title: Reduced corticomotor excitability and motor skills development in children born preterm.
abstract: The mechanisms underlying the altered neurodevelopment commonly experienced by children born preterm, but without brain lesions, remain unknown. While individuals born the earliest are at most risk, late preterm children also experience significant motor, cognitive and behavioural dysfunction from school age, and reduced income and educational attainment in adulthood. We used transcranial magnetic stimulation and functional assessments to examine corticomotor development in 151 children without cerebral palsy, aged 10-13 years and born after gestations of 25-41 completed weeks. We hypothesized that motor cortex and corticospinal development are altered in preterm children, which underpins at least some of their motor dysfunction. We report for the first time that every week of reduced gestation is associated with a reduction in corticomotor excitability that remains evident in late childhood. This reduced excitability was associated with poorer motor skill development, particularly manual dexterity. However, child adiposity, sex and socio-economic factors regarding the child's home environment soon after birth were also powerful influences on development of motor skills. Preterm birth was also associated with reduced left hemisphere lateralization, but without increasing the likelihood of being left handed per se. These corticomotor findings have implications for normal motor development, but also raise questions regarding possible longer term consequences of preterm birth on motor function.
authors.affiliation: Research Centre for Early Origins of Health and Disease, Robinson Institute, School of Paediatrics & Reproductive Health, University of Adelaide, SA 5005, Australia. julia.pitcher@adelaide.edu.au
authors.forename: Julia B
authors.initials: JB
authors.lastname: Pitcher
authors.forename: Luke A
authors.initials: LA
authors.lastname: Schneider
authors.forename: Nicholas R
authors.initials: NR
authors.lastname: Burns
authors.forename: John L
authors.initials: JL
authors.lastname: Drysdale
authors.forename: Ryan D
authors.initials: RD
authors.lastname: Higgins
authors.forename: Michael C
authors.initials: MC
authors.lastname: Ridding
authors.forename: Theodore J
authors.initials: TJ
authors.lastname: Nettelbeck
authors.forename: Ross R
authors.initials: RR
authors.lastname: Haslam
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Robinson
mesh_terms: D050154:Adiposity; D016022:Case-Control Studies; D002657:Child Development / Q000502:physiology*; D019054:Evoked Potentials, Motor; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008137:Longitudinal Studies; D008297:Male; D009044:Motor Cortex / Q000254:growth & development / Q000502:physiology*; D009048:Motor Skills / Q000502:physiology*; D011712:Pyramidal Tracts / Q000502:physiology; D012959:Socioeconomic Factors; D050781:Transcranial Magnetic Stimulation