Background. The etiology of motor impairments in preterm infants is multifactorial and incompletely understood. Whether corpus callosum development is related to impaired motor function is unclear. Potential associations between motor-related measures and diffusion tensor imaging (DTI) of the corpus callosum in preterm infants were explored. Methods. Eight very preterm infants (gestational age of 28–32 weeks) underwent the Hammersmith neonatal neurological examination and DTI assessments at gestational age of 42 weeks. The total Hammersmith score and a motor-specific score (sum of Hammersmith motor subcategories) were calculated. Six corpus callosum regions of interest were defined on the mid-sagittal DTI slice—genu, rostral body, anterior midbody, posterior midbody, isthmus, and splenium. The fractional anisotropy (FA) and mean diffusivity (MD) of these regions were computed, and correlations between these and Hammersmith measures were sought. Results. Anterior midbody FA measures correlated positively with total Hammersmith (rho , ) and motor-specific scores (rho , ). Total Hammersmith scores also negatively correlated with anterior midbody MD measures (rho , ). Discussion. These results suggest the integrity of corpus callosum axons, particularly anterior midbody axons, is important in mediating neurological functions. Greater callosal maturation was associated with greater motor function. Corpus callosum DTI may prove to be a valuable screening or prognostic marker. 1. Introduction Preterm infants are at a high risk of motor deficits in later life, with approximately fourteen percent of very preterm infants developing cerebral palsy (CP) [1], and up to forty percent of very preterm infants demonstrating mild motor deficits [2]. The mechanisms underlying such motor impairments have not yet been fully elucidated, but have been related to a number of factors, including abnormal cerebral development (particularly in sensorimotor regions) [3], conditions such as periventricular leukomalacia, peri-intraventricular hemorrhage [4], and/or stressors in the neonatal intensive care unit (NICU) environment [5]. New insights into the neural structures and mechanisms, underlying motor function in preterm-born infants, should help in the development of new diagnostic and prognostic tools and provide information on the immediate efficacy of early intervention therapies. The corpus callosum is vital for communicating and integrating motor and somatosensory information between the hemispheres, and for bimanual motor coordination and function [6]. The maturation or
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