[Prognostic value of electroencephalographic background patterns in full-term neonates with asphyxia].

OBJECTIVE: Severe asphyxia during peripartum may lead to some sequela of the nervous system. Currently the neurologic outcome of asphyxiated neonates is assessed by using imaging techniques such as cranial ultrasound, CT and MRI except for evaluating perinatal abnormal factors and routine physical examinations of nervous system. These assessment approaches are based on the changes of anatomic structures of neonates. Electroencephalography (EEG) can show early abnormal cerebral functions. This study examined the EEG background activity and investigated the parameters associated with the prognostic assessment in full-term neonates with asphyxia.

METHODS: A standard EEG was recorded in 49 asphyxiated full-term neonates aged from 24 hrs to 8 days. Of the 49 neonates, 14 had concurrent mild, 5 had moderate and 9 had severe hypoxic-ischemic encephalopathy (HIE). Thirty-one aged-matched full-term neonates without asphyxia severed as the control group. Forty-three of 49 asphyxiated neonates were followed-up for neurological development for 6-12 months. Important parameters associated with neurological prognosis were evaluated by the principle of data statistics.

RESULTS: The mean interburst intervals was prolonged, the amplitude of brain electrical activity during all the states were lower, and the incidence of brief burst and sleep-wake cycle disturbance was higher in the asphyxiated group when compared with the control group (P < 0.05). In the follow-up, 4 infants had poor fine motor function and 7 showed retarded psychomotor development in the asphyxiated group. Gestational age, birth weightamplitude of brain electrical activity, severity of HIE, occurrence of sleep-wake cycle disturbance and imaging abnormality were shown as important parameters for predicting neurological outcomes in asphyxiated neonates. The infants who EEG showed isoelectric tracings or isoelectric tracings accompanied with much abnormal discharge had very poor prognosis.

CONCLUSIONS: EEG background pattern is valuable in predicting neurological outcomes for term neonates with asphyxia. EEG in combination with clinic data such as gestational age, birth weight, imaging examination, and severity of HIE may provide an accurate evaluation of neurological outcome.