Extrauterine life duration and ontogenic EEG parameters in preterm newborns with and without major ultrasound brain lesions.

OBJECTIVE

To determine whether extrauterine life duration is associated with different ontogenic electroencephalographic (EEG) patterns in premature infants compared with neonates born at later gestational ages (GAs).

METHODS

We included 97 preterm infants of 24-36 weeks GA. We performed neurosonography and EEG recordings at week 1 and 2 of postnatal life, then every two weeks until term conceptional age (CA). We analyzed background EEG and sleep states and compared them at matched CA.

RESULTS

In the group of infants without major ultrasound lesion (MUL), those <29 weeks GA showed increased sawtooth at 32-36 weeks CA and delta brushes from 34 to 40 weeks CA compared to infants > or =29 weeks GA. Infants with MUL compared to those without MUL showed significantly longer interburst intervals, shorter minimum burst duration at 2 and 4 weeks postnatal life, and higher incidence of sawtooth and delta brushes from 34 weeks CA to term. In addition, those of <29 weeks GA had higher rates of indeterminate sleep until 32 weeks CA. The type of MUL most frequently associated with dysmature EEG patterns was persistent ventricular dilatation.

CONCLUSIONS

Premature infants without MUL showed prolonged dysmature EEG patterns as from early CAs (> or =29 weeks). This finding was more evident in those with MUL.

SIGNIFICANCE

Extrauterine EEG development in prematures may differ from that of babies born at a later GA.