Some developmental aspects of infants cry.
Respiratory activity during crying was measured in a semilongitudianl study of 10 normal infants aged two days to eight months. Temporal aspects of respiration during crying showed marked change with age: athe duration of the expiratory phase steadily increased, while the duration of the inspiratory phase remained remarkable constant, producing an ever-lower I-fraction. A previous study reported no developmental changes in the temporal aspects of the acoustic cry signal from one to seven months of age. Reasons for the divergent findings of the present study arepresented, and it is suggested that respiratory behavior may be a better indicator of developmental changes in the crying act thanthe acoustic signal.
D002657:Child Development; D003448:Crying; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D012119:Respiration