Prolonged inactive phases during the discontinuous pattern of prematurity in the electroencephalogram of very-low-birthweight infants.

A consecutive cohort of 46 very-low-birthweight infants, who had routine electroencephalograms (EEGs) while in the neonatal intensive care unit, were studied. Two infants were lost to follow-up and were excluded, leaving a study population of 44 infants. Their mean birthweight was 945 +/- 166 g, gestation 27.1 +/- 1.7 weeks. Thirteen infants died before discharge. The remaining 31 had a mean corrected age of 26.1 +/- 8.7 months at the time of the last visit. Three groups were distinguished: normal survivors, handicapped survivors and non-survivors. The longest inactive phase encountered in the discontinuous EEG was the yardstick of the study with 3 subdivisions: less than 20 sec. 20-29 sec and equal to or more than 30 sec. The data showed a relative increase in poor outcome with increasing duration of inactivity (P less than 0.05) and, conversely, a favorable outcome with the absence of 20 sec or longer inactivity (P less than 0.001). All infants received therapeutic doses of phenobarbital during the early part of their illness which could have affected their EEG. Mean phenobarbital levels, obtained close to the time of the EEG, however, did not differ significantly and failed to show a significant relationship between the duration of the inactive phase and drug level observed. Inactive phases greater than or equal to 30 sec were more common (P less than 0.01) in infants with intraventricular hemorrhage. We conclude: although full recovery and normal outcome have been documented, prolonged isoelectric phases beyond 30 sec are more common in infants with fatal outcome.

The EEGs of infants with citrullinemia.

Three female infants with citrullinemia were followed clinically, biochemically and by electroencephalography. All three had episodes of vomiting, lethargy and hyperammonemia shortly after birth. The two more severe cases developed convulsions. They were saved by peritoneal dialysis, or repeated exchange transfusions followed by dietary adjustment. Multifocal spikes or repetitive paroxysmal activity of various kinds were seen in the EEGs at times of crisis. There was a lag in the EEG returning to normal after ammonia levels had returned to normal. Citrulline remained elevated in all cases. Follow-up over years revealed mild spasticity, mental retardation and, in one case, cortical atrophy.

[Seizures in premature and newborn infants under 2,500 grams birth weight]. / Krampfanfälle bei Früh- und Neugeborenen unter 2 500 Gramm Geburtsgewicht.

Seizures in premature babies pose a special problem which occur more often than in term neonates. The data of 156 neonates weighing less than 2 500 grams consecutively admitted to a neonatal intensive care unit during a 6 month period were evaluated. 33 infants (21%), of whom 21 were less than 31 weeks of gestational age suffered from seizures. Almost all of these 33 infants had a very bad outcome. Only 9 of them survived and only 4 showed normal development. In 26 infants a CT or brain autopsy was performed. The outcome was influenced by the presence of intraventricular haemorrhage. But even those preterm neonates without morphological abnormalities of the brain have only a small chance of developing normally in the presence of seizures. The EEG is an important diagnostic tool: Most of the patients showed paroxysmal activity. The background activity of the interictal EEG has prognostic value even in the preterm infant. There is, however, discrepancy between the EEG and the morphological findings. Therefore the EEG has to be seen as functional test which gives important additional information beyond brain imaging methods.

[Rhythmic alpha activity in the EEG of premature and newborn infants]. / Rhythmische alpha-Aktivität im EEG von Früh- und Neugeborenen.

The EEG of the newborn consists of a mixed activity which varies from 1 to 22/s. Waves in the alpha band may occur, but they indicate cerebral dysfunction if they are seen in a rhythmic uninterrupted sequence. Eight newborns who showed rhythmic alpha activity in their EEG are included in our study. This activity occurred together with rhythmic theta waves or was followed by them as part of ongoing electrographic seizure activity. All newborns studied were very sick. Three suffered from severe perinatal asphyxia with persistent fetal circulation; in addition one of them had bacterial meningitis. Two infants suffered from herpes encephalitis. In those cases the rhythmic alpha activity temporarily showed a certain periodicity. This EEG pattern was also seen in a small for gestational age premature infant who had septicemia and subarachnoid hemorrhage and in two extremely premature babies with intraventricular hemorrhage. Four infants were curarized. All of the others also had clinically observed seizures. Rhythmic alpha-activity in the neonatal EEG represents an electrical seizure discharge. It may also occur in premature infants who suffer from intraventricular hemorrhage. Obviously it does not have a diagnostic value. The prognostic value depends upon the underlying disease and the grade of background suppression in the EEG. Anticonvulsant therapy should be administered early using a sufficient dosage.

[EEG in newborn infants with intracranial hemorrhages: a comparison with clinical findings and CT scan]. / EEG bei Neugeborenen mit intrakraniellen Blutungen: Ein Vergleich mit klinischen Befunden und CT-Scan.

This study was undertaken to evaluate the usefulness of the EEG in neonates with intracranial hemorrhage (ICH) and to correlate the EEG with clinical findings and the CT-scan. Thirty-eight infants with intraventricular hemorrhage (IVH) and/or subarachnoid hemorrhage (SAH) had EEG examinations. Repetitive sharp waves were present in IVH (48%) and also seen in SAH (33%). They did not differentiate between IVH and SAH, nor were they related to the grade of IVH. The repetitive character of these wave forms suggest that it may be a type of seizure discharge. The value of the EEG in neonatal ICH lies not in the diagnosis of ICH and its extend. This can be done much better with CT-scan and ultrasound. But the EEG is valuable in the recognition of electrical seizure activity which should lead to early anticonvulsive therapy. Depressed background EEG activity was seen in all non-survivors and in all children with major neurological damage. Normal background activity in spite of seizure discharge was favorable prognostic criterion. The prognosis depends on the gestational age, clinical findings and morphological changes. The EEG reflects the actual cerebral function and can add to a more differentiated prognostic evaluation.

The usefulness of electroencephalography in curarized newborns.

Curare and other muscle relaxants are being used with increasing frequency in the management of infants who are mechanically ventilated for severe respiratory distress. Neurological evaluation of these paralyzed newborns is difficult and neonatal convulsions may go unrecognized. The present study includes 5 curarized infants in whom neurological impairment was suspected because of complicated pregnancies and perinatal asphyxia. All showed very abnormal EEGs with ongoing paroxysmal activity in the absence of clinical seizures or a severely depressed record. In two of these infants an improvement in the values of the blood-gases coincided with the administration of diazepam. In curarized infants the electroencephalogram is of importance in the evaluation of the background activity, the detection of convulsive brain activity, and in the management of anticonvulsive therapy.