Graduation Year


Document Type




Degree Granting Department

Communication Sciences and Disorders

Major Professor

Nathan D. Maxfield


Activation Spreading, Adults who Stutter, Attentional Control, Event-Related Potentials, Lexical Access, Masked Picture Priming



Objective: The aim of the present study was to investigate mechanisms of real-time language production of adults who stutter.

Method: Data were analyzed for 19 typically fluent young adults (TFA) and 19 young adults who stutter (AWS). Participants performed a masked picture priming task where priming stimuli consisted of two conditions 1) Identity- a masked printed prime word identical to the picture target label, and 2) Unrelated- a masked printed prime word unrelated to the picture target label. Brain event-related potentials (ERPs), time-locked to pictures eliciting spontaneous naming, were recorded, as well as naming accuracy and reaction times.

Results: Masked priming effects on ERP components were compared between groups. Priming modulated N400 amplitude in TFA while, at the same latency, priming modulated P300 amplitude in AWS. N400 is attributed to processing of meaningful stimuli, and P300 is a measure of effortful control. An even later priming effect generalized to both groups.

Conclusion: Results suggest that post-lexical processing was similar in AWS and TFA, while lexical-semantic processing operated differently. Whereas TFA evidenced automaticity in activation and selection of target picture labels, AWS evidenced enhanced attentional control during lexical selection. We propose that AWS recruited a compensatory attentional mechanism to stabilize activation of target words on the path to naming. These conclusions suggest that clinically, AWS may benefit from vocabulary enrichment and attentional control treatment.