Effect of intensive care unit exposure on temperament in low birth weight preterm infants.

This study examined the hypothesis that low birth weight, preterm infants, owing to their severe illness and exposure to intensive care units (ICU), are predisposed to a more difficult temperament. Temperament was compared among three groups (n = 92): high-risk (HR) preterm infants (mean birth weight 1244 g), low-risk (LR) preterm infants (mean birth weight 2050 g), and full-term (FT) infants (mean birth weight 3159 g). Mothers completed the Infant Temperament Questionnaire (ITQ) when infants were 6 months (adjusted) old. The most striking differences were in mothers' subjective ratings of their infants: 21% of the HR mothers rated their infants as more difficult than average, compared to 4% of full-term and 0% of low-risk preterm mothers. By contrast, according to objective rating, HR infants met none of the ITQ criteria for the diagnostic category of "difficult." However, HR infants did have less favorable scores in mood, adaptability, persistence, and distractibility than LR and FT. When the HR group was further analyzed, differences in mothers' objective ratings were accounted for by length of hospitalization, while differences in mothers' subjective ratings were accounted for by severity of disease. Results suggest that, in our sample, exposure to ICU may have led to some temperament differences, but its effect was more pervasive on parents' perceptions of their infants.

Patterns of looking behavior in full-term and low birth weight infants at 40 weeks post-conceptional age.

Given the usefulness of visual behavior as an assessment method in older infants, a simple method of visual behavioral evaluation applicable in clinical settings was utilized to gather descriptive data on 42 infants at term. Using an "infant control" method for determining the duration of stimulus presentation, a series of four patterned targets was presented to 25 healthy full-term (FT) and 17 low birth weight (LBW) infants at 40 weeks postconceptional age. Infants were examined in their nursery cribs, and each stimulus was presented until the infant reached a criterion of a 50% or greater decrement in looking time. LBW infants looked for longer time periods, without pause, than FT infants; LBW mean trial length was twice that of FTs. Although total looking time was longer for the LBW group, LBW infants took twice the length of time as FTs to reach the decrement criterion for the first target and thus viewed fewer targets than FT infants. Despite the longer looking of LBW infants, only 41%, as compared to 56% of the FT group, showed an increase in looking time when a new stimulus was presented. The quality of LBW infants' visual behavior was more often marked by long, continuous looking at the same pattern, in contrast to shorter, more discrete and rapidly decrementing looks by the FT newborn. While there was a large variability within groups, the differential patterns of visual behavior are considered likely to reflect variations in processing of information, possibly associated with differences in integrity or maturation of the visual system.