Acoustic characteristics of crying in infantile laryngomalacia.

The purpose of this study was to add to the extant data base of acoustic cry studies by profiling the condition of laryngomalacia. We hypothesized that the acoustic characteristics of crying produced by an infant with laryngomalacia would differ compared to previously reported cry data for normal infants. An entire episode of crying was audio recorded and acoustically analyzed for the occurrence of expiratory and inspiratory cry segments, as well as the long-time average spectral (LTAS) characteristics. Results obtained for the infant were found to be considerably different from what has been previously reported for normal infants. The overall duration of the infant's crying episode was longer, with proportionately fewer expiratory phonations and more inspiratory phonations compared to normal infants. The LTAS results were reflective of aperiodic components in the glottal source spectrum. Collectively, the infant's unusual crying aspects were not limited solely to those acoustic features resulting from a prolapse of supraglottic soft tissue, and therefore provide new insight into the vocal fold vibratory behavior characterizing infantile laryngomalacia.