Score for neonatal acute physiology-II and neonatal pain predict corticospinal tract development in premature newborns

Abstract

Premature infants are at risk for adverse motor outcomes, including cerebral palsy and developmental coordination disorder. The purpose of this study was to examine the relationship of antenatal, perinatal, and postnatal risk factors for abnormal development of the corticospinal tract, the major voluntary motor pathway, during the neonatal period. In a prospective cohort study, 126 premature neonates (24-32 weeks' gestational age) underwent serial brain imaging near birth and at term-equivalent age. With diffusion tensor tractography, mean diffusivity and fractional anisotropy of the corticospinal tract were measured to reflect microstructural development. Generalized estimating equation models examined associations of risk factors on corticospinal tract development. The perinatal risk factor of greater early illness severity (as measured by the Score for Neonatal Acute Physiology-II [SNAP-II]) was associated with a slower rise in fractional anisotropy of the corticospinal tract (P = 0.02), even after correcting for gestational age at birth and postnatal risk factors (P = 0.009). Consistent with previous findings, neonatal pain adjusted for morphine and postnatal infection were also associated with a slower rise in fractional anisotropy of the corticospinal tract (P = 0.03 and 0.02, respectively). Lessening illness severity in the first hours of life might offer potential to improve motor pathway development in premature newborns.

FIGURE 1. Diffusion Tensor Tractography of the Corticospinal Tract

A. Limiting region-of-interest in the white matter underlying the motor cortex; B. Seeding region-of-interest in the posterior limb of the internal capsule; C. Limiting region-of-interest in the cerebral peduncle; D. Corticospinal tract.

FIGURE 2. Corticospinal Tract Fractional Anisotropy by SNAP-II Scores

SNAP-II, Score for Acute Neonatal Physiology-II