PROJECT SUMMARY / ABSTRACT
Stuttering is a speech fluency disorder that negatively impacts the communicative abilities of 5–8% of children
and 1% of adults. Stuttering also limits the individual’s academic-occupational achievement and social-
psychological wellbeing. Unfortunately, existing stuttering treatments are associated with considerable individual
variation in their outcomes, and in some cases, are entirely ineffective. Additionally, existing treatments require
many sessions, and some are susceptible to as much as 70% relapse, leading to costly solutions with limited
accessibility, especially for individuals from lower socioeconomic backgrounds. A major barrier to developing
effective stuttering treatments is our incomplete understanding of the specific neural processes underlying the
behavioral aspects of stuttering. There is a critical need to (1) identify the deficient neural processes underlying
stuttering, (2) determine their functional contributions to breakdowns in speech fluency, and (3) develop neural
and behavioral interventions that specifically target the deficient processes, and thus, promote fluency in
individuals who stutter. Current speech theories posit that as the brain prepares speech movements, it uses its
predictions to prepare the sensory systems for more efficient and accurate speech monitoring. These predictive
sensorimotor processes and their interplay with error-detection processes are critical for fluent speech
production. This project’s overall objective is to elucidate the role of predictive sensorimotor processes in the
breakdowns of speech fluency in children and adults who stutter. We will address this question using behavioral
and neurophysiological recordings combined with neurostimulation techniques. Our central hypothesis is that
stuttering is associated with deficits in predictive sensorimotor processes, leading to inaccurate predictions. Aim
1 will evaluate the effects of exposure to auditory errors on predictive sensorimotor processes of individuals who
stutter across the lifespan. Aim 2 will characterize the temporal alignment of prediction and auditory feedback by
delaying auditory feedback or speech initiation. Aim 3 will determine the functional contributions of the speech
premotor cortex in predictive sensorimotor processes. Overall, the expected outcome of this mechanistic
research program is a detailed neuro-developmental account of deficits in predictive processes of stuttering
individuals across the lifespan. This project’s results will have a critical positive impact because (1) they will form
a robust scientific foundation for developing neural and behavioral interventions for stuttering, and (2) they will
have significant implications for theories of stuttering and speech production.