Research gives voice to hearing-impaired infants
J . Devin McAuley and Laura Dilley enjoy playtime with their daughter, Madeleine. The couple's research is investigating the importance of maternal speech to language development.
New parents have long used “baby talk” to coax grins and giggles out of their infants.
But that earliest form of communication, particularly coming from mothers with a singsong quality and clearer enunciation of sounds, has also been linked to speeded development of language and speech skills in children with normal hearing.
How hearing-impaired infants develop those skills, and what can be done to help them and their parents maximize the likelihood they’ll be able to use language and speech effectively, are the overarching goals of a nearly $2 million project involving two Bowling Green State University faculty members.
Drs. Laura Dilley, an assistant professor of psychology and communication disorders, and J. Devin McAuley, an associate professor of psychology, are working with Dr. Tonya Bergeson, the project leader from the Indiana University School of Medicine. The National Institutes of Health’s National Institute on Deafness and Other Communication Disorders is funding the research for five years through mid-2012, with BGSU’s share of the total just under $400,000.
“Baby talk” appears to help babies figure out where words are in speech and keep them from becoming bored with a monotone delivery.
Infants with normal hearing are more attentive to the melodious speech and more able to learn language when tuned in to it, added Dilley, calling it “a hallmark of development” across cultures.
Little is known, though, about how hearing-impaired infants, especially those with hearing aids or cochlear implants, develop attention to maternal speech and language ability, she said.
Knowing how hearing-impaired infants respond to speech gives an idea of how they’re learning language, Dilley said. But how does a mother respond to the challenge of speaking to a hearing-impaired child? Mothers talk to other adults differently than they do to children, she said, and when a child is hearing impaired, research findings have shown further differences—more repetition and simple utterances, and less responsiveness.
The subpar input they are providing may be undercutting the child’s chances of learning language , Dilley said.
That’s where clinicians come in, she added. Assuming that hearing aids or cochlear implants appear to be helping, the professionals can talk more to the mother and child to maximize the chances of language acquisition.
In the ongoing project, IU’s study is looking at the behavior of hearing-impaired infants and how their mothers talk to them. Mothers of infants with normal hearing have been recruited to join the study there.
The collected data is being sent to BGSU for analysis, including acoustic analysis by undergraduate students, Dilley said. Among other things, they measure frequency, timing and amplitude information from the mothers’ recorded speech.
Evidence indicates that adult listeners are good at using timing and temporal aspects of speech, Dilley said, but the question remains if children can acquire similar ability. “Temporal cues” include when a sound begins and ends, as well as rhythm. Just as Morse code has a rhythmic pattern, so, too, does speech have rhythmic components, McAuley noted.
The project is long to allow tracking of the participating children’s language development, and the grant is large because the work is labor intensive, Dilley said. It also has possibilities for substantial impact, she said, pointing out that the biggest concern of parents with a hearing-impaired child is if their child will be able to understand and speak language.
“It would be very empowering for those parents” to be able to help their child simply by changing their speech, she said. “This project has the potential to identify which course of action they could be taking to help the child articulate language and understand spoken language.”