Clemson Scientist Uses $1 Million Grant to Research Hearing Defects

CLEMSON, SC – February 19, 2009 – A Clemson University scientist has received a $1 million National Institutes of Health grant to study the development of the middle ear. The research seeks to help scientists and medical experts identify genetic problems and repair hearing defects while a child is still in the womb.

Susan Chapman, a neuroscientist and developmental biologist in the biology department, seeks to unlock a puzzle: How do cells in an embryo develop into the elaborate structure of the ear?

Studying chicken embryos, Chapman is looking at where the cells that help create the middle ear come from and what genetic signals the cells get to build the structures. The ear has a number of parts that need to develop and interact correctly for normal hearing. Because the interactions are so complex, there are many ways that defects occur during development. Understanding genetic triggers for the cells can lead to cellular repair when it’s needed.

In chickens and humans alike, the inner ear controls hearing and balance, while the outer ear directs sounds to the inner ear via small bones — ossicles — in the middle ear. In chickens, a single bone — the columella — is needed for transmitting sound.

For humans, the middle ear has three bones crucial for hearing. The bones move, triggering pressure on the cochlea, a snail-shaped, fluid-filled organ that stimulates hair cells sending signals to nerves and ultimately the brain where sound is perceived. Hair cells can be harmed by disease, trauma or a developmental miscue.

Chapman is optimistic that the research will provide a way to deal with some hearing losses. About three in 1,000 babies are born with hearing impairment, making it the most common birth defect.

“We are working closely with physicians to get our results into hospitals and clinics,” said Chapman. “It’s very gratifying work.”