The cry characteristics of an infant who died of the sudden infant death syndrome.

Fourteen cries of a four day old infant who subsequently died suddenly of unexplained causes were analyzed on nine acoustic characteristics including fo, duration, formant frequencies and sound pressure level. In comparison to a group of newborn controls, the Sudden Infant Death Syndrome (SIDS) victim's cries exhibited a lower fo, longer duration, lower formant frequencies and greater sound pressure level throughout the spectrum. Cry duration and sound pressure levels, however, deviated in excess on one standard deviation from the mean of the other newborns. Similar findings resulted when the SIDS infant was compared to a group of full term infants who were siblings of SIDS victims, although the magnitude of the differences was slightly less especially with respect to sound pressure level. Measurement of selected acoustic variables in a newborn's cry may be of value in our understanding of SIDS and for identifying infants at risk.