Developmental changes in respiratory and laryngeal function during Fo and intensity modulation

By K.J. Reilly, C.A. Moore, R.W. Steeve, K.P. Connaghan, and K.A. Burkard

This research proposal is designed to investigate respiratory and laryngeal functioning during changes in fundamental frequency (F_O) and intensity in groups of 7 month olds and adult speakers. Increases/decreases in F_O and intensity are elicited by auditory feedback manipulation of subjects’ fundamental frequency, intensity, and signal-to-noise ratios (i.e., Lombard effect) during a vowel imitation task. The magnitude and peak velocities of F_O and intensity changes are analyzed to determine whether ascending F_O and intensity contours are acquired later than descending contours or whether both types are present by 6 months of age. Although changes are elicited in only one parameter (e.g., F_O), corresponding changes in the non – target parameter (e.g., intensity) will be used to provide information regarding the extent to which F_O and intensity are differentially modulated. Co-occurring changes in chest wall configuration provides insight into the nature of respiratory support for these behaviors. Specifically, the proposed investigation will examine whether infants and young children alter the posturing of their chest wall during changes in F_O and intensity, whether different chest wall configurations are used for F_O vs. intensity modulation, and how such alterations are partitioned between the abdomen and rib cage.