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Introduction: Knowledge is lacking concerning long-term influences of preterm birth on action-cognition integrations related to corpus callosum (CC) maturation/myelination. Here, we investigate long-term-effects of preterm-birth on CC microstructures/organization in relation to cognition and functional-laterality.

Patients and methods: The sample included 82 children, 41 term-born (M-age=8.1y), and 41 preterm-born (M-age=8.2y); subdivided into V-PT, (GA=25–32w, N=23), and M-PT, (GA=33–35w, N=18), without major brain-deficits. DTI performed in 3T-MRI-scanners, generated maps of CC Genu, Truncus, Splenium (FA, MD, AD, RD-values). Results from WISC-IV (verbal-comprehension-VCI, perceptual-reasoning-PRI, working-memory-WM, processing-speed-PS, FSIQ), and Laterality-index (hand-, foot-, eye-preference) were analyzed related to DTI-outcomes.

Results: Significant group difference found regarding CC-FA-values (F(2,79)=5,3527, p=.006), post-hoc-test showed that VPT differed from term (p=.015) and MPT-born (p=.016), by lower FA-Genu, Truncus, Splenium. This pattern also found for MD, RD, and AD-values. Positive-correlations (p<.01) found between GA and all CC-FA-values, and negatively for all MD, RD and AD-Splenium. VPT-born showed lower (p=.005) FSIQ (M=93) than term (M=103). Correlations (p<.05) found between WM and CC-FA-values in Genu for VPT-born, and between CC-FA-values in Genu, Truncus and PRI-index (p<.01) for term-born. VPT-born showed lower Hand- and overall-laterality-index than term and MPT, and no significant correlations between laterality-index and CC-values. Term and MPT-children showed positive correlations (p<.01) between decreasing overall-laterality-index and FA-values, and negative for MD-Splenum, RD-Splenium and RD-Truncus. 

Conclusion: DTI revealed evidence for long-term impact of very-premature birth on CC related to atypical hemispheric maturation and behavioral integrations compared to term-born controls. The findings highlight importance of including functional-laterality to models investigating brain white-matter-microstructures.