From Eye to Mind : Early Visuomotor Performance and Developmental Trajectories in Children Born Preterm

Children born very preterm, at less than 32 weeks of gestation, have an increased risk of developing problems with attention, cognition, perception and motor function. Despite this, the developmental trajectories leading from preterm birth to later impairments are not fully understood. This thesis focused on investigating the development of the visuomotor system in infants born very preterm, in relation to neurodevelopment at 2.5-3 years (including cognitive, language and motor functions) and 6.5 years (including cognitive functions and attention). Two early visuomotor functions were investigated: at 4 months of corrected age we looked at their visual tracking of moving objects and at 8 months of corrected age we examined how they reached for moving objects. Visual tracking performance is the ability to follow, sustain attention on and predict the future positions of a moving object. When infants reach for moving objects, these requirements are enhanced by movements of the arm and hand. This was a prospective, population-based cohort study of children born very preterm in 2004-2007, who were longitudinally assessed from the neonatal period until 6.5 years of age. The results showed that the two most important early visual tracking parameters were gaze gain, which is effectively combining eye and head movements to follow the trajectory of the object, and timing of gaze to the motion of the object. Gaze gain correlated with neurodevelopment at 2.5-3 years and with cognition and attention at 6.5 years. Early reaching was also related to outcomes at 2.5-3 years, but the pattern differed for children born before and after 28 weeks of gestation. Parameters of prediction and movement planning were the most important factors for the children of the lowest gestational age, but strategies and success had greater associations with later function in those who were less premature. The results confirmed that children born very preterm in the first decade of the 2000’s still faced increased risks of developmental delays. Early visual tracking performance, and reaching for moving objects, were shown to be important visuomotor functions in the developmental process of children born very preterm. The studies in this thesis illustrate how early basic functions were related to different neurodevelopmental areas at a later stage and offer important new insights into developmental trajectories of children at risk of developmental impairments. These findings suggest that attention and predictive elements of adjusting one´s movements to motion, may be key mechanisms and possible targets in future intervention studies