When Torrey Loucks talks about the vital human capabilities of speech and hearing that are at the heart of his research, he sounds like a physicist who has a deep appreciation of biology, as well as the human condition.
“The hearing mechanism is so elegantly organized in humans and yet it provides so much of the basis for who we are and our ability to communicate with other people,” Loucks said. “A hearing impairment, whether it’s deafness from birth or a later acquired hearing impairment, just profoundly affects our ability to communicate. That devastating loss of something that so defines ourselves, that has encouraged me to study these phenomena further.”
While Loucks seeks to understand hearing and speech production at fundamental, physical levels in the brain and the speech motor production system, he also is very much focused on the human side of the equation, the one where disorders like stuttering can cause so much anguish to those who suffer from them. An Assistant Professor of Speech and Hearing Science (SHS) and faculty in the Beckman Institute’s Cognitive Neuroscience group, Loucks is also a key member of the Illinois International Stuttering Research Program. His work investigates stuttering both toward understanding and treating the disorder, as well as to understand the bases of normal speech.
“Stuttering is very interesting because it appears to occur at the junction point between formulating what you want to say and actually being able to express it,” Loucks said. “So it’s one of those disorders that show how language and speech are so intricately connected.
“The possible gain in the research of stuttering is tremendous for the basic understanding of communication. Stuttering is really one of those border disorders that reveals the function of two separate systems, or a much broader system than what is just implicated. For that reason, studying stuttering is so important for advancing our basic knowledge of human communication.”
Loucks’ work with the Stuttering Research Program – known internationally in the field for its efforts – is based on scientific results, but also geared toward creating an understanding of the difficulties faced by people who stutter.
“It is a neurological disorder with a biological basis and a genetic basis that is expressed as changes in the neurological control of speech,” Loucks said. “There are no predisposing events that make a person stutter that could be prevented either by being a better parent or being a different sort of child. No one is to blame for the occurrence of stuttering because it is a biological disorder.
“Nonetheless, the stigma of stuttering can be reduced considerably by realizing that we need to accept communication disorders as occurring in the population. There’s nothing negative about having a communication disorder and people should know that stuttering does not affect a person’s ability to learn, to succeed academically, all of those things. It has nothing to do with intelligence and should not be in any way a barrier to a person realizing their full potential. It is a neurobiological disorder that no one could prevent, but which we can find better ways to treat and possibly cure in the future.”
– Torrey Loucks
Toward that end, Loucks’ current research is focused on the study of adults who stutter (AWS), and specifically differences in the brain between AWS and normally fluent adults (NFA). He uses functional and structural magnetic resonance imaging (MRI) techniques to study the neural bases of stuttering, and plans to employ optical imaging methods in future work.
“I try to understand the brain-behavioral relationships involved in the production of speech,” Loucks said of his research. “This is such a fundamental ability for humans and yet it is so easily compromised by acquired diseases and developmental disorders, that we often take it for granted.
“And yet its complexity is so enormous that we need combined approaches looking at brain functions, looking at how we actually produce speech in a very detailed, experimental manner in order to uncover the basic relationships. And then take these basic relationships and turn them into effective intervention techniques so that we can restore communication abilities to people who have diseases or developmental disorders that resulted in compromise of these abilities.”
Loucks earned his Ph.D. at the University of Toronto and was doing a doing a postdoc in neuroscience of communication disorders at the National Institute of Neurological Disorders and Stroke looking at brain control of vocalization when an opportunity at Illinois arose. He met Ehud Yairi, an SHS professor, at an NIH conference and after more talks, Loucks applied for a position at Illinois. He joined the University in 2007 and still works closely with Yairi and Nicoline Ambrose from SHS, the founders of the Illinois International Research Program. Loucks said the program “has had a very strong record of research in stuttering over the past 20 years.”
Loucks directs the NeuroSpeech Laboratory and is Associate Director of the Speech Dynamics Laboratory, both of which boast advanced equipment for speech experimental testing. He also uses the MRI facilities at Beckman’s Biomedical Imaging Center to look at brain activity. His recent research and papers have focused on differences in the brains of AWS and NFA subjects.
“We’ve found that there are some profound sensory-motor relationships, even in adults, that are determining how well they are able to coordinate their speech,” Loucks said. “This research is so convincing that we have modified our goals to uncover what is the relationship between what you hear and what you say in stuttering.”
A series of ongoing studies by Loucks and his collaborators have shown that modifying how AWS hear their voice changes their coordination pattern and can result in a reduction of stuttering occurrences.
“We’ve found that persons who stutter are remarkably dependent on hearing their own voice,” Loucks said. “So changing their auditory feedback, changing, more specifically, the delay time in which persons who stutter hear their own voice, can improve their speech coordination. That’s if it is a short delay, but it can profoundly make their speech more disfluent at longer delays.
“Delayed feedback is known to have opposing effects on fluency but these opposing effects on speech movement coordination are new discoveries. But we think that these opposing effects on speech coordination may open a window into more automatic ways to modulate fluency in speech production.”
A recent study by Loucks and his collaborators looking at brain structure found that in the corpus callosum (CC) – responsible for most interhemispheric transfer of information between the left and right cerebral hemispheres of the brain – the rostrum and anterior midbody were larger in AWS than NFA, and that this structural difference, as they reported, “may be associated with the atypical functional brain organization in AWS and may be a factor in the performance of AWS on tasks.”
A follow-up fMRI study by Loucks showed that even using brief speech tasks and very simple stimuli, such as single word picture naming, is associated with altered neurological activation in the cortex and sub-cortical structures in AWS that are predominantly lateralized to the right hemisphere of the brain.
“Altered hemispheric organization seems to be part of the basic organization of speech production in persons who stutter, and this differs fundamentally from the left lateralized activation that we see in normally fluent people,” he said. “This has been suspected and shown in studies by other investigators but typically with longer paradigms and more complicated speech tasks. The fact that you can even see this with single word picture naming suggests that it’s a fundamental aspect of their speech production network in the brain.”
Loucks said the structural study focusing on the corpus callosum suggests that AWS “may have not established the dominance of one hemisphere for certain language tasks.
“Now because many speech areas are interconnected across the two hemispheres through the corpus callosum, it might suggest that hemispheric dominance for speech and language has not been established to the same degree as it has been for normally fluent adults.”
Loucks explained the importance of their findings for the field.
“There’s a lot of research going on with imaging and stuttering, but our work is making an important contribution because it shows that these differences are likely associated with automatic mechanisms that have some structural basis,” he said. “It’s not just where the brain is activating, but that these changes in activation are associated with changes in the wiring of the brain as well.”
Loucks also has collaborations with other Beckman faculty. He works with Mark Hasegawa-Johnson in a project that uses measures of speech physiology to improve automatic speech recognition systems for people whose speech production is severely compromised by cerebral palsy. He also collaborates with Ryan Shosted, as well as physicians at Carle Foundation Hospital, in a project that seeks to improve speech production for people who are using cochlear implants and learning or relearning to produce the all-important ‘s’ sound.
Loucks said his work on stuttering is an enduring long-term goal which focuses on those who suffer from it, and on advancing biological science.
“If we were to unravel the riddle of stuttering, we would know a lot more about how what you want to say is formulated into the movements that produce the acoustic patterns of speech,” he said.