Object permanence and the development of attention capacity in preterm and term infants: an eye-tracking study

Background: The relationship between premature birth and early cognitive function as measured by eye-tracking data remains unexplored. The aim of this study was to determine the effect of prematurity on the development of object permanence and attention capacity using eye-tracking measures. Methods: We prospectively studied very low birth weight (VLBW < 1500 g) preterm infants who were admitted to the Neonatal Intensive Care Unit of Hanyang University College of Medicine, Seoul, Korea and visited a follow-up clinic. Using eye-tracking measures, object permanence was assessed in 15 VLBW preterm and 10 term infants at a corrected age of 6–10 months, and attention capacity was measured in 26 VLBW preterm and 18 term children who were age-matched for the corrected age of 6–10 or18 months. Results: No differences were found in chronologic age (corrected age for prematurity), sex, or maternal education between the study groups. The VLBW preterm infants had lower scores than term infants on eye-tracking measures of object permanence than the term infants did at 6–10 months (P = 0.042). The VLBW preterm infants had a shorter referential gaze than the term infants did at 6–10 months (P = 0.038); moreover, the length of referential gaze of the VLBW preterm infants was significantly lower at 6–10 months than at 18 months (P = 0.047), possibly indicating a delayed trajectory of attention development. Conclusion: The VLBW preterm infants have different attention capacities and object permanence developmental markers than term infants at the corrected age of 6–10 months.