The developmental course of behavioral states in preterm infants: a descriptive study

This study describes longitudinal changes in observable states of 58 preterm infants, 29-40 weeks conceptional age, after various forms of stimulation were given during a standardized neurologic examination. The states used in this investigation were considered only in terms of observable behavior. The data indicate that regardless of conceptional age, the level of arousal increased as the examination progressed. Both the rapidity of change from lower to higher states and the predominant highest state reached were clearly dependent upon conceptional age. No relationship between length of extrauterine life with states at 40 weeks was found.