Motor sequence learning, retention and transfer in children who stutter

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Speech is one of the most intricate motor behaviours in humans characterized by very fast and precise articulatory movements. The sensorimotor mechanisms that control speech and its development are not well understood. They are investigated using typical as well as disordered speech production in adults and children. The current proposal focuses on speech production in children who stutter, which is a developmental disorder, typically first diagnosed in prepubescent children, characterized by disruptions of speech fluency. Because it is characterized by both fluent and disfluent speech, the severity of which can be manipulated, it constitutes a natural model for studying speech production and its perturbations. Previous research completed by our group has shown that stuttering adults show a deficit in their ability to acquire novel motor sequences. Because this is apparent in both speech and nonspeech behaviour we have hypothesized the presence of a generalized motor deficit. This observation allows us to use nonspeech motor tasks to gain insight into processes that are important for speech production also. However, data obtained in adults may not necessarily be relevant to younger children who are still developing their motor skills. We plan to extend our earlier research by investigating speech and nonspeech motor learning in children who do and do not stutter. A number of studies will be completed investigating children's abilities to learn novel speech and nonspeech (finger tapping) sequences. Motor practice will be presented either explicitly (children are told what to practice) or implicitly (children are not aware of the practice task). In addition, experiments are proposed which manipulate the frequency of feedback provided during task completion. Finally, a functional magnetic resonance imaging study is proposed to analyze the neural processes underlying motor learning in children. The results from this study will allow us to contribute to the understanding of the development of speech motor control processes and to gain a deeper understanding in the processes that may underlie disordered speech.