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[Sleep organization in normal premature newborn infants. Polygraphic study]
Insights
Neonatal sleep state analysis reveals active sleep (AS) is consistent, but quiet sleep (QS) is often interrupted in preterm infants. Concordance of QS criteria does not improve with conceptional age.
Area of Science:
- Neonatal Sleep Physiology
- Developmental Neuroscience
- Polygraphic Sleep Studies
Context:
- Understanding sleep architecture in preterm neonates is crucial for assessing neurodevelopmental outcomes.
- Previous studies have utilized polygraphic recordings to characterize sleep states in infants.
- The conceptional age (CA) significantly influences sleep patterns during early development.
Purpose:
- To analyze the concordance of various polygraphic parameters for defining sleep states in preterm neonates.
- To investigate the duration and characteristics of active sleep (AS) and quiet sleep (QS) in relation to conceptional age.
- To assess the reliability of different criteria for identifying QS in developing infants.
Summary:
- Polygraphic recordings (EEG, REM, EMG, respiration) were conducted on 23 neonates aged 31-38 weeks CA.
- Active sleep (AS) duration was consistent across sleep cycles and unaffected by additional criteria.
- Quiet sleep (QS) duration was frequently shortened and interrupted by indeterminate sleep (IS) when considering respiration and motility, with no improved concordance at later CA.
Impact:
- Highlights the challenges in definitively classifying quiet sleep in preterm neonates using standard polygraphic measures.
- Suggests that respiratory and motility data can fragment quiet sleep, impacting its apparent duration and stability.
- Provides insights into the maturational changes in sleep regulation and the limitations of current sleep scoring criteria in this population.
Abstract:
Polygraphic recordings including EEG, eye movements (REMs) and limb movements (recorded by piezo-electric crystals), chin EMG and respiratory rate, were performed in 23 normal neonates of 31 to 38 weeks conceptional age (CA). The concordance between various parameters characteristic for sleep states was analysed. For all infants, it was possible to define periods (greater than 7 min) of active (AS) and quiet sleep (QS) according to EEG and REM criteria. Mean duration of the 1st sleep cycle (including both AS and QS) lasted 57 to 65 min; no significant difference regarding CA was observed. According to EEG and REM criteria, AS accounted for 47 to 52% of each sleep cycle; QS rose from 27% at 31-34 wCA to 33% at 35-36 wCA (P less than 0.05); indeterminate sleep (IS) decreased from 32% at 31-34 wCA to 10% at 35-36 wCA (P less than 0.01). At all ages studied, the observed duration of AS was not modified when other criteria were considered in addition to EEG and REMs. On the contrary, the observed duration of QS was frequently shortened and scattered with interruptions (indeterminate sleep) when respiration and body motility were considered; but the tonic EMG remained for 80% of QS. The concordance between different criteria characteristic for QS was not better at 37-38 wCA compared to 31-34 wCA.