May 21, 2024 | Anna Flanagan
By ANNA FLANAGAN
Under the mentorship of world-renowned scholars, doctoral students make significant contributions to the advancement of theory and practice in speech and hearing science through their dissertation research, as they prepare to assume leadership roles in clinical, industrial and academic settings.
Below, three of our outstanding SHS doctoral students discuss their research, and the impact they hope to have on the field.
Conflict monitoring
Mentored by Department of Speech and Hearing Science Professor Raksha Mudar in the Aging and Neurocognition Lab, Lizzy Lydon is focusing her doctoral research on communication abilities in older adults with mild cognitive impairment (MCI). Her specific focus is on the cognitive construct called conflict monitoring, which helps individuals detect and resolve competing information in the environment. Lydon uses electroencephalography to examine alterations in brain waves when people with MCI perform different conflict monitoring tasks.
Before beginning her Ph.D. studies, Lydon worked as a speech-language pathologist with patients with MCI, many of whom reported communication challenges. “I often found it difficult to determine what type of treatment was the best choice for these individuals,” she said. “After looking through research, I realized there was a lack of evidence-based treatments for communication challenges in populations that experience mild changes to their cognition and language.”
Previous research had focused on understanding memory changes in adults with MCI. An emerging body of literature suggests that other cognitive functions such as conflict monitoring are affected. In using EEG in her research, Lydon may be able to identify neurophysiological markers that can be used for early diagnosis of MCI Research has shown that people with MCI are at a significantly greater risk of developing dementia than typically aging peers, Lydon noted, so it’s important not only to identify MCI earlier but also to better characterize the changes they experience.
“This can help to inform the development of interventions that have the potential to slow the progression to dementia and allow people to maintain independence and quality of life as long as possible,” she said.
In the fall, Lydon will join the faculty of the Department of Speech Pathology and Audiology at Miami University in Ohio as an assistant professor. She plans to continue to investigate how MCI affects different aspects of communication, as well as how these changes impact the ability to engage socially with others. “I am looking forward to this next adventure,” Lydon said, “and I’m so thankful for all the training I received here at Illinois.”
Listening effort
Silvia Murgia also plans to pursue an academic position after completing her degree this summer. For her dissertation, she is evaluating the impact of background noise and dysphonia, a voice disorder, on the mental energy needed to listen, or listening effort, of children performing a speech comprehension task. She is taking a comprehensive approach to her study, using subjective and objective measures of listening effort, including EEG analysis, as well as assessments of cognitive function to explain individual differences.
Murgia is mentored by SHS Associate Professor Pasquale Bottalico in the Speech Accommodation to Acoustics Lab. Understanding listening effort in children is crucial, Murgia said, as they spend a significant amount of time in school learning through communication activities. It is essential to minimize the amount of mental energy children use to listen in order to optimize the resources available for cognitive tasks such as memorization, comprehension and evaluation. Studies show that children’s cognition is affected by the speaker’s voice quality, the presence of background noise and the complexity of the listening task. Research also suggests that individual differences in executive function may be associated with variations in listening comprehension under adverse conditions. Her research addresses both external factors affecting listening effort and internal cognitive mechanisms that help children to cope with external challenges.
“My dissertation aims to provide a more nuanced understanding of how these adverse conditions impact listening effort and comprehension,” she said. “This could have significant implications for educational practices, especially in designing interventions and strategies to support children with different listening and cognitive profiles.”
In her academic career, Murgia plans to expand her research to include children with hearing loss and special needs. Her goal is to improve the academic outcomes and overall well-being of all children by identifying effective ways to reduce listening effort and optimize learning environments.
“I hope that my research empowers children by advocating for their communication needs and ensuring that they have access to the resources and support they require to succeed academically and socially,” she said. “I want to contribute to creating inclusive environments where all children can thrive.”
Vocal intensity
December 2023 graduate Simin Soleimanifar’s dissertation research investigated how using two cochlear implants, known as bilateral cochlear implantations, affected the ability of users to control variations in vocal intensity, or the volume of their voice, as compared to users with a unilateral cochlear implantation.
Soleimanifar noted that the challenges faced by bilateral cochlear implant users in controlling vocal intensity have not been widely researched. Through her study, she hoped to identify the underlying factors contributing to the challenges, with a specific focus on how differences in the perception of loudness growth between the two ears affect vocal performance.
“Vocal performance plays a crucial role in effective communication, and difficulties in controlling vocal intensity can lead to social and emotional consequences for the individuals affected,” Soleimanifar said. “By shedding light on the specific auditory perceptions that influence these difficulties, this research has the potential to lead to better-tailored cochlear implant programming and rehabilitation strategies, ultimately improving the communication outcomes for bilateral cochlear implantation users as well as their overall quality of life.”
Mentored by SHS Associate Professor Justin Aronoff in the Binaural Hearing Lab, Soleimanifar currently is a clinical research associate at the University of Illinois Urbana-Champaign and is pursuing a career that bridges research and clinical practice. In addition to providing empirical evidence on the impact of bilateral cochlear implantation on vocal intensity control and identifying the role that mismatched loudness growth perception between ears plays in vocal performance, she hopes to inform clinical practice by highlighting the need for individualized implant programming and rehabilitation approaches that consider the auditory perceptions specific to bilateral cochlear implantations. Soleimanifar is particularly interested in applying her research findings within a multidisciplinary team to develop innovative implant technologies and rehabilitation strategies.
