To examine whether a one-factor executive function (EF) model fit data for three groups of children differing in birth criteria (extremely low birth weight [ELBW], late preterm [LPT], and Term) at each of two chronological ages, 3 and 6 years, and whether the latent mean amount of EF differed. Methods: A retrospective observational cohort study of 1,079 participants; 668 aged 3 years born 2000¿2009 (93 ELBW, 398 LPT, and 177 Term) and 411 aged 6 years born 1998¿2006 (126 ELBW, 102 LPT, and 183 Term). Latent means analysis was conducted using five indicators for EF: noun fluency, action-verb fluency, similarities reasoning, matrices reasoning, and working memory. Results: A one-factor model had acceptable fit for all groups (RMSEA<.06, CFI >0.95, SRMR <0.08). Statistically significant between-groups differences were found for all comparisons except one; there were no statistically significant differences between LPT-Term at age 6. At age 3, ELBW was 0.98 and 1.70 SD below LPT and Term, respectively; LPT was 0.61 SD below Term. At age 6, ELBW was 0.70 and 0.78 SD below LPT and Term, respectively; LPT was 0.10 SD below Term. Conclusions: Executive deficit identified early in development after preterm birth could represent a transient developmental delay likely to resolve at older age or a more subtle adverse effect likely to persist over the life span. Study at multiple age points should assist in resolving this dilemma, which has important implications for early age neuropsychological screening and intervention.
