Transient EEG patterns during sleep in healthy newborns.

24 healthy full-term newborns underwent polygraphic recordings of EEG, EMG, EOG, ECG, abdominal and thoracic respiration during day-time-sleep. Transient EEG patterns (rhythmic alpha and beta activity, spikes/sharp waves and frontal sharp transients) were visually evaluated and quantified. Rhythmic alpha activity is not very prominent. It is found in all states of sleep and appears only as scattered waves and interrupted sequences. Their duration varies from 1 to 5 sec. Rhythmic beta activity is a feature of quiet and active-REM sleep, repeatedly in spindle-shaped formations. "Typical" sleep spindle activity, however, is very rare. In a few cases rhythmic beta activity also appears in the form of the delta brush pattern. Spikes/sharp waves are sporadic in appearance, non-repetitive in nature and occur mostly multifocal with parietal predominance. They are more frequent in quiet sleep (1 per 2.3 min on average) than in active-REM sleep (1 per 18 min), and were rare in transitional states of sleep (1 per hour). "Frontal sharp transients" show great variations of configuration. They occur most frequently in quiet sleep. Often they appear only unilaterally. Their voltage maximum is frontal, fronto-temporal or praecentral. They are more frequent in REM sleep after wakefulness than after quiet sleep. The individual as well as the sleep-state related frequencies of spike/sharp waves and "frontal sharp transients" tend to differ widely with a range of a factor 10. In some of the newborns these graphoelements are not observed at all during certain sleep phases.