Potential mechanisms of cerebellar hypoplasia in prematurity.

INTRODUCTION: The cerebellum undergoes dramatic growth and maturation over the neonatal period after preterm birth and is thus particularly sensitive to impaired development due to various clinical factors.
METHODS: Impairments in growth can occur independent of cerebellar parenchymal damage, such as from local hemorrhage, resulting from reduced expression of sonic hedgehog signaling to trigger the appropriate expansion of the granule precursor cells.
RESULTS: The primary risk factors for impaired cerebellar development include postnatal glucocorticoid exposure, which has direct effects on the sonic hedgehog pathway, and supratentorial brain injury, including intraventricular hemorrhage and white matter injury, which may result in crossed cerebellar diaschisis and local toxic effects of blood products on the external granular layer. Other cardiorespiratory and nutritional factors may also exist. Impaired cerebellar development is associated with adverse outcomes in motor and cognitive development.
CONCLUSION: New approaches to care to counteract these risk factors may help improve long-term outcome after preterm birth.