Funding from the U.S. Army will help a University of Texas at Dallas auditory neuroscientist investigate why the majority of people with autism spectrum disorder are unusually sensitive to sound — research that could lead to new and more effective treatments.
Dr. Kelly Jahn, assistant professor of speech, language, and hearing in the School of Behavioral and Brain Sciences, studies hyperacusis, a hearing disorder that involves difficulty tolerating everyday sounds like paper crinkling, vacuums or honking cars, even to the point of discomfort or pain.
The condition is particularly prevalent among people with autism, which affects 3.5 million Americans, including some 35,000 U.S. military dependents. In addition, more than 2.3 million veterans are affected by hearing loss or tinnitus; those conditions are often comorbid with hyperacusis.
The three-year, $850,000 grant from the U.S. Army Medical Research and Development Command will support Jahn’s search for biomarkers for the condition, which occurs in 50% to 70% of autistic people and frequently limits their social interactions, health care access, education and employment opportunities. Objectively diagnosing hyperacusis is difficult, and the connection between it and autism is unclear.
“Hyperacusis can occur independent of autism, but few people recognize it unless you put it in that context,” Jahn said. “It can occur in people with little to no measurable hearing loss. Some people suffer physical pain. It makes it hard to go about daily life.”
Jahn, who directs the Neuroaudiology Lab at the Callier Center for Communication Disorders, is searching for a potential mechanism behind hyperacusis that will enable development of ways to monitor its symptoms.
“Animal studies show that when you damage the auditory system in some way, you get enhanced responses to sound in the brain and in other parts of the central nervous system,” she said. “So, one leading theory is that there is hyperactivity in the brain, but we need more research in humans to confirm or refute that.”
Jahn’s research team plans to collect data from four groups, each ranging in age from 18 to 35: autistic and nonautistic young adults with and without hyperacusis. Future studies will include children, she said.
“We will record brain waves via EEG, pupil size changes and sweat secretions, looking for similar hyperactivity to what we see in animal models,” she said. “These indicators are well established in terms of correlation to emotional arousal and loudness perception.”
Jahn explained that the electroencephalogram will measure responses that can be easily compared across the groups, with tailored intensity levels of sound for individual participants.
“Participants might not all tolerate the same intensity, so the sound we created modulates up and down, not surpassing what should be comfortable,” she said. “We expect to see elevated central nervous system responses in the autistic patients with hyperacusis relative to other cohorts.”
Results of the study will point the way for future research and help clarify if treatments used for people who are not autistic could be used effectively for those who are.
“One of the primary treatments for hyperacusis is cognitive behavioral therapy combined with some level of exposure to sound, gradually increasing over time,” Jahn said. “That doesn’t work for every patient though, especially if they have physical pain when they hear sound.”
To learn more about how UT Dallas is enhancing lives through transformative research, explore New Dimensions: The Campaign for UT Dallas.
As an audiologist, Jahn has met many people for whom there’s no current solution. This motivates her push for an objective diagnostic measure that goes beyond reliance on a patient’s subjective feedback.
“Children who come in — especially the autistic population — can’t describe this situation very well,” she said. “If this condition is all you’ve ever known, and you don’t know that most people don’t experience this, how do you ask for help? That’s why a less subjective evaluation in the clinic is so important.”
Complicating hyperacusis research is the range of conditions that are connected to sound sensitivity, including tinnitus, post-traumatic stress disorder, migraines and traumatic brain injury.
“Still, there are plenty of people who present with hyperacusis without an obvious comorbidity alongside it,” Jahn said.
In 2021, Jahn received a three-year National Institutes of Health Mentored Research Scientist Development Award from the National Institute on Deafness and Other Communication Disorders to identify physiological biomarkers in individuals with hyperacusis, research that she hopes will evolve into a new class of clinical diagnostic tools for evaluating sound intolerance.