In a prospective study, preterm infants of less than 33 weeks gestation were routinely evaluated by cranial ultrasonography at frequent intervals during their neonatal course. Thirteen survivors were found to have a spastic form of cerebral palsy at 12 to 36 months of age; two of the infants had a hemiparesis, 1 a monoparesis and 10 a diparesis. During the neonatal course of each handicapped infant, either or both of the following neurosonographic abnormalities were present: 1) frontally located periventricular porencephaly secondary to a grade IV intracranial hemorrhage (ICH), 2) extensive periventricular echodensity with subsequent cyst formation extending frontally. Ultrasound abnormalities consisting of ICH, or periventricular echodensity but without frontal porencephaly or persisting periventricular cysts were noted during the neonatal course of 49 other preterm infants who did not have cerebral palsy at age 12 to 36 months. The pathogenesis of the periventricular echodensities and subsequent cyst formation is unknown but the ultrasound studies are consistent with hemorrhagic infarction and ischemic lesions involving pyramidal tracts as they enter the internal capsule.
We conclude that spastic forms of cerebral palsy are likely to develop in preterm infants if neonatal ultrasound studies demonstrate persisting destructive lesions in frontally located periventricular brain structures.