The neonatal behavioral assessment scale as a biomarker of the effects of environmental agents on the newborn

Abstract

The organization of the newborn's brain and the nature of the effects of toxins and pollutants conspire to produce complex and difficult problems for the assessment of the behavioral effects of environmental agents. The newborn's brain can be characterized as relatively undifferentiated, and more vulnerable to, but potentially more capable of recovery from, the effects of environmental agents specific to this time period than it will be later in development. Environmental agents tend to have nonspecific, possibly subtle, effects that invade many areas of newborn functioning. These characteristics of the newborn and the behavioral effects of teratogens make assessment at this point in development difficult. Further exacerbating this difficulty is the nature of development. Development is critically dependent on the care the newborn receives. Distortions of a newborn's behavior can produce disturbances in the caretaking environment, and these caretaking disturbances can amplify the original behavioral distortion and produce other distortions. Attention to these types of effects must be built into an assessment. These considerations lead to the conclusion that an apical assessment of newborn behavior is required. The most standardized, valid, and reliable instrument currently available is the Neonatal Behavioral Assessment Scale developed by Brazelton. It assesses the integrated actions of the infant that function to regulate simultaneously the infant's internal state and exchanges with the animate (caretaking) and inanimate environment. The scale uses a set of reflex and behavioral items to assess the critical domains of infant functioning (e.g., the infant's ability to control his states of consciousness). It has been found to be sensitive to the behavioral effects of known teratogenic agents (e.g., PCBs) and to the potential disturbances in caretaking produced by them. However, because no single assessment is likely to be sufficient, a strategy may be needed in which the effects detected by repeated application of the Neonatal Assessment are followed up with more specific assessments of those effects, such as acoustical cry analysis.