Evidence for catch-up in cognition and receptive vocabulary among adolescents born very preterm

Abstract

Background: Very preterm adolescents display persistent deficits in neuropsychological functions.

Objective: To compare cognitive and language outcomes at 16 years and cognitive and receptive vocabulary trajectories throughout school years between very preterm and term children and to determine child and family factors associated with better developmental trajectories.

Design and methods: At 8, 12, and 16 years, 322 very preterm children with birth weights of 1250 g or less and 41 term children had cognitive and language testing. Hierarchical growth-curve modeling was used to delineate the differences in cognitive and receptive vocabulary development between participants. Cluster analyses allowed for the characterization of very preterm children with different patterns of cognitive and receptive vocabulary development.

Results: At 16 years, very preterm adolescents had deficits in general cognition and higher-order language skills (phonological awareness and phonemic decoding) compared with term peers. Although the between-group difference in cognitive scores remained stable from 8 to 16 years, very preterm children demonstrated catch-up gains in receptive vocabulary during the same period. Moreover, subgroups of very preterm children displayed developmental trajectories in cognition similar to term children (55% on the vocabulary and 46% on the block-design subtests). These children had lower rates of neurosensory impairment and mothers with higher education and were from an ethnic nonminority.

Conclusions: Significant catch-up in receptive vocabulary is observed by the age of 16 years among very preterm children compared to term peers. The absence of neurosensory impairment and residing in a favorable socioeconomic milieu are associated with the most optimal developmental trajectories.

Figures

FIGURE 1

Patterns of cognitive development from the age of 8 to 16 years: A, WISC-III vocabulary raw score; B, WISC-III block-design raw score. Raw scores of term children are indicated with the bold line. The shadow represents CIs. Subgroups A and A* show similar patterns of cognitive development to the term cohort. Subgroup C also is catching up to the term group by the age of 16 years.

FIGURE 2

Patterns of receptive language development from the age of 8 to 16 years. PPVT-R raw scores of term children are indicated with the bold line. The shadow represents CIs. By the age of 16 years, subgroups A' and B' are catching up to the term group.