Phonation in the newborn, infant cry.

Sound spectrographic studies have shown that the crying of newborn infants has a fundamental frequency of about 400-600 cycles per second, and mostly a slightly rising-falling melody contour. In sick infants, and especially those with diseases affecting the central nervous system, abnormal cry characteristics occur. The fundamental frequency has been increased, and the melody contour is unstable. Various cry characteristics, which rarely occur in cries of healthy infants, are more often present in cries of the sick ones. Studies of cries in newborn infants have been especially aimed to determine whether cry analysis could be successful in diagnostics and in the early detection of the infant at risk for developmental difficulties.