Midline electrographic abnormalities and cerebral lesions in the newborn brain.

Electroencephalographic (EEG) abnormalities arising from the midline region were identified in 154 of 1008 (15.2%) consecutive neonatal EEGs during a 24-month period. These records were obtained on 97 neonates with a variety of clinical diagnoses. Premature infants made up 79% (77/97) of this group. All patients received at least one cranial ultrasound at 7 to 10 days of life. Sixty-two percent (60/97) of the patients had radiographic and/or neuropathological documentation of cerebral lesions: intraventricular hemorrhage (25), periventricular leukomalacia (18), cerebral infarction (10), cerebral malformation (4), and miscellaneous lesions (3). Six types of midline EEG abnormalities are described: negative sharp waves, positive sharp waves, electrographic discharges associated with myoclonus, electrographic seizures, attenuation of background, and rhythmic monofrequencies. Approximately 90% of the patients with background attenuation, discharges with myoclonus, and positive sharp waves and 72% of patients with EEG seizures had cerebral lesions. Midline positive sharp waves were associated with periventricular leukomalacia as well as intraventricular hemorrhage. No midline positive sharp waves, attenuation, EEG seizures or discharges with myoclonus were found in 25 healthy, asymptomatic neonates. Besides positive sharp waves, other specific midline EEG abnormalities can be associated with cerebral lesions in the neonate. The rapid identification of midline EEG abnormalities in neonatal recordings can enhance the accuracy of both electrographic diagnosis and anatomic localization of associated cerebral lesions.