Bryan Brown studies the factors that cause stuttering. To say he wants to get to the root of the problem, though, is too simplistic. Ideally, he would like to pinpoint it, but he says stuttering is such a complex disorder that a single cause may never be found.
“There’s a constellation of factors that can contribute to whether a child will stutter,” Brown says. The literature refers to it as a “variable and dynamic disorder,” with contributing factors that include temperament, language ability, motor ability, and genetic predisposition.
“Not every child who stutters has that same constellation of factors, or the factors in the same proportions,” says Brown. “It makes stuttering a very difficult but exciting field to study.”
After working as a speech pathologist for two years in Seattle, Brown went back to school to study developmental stuttering. He was drawn to the University of Iowa by the strong reputation of the school and the Communications Sciences and Disorders Department He wanted to work with Tricia Zebrowski, who specializes in developmental stuttering and the effect of relationships on stuttering. She was strongly recommended by his mentors at Western Michigan University, where he earned his bachelor’s and master’s degrees in speech pathology.
Brown says that researchers in the field have developed a solid understanding of stuttering’s effect on adults but, until recently, there has been little information uncovered about possible causes.
His research, funded by a grant from the National Institutes of Health, looks at children at the onset of stuttering and examines factors that contribute to recovery. Three-quarters of children who stutter recover on their own, without intervention. These children simply stop showing any signs or symptoms of stuttering. Using a five-year longitudinal study, Brown and his colleagues want to understand all the factors that contribute to this type of unassisted recovery.
Brown’s study includes tests that help researchers understand both the physical and cognitive aspects of stuttering. One test examines the coordination of the lips and jaw during speech using a motion-capturing 3-D camera called the Opti-Track. Children have LED lights taped to their upper lip, lower lip and jaw, and the camera records them as they speak sentences.
“We’re looking at how fluid the motion of speech is, even when children who stutter aren’t stuttering,” says Brown.
Brown also asks the children participating in the study to complete a clapping and tapping task. Because timing is an important element of speech, Brown wonders if there might be a “central timing issue” in children who stutter.
Understanding the cognitive side of stuttering involves measuring electrical changes in the brain that result from groups of neurons firing in response to a specific stimulus. To do this, Brown administers two different “beep” sounds to the children and then measures their brain responses.
“There’s a specific response we’re looking for which is thought to reflect working memory update,” says Brown.
Because stuttering and language are inextricably linked, Brown says stuttering may be related to language formulation, which depends on working memory. A reduction in working memory might explain the differences in language seen in some children who stutter and might contribute to stuttering itself.
According to Brown, measuring the brain and motor system development of the same children over a five-year period makes this study especially important.
“We’re seeing how stuttering changes,” Brown says. “We’re seeing who recovers and who doesn’t recover. How are they different from each other? And how are they different from people who never stutter?”
Longitudinal studies like this are logistically difficult and don’t happen often. They are expensive. They require a big commitment from subjects, and results take a long time to come in. The lengthy process is sometimes too risky for fledgling academics hoping to secure tenure. But Brown says it’s really the best way to understand disorders of childhood.
As a person who stutters, Brown says he hopes his work will raise awareness and help people know what stuttering is and what stuttering isn’t.
“We’re not crazy, we just talk different,” says Brown.
He hopes this study will improve the lives of children. “For children who don’t experience unassisted recovery, we can shape the interventions to help them toward the path of recovery.”