Selected temporal parameters of coordination associated with stuttering in children

The purpose of this investigation was to describe specific temporal parameters of coordination—onsets and sequencing of muscle activity and structural movement—associated with five young stutterers' stuttered ( N = 96) and five normally fluent children's fluent ( N = 96) speech productions. Simultaneous recordings of physiological events in the three major components of the speech production system (respiratory, laryngeal, and supralaryngeal) were made using noninvasive, minimally intrusive instrumentation. Measurements of onsets, offsets, and durations of respiratory and laryngeal movements and supralaryngeal muscle activity permitted objective assessment of coordination within a particular component of the speech production system (e.g., onset of lower lip closing relative to lower lip opening muscle activity) and between different components of the speech production system (e.g., onset of rib cage deflation relative to onset of vocal fold contact). Results indicated that, during stuttering, the absolute mean onsets of young stutterers' various speech production events were typically earlier than those during normals' fluent utterances; however, the relative temporal sequence of these same events during stutterings was comparable to that associated with normally fluent children's fluent productions. These findings suggest that young stutterers are grossly within normal limits with regard to selected temporal aspects of coordination for speech production, a finding in contrast to previous reports of adult stutterers' apparent difficulties in coordinating multiple components for speech production.