Continuous four-channel EEG monitoring in the evaluation of echodense ultrasound lesions and cystic leucomalacia.

Continuous monitoring by electroencephalography (EEG) was performed in 31 preterm infants with echodense ultrasound lesions using the Oxford Medilog four channel recorder. In 12 infants these densities preceded cyst formation, eight in the periventricular and four in the subcortical region. In the 19 other infants the densities resolved. The most severe EEG depression occurred in the four infants with subcortical cysts, who also had the poorest outcome. Six of eight infants with periventricular lesions had lesser degrees of abnormality though all infants had moderate to severe handicap at follow up. Similar abnormalities were seen on EEG recording in three infants in whom the densities resolved without cyst formation and these infants also had an abnormal outcome. An abnormal EEG recording provides a sensitive early guide to the severity and prognosis of these lesions, even before they can be seen on ultrasonography.