title: Development of the optic radiations and visual function after premature birth.
abstract: BACKGROUND
  Visual impairment in preterm infants at term equivalent age (TEA) is associated with impaired microstructural development in the optic radiation, measured as reduced fractional anisotropy (FA) by Diffusion Tensor Imaging (DTI). We tested the hypothesis that these abnormalities develop during the late preterm period.
  
  
  METHODS
  DTI was performed in 53 infants born at a median (range) of 30(+1) (25(+4)-34(+6)) weeks post-menstrual age (PMA), 22 of whom were imaged twice.
  
  
  RESULTS
  FA in the optic radiation at TEA was related to: visual function (p = .003); PMA at birth (p = .015); and PMA at scan (p = .008); while a significant interaction between PMA at birth and scan (p = .019) revealed an effect of the period of premature extra-uterine life additional to the degree of prematurity. We explored this further in a sub-group of 22 infants who were studied twice. FA increased from mean (95% CI) .174 (.164-.176) on the first image at 32(+5) (29(+5)-36) weeks PMA, to .198 (.190-.206) on the second image at 40(+6) (39(+2)-46) weeks PMA. Visual function was not predicted by FA on the images obtained in the early neonatal period, but was significantly related to the rate of increase in FA between scans (p = .027) and to FA on the second image (p = .015).
  
  
  CONCLUSIONS
  Microstructural maturation during the late preterm period is thus required for normal visual function, suggesting that interventions applied after 30 weeks PMA might reduce impairment in preterm infants.
authors.affiliation: Centre for the Developing Brain, Imperial College, London, United Kingdom; NICU, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Università degli Studi di Milano, Milano, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Groppo
authors.affiliation: Paediatric Neurology Unit, Catholic University, Rome, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Ricci
authors.affiliation: Centre for the Developing Brain, Imperial College, London, United Kingdom; NICU, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Università degli Studi di Milano, Milano, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Bassi
authors.affiliation: Centre for the Developing Brain, Imperial College, London, United Kingdom; MRC Clinical Sciences Centre, Hammersmith Hospital, London, United Kingdom.
authors.forename: Nazakat
authors.initials: N
authors.lastname: Merchant
authors.affiliation: Centre for the Developing Brain, Imperial College, London, United Kingdom; MRC Clinical Sciences Centre, Hammersmith Hospital, London, United Kingdom.
authors.forename: Valentina
authors.initials: V
authors.lastname: Doria
authors.affiliation: Centre for the Developing Brain, Imperial College, London, United Kingdom; MRC Clinical Sciences Centre, Hammersmith Hospital, London, United Kingdom.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Arichi
authors.affiliation: Centre for the Developing Brain, Imperial College, London, United Kingdom; MRC Clinical Sciences Centre, Hammersmith Hospital, London, United Kingdom.
authors.forename: Joanna M
authors.initials: JM
authors.lastname: Allsop
authors.affiliation: NICU, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Università degli Studi di Milano, Milano, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Ramenghi
authors.affiliation: Centre for the Developing Brain, Imperial College, London, United Kingdom; MRC Clinical Sciences Centre, Hammersmith Hospital, London, United Kingdom.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Fox
authors.affiliation: Centre for the Developing Brain, Imperial College, London, United Kingdom.
authors.forename: Frances M
authors.initials: FM
authors.lastname: Cowan
authors.affiliation: Centre for the Developing Brain, Imperial College, London, United Kingdom; MRC Clinical Sciences Centre, Hammersmith Hospital, London, United Kingdom. Electronic address: serena.counsell@imperial.ac.uk.
authors.forename: Serena J
authors.initials: SJ
authors.lastname: Counsell
authors.affiliation: Centre for the Developing Brain, Imperial College, London, United Kingdom; MRC Clinical Sciences Centre, Hammersmith Hospital, London, United Kingdom.
authors.forename: A David
authors.initials: AD
authors.lastname: Edwards
mesh_terms: D016880:Anisotropy; D001921:Brain / Q000254:growth & development / Q000503:physiopathology*; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D019102:Infant, Very Low Birth Weight; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000502:physiology*; D014786:Vision Disorders / Q000503:physiopathology*; D014785:Vision, Ocular / Q000502:physiology*