Do You Hear What I Hear?

Babies with cochlear implants don't know to prioritize speech

(RxWiki News) Imagine a wonderful world with all new feeling sensations, new sights and new tastes. No sounds are available, but all these new touches, sights and tastes are pretty thrilling.

This is how an infant born deaf experiences the world: Lots of wonderful, new things. Just no sound, which they don't know exists anyway.

Cochlear implants can allow deaf infants to hear speech, which eventually can allow language development.  A new study shows that these children receiving implants don't automatically know how to listen when people speak to them because their world has been filled with other things to learn besides speech.

"Infants with cochlear implants can now hear but may have issues listening."

Cognitive psychologist Derek M. Houston, Ph.D., associate professor of otolaryngology and Philip F. Holton Scholar at Indiana University School of Medicine explains when infants are born deaf, their development is shaped by a world without sound.

This somehow demotes the importance of sounds in these deaf babies' learning centers. Houston continues to explain that these babies are motivated by sights, smells, and touches that seem relevant to their world.

Since sound isn't part of their world, it isn't important to them. Houston continues explaining that when they receive a cochlear implant, their world changes with the addition of sounds. Infants who have already adapted to a silent environment, sounds may not be relevant to them.

Prior research has shown that hearing infants will look longer at a checkerboard pattern when hearing something they like. Houston reports his study observed two groups of infants: the first group had cochlear implants while the second group had normal hearing.

He  measured babies' 'looking time' at the pattern when it was paired with a repeating speech sound. Then he measured the 'looking time' at the same pattern with no sound.

The babies with new cochlear implants seem to hear the sounds around them but not have any interest in them. This trait can slow language learning speech and word recognition abilities.

The first group with cochlear implants spent less time looking at the checkerboard pattern than the group with normal hearing infants.

Additionally, two years after receiving the cochlear implants, the children who were less attentive to speech early in their hearing experience performed  poorly on a word recognition task.

Review Date: 
May 30, 2011