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

OBJECTIVE: 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.
METHODS: 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.
RESULTS: 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.
CONCLUSIONS: 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.