Examining the science of stuttering, from childhood into adulthood

Stuttering is a neurological condition that affects more than 3 million Americans, including the Democratic nominee for president.

Joe Biden has made no secret of his struggles with stuttering, often noting in his speeches he practiced reading poetry in front of a mirror as a child to reduce his stutter. While on the campaign trail, he has also shared how he marks up his speeches to improve his fluency when reading them in public.

About 80% of those who stutter as children recover before they are teenagers, even if they don’t receive speech services or other interventions. For the 20% who stutter into adulthood, persistent stuttering becomes a part of everyday life, said Evan Usler, an assistant professor in the University of Delaware Department of Communication Sciences and Disorders.

Usler studies motor speech and fluency disorders, including stuttering. He also looks at the neurophysiology of speech production, including the role of language, emotion and cognition.

Like Biden, Usler is among those who continue to stutter into adulthood, and he knows firsthand what it’s like to stumble over a sound or struggle with a word. 

“It needs to be better understood that recovery or ‘overcoming’ stuttering does not mean never stuttering,” Usler said. “Instead, it means living a healthy life with meaning and purpose necessary for the development of an authentic self, despite the annoying moments of stuttering.”

Usler recently answered questions about stuttering and the ongoing research around it.

What causes stuttering?

The causes of stuttering remain unclear. However, it is likely not caused by a single event, such as an injury or traumatic event. Instead, stuttering behaviors emerge due to an interaction of stressors on the developing speech motor system of some children.

Speaking is a fine motor skill that is learned and refined protractedly during childhood. Between the ages of 2 and 4, stuttering disfluencies appear in approximately 10 percent of children during language and emotional development.

Are some situations more likely to cause stuttering?

Stuttering occurs with high-situational variability. People who stutter are usually fluent when speaking alone but can stutter quite a bit when speaking in high-stress situations. Speaking on the telephone or to a group of people is a particularly difficult situation that can elicit stuttering disfluencies. Like other neurodevelopmental disorders, anxiety doesn’t cause stuttering, but can exacerbate the symptoms.

How is stuttering different than other interruptions in speech that can occur?

All people, particularly young children, produce what we call “typical” disfluencies. These are the “um”, “like”, “you know,” filler words. Some of us produce these more than others and they are usually made when we need more time to process the language we are speaking or when we change thoughts in the middle of a sentence.

Stuttering is different. What often happens is that children soon realize that they stutter on certain sounds or words and in certain social situations. Then they start to fear those words and situations and learn to avoid them. Children become very good at hiding their stutter (often called covert stuttering), substituting words that think they can’t say for words they can say, or otherwise avoiding speaking — such as texting instead of using the phone.

This creates a vicious cycle of maladaptive physiological and psychological habits that reinforce each other which can be very hard to lessen.

Can you explain your research in fluency?

In my Interpersonal Neurophysiology Lab in the Tower at STAR, we study speech and language performance and how these interact with cognition and emotion. We use electroencephalogram (EEG), electromyography (EMG), electrodermal and optical motion capture technologies to study how our brains and bodies function when we listen and speak to others.

A central line of research involves stuttering and cluttering, two related fluency disorders. My colleague, Dr. Ho Ming Chow, provides an expertise in neuroimaging and genetics. He is working on a potential animal model for stuttering.

More specifically, we investigate how stuttering develops in children and adults, what are the factors that make some people recover from stuttering while others persist, and how we can improve current treatment approaches for people who stutter.

What is the long-term outlook for people with a chronic stutter?

For the minority of children who do not recover and stutter chronically into adulthood, stuttering can become a serious existential problem. The cruelest aspect of the disorder is the more you want to be fluent, often the less fluent you are likely to be. You may be relatively fluent when speaking informally to friends and family, but the stuttering often comes with a vengeance during an oral exam, a first date, a job interview or a traffic stop. I view these as regular traumatic experiences that can be disastrous to one’s social connectivity, ambitions, motivations and sense of self agency.

Current best treatment approaches often include taking part in self-advocacy organizations, such as the National Stuttering Association, as well as cognitive-behavioral therapies that reduce avoidance of speaking by knowledgeable and empathetic speech language pathologists. The UD Speech-Language-Hearing Clinic is a wonderful resource for people who stutter in our community.

Joe Biden has been open about the ways he has dealt with his stuttering over the years. Are those strategies commonly used?

Mr. Biden speaks about certain strategies that helped him, like reciting the poetry of [William Butler] Yeats. Such strategies have been used by people who stutter to improve their speech for millennia. They seemed to have worked for him, but interestingly, we do not have solid scientific evidence how, or to what extent, such speaking practices work.

Speaking is a fine motor skill, so it makes sense that recitation of fluent speech improves fluency. Using external sources of rhythm, such as speaking with a metronome or in unison with others, also improves fluency.

More important than strategies is the conviction to stutter openly and confidently, as it often then that fluency seems to emerge.