Does bladder voiding during sleep and wakefulness change the behavioural state of infants?

Abstract

To evaluate whether bladder voiding in healthy infants is accompanied by body movements or any changes in heart rate (HR), respiratory frequency (RF) or electroencephalogram (EEG) frequency during sleep and during wakefulness. Polygraphic recordings were performed on 33 healthy infants (17 female) born at term. The infants' age at study entry was 41+/-10 d, and actual body weight was 4876+/-403 g (mean+/-SD). Bladder voiding was recorded by an adapted enuresis detector connected to the polygraphic computer unit. Awakening was observed in 12 (36%) infants 77+/-9 s before bladder voiding. Twenty-one infants (64%) continued sleeping during bladder voiding. In sleeping infants, bladder voiding occurred during non-REM sleep only, and was accompanied by a cortical arousal. During wakefulness, RF was lower, and HR and EEG frequency were higher, but stayed constant during bladder voiding. Our observations demonstrate that bladder voiding in healthy infants during sleep is accompanied by body movements and changes in HR and EEG frequency, indicating cortical arousals, whereas during wakefulness these changes cannot be observed.