Poster C42, Friday, August 17, 10:30 am – 12:15 pm, Room 2000AB
Exploring neural organization for two different auditory-motor tasks in typical adults and adults who stutter.
Anastasia Sares1,4, Mickael Deroche1,4, Hiroki Ohashi2, Douglas Shiller3,4, Vincent Gracco1,2,4;1Integrated Program in Neuroscience and School of Communication Sciences and Disorders, McGill University, Montréal, QC, Canada, 2Haskins Laboratories, New Haven, CT, USA, 3School of Speech-Language Pathology & Audiology, Université de Montréal, Montréal, QC, Canada, 4Centre for Research in Brain, Language, and Music, Montreal, QC, Canada
Introduction: Persistent stuttering is a neurodevelopmental disorder that starts as early as two years of age and continues through adulthood. The potential impact of the disorder on the development of neural networks is unknown, although recent resting state connectivity analyses are consistent with atypical functional organization (Chang et al., 2017). The current project is focused on examining the impact of the disorder on the neural organization of sensorimotor networks for speech and nonspeech. We examined the behavior and brain contributions of individuals who stutter (IWS) to two auditory-motor tasks, vowel production and paced tapping. We examined the task positive and task negative networks for each behavior and evaluated the independent components that comprise each. Methods: For the speech task, participants produced the vowel /a/ while hearing their own voice in real time through headphones. On some trials, the pitch of the feedback was shifted, eliciting a compensatory response. For the tapping task, participants listened to a metronome stimulus and kept time by squeezing a pressure pad between their fingers. The metronome stimulus contained sudden increases or decreases in tempo, and the participant had to adjust their production to the change. Both tasks were completed inside and outside of an MRI scanner. In addition to a univariate general linear modeling (GLM) approach to examine both task positive and task negative differences in the groups, we used independent component analysis (ICA) to extract information from the data not apparent from GLM results. Results: The behavioral performance for both tasks was comparable across the groups. Differences in performance were primarily related to increased timing variability in the stuttering group. Neural activation and deactivation and the composition of the independent positive and negative components differed in a number of ways. For the speech task, IWS had, on average, reduced cerebellar and supplementary motor area activation, and increased insular and temporal cortical activation on the right hemisphere. Areas of deactivation were differentially distributed and sometimes missing for IWS. For tapping, similar neural patterns were observed in auditory-motor integration areas. Differences in the independent components were observed reflecting an atypical neural organization for the IWS with different patterns of correlated-anti-correlated connectivity within components. Conclusion: While the sensorimotor behavior of IWS is only mildly impacted by the disorder, functional neural organization is substantially affected, likely reflecting compensatory development. These differences were observed in speech and nonspeech behavior, possibly due to a common impact on sensorimotor timing. The atypical neural organization, including differences in distribution and balance of task activation and deactivation, highlight an importance consequence of neurodevelopmental problems with substantial implications for treatment. Chang, S. E., Angstadt, M., Chow, H. M., Etchell, A. C., Garnett, E. O., Choo, A. L., ... & Sripada, C. (2017). Anomalous network architecture of the resting brain in children who stutter. Journal of fluency disorders.
Topic Area: Language Disorders