UF findings may lead to new field of study in speech production among users of cochlear implants

Researcher applies sensors to participant's mouth
Dr. Matthew Masapollo fits undergraduate student Morgan Powell with EMA sensors that attach with dental glue to her lips, tongue and jaw. Photos by Jesse S. Jones.

A University of Florida team is the first to demonstrate that a novel technology that allows researchers to track speech movements within the inner reaches of the vocal tract can effectively be used to assess speech development in children born deaf who received cochlear implants.

The findings, which appear in the Acoustical Society of America journal JASA Express Letters, are expected to facilitate advancements in scientific understanding of the role of auditory input on speech motor control, said lead author Matthew Masapollo, Ph.D., an assistant professor in the department of speech, language, and hearing sciences at the UF College of Public Health and Health Professions.

“This could become a major field of study within the next decade,” he said.

Cochlear implants may help children born with severe hearing loss develop intelligible speech, but problems persist, Masapollo said. The auditory information the implants provide may not be sufficient for young children to develop connections between speech production and the auditory signals received through the implant.

two people reviewing data on a monitor
Jessica Goel, an undergraduate research assistant, and Dr. Matthew Masapollo review speech production data as Morgan Powell speaks. The EMA system provides information on movements within the vocal tract on a millisecond-by-millisecond basis.

“Young children with cochlear implants often lag behind their peers in speech production, but it has been difficult to understand the causes because we don’t know what is happening in their vocal tracts,” said Masapollo, the director of the Hearing Health Foundation-funded UF Laboratory for the Study of Cognition, Action, and Perception of Speech. “It is essential that as a field we find a way to circumvent this problem.”

With funding from the college, Masapollo’s lab purchased an electromagnetic articulography, or EMA, system, which allows researchers to view, in real-time, the precise choreography of the vocal tract as a participant speaks. Masapollo’s lab is one of only a very few in the world to own the EMA equipment, which is manufactured by a company in Germany.

Because both EMA and cochlear implants use magnetic fields, there has been concern that the implants could affect recordings obtained from the EMA or that the EMA could interfere with the implants’ signal processing.

“We demonstrate in our new study that there is no cross-interference between EMA and cochlear implants, and that EMA is a valid and reliable method for assessing speech production in cochlear implant users,” Masapollo said. “These findings have important implications that will set the stage for systematic use of EMA to study speech production in children with cochlear implants.”

four individuals standing in front of HPNP Complex.
The Laboratory for the Study of Cognition, Action, and Perception of Speech team: Dr. Yonghee Oh, an assistant professor in SLHS; Jessica Goel, an undergraduate studying biomedical engineering; Dr. Matthew Masapollo; and Dr. Susan Nittrouer, a professor in SLHS.