Cognitive development in preterm and fullterm infants.

Abstract

The purpose of this project was to investigate four markers of early cognitive development in preterm and fullterm infants with uncomplicated pre- and peri-natal medical histories. These included object memory, location memory, memory and manual search, and inhibitory control of reaching. In addition, the relation between behavioral organization at term and the development of these abilities was investigated. For all test sessions, the PT infants were tested at corrected age (age since expected due date) rather than chronological age (age since birth). The Assessment of Preterm Infant Behavior (APIB) was used to measure regulation of attention, orientation to visual stimuli, motor functioning, and modulatory abilities at 2 weeks corrected age. At 2.5, 4.5, and 6.5 months corrected age, each infant was tested on Visual Paired Comparison and Visual Search. At 8.5, 10.5, and 12.5 months of corrected age each infant was tested on A-not-B and Object Retrieval. Successful performance on VPC and VS is thought to depend on the functional development of the object vision and spatial vision systems, respectively. Successful performance on A-not-B and OR depends on the functional integrity of the dorsolateral prefrontal cortex. FT infants evidenced better performance on all domains of functioning measured by the APIB. While the infants did not evidence object memory at any age tested, which was attributed to difficulty of task demands, they did evidence location memory at all ages tested. There was not a direct effect of PT birth on VPC or VS performance. However, there was an indirect effect of PT birth, mediated by APIB performance, on attention behaviors during both tasks. There was not a direct effect of PT birth on A-not-B or OR performance. However, there was an indirect effect of PT birth, mediated by APIB performance, on the development of OR abilities. These findings indicate that group differences in behavioral organization at 2 weeks of age differentially predict rates of development on some cognitive tasks. Finally, the overall pattern of results indicates that uncomplicated PT birth does not alter the functional development of the neural systems studied.