By Ellie Rose Mattoon. Mentored and edited by Rachel Butch.
There’s more to a stutter than what we can hear. The condition – characterized by repetition of sounds, syllables, and words or interruptions in speech – is viewed by many as a childhood speech disorder that most people grow out of by adulthood. New evidence presented by a panel at the American Association for the Advancement of Science (AAAS) annual meeting explained that a more nuanced view of stuttering as a neurodevelopmental disorder may be necessary to address both the biological and social needs of people who stutter.
Roughly 3 million Americans stutter. The condition affects people of all ages, but occurs most often in young children as they develop their language skills. According to Bridget Walsh, assistant professor from Michigan State University, 5-11% of preschool-aged children struggle with a stutter. While 75-80% of these children recover on their own, children with persistent stuttering are at a greater risk for low self-esteem, social anxiety, and depression. Stuttering that continues into adulthood is associated with underemployment and reduced earnings.
A common misconception is that persistent stuttering is a product of bad parenting or emotional trauma. However, evidence presented by all three panelists reinforces the case that persistent stuttering is based on multiple biological and demographic factors.
One such factor contributing to persistent stuttering may be access to early therapy, said Walsh. New data from Walsh’s research indicates that early intervention may prevent stuttering from persisting into adulthood.
“Parents are often counseled to postpone therapy to allow time for natural remission, but to delay therapy for the 25% or so of preschoolers at greater risk for persistence is to permit maladaptive speech and motor networks to form,” said Walsh.
According to Ho Ming Chow, assistant professor from the University of Delaware, understanding which of these networks cause stuttering to persist or recede offers explanations not only for the biological origins of stuttering, but also what neural pathways researchers can target when developing new therapies.
“If we can find a way to promote this compensatory process, there is a chance that we can increase the recovery rate in stuttering,” Chow said.
In one experiment, Chow explained, a research group performed MRIs on children who stuttered and on typically-developing children. The group revisited the children each year for up to four years to see what differences emerged between children who continued to stutter and those who recovered.
Chow’s work found that children whose stuttering persisted had a smaller putamen, a part of the brain that plays a role in motor skills, than children who have recovered from stuttering or typically-developing children. In addition, these children had a smaller volume of white matter, which acts like a highway connecting various regions of the brain to one another. Interestingly, children who recovered from stuttering experienced a substantial increase in white-matter volume between their first and last visits, suggesting that this area may play an important role in their recovery.
While Chow presented the anatomical basis for stuttering persistence, Walsh’s research group followed young children who struggled with stuttering over time to investigate the factors that distinguished those whose stuttering persisted from those who recovered. Using both demographic, clinical, and physiological tests, her team was able to develop a statistical model that showed the highest rate of true positive and true negative predictions of stuttering persistence when compared to models that had taken fewer factors into account.
Walsh acknowledged that her team’s model confirmed known risk factors for stuttering persistance, such as a family history or sex (males are more likely to struggle with a persistent stutter), she also noted that no single factor serves an on/off switch for stuttering. Instead, several different factors combined may determine whether a child develops a persistent stutter.
With this research improving the scientific community’s understanding of what allows a stutter to persist, the panel looked ahead towards future treatment options for adults who continue to struggle with a stutter.
Gerald Maguire, professor emeritus from the University of California Riverside School of Medicine, was open about his own struggles with stuttering as an adult. He expressed hope that, with clinical trials of antipsychotics such as Risperidone showing promise for stuttering treatment in adults, more individuals may feel empowered to seek therapy. Maguire compared this to the increase in individuals seeking treatment for obsessive-compulsive disorder (OCD) after the release of the first pharmacological medications.
“Individuals who had been living in silence began going into therapy. So, the emerging pharmacologic treatments brought forth more individuals to seek this multidisciplinary care,” Maguire said.
Although it was once hardly regarded as a scientific question, researchers are learning more about the nuanced factors that can begin and end a stutter. While those who stutter still experience challenges, increased progress in science and society in the coming decade has the opportunity to improve the lives of millions who struggle.
Ellie Rose Mattoon is a sophomore at the Johns Hopkins University majoring in Molecular/Cellular Biology and Public Health. She is the editor of the Science-Technology section of her school’s independent student newspaper _The Johns Hopkins News-Letter. _Follow her on Twitter @ermattoon or email her at ellierosemattoon@gmail.com.
Image: New research investigating how stuttering either persists or recedes may allow researchers to target early interventions to children who struggle to express themselves due to the condition. Credit: Courtesy of Jason Rosewell / cc0 1.0
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