Behavioral outcomes of environmental or care‐giving hospital‐based interventions for preterm infants: a critical overview

For many years the primary goal in Neonatal Intensive Care Units (NICU) has been to improve survival rates. With increased survival rates in this population there has been a shift in emphasis from survival only to improved quality of life. The high-technology environment of the NICU is strikingly different from the intrauterine milieu. It is conceivable that the imposed stay in the NICU environment, even in the absence of major medical complications, could have an impact on the future development and behavior of the neonate, either directly, or through the experience of the parents and their subsequent parenting skills and expectations. Beginning in the 1960s, researchers have investigated the effect of the NICU environment on shortand longterm development of the preterm infant. Some investigators have hypothesized that the NICU environment is a source of sensory deprivation for the preterm infant ( 1 ) and consequently various types of stimulation (auditory, kinesthetic, tactile, vestibular/proprioceptive, visual) have been offered. Field (2) reviewed 23 studies on supplementary stimulation of preterm neonates, most of which cited some benefits for the stimulated infants, ranging from weight gain and changes in activity level to better performance on developmental assessments. However, some of these effects were transient. The most sustained effects were demonstrated in studies when the stimulation was continued after the infant was discharged home. Field (2) identified many methodological concerns in the reviewed studies including: selection of subjects, lack of information about the environment in the NICU and the outcome measures. Ottenbacher et al. (3), in a meta-analysis on the effectiveness of tactile stimulation for “at risk” infants, concluded that infants who received some form of controlled tactile stimulation performed better than controls. However, they identified methodological problems such as missing data and lack of long-term follow-up of infants and found that larger treatment effects were associated with poor study design and with studies in which the internal validity was rated as poor. In addition to the effects of stimulation, researchers have investigated the impact of other changes in the infant’s environment or care on the overall development of the infant. These have included positioning of the infant, reduction of handling of the infant, care based on the infant’s behavior, maternal education about the infant’s behavior and the use of non-nutritive sucking. Most NICUs have not instituted sensory stimulation programs on a regular basis. An increasing number of units are adopting programs based on a developmental care model. This model uses individual assessments of an infant’s responses to care-giving and environmental stimulation to determine appropriate interactions and interventions. The purpose of this overview is to review controlled studies published since the 1980 review of stimulation studies by Field (2) and to expand the review to studies which explored the use of any tospital-based intervention that was designed tg aher the preterm infant’s environment or care-giving and which had behavioral outcome measures.