April 20, 2010 -- The sooner children with hearing loss receive cochlear implants, the better, according to new research in the April 21 issue of the Journal of the American Medical Association. Children who receive cochlear implants before 18 months of age are better able to hear, comprehend sound and music, and speak than are their counterparts who receive the implants at a later age.
“Early-onset deafness is a common childhood disability that we can do something about,” lead study author John Niparko, MD, the director of otology, neurotology & skull base surgery at Johns Hopkins Medicine in Baltimore, says in an email. “Using this technology in a strategic manner appears to carry profoundly positive effects.”
What Are Cochlear Implants?
Often referred to as “bionic ears,” cochlear implants are much different than hearing aids, which only amplify sounds. By contrast, cochlear implants bypass damaged parts of the ear and stimulate the auditory nerve. The implant generates signals that are sent to the brain via the auditory nerve. The brain then recognizes these signals as sound. These small electronic devices consist of an external component that sits behind the ear, and a second part that is surgically placed under the skin.
Hearing loss can completely disrupt a child’s ability to learn to talk and understand what people are saying, Niparko says. “Children normally begin to pair the sounds of speech with meaning between six months and one year, [but] if a child cannot hear the full range of speech sounds at this age, the opportunities of learning speech and reflecting their thoughts by talking begin to diminish,” he says.
Earlier Implants Can Close Language Gap
Enter cochlear implants.
In the new study, 188 children aged 6 months to 5 years were followed for three years after they received cochlear implants. Researchers then analyzed their language development and compared it to that of 97 children without hearing loss.
Children who received the implants before they turned 18 months showed speaking ability that stayed close to that of their hearing counterparts, the study showed. Children who received the cochlear implant after they turned 3, however, still exhibited some gaps when compared to same-age children without hearing loss.
For each year that a child with hearing loss does not receive a cochlear implant, they will lag behind in the rate of improvement in language development, Niparko and colleagues write.
“Children who receive the cochlear implant early and are supported with experiences that engage their interest through speech can overcome early deprivation effects,” he says. “Their rate of learning to understand and produce speech can approximate those of hearing children.”
The more support and interaction from caregivers and loved ones, the greater the benefit, the study showed.
“If you have a child who has severe hearing loss in both ears, implanting earlier is associated with better language and speech outcomes and less of a gap versus kids with normal hearing,” says Kay W. Chang, MD, an associate professor of otolaryngology at Stanford University and a pediatric cochlear implant surgeon at Lucile Packard Hospital of Stanford University in Palo Alto, Calif.
Everyone can benefit from cochlear implants, but the kids that were younger when they received the implants benefited more, he says. “This highlights the importance of the early identification of kids with hearing loss.” Early diagnosis coupled with implant evaluation by a team that includes a speech pathologist, an audiologist, a child psychiatrist, and a surgeon is needed to make sure children can receive cochlear implants in a timely manner.
Cochlear Implant Just the First Step
There is a lot of work involved in the evaluation process, and after implantation as well, experts tell WebMD.
“If you put an implant on a child, you have to be sure to have the family on board with doing everything that needs to be done,” says Anne Oyler, an audiologist and the associate director of Audiology Professional Practice at the American Speech-Language-Hearing Association in Rockville, Md. This includes teaching the child to develop listening skills and interacting with the child.
“You can’t just put a cochlear implant on a child and be done with it,” she says. “There is still work involved with helping to develop speaking skills,” Oyler tells WebMD. “In and of itself, a cochlear implant is not a cure.”
Hearing aids also play a role in helping children with hearing loss who go on to get cochlear implants. “Even if child can’t hear and understand speech with a hearing aid, there is some stimulation and that is very important for later on,” she says.
Parents need to make sure newborns get a hearing screen within the first month of their life. “If they don’t pass, they need to follow up, and if they do have hearing loss, get started with hearing aids, and if the hearing aid is not helping, go on to cochlear implants,” says cochlear implant surgeon Mark Wiet, MD, head of the section of otology, neurotology, and skull base surgery at Rush University Medical Center in Chicago.
There is always a hearing aid trial before implants, he says.
That said, “cochlear implants are a modern miracle. Kids that are implanted can be mainstreamed in school, so it can change the course of their life,” he says.