Refinement of Speech Breathing in Normal Young Children
C Boliek, T Hixon, P Watson, P Jones
Speech breathing, like any other motor skill, can be conceptualized as progressing through periods of emergence, refinement, and adaptation. The emergent breathing characteristics associated with vocalizations from infants and young children are different from the adult-like speech breathing behaviors observed in children at age 10 years. Speech breathing function involving the earliest portion of the refinement period, particularly during unencumbered conversational speaking, is not well understood. Sixty children, 10 boys and 10 girls each at ages 4, 5, and 6 years participated in this study. We acquired calibrated kinematic measurements of the chest wall during conversational speaking. Eighteen speech breathing variables were derived for each breath group. We found that: (a) there were no sex differences, (b) lung volume events often occurred in the midrange of predicted vital capacity and became less variable with increasing age, (c) percent rib cage contribution to lung volume excursion remained variable within and across age groups, and (d) older children produced more syllables per breath group with greater valving efficiency than younger children. These data offer a better understanding of the development of neuromotor control for speech breathing and provide normative information that will be useful as a standard for clinical evaluation and management of young children with breathing-based speech disorders.