What is stuttering?
Developmental stuttering — from here, “stuttering” — emerges during early childhood and manifests itself most saliently as intermittent interruptions in speech. The intermittency or variability of stuttering is arguably the most challenging aspect for researchers, clinicians, and most importantly, people who stutter. Imagine being able to say your name with ease while alone or with your pet, but struggling to introduce yourself when meeting a new classmate or co-worker. Navigating the minefield of stuttering can be overwhelming for those who stutter, especially younger speakers who are susceptible to teasing and bullying. Stuttering and how one responds to it can significantly negatively impact academic, career, and social opportunities for those who stutter. Approximately 3 million Americans and 50 million individuals worldwide stutter.
Source of variability…
Anticipation and Social Interaction are primary sources of stuttering variability, though they operate at different levels.
Anticipation refers to the awareness a speaker has that upcoming speech will be stuttered, should that speech be executed as planned. With this awareness, the speaker can choose to disguise, conceal, or modify stuttering by stalling or switching words, or using a speaking strategy. In these instances, stuttering occurs but may not be noticeable to the listener.
Social interaction involves the exchange of information between speakers and their listener(s). An individual may stutter on a particular word with one individual or in one context, but not stutter on that same word with a different individual or in a different context. The impact of social interaction is unique to the speaker as speakers have individual social experiences, and the role of social interaction changes throughout development. Thus, social interaction triggers the underlying stuttering event which reflects a neural-behavioral-environmental integration problem, whereas anticipation shapes the resulting stuttering behavior. In the savvy lab, we study the variability of stuttering and its sources (i.e., social interaction, anticipation) at neural, behavioral, and environmental levels.
Stuttering and the Social Brain – In collaboration with Dr. Joy Hirsch and her team at the Yale Brain Function Laboratory, we are using functional near-infrared spectroscopy (fNIRS) to identify the neural correlates of stuttered and non-stuttered speech in adults (and soon, children) during face-to-face interaction. In addition, we are studying a phenomenon called private speech (i.e., speaking out loud but not addressing anybody, either actually or in thought). Interestingly, for the most part, people do not stutter when engaging in private speech. We are testing the hypothesis that stuttering requires communicative exchange, with real or imagined listeners.
Stuttering Anticipation and Links to Temperament – This work examines stuttering anticipation and characterizes and quantifies responses to anticipation in children and adults who stutter. In collaboration with Dr. Patricia Zebrowski and doctoral students Naomi Hertsberg Rogers and Hope Gerlach, this work has led to the development of a clinical tool, the Stuttering Anticipation Scale (SAS), that assesses responses to stuttering anticipation in children and adults who stutter. In addition, we are exploring the link between temperament and anticipation in children and adults.
Quantification of Speech Variability – This work extends Dr. Jackson’s dissertation work which introduced a novel approach, recurrence quantification analysis (RQA), to assess kinematic variability in speakers who stutter and those who do not. We are currently exploring the use of RQA with other signals (e.g., acoustic, autonomic).