Research in the Speech Disfluency Laboratory (SDL) is generally aimed at acquiring a better understanding of the underlying origin and development of childhood stuttering. The primary focus of our research is on domain-general cognitive processes, spoken language production, and fluency development. The studies associated with these lines of research are further described below.

Cognitive-Linguistic Processes in Developmental Stuttering

The SDL is currently conducting a series of projects, funded by the National Institute of Health (NIH, R01DC012517), to determine the role of cognitive-linguistic processes in preschool children who do and do not stutter.

Project 1: Executive Function

The purpose of this research is to identify the role of executive function in developmental stuttering. The specific aims are to examine (a) children's ability to supress an inappropriate response or to ignore irrelevant information, (b) phonological and semantic contributions to verbal short-term memory, and (c) cognitive flexibility for categorical and perceptual information. This research will provide critical new information about the nature and extent to which executive function contributes to the development of stuttering in preschool children.

Project 2: Controlled Attention

This research aims to define the role of verbal and nonverbal auditory sustained and/or selective attention, which are critical to the development of executive function and spoken language, in developmental stuttering. This project will provide insights into the ability of children who do and do not stutter to focus and maintain attention, particularly in response to changes in verbal demand.

Project 3: Interaction Between Domain-General Processes and Spoken Language Production

The objective of this research is to determine how semantic and phonological spoken word processes interact with executive function--namely, verbal working memory--and controlled attention in developmental stuttering. Findings from this project will advance our understanding of the language processing skills of children who stutter and their relationship to the domain-general processes of verbal working memory and attention.

In general, findings from these projects will provide an explanatory framework for better understanding the role of multiple factors in developmental stuttering and contribute to models of domain-general processes in typical development. This knowledge will ultimately lead to the development of more effective, innovative approaches for treating childhood stuttering.

Spoken Language Development in Childhood Stuttering

In addition to the NIH-funded series of projects described above, we are conducting several other investigations related to (a) lexical-sublexical knowledge effects on the nonword repetition performance of children who stutter, and (b) the effect of utterance and word level factors on the fluency of speech production.