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. Author manuscript; available in PMC: 2014 Aug 1.
Published in final edited form as: Crit Care Med. 2013 Aug;41(8):10.1097/CCM.0b013e31828a3f75. doi: 10.1097/CCM.0b013e31828a3f75

Figure 4.

Figure 4

Examples of atypical electroencephalography (EEG) findings which if scored using standard sleep staging criteria would cause misleading results. A, Polysomnography (PSG) demonstrating burst suppression, which if standard scoring criteria were used, would be misleadingly scored as stage N1 sleep. This epoch would be scored as stage At4 by the proposed scoring criteria. B, PSG demonstrating EEG waveforms with lack of background activity are only seen in pathologic states. This epoch would be scored as At3 by the proposed criteria. C, PSG demonstrating onset of rhythmic delta activity after stimulations of patient (suctioning), which would be misleadingly scored as stage N3 sleep if standard scoring criteria were used. Using the proposed criteria, this epoch would be scored as At2.