Dynamic changes in EEG spectra during obstructive apnea in children

Children are less likely to demonstrate EEG arousal during obstructive slee p apnea (OSA) than adults. We hypothesized that changes in spectral EEG cha racteristics occur during REM-associated OSA in the absence of arousal. Eig ht snoring children underwent overnight polysomnography. OSA events during REM periods not associated with EEG or behavioral arousal were identified. EEG signals from C3A2 and C4A1 leads corresponding to 1) less than or equal to 10-sec epochs preceding OSA (PRE), 2) the obstructed period (OSA), and 3) less than or equal to 10-sec epochs following airflow resumption (POST) were subjected to fast Fourier transform (FFT) routines. Seventy-two isolat ed OSA, and 14 clusters of > 4 OSA events were analyzed. In single OSA, delta OSA amplitude was lower than in PRE (P < 0.01) and in POST (P < 0.001). Furthermore, POST delta amplitude was higher than PRE (P < 0.01). In contrast, in OSA clusters, the dynamic differences in delta amp litude disappeared after the second OSA. Reciprocal increases and decreases occurred for the theta frequency domain during OSA and post-OSA, while sig ma and beta frequency power did not change. We conclude that during isolated OSA episodes without arousal, significant decreases in power selectively occur for delta frequency, and are followed by a rebound increase upon termination of apnea. The delta changes are prog ressively attenuated during repeated OSA. We postulate that delta changes m ay reflect ongoing adaptations in sleep pressure which are necessary to rel ieve the respiratory compromise, and may represent subtle evidence for arou sal and consequent sleep fragmentation in children with OSAS. Pediatr Pulmo nol, 2000; 29:359-365, (C) 2000 Wiley-Liss, Inc.