title: Power spectral analysis of the neonatal primate electroencephalogram during acute hypoxemia.
abstract: The effect of acute graded hypoxemia on the electroencephalogram (EEG) of five prematures and five full term Macaca nemestrina in the neonatal period was determined using power spectral analysis--a technique that obviates the limitations of visual inspection. The EEG of selected epochs was analyzed by a Fast Fourier Transform program (POWER) during the 20 min of each trial of hypoxemia and compared with simultaneous arterial oxygen tensions. Levels of hypoxemia were graded as profound (PaO2=15-25 Torr); severe (PaO2=26-35 Torr), moderate (PaO2=36-50 Torr), or mild (PaO2=51-75 Torr). The EEG during normoxemia had a band width of 0.5 to 10 Hz and a peak power at 1-3 Hz. During mild hypoxemia, an increase in power in the delta range (0-3.5 Hz) occurred in the oldest animals. At moderate hypoxemia, the youngest animals showed a depression of absolute power in the delta band. A slowing of the EEG and decrease in power in the theta frequency range (4-8 Hz) followed when severe hypoxemic levels are reached. During profound hypoxemia, all animals at each postnatal age exhibited a significant decrease in EEG power at the delta and theta frequencies (P less than 0.025) except 3-wk-old full term animals in which there was no significant change in the delta band. These results clarify and extend previously reported effects of hypoxemia on the neonatal EEG.
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001921:Brain / Q000378:metabolism / Q000473:pathology; D004569:Electroencephalography; D005260:Female; D005311:Fetal Hypoxia / Q000503:physiopathology; D000860:Hypoxia / Q000503:physiopathology*; D008254:Macaca nemestrina; D011247:Pregnancy