Neonatal neurobehavior after therapeutic hypothermia for hypoxic ischemic encephalopathy

Background: Perinatal hypoxic ischemic encephalopathy (HIE) is a major cause of neurodevelopmental impairment including cerebral palsy and intellectual disability. Brain magnetic resonance imaging is the gold standard for acute assessment of cerebral injury in HIE. Limited data are available regarding the significance of clinically manifested neurobehavioral impairments in the neonatal period.

Aim: To evaluate brain structure-function relationships in newborns with HIE using diffusion tensor imaging (DTI) and the NICU Network Neurobehavioral Scale (NNNS).

Study design: Prospective observational study with secondary longitudinal component.

Subjects: Forty-five newborns (62% male) with HIE referred for therapeutic hypothermia who underwent MRI and neurobehavioral assessment prior to discharge.

Outcome measures: DTI was performed at median age of 8 days (range 5-16) and NNNS at median 12 days of life (range 5-20, postmenstrual age 40±2 weeks). Developmental assessment with the Bayley Scales of Infant Development-II was performed at median age of 21.6 months (range 20.8-30.6).

Results: Significant associations were observed between DTI corticospinal tract integrity and NNNS neuromotor performance in HIE newborns. Neonatal neuromotor performance was also related to later early childhood motor outcomes.

Conclusions: NNNS performed after therapeutic hypothermia in newborns with HIE can identify neuromotor abnormalities that are related to microstructural brain injury in the corticospinal tract and later motor outcomes in early childhood. These data support the NNNS as a valid early functional assessment of perinatal brain injury.