New Evidence on Unexplained Early Infant Crying by Ronald G. Barr

After a feed, infants with colic were calmed less by both sucrose and water. Before a feed, these differences in calming were specific to sucrose taste. These differential effects could not be accounted for by differences in crying when the stimulus was applied or by differences in mouthing behavior. As predicted, infants with colic were less effectively calmed by sucrose taste than infants without.

Consequently we predicted that, if the regulation of crying by sucrose taste is relevant to the crying of infants with colic, calming responses to sucrose taste should be less effective in 6-week-old infants with colic compared with those without.Īs in newborns, a significant calming effect of sucrose taste that persisted beyond the cessation of mouthing could be elicited in crying 6-week-old infants, but it required a stronger taste stimulus to do so. Third, effectiveness of sucrose calming diminishes in normal infants by 4 to 6 weeks of age, consistent with the developmental increase in crying duration common to infants with and without colic. Second, convergent evidence from studies in both nonhuman and human infants suggests that sucrose calming reflects the function of central distress regulatory systems that are opioid-dependent. First, sucrose taste has been shown to be a potent regulator of crying in human newborns. To investigate this difference objectively, we used response to sucrose taste as a probe of colic-normal differences in regulation of crying for three reasons. This implies that, once infants with colic begin crying, they do not calm as well as infants without colic. Both clinical anecdotal descriptions and controlled observations converge in suggesting that a defining characteristic of the crying behavior is the longer duration of the crying bouts, especially during the second month of life when colic is at its peak. Colic is a behavioral syndrome of early infancy of unknown etiology whose core symptom is increased crying.

New Evidence on Unexplained Early Infant Crying by Ronald G. Barr