The relationship between stuttering severity and kinesthetic acuity for jaw movements in adults who stutter

Abstract

Previous research using a minimal movement paradigm has suggested a deficiency in the processing of oral kinesthetic sensations in adults who stutter. In the present study, the relationship between oral kinesthesia and stuttering severity was investigated. Eight stuttering adults (four very mild and four moderate/severe), and four normally fluent speakers were instructed to make the smallest possible movements with the jaw, both with and without continuous visual feedback. The adults with very mild stuttering showed a significantly larger increase in jaw displacement from the visual to the nonvisual condition compared to the normally fluent control group. Significant group differences also were found for movement duration. When only proprioceptive information was available to judge articulatory movements, the adults with moderate/severe stuttering took significantly longer than either of the other two subject groups to complete movements of the jaw. While providing partial support for the hypothesis that adults who stutter have a reduced oral kinesthetic acuity, the present data confirm previous findings that the most robust differences between stuttering and nonstuttering adults are observed for the movements of the jaw. The significance of this observation for our understanding of the role of temporal discoordinations in stuttering is discussed.