Neurocognitive and Academic Outcomes at Age 10 Years of Extremely Preterm Newborns

Abstract

Background and objective: Despite reductions in mortality and morbidity among children born extremely preterm, they remain at high risk of neurocognitive deficits, with up to 40% having significant cognitive deficits at school age. We assessed the rate of neurocognitive impairment in a contemporary US cohort of 873 children aged 10 years who were born <28 weeks' gestation.

Methods: The families of 889 of 966 (92%) children enrolled from 2002 to 2004 at 14 sites in 5 states returned at age 10 years for a comprehensive assessment of IQ, language, attention, executive function, processing speed, visual perception, visual-motor function, and academic achievement.

Results: A total of 873 children were assessed with well-validated tests of cognitive and academic function. Distributions of test scores were consistently and markedly shifted below normative expectation, with one-third to two-thirds of children performing >1 SD below age expectation. The most extreme downward shifts were on measures of executive control and processing speed. Multivariate analyses, adjusted for socioeconomic status, growth restriction, and other potential confounders, revealed that the risk of poor outcome was highest at the lowest gestational age across all 18 measures.

Conclusions: More than half of our extremely preterm cohort exhibited moderate or severe neurocognitive deficits at age 10 years, with the most extensive impairments found among those born at the lowest gestational age. Children born extremely preterm continue to be at significant risk of persistent impairments in neurocognitive function and academic achievement, underscoring the need for monitoring and remediating such outcomes beginning in early childhood.

FIGURE 1

Box-and-whisker plots of each neurocognitive subtest by GA category. z Scores according to DAS-II, OWLS, and WIAT-III (A) and NEPSY-II (B) were adjusted to population norms. Maximum N = 873. Light gray bars indicate 23–24 weeks, medium gray bars indicate 25–26 weeks, and dark gray bars represent 27 weeks. The central line in the boxes indicates the median (50th centile), the top of the boxes indicates the 75th centile, and the bottom of the boxes indicates the 25th centile. Solid circles represent outliers. If ELGAN participants had the expected normal distribution of term-born children, the middle of the box would be at z = 0 and the upper and lower ends of the box would be at z = 1 and z = −1, respectively. AA, Auditory Attention; AS, Animal Sorting; AW, Arrows; GEO, Geometric Puzzles; INI, Inhibition Inhibition; INN, Inhibition Naming; INS, Inhibition Switching; LC, Listening Comprehension; NO, Numeric Operations; NV, Nonverbal Reasoning; OE, Oral Expression; OWLS, Oral and Written Language Scales; PdD, Pseudoword Decoding; RS, Auditory Response Set; Sp, Spelling; WM, Working Memory; WR, Word Reading; V, Verbal.

FIGURE 2

Forest plots of odds ratios and 95% confidence intervals of z scores ≤ −2 (left panels) and z scores > −2 but ≤ −1 (right panels) for each DAS-II, OWLS, NEPSY-II, and WIAT-III assessment at age 10 years associated with a GA of 23–24 weeks (top panel) or a GA of 25–26 weeks (bottom panel). All odds ratios were adjusted for maternal IQ (KBIT-2 z score ≤ −1), maternal education ≤12 years, black race, male gender, and birth weight z score < −1. Large black dots indicate odds ratios that were significantly >1.0. Maximum N = 873. OWLS, Oral and Written Language Scales.