Integrating Cognitive and Sensorimotor Systems in Stuttering and Speech Production

University Of Iowa, Iowa City IA

Investigators

Abstract

The Directorate of Social, Behavioral and Economic Sciences offers postdoctoral research fellowships to provide opportunities for recent doctoral graduates to obtain additional training, to gain research experience under the sponsorship of established scientists, and to broaden their scientific horizons beyond their undergraduate and graduate training. Postdoctoral fellowships are further designed to assist new scientists to direct their research efforts across traditional disciplinary lines and to avail themselves of unique research resources, sites, and facilities, including at foreign locations. This postdoctoral fellowship supports a rising scientist in the interdisciplinary area of speech production, cognitive science and neurocomputational modeling. Speech production is a complex skill that hinges on the real-time integration of cognitive and sensorimotor processes. Contemporary models of speech production pay little attention to salient cognitive processes such as intention, attention, and awareness. One way to further basic understanding of the critical link between cognitive and sensorimotor systems during speech production is to examine typically and atypically developing systems. This project investigates stuttering, a neurodevelopmental speech disorder, by leveraging the well-known phenomenon of anticipation. Anticipation refers to the a priori sense a speaker has that upcoming speech will be stuttered. Examining anticipation and speech behavior through the lens of a pathological system (i.e., a stuttering system) will ultimately shed light on a basic question in speech research?how cognition, perception, and action underlie speech production and its development. Findings from this work will also have real-world applicability as they will support the development of tailored diagnostic and clinical procedures for those who experience stuttering and its related social and emotional consequences. This innovative work combines computational modeling and empirical investigation to develop and test a model of stuttered speech production. It applies principles of Dynamic Field Theory (DFT), an established neurocomputational approach to modeling that formalizes the relationship between cognitive and sensorimotor systems. DFT has benefitted from recent advances in cognitive science, mathematical biology, motor control, developmental psychology, and theoretical neuroscience, highlighting the multidisciplinary nature of this work. Critically, DFT integrates real-time processes with processes of learning and development. Thus, the framework is poised to contribute to an understanding of the relationship between in-the-moment speech behaviors and their cognitive underpinnings that often occur over longer timescales, and are more difficult to observe. The experimental component of this project employs optical tracking and functional near-infrared spectroscopy, allowing for direct comparisons at behavioral, kinematic, and neurophysiological levels. Specific aims of this project include: (1) extending a preliminary DFT-based model of typical speech production, as well as attempting to break the model in ways that are reflective of stuttering; and (2) testing the model empirically in a cross-sectional study that examines the development of anticipation of stuttering across the life span. This proposal is also supported by the NSF EPSCoR.