as they took a game Billiel on a radical new surgery. Reporter: A Tuesday morning in Boston. 17-month-old Alex is being prepped for what is certainly the biggest day in his young life. In this hospital room with him, his mother, Stephanie, and his dad Phil. Alex cannot hear. But if all goes well in the next few hours, that all could change. Along with the Frederick family this day is a team of doctors from Massachusetts general and Massachusetts eye and ear infirmary, plus a surgeon from Italy who flew in just for the operation. It's not even approved yet here in the U.S. For children, but one that everyone hopes will make it possible for him to hear. As they escortal lex down to the operating room, it is still only a gamble whether this will work. All they know for certain is he'll be in there for the next 5 1/2 hours. But in a way, Alex parents' have been waiting all hi short life for this moment. The day that newborn Alex came home from the hospital, he had already faced a lifetime of challenge. Just four pounds, four ounces, Alex arrived two months premature and spent the first month of his life here in the neonatal intensive care unit of the St. John hospital. I felt that I didn't do something perfectly during the pregnancy. I had two healthy kids in the beginning and all of a sudden our third child has all these issues and we didn't know what was going on. I don't know. I was overwhelmed. Reporter: But at least his parents knew then he was going to make it. What they did not know at first was what he was still up against. Scans would show that little Alex had a heart condition and his vision appeared to be compromised. Anticipa and then there was the matter of his hearing. Alex failed this hearing test that all newborns get and then a second one two months later. That was a blow. The most difficult part for me was the first part where he failed his first hearing screen. I really thought this was going to go fine. For me, that was my most heart wrenching point. They had to learn about raising a child who could not hear. New ways to communicate other than calling his name. Being able to pick up signals from him that had nothing to do with sound and figuring out how to adapt in general to the ways in which he would be different to the rest of the family. Like the day Phil watched his oldest daughter, Alex sister's Evelyn as she played with her baby brother. She wanted to get a response from him. Something she was doing with a toy. I said Evelyn, he can't hear. He may not see what you're trying to hand him. She said no, I don't want that for him. How is he ever going to play with us or how is he ever going to play with anyone. When Alex was 1-year-old, they tried a cochlear implant, a 40-year-old technology that uses electrodes to stimulate auditory nerve, but that implant surgery did not work due to the irregular structure of his inner ear. He walked in and he goes I have bad news. It didn't work. He said it was the first time in 25 years that he's been doing the surgery that he could not -- First time in 25 years he couldn't do it. On your kid. Yeah. Reporter: Through all this, life for Alex went on as a constant round of visits to specialists. More tests for his heart. And then beginning classes in sign language. More. Of. And still for his parent, it's only sinking in what all this meant. There are things that were going to happen for his life that I won't be there, I wouldn't understand. I wouldn't know how to help them through those situations where he needed help. Which is why Phil kept looking for some other answer, some other technology. He spent hours online. And then he learned about an approach that had been pioneered in Italy for use in children by a doctor, one that was going to undergo clinical trials here in the U.S. To win fda approval. It's call ed abi. It gets implanted on the actual brain stem to pick up signals from a tiny microphone worn on the ear and relay them inside as electrical signals that relay to the area of the brain that interprets sound. This is one of Dr. Caletti's success stories. A young woman, previously deaf, now carrying on a phone conversation. But it must be noted it took her years to be able to do this after the abi was placed inside her head. That's really remarkable. That's the reason that motivated me. Here's another abi patient. A B a boy bhwhose case proves that for children who's never heard, getting the device is only the start of hearing. It takes years to understand what hearing means. Andrea even learned to play the guitar. Phil heard about the abi and decided he needed to get Alex in line for one of these trials. He sat down and started sending out e-mails. We ended up finding three different places who were doing the trials. And Phil contacted them all. Finally he heard back last August. There was an opening in the trial being run at the Massachusetts eye and ear infirmary in Boston under the direction of Dr. Daniel lee. Abi surgery in a child who cannot get a cochlear implant can result in meaningful sound awareness and speech perception with time, but it takes work. The good news. The Alex is exactly the kind of kid the trial needs. It is October 5, 2013. We're leafing fr ingleaving from Michigan and hopefully by tomorrow afternoon, we will be in Boston. And so the Fred rakeericks make their way from their Michigan home, full of fear but also full of hope. Welcome to Massachusetts. On that Tuesday morning in it is now the second hour of his surgery. Surgery that costs hundreds of thousands of dollars. But is being paid for by the family's insurance company. This is video the hospital provided of the abi being implanted into his brain. While this is going on, Alex's parents take his sisters who a nearby park to keep them distracted. But the hospital calls in with regular updates. When did you get the last call from him? 13 minutes ago. They were actually at the brain stem and using the electrodes to figure out where to place the abi on the brain stem. After 5 1/2 hour, they wheel Alex into intensive care. Under that cap of bandages on his head, the clusters of wires that the doctors hope will allow him to hear. It looks good. Reporter: But still, it is only a beginning. One of the joys of doing something like this is working with other people who all are as committed to the outcome as each of us individually are. It is now several weeks later. Healed and healthy, Alex returns to have his abi switched on for the very first time. Those wires connect the device inside his head to a sound generator controlled from this doctor's computer. In a moment, they will switch it all with everyone hoping and watching to see if he reacts. Are you first, the door opens because Phil and Stephanie have decided they want the first thing Alex to hear to be his sisters' voices. Can you say hi? Hi Alex. Hi Alex. The device is now on. There's no reaction. Others try raising the sound level. Again, no reaction. And then to everyone's surprise, that doctor on the left there, nearly offscreen, she starts to slam her keys into the side of her desk. And there it was. That little turn of the head. Then he all of a sudden, he just looked. He stopped everything that he was doing and he looked. I felt right away. I was like he definitely heard that. He was completely focused on his toy. And then he just, he looked. It's always a challenge and it's always good to see it go well. First step of a long journey. Hearing day, right? This is hearing day. Bah, bah, bah, bah, bah. Since them, Alex and his parents return to Boston where doctors continue to test his hearing response as they fine tune the electronics inside his skull. That is the hardware side of the equation. The software side, so to speak, involves the still long process of his learning what sound actually is and how it has meaning. Maybe even meaning as words. Speech therapy and it takes a lot of commitment on the part of the family. We're very lucky that our patient has unbelievably dedicated parents that are going to see this to a successful outcome. A long journey remains for Alex. But the start of it was that little turn of the head. Alex Frederick, connection made. For "Nightline," I'm John donvan. By the way, they've been back to Boston for follow-ups since Alex got that implant. They're there right now, in fact, for their March appointment.
This transcript has been automatically generated and may not be 100% accurate.