White matter properties associated with pre-reading skills in 6-year-old children born preterm and at term.

AIM: To assess associations between white matter properties and pre-reading skills (phonological awareness and receptive and expressive language) in children born preterm and at term at the onset of reading acquisition. METHOD: Six-year-old children born preterm (n=36; gestational age 22-32wks) and at term (n=43) underwent diffusion magnetic resonance imaging and behavioural assessments. Tracts were selected a priori based on findings from a study of 6-year-old children born at term: the left-hemisphere arcuate fasciculus and superior longitudinal fasciculus, and right-hemisphere uncinate fasciculus. Using linear regression, we assessed associations between fractional anisotropy of tracts and phonological awareness and receptive and expressive language scores. We investigated whether associations were moderated by prematurity. RESULTS: Fractional anisotropy of the left-hemisphere arcuate fasciculus contributed unique variance to phonological awareness across birth groups. The association between fractional anisotropy of the right-hemisphere uncinate fasciculus and receptive and expressive language was significantly moderated by prematurity. INTERPRETATION: A left-hemisphere tract was associated with phonological awareness in both birth groups. A right-hemisphere tract was associated with language only in the term group, suggesting that expressive and receptive language is mediated by different white matter pathways in 6-year-old children born preterm. These findings provide novel insights into similarities and differences of the neurobiology of pre-reading skills between children born preterm and at term at reading onset. WHAT THIS PAPER ADDS: White matter properties and pre-reading abilities were associated in children born preterm at the onset of reading. The neurobiology of phonological awareness was similar in children born preterm versus children born at term at 6 years. The neurobiology of language was different in children born preterm versus children born at term at 6 years.