Consistency and change in the development of premature infants weighing less than 1,501 grams at birth.

Ninety-four infants with birth weights less than 1,501 g were evaluated on neurologic functioning and mental abilities at 1 year and, again, at 3 to 4 years of age. Results of the examination showed high correspondence in neurologic status and in mental ability between infancy and the preschool period, particularly for children who were diagnosed as clearly normal or abnormal at 1 year. In addition, poorer performance in a test of infant mental ability (which relies primarily on sensorimotor skills), in motor skills, and in neurologic functioning, respectively, were linked to lower IQ, difficulties in expressive language, and articulation deficits at the preschool age. Socioeconomic status predicted 3-year IQ scores and changes in mental ability scores but was not a factor in determining either preschool age neurologic status or changes in neurologic status in the children studied. Socioeconomic status of the children was less predictive of preschool outcome than results of the 1-year examinations.