title: Interhemispheric temporal lobe connectivity predicts language impairment in adolescents born preterm.
abstract: Although language difficulties are common in children born prematurely, robust neuroanatomical correlates of these impairments remain to be established. This study investigated whether the greater prevalence of language problems in preterm (versus term-born) children might reflect injury to major intra- or interhemispheric white matter pathways connecting frontal and temporal language regions. To investigate this, we performed a comprehensive assessment of language and academic abilities in a group of adolescents born prematurely, some of whom had evidence of brain injury at birth (n = 50, mean age: 16 years, mean gestational age: 27 weeks) and compared them to a term-born control group (n = 30). Detailed structural magnetic resonance imaging and diffusion-tractography analyses of intrahemispheric and interhemispheric white matter bundles were performed. Analysis of intrahemispheric pathways included the arcuate fasciculus (dorsal language pathway) and uncinate fasciculus/extreme capsule (ventral language pathway). Analysis of interhemispheric pathways (in particular, connections between the temporal lobes) included the two major commissural bundles: the corpus callosum and anterior commissure. We found language impairment in 38% of adolescents born preterm. Language impairment was not related to abnormalities of the arcuate fasciculus (or its subsegments), but was associated with bilateral volume reductions in the ventral language pathway. However, the most significant volume reduction was detected in the posterior corpus callosum (splenium), which contains interhemispheric connections between the occipital, parietal and temporal lobes. Diffusion tractography showed that of the three groups of interhemispheric fibres within the splenium, only those connecting the temporal lobes were reduced. Crucially, we found that language impairment was only detectable if the anterior commissure (a second temporal lobe commissural pathway) was also small. Regression analyses showed that a combination of anatomical measures of temporal interhemispheric connectivity (through the splenium of the corpus callosum and anterior commissure) explained 57% of the variance in language abilities. This supports recent theories emphasizing the importance of interhemispheric connections for language, particularly in the developing brain.
authors.affiliation: Developmental Cognitive Neuroscience Unit, UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK.
authors.forename: Gemma B
authors.initials: GB
authors.lastname: Northam
authors.forename: Frédérique
authors.initials: F
authors.lastname: Liégeois
authors.forename: Jacques-Donald
authors.initials: JD
authors.lastname: Tournier
authors.forename: Louise J
authors.initials: LJ
authors.lastname: Croft
authors.forename: Paul N
authors.initials: PN
authors.lastname: Johns
authors.forename: Wui K
authors.initials: WK
authors.lastname: Chong
authors.forename: John S
authors.initials: JS
authors.lastname: Wyatt
authors.forename: Torsten
authors.initials: T
authors.lastname: Baldeweg
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D001931:Brain Mapping; D003337:Corpus Callosum / Q000473:pathology*; D056324:Diffusion Tensor Imaging; D004522:Educational Status; D005260:Female; D005500:Follow-Up Studies; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007805:Language Development Disorders / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000473:pathology; D011237:Predictive Value of Tests; D013702:Temporal Lobe / Q000473:pathology*