Obstructive Sleep Apnea Syndrome (OSAS) is a very common sleep disorder that is associated with cardiovascular and neurocognitive impairments. The pathophysiological mechanisms underlying the morbidity of OSAS are not completely understood, which make the research on the OSAS an important issue. Obstructive sleep apnea episodes were carefully selected and segmented in three parts, the OSA event and a certain period immediately preceding and following the event, in order to assess the dynamic electroencephalographic (EEG) power changes, in four frequency bands: delta, theta, alpha and beta. Autonomic Nervous System activity was also assessed through the spectral analysis of heart rate variability components in the three mentioned periods. Continuous wavelet transform was the elected spectral analysis technique. To better visualize the EEG spectral changes during OSA episodes across the whole brain, topographic EEG brain mapping was carried out. This research should be especially useful to health professionals, who are focused on sleep disorders, or to engineers interested in the analysis of biomedical signals.