(a) N(PSG) (30 s per epoch) during N2 sleep (epoch 555) immediately preceding the first sleep masturbation episode (epoch 556 – Fig. 1 b). EEG montage (channels 12–19) shows K-complexes and spindles. The electrooculogram (channels 7–8) indicates no rapid eye movements. The electrocardiogram (channel 11) shows no change in heart rate. Channels 20–23 represent the nasal/oral airflow, chest respiratory effort, abdomen respiratory effort and O2 saturation, which do not show any sleep apnea or oxygen desaturation during the epoch. (b) Onset of first sleep masturbation episode from N2 sleep (epoch 556).
