Neurobehavioural Development of Infants Born <30 Weeks Gestational Age Between Birth and Five Years of Age

Research question: The primary aim of this study is to compare the prevalence of motor impairment from birth to five years of age between children born <30 weeks and term-born controls, and to determine whether persistent abnormal motor assessments in the newborn period in those born <30 weeks predict abnormal motor functioning at age five years. Secondary aims for both children born<30 weeks and term children are i) to determine whether novel early magnetic resonance imaging (MRI) - based structural or functional biomarkers are detectable in the neonatal period that can predict motor impairments at five years, ii) to investigate the association between motor impairments and concurrent deficits in body structure and function at five years of age, and iii) to explore how motor impairments at five years, including abnormalities of gait, postural control and strength, are associated with concurrent functional outcomes including physical activity, cognitive and learning ability, behavioural and emotional problems.

Design: Prospective longitudinal cohort study. Participants and Setting: 150 preterm children (born <30 weeks) and 151 term-born children (born >36 completed weeks' gestation and weighing>2499 g) admitted to the Royal Women's Hospital, Melbourne, were recruited at birth and will be invited to participate in a five-year follow-up study.

Procedure: This study will examine previously collected data (from birth to two years) that comprises the following: detailed motor assessments and structural and functional brain MRI images. At five years, preterm and term children will be examined using comprehensive motor assessments including the Movement Assessment Battery for Children - 2nd edition and measures of gait function through spatiotemporal (assessed with the GAITRite® Walkway), dynamic postural control (assessed with Microsoft Kinect) variables and hand grip strength (assessed with a dynamometer); and measures of physical activity (assessed using accelerometry), cognitive development (assessed with Wechsler Preschool and Primary Scale of Intelligence) and emotional and behavioural status (assessed with the Strengths and Difficulties Questionnaire and the Developmental and Wellbeing Assessment). Caregivers will be asked to complete questionnaires on demographics, physical activity, activities of daily living and motor function (assessed with Pediatric Evaluation of Disability Inventory, Pediatric Quality of Life Questionnaire, the Little Developmental Co-ordination Questionnaire and an activity diary) at the 5 year assessment.

Analysis: For the primary aim the prevalence of motor impairment from birth to 5 years will be compared between children born <30 weeks and term-born peers using the proportion of children classified as abnormal at each of the time points (term age, one, two and five years). Persistent motor impairments during the neonatal period will be assessed as a predictor of severity of motor impairment at 5 years of age in children born <30 weeks using linear regression. Models will be fitted using generalised estimating equations with results reported using robust standard errors, to allow for the clustering of multiple births.

Discussion/Significance: Understanding the developmental precursors of motor impairment in children born <30 weeks is essential to limit disruption to skill development, and potential secondary impacts on physical activity, participation, academic achievement, self-esteem and associated outcomes, such as obesity, poor physical fitness and social isolation. Better understanding of motor skill development will enable targeting of intervention and streamlining of services to the individuals who are at highest risk of motor impairments.