Fractional anisotropy alterations in individuals born preterm: a diffusion tensor imaging meta-analysis

Neonatal Magnesium Levels Between 24 and 48 Hours of Life and Outcomes for Epilepsy and Motor Impairment in Premature Infants

OBJECTIVE

Elevated rates of epilepsy and motor impairments including cerebral palsy are observed in children who were born prematurely. Maternal antenatal magnesium supplementation has been associated with decreased rates of cerebral palsy in infants born prematurely. Our objective was to determine whether the neonatal serum magnesium level between 24 and 48 hours after birth is associated with better long-term neurodevelopmental outcomes (epilepsy, motor impairment) in premature infants.

METHODS

We performed a retrospective cohort analysis in infants born less than 37-weeks gestation over a ten-year period. Prenatal, perinatal, and postnatal clinical and demographic information was collected. Crude and adjusted odds ratios were estimated under generalized linear models with generalized estimating equations to examine the association of the neonatal serum magnesium level between 24 and 48 hours after birth with the risk of epilepsy and/or motor impairment (spasticity; hypotonia; cerebral palsy).

RESULTS

The final cohort included 5461 infants born less than 37-weeks gestation from 2002 to 2011. The adjusted relative risk ratio for the combined outcomes of epilepsy and/or motor impairment, controlling for gestational age, current age, maternal magnesium supplementation, maternal steroid administration, five-minute Apgar score, neonatal infection, need for vasopressor use, and birth weight and with serum magnesium level as the main independent variable, was 0.85 (P = 0.24). Stratified analyses by gestational age less than 32 or greater than 32 weeks were not significantly associated with adverse neurodevelopmental outcome (risk ratio = 0.79 and 1.2, P = 0.12 and 0.49, respectively). A multivariate analysis for the risk of motor impairment alone had a risk ratio of 0.94 (P = 0.72).

CONCLUSION

This study demostrates that the neonatal magnesium level between 24 and 48 hours of life in premature infants is not significantly associated with the risk for developing epilepsy or motor impairment.

Bäuml J, Meng C, M. Wohlschläger A, Sorg C, Busch B, Baumann N, Wolke D, Bartmann P, Hattingen E, Boecker H. White matter alterations of the corticospinal tract in adults born very preterm and/or with very low birth weight

White matter (WM) injury, either visible on conventional magnetic resonance images (MRI) or measurable by diffusion tensor imaging (DTI), is frequent in preterm born individuals and often affects the corticospinal tract (CST). The relation between visible and invisible white mater alterations in the reconstructed CST of preterm subjects has so far been studied in infants, children and up to adolescence. Therefore, we probabilistically tracked the CST in 53 term-born and 56 very preterm and/or low birth weight (VP/VLBW, < 32 weeks of gestation and/or birth weight < 1,500 g) adults (mean age 26 years) and compared their DTI parameters (axial, radial, mean diffusivity--AD, RD, MD, fractional anisotropy--FA) in the whole CST and slice-wise along the CST. Additionally, we used the automatic, tract-based-spatial-statistics (TBSS) as an alternative to tractography. We compared control and VP/VLBW and subgroups with and without CST WM lesions visible on conventional MRI. Compared to controls, VP/VLBW subjects had significantly higher diffusivity (AD, RD, MD) in the whole CST, slice-wise along the CST, and in multiple regions along the TBSS skeleton. VP/VLBW subjects also had significantly lower (TBSS) and higher (tractography) FA in regions along the CST, but no different mean FA in the tracked CST as a whole. Diffusion changes were weaker, but remained significant for both, tractography and TBSS, when excluding subjects with visible CST lesions. Chronic CST injury persists in VP/VLBW adults even in the absence of visible WM lesions, indicating long-term structural WM changes induced by premature birth.