Neonatal watershed brain injury on magnetic resonance imaging correlates with verbal IQ at 4 years.

Abstract

We have previously described patterns of neonatal brain injury that correlate with global cognitive and motor outcomes. We now examine, in survivors of neonatal encephalopathy (presumed secondary to hypoxia-ischemia) without functional motor deficits, whether the severity and neuroanatomical involvement on neonatal MRI are associated with domain-specific cognitive outcomes, verbal and performance IQ, at 4 years of age. In this prospective study, neonatal MRIs of 81 term infants with neonatal encephalopathy were scored for degree of injury in 2 common patterns: watershed distribution and basal ganglia distribution. Follow-up evaluation at 4 years of age by examiners blinded to clinical history and MRIs included a 5-point neuromotor score and the Wechsler Preschool and Primary Scale of Intelligence-Revised. In 64 subjects with no functional motor impairment, test of trend was used to examine the association of ordered watershed-distribution and basal ganglia-distribution MRI scores with mean verbal and performance IQ. Lower verbal and performance IQs were seen with increasing degree of injury on both watershed-distribution and basal ganglia-distribution scales in univariate analyses. When each MRI pattern score was adjusted for the other, only the association of decreasing verbal IQ with increasing watershed-distribution injury remained significant. A suggestion of decreasing verbal IQ with increasing basal ganglia-distribution injury was also seen in the multivariate model, whereas no association was seen between performance IQ and severity of injury in either MRI pattern. In survivors of neonatal encephalopathy without functional motor deficits at 4 years of age, an increasing severity of watershed-distribution injury is associated with more impaired language-related abilities.