Effects of preterm experience on the developing visual system: a longitudinal study of shifts of attention and gaze in early infancy.

Several studies on visual development support the notion that healthy, low-risk preterm infants benefit from their early exposure to the visual world. It has been suggested, however, that mainly early developing sensory and motor processes are enhanced as a result of visual experience and early exercise, whereas later maturing processes might not. This study investigates whether preterm infants' visual and attentional development is accelerated as a consequence of their early visual experience and whether early and later maturing processes are affected differently. Preterm and full-term infants' performance on a gaze and attention shifting task was examined during the first six months of life. Until about 16 weeks post- term, preterm infants were faster in disengaging and shifting their attention and gaze from a stimulus in their central visual field to the periphery, whereas no difference was found for simple gaze shifts without disengagement. This finding is in contrast to earlier accounts that only early developing mechanisms might be advanced as a result of additional visual experience, whereas later developing cortical processes might depend mainly on preprogrammed maturation processes. However, it is consistent with a number of findings on visual, motor, and speech development, which have indicated accelerated cortical functioning in healthy preterm infants before.