Cognitive and motor development in preterm children from 6 to 36 months of age: Trajectories, risk factors and predictability.

Background: Although numerous studies have examined the development of preterm children born very low birth weight (VLBW, birth body weight < 1500 g), variations of developmental progress within individuals have rarely been explored. The aim of this research was to examine the cognitive and motor trajectories in preterm children born VLBW at early ages and to assess the risk factors and predictability of these trajectories.

Method: Five hundred and eighty preterm infants born VLBW from three cohort studies (2003 to 2014) were prospectively assessed their mental and motor development using the Bayley Scales at 6, 12, 24, and 36 months, and cognitive, motor and behavioral outcomes using the Movement Assessment Battery for Children and the Child Behavior Checklist for Ages 1.5-5 at 4 years of age.

Results: Preterm children born VLBW manifested three cognitive patterns (stably normal [64.0 %], deteriorating [31.4 %], and persistently delayed [4.6 %]) and four motor patterns (above average [6.3 %], stably normal [60.0 %], deteriorating [28.5 %], and persistently delayed [5.2 %]) during 6-36 months. Low birth body weight, stage III-IV retinopathy of prematurity and low parental socio-economic status were associated with the deteriorating patterns; prolonged hospitalization and major brain damage were additionally associated with the persistently delayed patterns. Furthermore, the cognitive and motor deteriorating pattern was each predictive of cognitive and motor impairment at 4 years of age; whereas, the persistently delayed patterns were predictive of multiple impairments.

Conclusion And Implications: Preterm children born VLBW display heterogeneous trajectories in early cognitive and motor development that predict subsequent developmental and behavioral outcomes.