Learning to Hear
PhD student Sharon Miller is helping to make language and speech acquisition even more successful for those with cochlear implants
Cochlear implants can make a major difference in the lives of people with severe to profound hearing loss, allowing them to perceive the sensation of sound. But understanding speech with implants can be challenging. The way the device codes pitch can make it difficult to perceive music, be in noisy environments and identify the difference between sounds (like "s" and "sh") -- and children born with profound hearing loss who grow up with cochlear implants learn language based on distorted sounds and tend to have smaller vocabularies.
Through examining the neural and behavioral responses to auditory training, speech-language hearing sciences PhD student Sharon Miller wants to make language and speech acquisition even more successful for those with cochlear implants. By understanding the brain mechanisms behind speech and hearing challenges experienced by implant users, she hopes to develop more effective rehabilitation techniques.
The adult brain has to relearn and readjust to speech after receiving a cochlear implant. Training and rehabilitation depend on cortical plasticity, the brain's ability to change over one's lifespan. Miller's research shows that even when we're older, our brains are still plastic and there is still room to learn. She measures electrical activity in the brain with EEG, a technology that can tell whether people are receiving sound and if sound differences are perceived. She hopes that her research will inform clinical assessments, such as the cochlear implant fitting process.
In her dissertation, Miller measures implant users' brain responses before and after auditory training, which involves practice with different speakers and multiple talkers. She found that cochlear implant users were better able to perceive sounds after the training because their brain response to sound changed. The brain's attention shifted from variations within a particular sound category (such as the "R" sound) to differences between sound categories, such as the difference between how "R" and "L" sounds.
Inspired by a lifelong interest in communication and experiences with having a cousin with autism, a disorder that can impact language development, Miller studied psychology and communication sciences and disorders as an undergraduate at Northwestern University. She found the area of study to be a natural fit, combining her desire to help others with scientific and clinical aspects. "We take speech and language for granted," she says. "I had never understood how important communication is to me."
After receiving her master's from the University of Minnesota, her thesis focusing on the effects of pitch on speech perception, she worked as an audiologist. Though she enjoyed building relationships with and helping patients, she noticed that some patients with hearing aids experienced social isolation and frustration due to speech and language perception difficulties. Seeing these challenges prompted her to go back to school to further help children and adults with hearing loss.
Through her research, Miller hopes to improve professional outcomes and personal relationships for people with hearing aids and cochlear implants, since an individual's speech and language challenges can affect careers and families. She recalls a positive moment with a former audiology patient -- a mother noting that her daughter improved in school after receiving her hearing aid.
A 2010 hearing aid fitting mission in India, where she helped equip those in need with technologically advanced devices, is another experience that motivates Miller's commitment to helping persons with hearing loss. After one girl's body-worn hearing aid was replaced with the latest model, she progressed two grade levels in school due to having better access to sound. "Stories like this keep me going," Miller says. "My motivation is personal. I want to help people with hearing loss enjoy life."
After receiving her Ph.D during the 2014-15 academic year, Miller hopes to teach audiology graduate students as a clinical faculty member and continue her research.A winner of the Graduate School's 2012-13 Doctoral Dissertation Fellowship, she emphasizes the support the University of Minnesota has provided throughout her master's and Ph.D. education. She also values the speech-language hearing department's professors, advisers and students.
"I aspire to pass along a passion for learning and provide the same positive experience that professors have given to me," she says.
– Lyra Fontaine