The prospective, longitudinal cohort study examined the rate and stability of impairments in children born preterm (<32 weeks gestation). Neurological, motor, cognitive, and behavioural outcomes were assessed at 2 and 10 years of age. It was found that with increasing age, more children experienced a moderate-severe impairment in the neurological, motor, cognitive and/or behavioural domain. Children with a moderate-severe impairment in any domain at 2 years of age were likely to experience persisting moderate-severe impairments at 10 years of age. Most changes in severity were seen in the neurological domain with the majority shifting to a less severe category. However, the largest aggravations in severity were seen in children with normal outcomes at 2 years of age. These results were significant on an individual level only, highlighting the importance of long-term follow-up for children born preterm.
Preterm born children may develop impairments in multiple domains of functioning, as the period between 20 and 32 weeks after conception is one of rapid brain growth and development. To fully understand the extent of difficulties experienced by children born preterm, the study aimed primarily at investigating the rate and stability of impairments within multiple key developmental domains at two timepoints. Further objectives were to assess a composite impairment score, report the co-occurrence of impairments for each child and to assess the individual changes in each category over time.
Data from a large single-center longitudinal study on neuroimaging and outcome after preterm birth was used, including children born preterm (<32 weeks gestation), who were admitted to the tertiary neonatal unit of Leiden University Medical Center in the Netherlands between May 2006 and November 2007. In this study, only children with follow-up data at 2 years and 10 years of age were included. Both follow-up visits included standardised examinations in four domains: paediatric, neurologic, cognitive and motor functioning. Furthermore, parents were asked to report on the presence of problem behaviour. Based on the follow-up data, two scores were created: a composite and a multidomain impairment score. The composite impairment score categorised children into three groups: no impairment, mild impairment or moderate-severe impairment. Mild impairment was defined as having at least one mild impairment in neurological, motor, cognitive or behavioural functioning, in absence of any moderate-severe impairment. The multidomain impairment score counted the number of domains in which a child experienced impairment. When a child had a mild or moderate-severe outcome in two or more domains, multidomain impairment was present. The differences over time were investigated on a group and an individual level for each domain.
Follow-up data at both timepoints was available for 71 (76 %) children. At group level, there were no significant changes in the distribution of normal, mild and moderate-severe development between 2 and 10 years of age per domain. However, at individual level significant changes were seen in the neurological, motor and cognitive domain. Within the neurological domain, almost half of the children (40%) shifted either to a more severe (46%) or to a less severe category (54%). The number of children with a mild composite score decreased significantly from 44% at 2 years of age to 20% at 10 years of age. Simultaneously, the number of children with a moderate-severe composite score increased from 2 years of age to 10 years of age from 12% to 35%.
The results show that children with early moderate-severe impairments are likely experiencing moderate-severe impairments within the same domain later on. Additionally, early normal/mild outcomes should be interpreted with care, considering the large individual shifts in severity over time. The study team concludes that long-term follow-up in a broad range of developmental domains in children born preterm is clinically relevant and must therefore be continued to at least school age.
Paper available at: Frontiers in Pediatrics | Neonatology
Full list of authors: Lisette Jansen, Cacha M. P. C. D. Peeters-Scholte, Annette A. van den Berg-Huysmans, Jeanine M. M. van Klink, Monique Rijken, Janneke C. van Egmond-van Dam, Robert R. J. M. Vermeiren and Sylke J. Steggerda