INDIVIDUAL PAPER AND INDIVIDUAL POSTER: ABSTRACT SUBMISSION FORM (C) XIIth European Conference on Developmental Psychology Submission Deadline: December 1, 2004 Please indicate what type of abstract you are submitting by putting an “X” on the appropriate line either _x_ Individual Paper _x_ Individual Poster Max. 200 words. Font: Times New Roman, 12 points. Please send your abstract by e-mail or regular mail. Title of the individual Paper/ Poster: Differences in Developmental Trajectories as a Function of Age and Weight at Birth in Premature Infants M. Gardner1,2, Bernard Z. Karmel1,2, Anthony Barone2, Anantham Harin2, & Michael J. Flory1 Name(s): Judith Address of Institution(s): 1NYS Institute for Basic Research, 1050 Forest Hill Rd., Staten Island, NY 10314, and 2St. Vincents Catholic Medical Centers of NY, St. Vincent's Staten Island, 355 Bard Ave., Staten Island, NY 10310 USA Tel: +1-718-494-5178 Fax: +1-718-494-4806 E-mail: karmelgardner@si.rr.com Major advances in pre- and postnatal care have produced a growing number of infants with shorter gestations, lower birth weight (BW), and the products of multiple birth. However, long-term outcome is poorly understood. We will report on early medical indices used for predicting neurofunctional outcome over the first two years in 318 surviving infants born ≤ 32 weeks gestational age (GA) weighing ≤ 1500 g, who were part of a developmental follow-up study of at-risk infants from birth to 5 years (21% were ≤ 26 weeks and 17% were ≤ 750 g). Bayley Scales of Infant Development were administered every three months from 4-25 months. Multiple regression indicated no significant differences in GA or BW due to gender, ethnicity, or maternal education. Hierarchical regression indicated as GA or BW decreased, there were different functions across the Mental Development Index (MDI) and Psychomotor Development Index (PDI). PDI tended to be lower and decreased more rapidly, the lower the GA or BW over age at test. Increased severity of CNS injury also predicted lower MDI and PDI across age. Severity of CNS injury combined with degree of immaturity predicted developmental trajectories best, increasing multiple R from .40 to .50