Maturation of Phasic and Continuity Measures during Sleep in Preterm Neonates

Abstract

Different physiologic measures during EEG sleep peri-discontinuous periods of EEG activity (i.e. quiet sleep). ods in preterm neonates are postulated to change with Sleep efficiency (p < 0.001), maintenance ( p < 0.001), and maturation and reflect functional brain development. For-latency (p = 0.01) also decreased with increasing postconty-three healthy preterm neonates received 3-h EEG sleep ceptional age. Cycle length between two segments of constudies in an environmentally controlled setting. Postcon-tinuous EEG with an intervening period of EEG disconticeptional ages of neonates at each recording session ranged nuity also lengthened with maturation ( p < 0.001). These from 28 to 35 wk. Minute-by-minute analyses of EEG findings are discussed in the context of previously reported discontinuity, motility, arousals, and REM were per-differences in phasic and continuity measures noted beformed. Eight phasic events and continuity measures of tween preterm and full-term infants at matched full-term sleep were tabulated. Data were analyzed using Spearman postco~ceptional ages. Changes in phasic and continuity rank order correlation coefficients. Increases in arousal measures with increasing postconceptional ages reflect numbers ( p < 0.001) and durations ( p < 0.001) were noted maturation of specific neuronal processes of the CNS with age only during continuous periods of EEG activity within a rudimentary sleep cycle of the preterm neonate. The concept of state during early brain ontogenesis of the preterm infant is controversial. It is generally accepted that patterns representing sleep in preterm infants are highly variable (1) and less organized than patterns described for full-term infants (24). Conventional wisdom dictates that organized sleep states do not appear before 31 w k (1, 2) and are not well established until 36 w k postconceptional age (1-6). Several researchers, however, have questioned this assumption based on studies of sleep in preterm infants. Rudimentary state differentiation in terms of motor, EEG discontinuity, and autonomic function have recently been described in early preterm infants (4,(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18). Although four well-developed Received February 8, 1993; accepted May 18, 1994. Correspondence and reprint requests: Mark S. Scher, M.D., Developmental Neurophysiology Laboratory, Magee-Womens Hospital, 300 Halket St., Pittsburgh, PA 15213-3180. Supported in part by Grants NSO1110, NS26793, and MOlRR00084, the Twenty-Five Club of Magee-Womens Hospital, and the Scaife Family Fund.'Presented in part at the 7th International Child Neurology Meeting, Buenos Aires, Argentina, November 1992. sleep state segments of the full-term infant are not observed on the EEG recordings of preterm infants, specific physiologic measures may already have an established association during specific segments of the rudimentary EEG sleep cycle.Studies of the maturational trends of polysomnographic measures in asymptomatic, presumably healthy neonates will assist in the documenta...

Review of sleep-EEG in preterm and term neonates

“…In our own cohort with PMA between 27 and 31 weeks, we found a slightly shorter cycle duration between two successive QS periods based on quantitative analysis (for detailed description of this study group see [37]). This is comparable to results of visual EEG-assessment of Curzi Dascalavoa et al, and coherent with the observation of a shorter cycle duration reported by Vecchierini et al [44]. Nevertheless, there is still a notable wide range in cycle duration.…”

“…From 30 to 31 weeks onwards, physical parameters of rapid eye movement, body movement and respiration are gradually integrated and time-locked with more specific recognizable EEG patterns for QS and AS [11,17,29,43], with increasing concordance over age [20,44]. This give rise to a less chaotic and more predictable stable sleep wake organization, modulated by the developing afferent connections from the deeper brain nuclei (e.g.…”

Neonatal EEG/Sleep State Analyses: A Complex Phenotype of Developmental Neural Plasticity

“…This has been illustrated by neurophysiologic studies that compared differences between healthy preterm and full-term infants at matched postmenstrual term ages concerning sleep architecture, continuity, phasic, spectral, cardiorespiratory and temperature behaviors [21,[79][80][81][82][83] . Compared with the full-term infant, sleep of the preterm infant adapts to conditions of prematurity (i.e.…”

A neurophysiological perspective on sleep and its maturation

“…63 The temporal association of REMs with continuous EEG becomes consistent by 30 to 31 weeks' gestational age. 64,65 In infants younger than 36 weeks' gestational age, the association between REMs and continuous EEG is closer than with other features of AS, such as heart or respiratory rate variability, change in body temperature, or motility. 66 REM sleep is sometimes referred to as 'paradoxical sleep' because its EEG features have been likened to those of wakefulness.…”