For this they will be monitored in continuous form from the birth to 10 premature babies <30 weeks of gestational age for 7 days, previous obtaining of informed consent. Protocols will be applied:quality of sign and specifics according to the raised aims. The analysis will be done by means of programs EEG Viewer and Chart Analyzer.The analysis of the bosses of aEEG and of his variations will be realized manually, applying the Burdjalov and Spitzer score. The periods before, during and after the administration of Surfactant, Indomethacin and Aminophyline were selected . In case of apneas, bradycardias and desaturation it will be compared 1 minute before with the properly such episode. These episodes will be transfer to an Excel schedule for his numerical analysis. This will allow the obtaining of averages and standard diversion of the extent of voltage of every episode and it's going to be calculated if there is any difference before and after each episode. The same is going to be done for Surfactant (5 minutes before and after), Indometacin(30 minutes before and during the 3 rates of infusion) and Aminophyline(15 minutes before and after) The level of statistics significance for all the test will be p < 0,05.