Current research projects

Longitudinal study of brain development in childhood stuttering, persistence, and recovery

This study involves collecting longitudinal data (behavioral, neuroimaging) from young children who stutter and their age-matched peers, starting from close to stuttering onset (ages 3 and up). Multiple acquisition of these data points from each child enables us to examine brain developmental trajectories that differ between children who do and do not stutter, and further help elucidate factors that are associated with persistent forms of stuttering. We are also investigating how brain and behavioral changes that correlate with persistent developmental stuttering differ between the two sexes.

These analyses will help us answer some long-standing questions about stuttering, such as: Why do some children recover naturally from stuttering while others don't? Why do more boys stutter than girls?

The findings from this research have potential to lead to early objective prognostic markers for persistent stuttering, elucidate neural subtypes, and pave the way for neuroscience-based treatment development.

This research is funded through an NIDCD/NIH grant R01 DC011277 (PI Chang).

Neural oscillations during speech perception and production with and without rhythmic entrainment

Examining neural oscillations -- rhythmic fluctuations of neural excitability -- provides an opportunity to better understand the neurophysiological bases of the auditory-motor coordination deficits that have been reported in stuttering speakers. Fluent speech requires coordinated neuronal activity that is achieved through neural oscillatory synchrony across brain structures. The overall objective of this study is to determine how children who stutter (CWS) differ from fluent peers in neural oscillatory synchrony across auditory-motor structures during speech perception, planning, and production under two conditions - with and without rhythmic entrainment. Guided by EEG and MRI data collected from children who do and do not stutter, our central hypothesis is that beta oscillations, which control predictive timing of movements through coordination of motor to auditory systems, will show aberrant power, reduced inter-trial phase clustering, and reduced interregional oscillatory phase synchrony in CWS. A better understanding in this area has exciting treatment implications, since manipulation of synchrony within oscillatory patterns in auditory-motor systems may be possible through entrainment with external sensory stimuli and non-invasive brain stimulation. This project will thus allow us to lay the groundwork towards systematic, neurobiology-based intervention development for CWS. This research will be the first series of studies designed to characterize neural oscillatory synchrony specific to speech processing in CWS, which may serve as a highly predictive neural marker for persistent stuttering during early childhood. The findings are expected to elucidate, for the first time, causal mechanisms behind auditory-motor integration deficits in persistent stuttering. Such results will have an important positive impact, as the identified neural mechanisms underlying fluent speech will lay the foundation for effective early intervention for stuttering.

This research is funded through an NIDCD/NIH R01 grant R01DC018283 (PI: Chang)

Rhythm perception and production in people who stutter

Many models of speech timing have proposed that speech, like other motor activities, is rhythmically structured in time. Rhythm can be defined as a pattern of durations marked by a series of events, and perceptually as the temporal organization of the physical sound pattern. One of the hallmarks of skilled motor behavior such as fluent speech production is accurate timing, and the possible critical role of aberrant temporal processing in stuttering has been one of the oldest and most dominant perspectives in the field. However, studies examining temporal processing in children who stutter have been rare. In our studies, we have used a rhythm perception task (auditory perceptual timing) to show that children who stutter exhibit significantly reduced rhythm discrimination performance compared to controls. The task relies on the ability to perceive the temporal organization of a sequence of tones, which taxes intrinsic timing ability (i.e., internal generation of a beat) without the confounding effects of speech production. CWS showed poorer rhythm discrimination relative to controls, especially in the complex condition where the “beats” occurring in rhythms are not explicitly marked and hence require greater internal generation of timing. In addition, CWS showed aberrant brain connectivity involving the cortico-BG networks, and a negative correlation between rhythm discrimination performance and functional connectivity of basal ganglia (BG) and cerebellum (CE). In terms of rhythm production (motor timing), the extant data are conflicting, for example based on tapping task performance in adults who stutter. Examining the relationship between performance on temporal processing tasks and brain connectivity in the “timing networks” that involve both BG and CE circuits is expected to provide breakthroughs in our understanding of the neurobiological bases of timing control deficits that may underlie persistent developmental stuttering.

Combining neuroimaging and behavioral experiments that involve rhythm perception and production tasks, we are conducting parallel series of studies to investigate a novel rhythm deficit hypothesis in stuttering. This study is in collaboration with Drs. Devin McAuley at Michigan State University.

This study is funded by the NIDCD/NIH grant R01 DC011277 (PI Chang), Grammy Foundation and the RAIND (Research in Autism, Intellectual, and Neurodevelopmental Disabilities) pilot grant (PIs McAuley, Chang, Wade, Dilley).

Other projects with U of M and outside collaborators

ERN study on the psychological and neurophysiological risk markers of persistent stuttering in early development (funded by the U of M Center for Human Growth and Development Rauner Family Pilot grant; PIs Fitzgerald and Chang): with Drs. Kate Fitzgerald, Yanni Liu (University of Michigan) and NIDCD R21DC016681 (PI: Liu)

Executive control in children who stutter: With Dr. Amanda Hampton Wray (University of Pittsburgh); funded by NIDCD R21DC015875 (PI Hampton Wray)

Speech motor adaptation to auditory perturbation in children who stutter: With Drs. Frank Guenther, Ayoub Daliri, Shanqing Cai (Boston University)

Imaging-Genetics investigation of developmental stuttering: with Dr. Ho Ming Chow (University of Delaware) and Dr. Jorge Sepulcre (Harvard University/MGH) (Currently funded by the Matthew K. Smith Stuttering Research fund)

tDCS (transcranial direct current stimulation) effects on speech motor learning: with Drs. Benjamin Hampstead, Marom Bikson, Alex DaSilva (Funded by ASHFoundation and the Matthew K. Smith Stuttering Research Fund)

Surface-based analysis of brain morphometry in children who stutter: With Drs. Jason Tourville and Frank Guenther (Boston University)