Cranial sonography and neurological examination of extremely preterm infants.

Fifty-one extremely preterm infants were studied to ascertain whether there is an association between sonographic abnormalities and neurological examination at term, controlling for factors such as low birthweight and chronic lung-disease. Their mean birthweight was 956g and mean gestational age was 27.9 weeks. Sonography was performed at least once during the first week, twice within the first month, and once within a month of term-corrected age. Neurological assessment was used to classify the infants as normal, suspect or abnormal at term. Infants were divided into three groups, based on sonographic findings: group 1 (no hemorrhage), group 2 (grade 1 to 3 hemorrhage but normal sonogram or unilateral ventriculomegaly at term) and group 3 (periventricular leukomalacia, grade 4 hemorrhage or ventriculomegaly at term). On neurological examination, 23 infants were found to be normal, 15 suspect and 13 abnormal. On sonography, 27 infants were placed in group 1, 12 in group 2 and 12 in group 3. Sonographic findings and birthweight were the best predictors of the infant's performance on the neurological examination at term.