Figure 1From: A transition-constrained discrete hidden Markov model for automatic sleep staging Typical polygraphic recordings during the wake (WK), stage 1 (S1), stage 2 (S2) light sleep, slow-wave sleep (SWS) associated with deep sleep, and rapid-eye movement (REM) states. Legend: Each raw shows the electroencephalography (EEG), electrooculography (EOG) and chin electromyography (EMG) data during the corresponding sleep stage.Back to article page