Development of ultradian rhythm of EEG activities in premature babies.
Ultradian rhythms in electroencephalogram (EEG) activity in premature neonates were studied. The values of square roots of total power (SQP) of EEG showed a normal Gaussian distribution. We analyzed the smoothed time series of SQP by autoregressive analysis and component analysis. Ultradian rhythm was divided into four groups by period length (group I: 5-30 min, group II: 30-60 min, group III: 60-100 min, group IV: longer than 100 min). Group IV rhythms were not detected before 32 weeks of gestation. Changes in the characteristic values of ultradian components in group II showed that there were critical periods in the development of central nervous activity at 29 and 33 weeks of gestation. This method allowed detection of ultradian rhythms, even at very early gestation, directly from the neonatal central nervous system. This method may be applicable to ill infants.
Wakayama
K
K
Department of Pediatrics, Oita Medical University, Japan.
Ogawa
T
T
Goto
K
K
Sonoda
H
H
D000204:Activity Cycles; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography; D005260:Female; D005500:Follow-Up Studies; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D008297:Male; D012044:Regression Analysis