A Breakthrough in Hearing

As more children survive extremely premature birth, they are more likely to live with complications of prematurity, which can include both deafness and developmental delays. A new study from the Stanford University School of Medicine and Lucile Packard Children's Hospital suggests that doctors can treat this combination of conditions better—and sooner—by providing cochlear implants early in life for deaf children with developmental delays.

Physicians frequently choose not to use these devices — sometimes called “bionic ears” — in babies with developmental delays that indicate probable mental retardation later in life. But the new findings suggest the implants could benefit these children’s intellectual development and quality of life, even if their cognitive problems make it unlikely that they will ever learn to speak.

 "If we can fix this deficit, it might help developmentally delayed children in other ways outside of hearing," said John Oghalai, MD, who led a study presenting the new findings.

Providing cochlear implants for developmentally delayed children has often taken a back seat to their other medical issues, Oghalai said, and physicians also have been wary of whether the implants would benefit the children. Cochlear implants send electronic signals from a microphone on the outside of the head directly to the auditory nerve, and children typically require intensive speech and auditory therapy to learn to use the implants.

In the study, Oghalai and his colleagues found that cognitively normal children got cochlear implants 11 months earlier in life, on average, than developmentally delayed children.

Later implantation had detrimental results. Not only did the delayed children start with lower intelligence, they also had slower intellectual development, perhaps because they spent more time unable to hear. The results suggested that lack of hearing plays a role in causing developmentally delayed children to fall further behind their peers.
"Some of these kids are missing more than just hearing," Oghalai said. "They're often having trouble with vision or touch as well. If you can fix one of the sensory problems, it might help to mitigate the effects of the other disabilities."

Oghalai's team is now conducting a more comprehensive trial funded by the National Institutes of Health to determine whether cochlear implants benefit a large cross-section of developmentally delayed deaf children.

Cochlear implants will not make a developmentally delayed child cognitively normal, Oghalai said. "But if the implants can improve the children's quality of life, make them happier, and prevent them from falling further behind their peers, they may be a very worthwhile endeavor.”