Neurobiology of Stuttering: New Insights Presented at STARS Conference

CONFERENCE REPORTER

At a recent conference on stuttering, Shahriar SheikhBahaei, PhD, assistant professor of neurobiology and behavior at SUNY Stony Brook University, discussed new insights into the neurobiology of speech and the mechanisms that may contribute to stuttering. The STARS (Stuttering Treatment and Research Society) Inaugural Education and Research Conference was held in Dana Point, California, September 13 2025. SheikhBahaei, who also stutters, is an advisory committee member of STARS.¹

SheikhBahaei emphasized the complexity of speech production. “Speech is a very complex motor behavior,” he said in an exclusive interview with Psychiatric Times during the conference, adding that it involves “more than 100 muscles in the body that…have to work together in concert.” Although researchers know some of the brain circuits and auditory feedback systems involved, he explained that the development of animal models has transformed the field by allowing scientists to examine cellular and circuit-level processes. “Now we know what type of circuits are involved. We know the role of inhibitory circuits, excitatory circuits. All of those lead us to a more comprehensive understanding about the neurobiology of speech.”

One key focus has been the role of dopamine, which is central to both motor function and learning. “Dopamine has been taught to be important for speech,” SheikhBahaei said, adding that regions rich in dopamine are deeply involved in vocal motor behaviors.

He also highlighted findings on the coordination between speech and breathing. “Almost all species except frogs…only make meaningful vocalization during exhalation,” he explained. In both animal models of stuttering and human studies, abnormalities in respiratory circuits have been identified, suggesting that “this coordination of activities between these two important circuits are affected.”

SheikhBahaei noted one of the enduring mysteries in the field: why some children naturally outgrow stuttering while others do not. “It persists in about 1% of population which is still huge—that’s close to 80 million people worldwide,” he said. Evidence suggests that disrupted development and refinement of motor circuits controlling respiration, orofacial movement, and vocalization may play a role.

Finally, SheikhBahaei addressed the interaction between stuttering and anxiety. “From existing data from human subjects, we know that people who stutter, they are not more anxious, but we also know that anxiety makes stuttering worse,” he explained. Because speaking requires rapid, tightly coordinated brain activity, even small disruptions in timing may tip the balance and trigger stuttering in some individuals.

Reference

1. SheikhBahaei S. A Neurobiologic Understanding of Stuttering. Presented at STARS Inaugural Education and Research Conference; Dana Point, California; September 13, 2025.