Altered language network microstructure links with impaired language function and development in very preterm/very...

Premature birth is associated with impaired language function. In premature-born children, language function has been linked with microstructural alterations of the language network.Whether these brain-language associations persist into adulthood remains unclear. We investigated the microstructural properties of major dorsal and ventral language pathways in very preterm/very low birth weight (VPT/VLBW) adults and their associations with language performance in adulthood and childhood. Sixty-three VPT/VLBW and eighty full-term-born adults (mean age 26.8 years) underwent diffusion-weighted imaging and language assessment. The arcuate fasciculus, superior longitudinal fasciculus, uncinate fasciculus and inferior fronto-occipital fasciculus were reconstructed using probabilistic tractography from which fractional anisotropy (FA) and mean diffusivity (MD) measures were extracted. Adult language function was assessed via the Regensburg word fluency test, rapid automatized naming and verbal IQ; childhood language was assessed at the mean age of 8 using the Kaufman Assessment Battery for children. We observed altered language network microstructure in VPT/VLBW participants, illustrated by lower FA and higher MD in the SLF and UF. These microstructural alterations were associated with language function in adulthood, but also with language development in childhood. We found that the association between tract microstructure and language abilities differed between groups. Our results demonstrate altered language network microstructure in premature born adults, which links with impaired language function and development. These findings extend previous work by comprehensively characterizing the adult dorsal and ventral language network and relating its microstructural properties to language function across development. The selective follow-up sample may limit generalizability to the broader VPT/VLBW population.