Figure 1.

Sample EEG signals in the time domain. Thirty-second EEG tracings in three sleep states: stage 2 and stage 4 NREM and REM sleep. The top row is taken from a male in the children's cohort who was 10.2 years of age at the time of the initial recording and 12.3 years of age at follow-up. The bottom row shows the EEG of a female in the teen cohort who was 15.7 years of age at the initial recording and 18.2 years of age at the follow-up session. The amplitude of the signal decreases with increasing age.