Deaf Toddler Has Second Brainstem Device Surgery to Help Him Hear

— -- A deaf toddler who underwent surgery to have a radical auditory device implanted into his brainstem to help him hear is showing vast improvement after undergoing the surgery a second time, his doctors said, giving new hope that the device could one day be a common treatment option for deaf children.

Alex Frederick, a 2-year-old boy from Washington Township, Mich., was just 17 months old when Dr. Daniel Lee from Massachusetts Eye and Ear Infirmary and a team of specialists from Massachusetts General Hospital, both located in Boston, implanted a device called an Auditory Brainstem Implant, or ABI, into Alex’s brain last year.

Alex was born with little to no hearing and the ABI acts as a kind of "digital ear." It's made up of a small antenna that is implanted on the brainstem so that it can pick up signals from a tiny microphone worn on the ear and relay them back inside as electrical signals that reach the area of the brain associated with interpreting sound.

An Italian surgeon named Dr. Vittorio Colletti pioneered the use of the device and implanting procedure in children -- previously the device had been used as a common approach for treating adults with brain tumors. The device is currently not approved by the U.S. Food and Drug Administration, but is undergoing a series of clinical trials to win approval. Alex was selected as a participant in one of these trials last year. “Nightline” has followed him and his parents on their months-long journey throughout the process.

WATCH: Deaf Toddler's Journey to Hearing for First Time

Alex's first surgery was a success, but a few weeks ago, the toddler fell and hit his head on a table. The impact broke the speech processor and damaged the surgically implanted plate in his skull that holds the device in place, doctors said.

On July 2, Alex underwent a five-hour "revision" surgery at Massachusetts General to have the entire device re-implanted. His team of doctors successfully replaced the broken ABI with a new one, in the same location on the left side of his brainstem, and Alex seems to be improving quickly.

“The responses looked encouraging. That could be associated with stimulation of the first brainstem implant," Dr. Lee told "Nightline" today. "In order for brain development to continue it needs to be stimulated whether it is through sight or through hearing, through sound. In the case of the ABI, the device is electrically stimulating the path of sound in the brain, which means that the neural network can continue to mature. A mature network of the auditory pathway is associated with better responses.”

WATCH: Alex The Day After His Recovery from Second ABI Surgery

Alex returned home just four days after the second surgery and his parents remain optimistic.

He is "alert and playing with toys less than 48 hours after surgery completion,” Alex’s father Phil Frederick told “Nightline” over email. “Not trying to jinx things but he is healing faster than last time.”

“We are just so happy right now and excited things are looking up,” he added.

At the time of Alex's first surgery in November 2013, he was the youngest person in the United States to receive the ABI device and is one of a very few pediatric patients in the world to undergo ABI revision surgery. Worldwide, about 10 children are known to have had the device re-implanted.

Since the procedure on children is still new, Dr. Lee said he and the rest of Alex's surgical team discussed whether to re-implant Alex's device in the same location, or try to place it around his other ear.

“The decision was not so clear, as far as whether you implant the same ear and encounter scarring, which would make the surgery difficult, or consider doing an ABI on the other ear, which has not been implanted yet," Dr. Lee said. "In the end we decided to attempt replacing the first ABI because it was working well and because the experience of one particular ABI surgeon, Dr. Colletti, was that revising these ABI’s is possible if done carefully. We went ahead after much deliberation to do the ABI on the same side."

Alex was born two months prematurely, weighing just four pounds and four ounces at birth. He spent the first month of his life in the neonatal intensive care unit of St. John Hospital in Detroit. Scans later showed that Alex had a heart condition, his vision was compromised and he was deaf.

When Alex was 1 year old, his parents tried for a cochlear implant, a 40-year-old technology that uses electrodes to stimulate auditory nerves. The surgery commenced, but was halted mid-operation when it became evident it would not work due to the irregular structure of Alex's inner ear. The scar from that failure is still evident behind his right ear.

Alex’s parents kept looking for an answer, for some other technology that would help their son hear. In the course his research, Phil Frederick learned about Dr. Colletti’s approach for placing ABIs in children, and that the device was about to undergo a series of clinical trials in the U.S. to win FDA approval.

After finding out about the ABI surgery, Frederick looked up which U.S. hospitals where hosting the clinical trials and emailed them all individually to get Alex on the list. In August 2013, the family got word there was an opening in a trial being conducted at the Massachusetts Eye and Ear Infirmary in Boston, under the direction of Dr. 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," Dr. Lee told “Nightline” in a previous interview.

On Oct. 5, 2013, the Fredericks traveled from Michigan to Boston for Alex to undergo the initial surgery, for which Dr. Colletti flew in from Italy to observe. Alex's surgeries cost hundreds of thousands of dollars, but were paid for by the family's insurance company.

Several weeks after the first surgery, Alex and his family returned to Massachusetts Eye and Ear Infirmary in November 2013 to have his ABI switched on for the first time. Wires connected the device inside his head to a sound generator controlled from a computer, where a doctor could manipulate the sound level on the device. “Nightline” was there when the device was first switched on.

Alex's parents decided that they wanted the first sound their son to hear to be his older sisters' voices, so after the device was turned on, Evelyn, 6, and Izabella, 3, started talking, but it didn't elicit a reaction from Alex. Others in the room tried raising the sound level, but still nothing at first.

Then, to everyone's surprise, a doctor in the room slammed her keys into the side of a desk, and Alex turned towards the sound. With that little turn of his head, Alex had made the connection to sound for the first time.

Alex and his parents are eager to get back to the long process of Alex learning what sound actually is and how it has meaning, even meaning as words. They will return to Massachusetts Eye and Ear Infirmary next month, where an audiologist will activate the newly implanted device, and the family will continue to travel back and forth to Boston every month, so that doctors can test Alex's hearing response as they fine-tune the software that interacts with the electronics inside his skull.

Since Alex's surgery, Dr. Lee has implanted the device in an 11-month-old girl from Austin, Texas, and on Wednesday, the teams at Massachusetts General and Massachusetts Eye and Ear Infirmary will meet again to perform the same surgery on a 15-month-old girl from Oregon.