You're about to meet a toddler who was born into a world of silence. But his persistent parents have been committed to trying to change that. We follow every step of their journey as they take a big... See More
You're about to meet a toddler who was born into a world of silence. But his persistent parents have been committed to trying to change that. We follow every step of their journey as they take a big gamble on a radical new surgery that costs hundreds of thousands of dollars. So will their son hear for the first time? We're there for the results. Here's air force base's John donvan. 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 his 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 could change. We need to just mark the sides -- Reporter: Along with the Frederick family is a team of doctors from Massachusetts general and Massachusetts eye and ear informry, plus a surgeon from Italy who flew in just for the operation. What a beautiful child. This is Alex. Alex. Reporter: Alex will soon be in surgery where a device will be implanted in his brain. One not even approved yet in the U.S. For use in children. But one that everyone here hopes will make it possible for him to hear. I am confident. We go? Reporter: And as they escort Alex down to the operating room, it is still only a gamble whether this will work. All they know for certain is that he'll be in there for the next 5 1/2 hours. But in a way, Alex's parents have been waiting all his short life for this moment. The day that newborn Alex came home from the hospital, he had already faced a lifetime of challenge. Just 4 pounds 4 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 older kids in the beginning, all of a sudden our third child has all these issues, 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. And then there was the matter of his hearing. Alex failed this hearing test that all newborns get. Then a second one two months later. That was a blow. The most difficult part for me was that first time we were -- where he failed his first hearing screen. I really thought, this is going to go fine. That was the most -- for me personally the most heartwrenching point. Reporter: 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. Figuring out how to adapt in general to the ways in which he would be different from the rest of the family. Like the day Phil watched his oldest daughter, Alex's sister Evelyn, as she played with her baby brother. She wanted him -- to get a response from him. Something she was doing with a toy. I was like, Evelyn, he can't hear. He may not see what you're trying to hand him. She just said, no, I don't want that for him. How's he ever going to play with us or how's he ever going to play with anyone? Reporter: When Alex was 1 year old they tried a cochlear implant, a 40-year-old technology that uses electrodes to stimulate auditory nerves. But that implant surgery, which left its mark behind Alex's right ear, did not work due to the irregular structure of his inner ear. It was the first time in 25 years that he's been doing this surgery that he could not actually -- The 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. Reporter: Still for his parents, it was only sinking in what all this meant. There's things that were going to happen in his life that I wouldn't be there. I wouldn't understand. Reporter: Couldn'be there for him. I wouldn't know how to help him through those situations where he needed help. Reporter: 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 Dr. Vittorio Coletti, one that was about to undergo a series of clinical trials here in the U.S. To win fda approval. Auditory brain stem implant, abi. A small antenna that gets implanted on the actual brain stem so that it can pick up signals from a tiny microphone worn on the ear and relay them inside as electrical signals that reach the area of the brain associated with interpreting sound. ? Reporter: This is one of Dr. Coletti's success stories. A young woman, previously deaf, now carrying on a phone conversation. But it must be noted it tack her years to be able to do this after the abi was placed inside her head. That's really remarkable. And that's the reason that motivated me -- Reporter: 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 e-mails. Ended up finding three different places who were doing the trials. And Phil contacted themu?.k all. Reporter: Finally he heard back. 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 the child who cannot get a cochlear implant can result in meaningful sound awareness and speech perception with time but it takes work. Reporter: Good news, Alex is exactly the kind of kid the trial needs. It is October 5th, 2013. We're leaving from Michigan and hopefully by tomorrow afternoon we will be in Boston. Reporter: And so the Fredericks make their way from their Michigan home, full of fear but also full of hope. Lookee, here's a sign, welcome to Massachusetts. Reporter: On that Tuesday morning in Boston, where we began with Alex, 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 to a nearby park to keep them distracted. The hospital calls in with regular updates. Did you get the last call from him? It was 13 minutes ago. They were actually at the brain stem, they were using the electrodes to figure out where to place the abi on the brain stem. Reporter: After 5 1/2 hours, they wheel Alex into intensive care. Under that cap of bandages on his head, the cluster of wires that the doctors hope will allow him to hear. 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. Reporter: 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 a device inside his head to a sound generator controlled from this doctor's computer. In a moment they will switch it on with everyone hoping and watching to see if he reacts. But first the door opens. Because Phil and Stephanie have decided they want the first thing Alex to hear to be his sist sisters' voices. Can you say hi? Hi! Hi, Alex. Reporter: It does not quite work out that way. The device is now on. But there's no reaction. Then others in the room try raising the sound level. Again, no reaction. And then, to everyone's surprise, that doctor on the left there, nearly off-screen, 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 like looked R edlooked. He stopped everything he was doing and he look. I felt, he definitely heard that. I knew. He was completely focused on his toy, and then he just -- he looked. It's always a challenge. It's always good to see it go well. So, so well. First step. Of a long journey. A long journey, yeah. Hearing day. It's just hearing day. Reporter: Since then, Alex and his parents returned to Boston every few months. He's gotten a second device installed in the very same spot after he fell and damaged the first one. Doctors continue to test Alex's 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. It takes speech therapy and it takes a lot of commitment on the part of the family. We're very lucky our patient has unbelievably dedicated parents that are going to see this to a successful outcome. Reporter: A long journey remains for Alex. But the start of it was that little turn of the head. Connection made. For "Nightline," I'm John donvan in Boston.
This transcript has been automatically generated and may not be 100% accurate.