An acoustical analysis of infant crying

The crying sounds of a group of healthy infants, a group of apneic infants, and a hypoglycemic infant were evaluated using frequency spectrum analysis. These crying sounds were recorded while the infants were in both the prone and supine positions. The frequency analysis revealed that the fundamental frequency of apneic infant cries was significantly higher than the fundamental frequency of healthy infant cries, The fundamental frequency of the cries of the hypoglycemic infant was significantly less than that of the healthy infants. No significant correlation was found between positioning of the infant and the fundamental frequency of the cry. More broad-band noise was found in the frequency spectra of the apneic group and of the hypoglycemic patient than in the spectra of the healthy infants. Nineteen out of twenty healthy patient frequency spectra were dominated by tones. One apneic patient exhibited crying sounds that were dominated by tones in the prone position but the spectra were dominated by broad-band noise in the supine position, while another apneic infant had crying sounds that were dominated by broad-band noise in the prone position and cries that were dominated by tones in the supine position. No correlation between health status and overall-sound-pressure-levels of the crying sounds was found.