New clinical trial aims to help children who've never been able to hear

A child's ear.
A child's ear.
esther wieringa/Flickr Creative Commons

The Children's Hospital Los Angeles and House Research Institute (HRI) were recently awarded a grant for a five-year clinical trial that aims to help young children who have never been able to hear.

The National Institutes of Health will cover medical costs for an auditory brainstem implant (ABI) on 10 children between ages 2 and 5. The trial will only consider children with congenital deafness from a malformed or non-existent cochlear nerve, meaning they have not been able to hear in both ears since birth. The Food and Drug Administration approved the trial in December 2012.

This group of children would not benefit from cochlear implants, because this more common procedure transmits sound to their cochlear nerve. ABI bypasses this nerve and sends sound directly to their brain.

Although the House Research Institute first developed ABI in 1979 when it was a nonprofit called the House Ear Institute, the FDA had only approved its use on people over 12 years old.

Not only will this clinical trial be the first FDA approved use of ABI on young children, it will be the first test of its effectiveness on people who never had the ability to hear, said Dr. Mark Krieger, chief of medical staff at Children's Hospital Los Angeles.

“The new idea for the auditory brainstem implant is to take children who have never heard anything, whose brains aren’t even designed to receive hearing because they were born without cochlear nerves, which are the hearing nerves,” Krieger said. “By putting this in we’re actually bringing sound directly into the brain where it never got before.”

Until now ABI was used on patients who had hearing and subsequently lost it due to damage to their cochlear nerve.

Krieger said it is very hard to get FDA approval for procedures with children because they want proof that it is safe and effective, and it is difficult to enroll children in off-label use studies, or those not approved by the FDA.

However, a doctor in Italy, Dr. Vittorio Colletti, began performing the ABI procedure on young children at the University of Verona Hospital about 10 years ago. His work has not only demonstrated its effectiveness but also provided American doctors with the data and results needed to get FDA approval.

While it is difficult to estimate the number of children that benefited from Colletti’s work, Krieger estimates that if a child does not have any other ailments or physical issues, they have about a 50 percent chance of developing speech after getting the ABI.

The trial will focus on children younger than 5, because Colletti’s work suggests that the older a child is, the less sensitive their brain would be to developing new skills, such as speaking or hearing.

“The brain has circuits in place to learn how to talk, smell, hear, etcetera. But if there’s no input, these circuits tend to fade away,” Krieger said. “For example, with vision, if you don’t put visual stimuli in or if there’s damage to the eyes and the eyes don’t develop those parts of the brain that are supposed to perceive vision, they will only develop it in a very rudimentary way.”

Currently the HRI is putting together a Data Safety Monitoring Board, which will make sure rules regarding the clinical trial are followed, said Dr. Laurie Eisenberg, a scientist at HRI. They will include people from the National Institute of Deafness, an auditory neuroscientist and a biomedical engineer, among others.

Once the board is assembled and participants are chosen, the clinical trial will begin. Eisenberg said they are hoping the trial will begin in October.