Influence of gestational age, birth weight, and asphyxia on neonatal neurobehavioral performance.

The objectives of this study were to determine the influence of birth weight, gestational age, and asphyxia on neurobehavioral performance at 40 weeks conceptional age, and to demonstrate that this performance may differ in preterm high-risk infants when using low-risk preterm rather than healthy term infant norms. A cross-sectional comparative design was used to compare neurologic behavior in healthy and high-risk newborns at 40 weeks conceptional age using the Einstein Neonatal Neurobehavioral Assessment Scale. Seventy-four high-risk newborns were selected from a consecutive sample of asphyxiated, very-low-birth-weight, and small-for-gestational-age neonates. Controls did not fulfill any of the high-risk criteria and had no pre- or perinatal complications. There were 37 healthy term and 17 low-risk preterm controls. Statistically significant differences occurred between high-risk newborns and term controls for the total score (P < .001) as well as for most individual items (P < .05). Analysis of high-risk subgroups revealed that small-for-gestational-age and term asphyxiated newborns had the most abnormal responses. When comparing test performance between preterm high-risk and term controls, the majority of test items achieved significance (P < .05); however, when compared to low-risk preterm controls, fewer items were abnormal, and the probability level on abnormal items was less significant than expected. This disparity in interpretation of neurobehavioral status in preterm high-risk neonates using a preterm versus term reference sample warrants further investigation. Appropriate normative standards for preterm infants require definition because it may increase the utility of the neonatal neurologic examination and its prognostic value.