Pre- and posttreatment comparison of the kinematics of the fluent speech of persons who stutter.

This study reports changes in acoustic, respiratory, laryngeal, and articulatory kinematics of 3 males who stutter, following participation in a version of the Hollins Precision Fluency Shaping Program. Two nonstuttering controls received no treatment. Subjects repeated phrases of the form "He see CVC again" at self-selected slow, normal, and fast speaking rates. For experimental subjects, acoustic duration of the phrases increased significantly in 7 out of 9 comparisons of before- and after-treatment conditions, whereas controls decreased the duration of the phrases in 4 out of 6 comparisons of measurements made over approximately the time interval during which the experimental group received treatment. The experimental group increased inspiratory volume for 7 out of 9 conditions and average expiratory flow significantly for all conditions, whereas the controls decreased both. The experimental group prolonged laryngeal opening in 6 of 7 comparisons, but only 3 of the increases were significant. Lip and jaw movements for consonants were significantly reduced in amplitude for the experimental group for 30 of 36 measures. The direction of change for laryngeal and upper articulator measures was mixed for controls. These results show that behavioral treatment can produce significant changes in the fluent speech of persons who stutter with respect to respiration, laryngeal valving, and articulation. Possible relationships between the observed changes in speech production and the increased fluency of the subjects are discussed.