Early indications of delayed cognitive development in preschool children born very preterm: evidence from domain‐general and domain‐specific tasks

Abstract

Cognitive impairment often follows preterm birth but its early underlying nature is not well understood. We used a novel approach by investigating the development of colour cognition in 54 very preterm children born p30 weeks gestational age without severe neurosensory impairment and 37 age-matched term-born controls, aged 2-5 years. Quantitative and qualitative differences in the development of colour cognition are well charted throughout the preschool years, enabling delayed from deviant development to be determined. Standardized domain-general and experimental colourspecific tests of language, attention, and memory were employed. Very preterm children showed significantly depressed language than term controls, with very preterm group girls significantly outperforming boys. Very preterm children also showed poorer attention and memory than term controls, but not significantly so. Importantly, colour-specific tests showed qualitatively similar performance, but for naming and executive planning quantitatively poorer performance, across groups, indicating typical but delayed development. Hence, even before school entry, compared with term-born peers, very preterm children show delayed development of cognitive processes that underpin later scholastic abilities, but the nature by which these processes operate appears to be typical of term children. If left untreated these early developmental delays may underpin later deviations from the typical developmental trajectory.

Early Psychological Development of Very Preterm and/or Low Birth Weight Children: A Review of the Literature

“…In relation to cognitive development, the research found global cognitive delays in children born prematurely, but the specific cognitive processes most affected are memory from 2 to 6 years (40,42,43,45,47,48,52), attention from the first year of birth (35,36,38,41,44) and visual-spatial processing at 3-4 years (42,43,45). However, there is no consensus on the degree of impairment of memory and executive function, because some studies find they are not affected in the first 2 years (37), and other studies find worse scores at 5 and 6 years (48, 52).…”

“…However, there are no conclusive data about problems in expressive and receptive language develop-ment in general, vocabulary size and communication skills. Some studies found that preterm children have problems in expressive and receptive language development in general in the first two years of life, and from 2 to 6 years of age (40,48,52,54,61,62,65). One study found that preterm children have no problems in expressive and receptive language development in general at 5 years (63) and other study found that these children have problems in some specific components of expressive language (sentences), but they do not have problems in other components (information) at 3 years old (60).…”

“…On the other hand, Pitchford et al (40), found significant differences in the development of attention and memory in preterm children at 2 years of age. They found that preterm boys are more likely to have cognitive problems than preterm girls (40).…”

“…At 2 years, preterm children have impaired comprehensive and expressive language, independent of social risk, and lower scores in listening comprehension and expressive communication (40,48). They use shorter sentences than full-term children (55) and have limited vocabulary and poor grammar skills in the use of predicates, verbs and adjectives, although they play more games and produce more animal noise words than full-term children (56).…”

“…Similarly, Roberts et al (48) found that at this age, preterm children had problems in receptive and expressive language, independent of social risk. They also present problems in vocabulary and spoken language grammar skills (47), and obtain lower scores in listening comprehension and expressive communica- tion (40). The problems with vocabulary and morphosyntactic skills that preterm children manifest at this age are considered predictors of cognitive problems (50).…”