Ontogenesis of sleep in human prematures after 32 weeks of conceptional age

Dreyfus-Brisac, C

doi:10.1002/dev.420030203

Cited by 209 publications

(101 citation statements)

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“…Cyclicity was initially suggested on the basis of (2,3,5,20,21), with the absence of cyclicity observed in encephalopathic infants (6) as well as asymptomatic high-risk infants for sudden infant death syndrome (22). Later reports by certain authors argued that more strict methods to define cyclicity failed to document sleep cycles until later during the first year of life.…”

Section: Discussionmentioning

confidence: 99%

Cyclicity of Neonatal Sleep Behaviors at 25 to 30 Weeks' Postconceptional Age

2005

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Previous sleep studies of preterm neonates describe the rudimentary expression of sleep state cyclicity after 30 wk postconceptional age (PCA), with stability over multiple cycles only after 36 wk PCA. The research objective for this study was to determine whether sleep state cyclicity was expressed in neonates of 25-30 wk PCA, using two criteria for state identification. Our neonatal sleep consortium includes a total cohort of 359 children who were healthy and medically ill neonates who were recruited from three obstetric-neonatal services and received multiple-hour EEG sleep studies. A subset of the 33 youngest preterm infants were selected to evaluate the first of serial 2-to 3-h EEG-sleep recordings to assess the presence of sleep state cyclicity. One neonatal neurophysiologist visually assigned EEG-sleep characteristics for each record. Rapid eye movement (REM) counts and EEG discontinuity were specifically chosen to assess whether sleep cyclicity was expressed. A combined measure of REM and EEG discontinuity were used in an autocovariance analysis to assess cycling and mean cycle duration. A mean cycle duration of 68 Ϯ 19 min with a range of 37-100 min was determined from the REM-EEG discontinuity state for 24 neonates. The remaining nine infants had absent or poor sleep cyclicity. Sleep state cyclicity is expressed for a majority of neonates between 25 and 30 wk PCA, reflecting an ultradian biologic rhythm during the early perinatal stage of brain development. (Pediatr Res 57: 879-882, 2005) Abbreviations GA, gestational age PCA, postconceptional age REM, rapid eye movement Functional brain organization can be assessed by applying analyses to EEG-sleep state architecture and continuity measures. The observation of sequentially recurring eye movement intervals alternating with no eye movement epochs was initially described in the newborn infant as early as the 1950s (1). Such a sequence suggests either the presence of a highly periodic process or, alternatively, the temporal coincidence, with variable predictability, among physiologic behaviors that sometimes define state transitions. Early investigators suggested the presence of periodicity in infant sleep measures (2,3). Sterman et al. (4) observed periodicity from early gestational ages (GAs), beginning with the basic rest-activity cycle in the fetus and the sleep cycle in infants. Globus (5) described cyclicity at all GAs, with predictable rhythmicity after 36 wk postconceptional age (PCA). Other authors stressed the clinical importance of sleep periodicity, as exemplified by reports of disturbed cyclic organization of sleep in infants with CNS disorders (6) as well as asymptomatic infants at risk for sudden infant death syndrome (7,8).Specific investigations questioned the definition of sleep state cyclicity when applying alternative methods, particularly when states were considered categorical events (5,9,10). On the basis of these specific methodologic approaches, sleep cyclicity did not appear until at least 6 wk of life (11), 4 -6 mo postnatally (...

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Section: Discussionmentioning

confidence: 99%

Cyclicity of Neonatal Sleep Behaviors at 25 to 30 Weeks' Postconceptional Age

2005

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“…Earlier studies suggested that organized sleep states do not appear before 32 weeks of gestation. 28,29 However, possibly because of improvements in neonatal intensive care in the last decades, more recent studies have described rudimentary sleep states in extremely premature infants. 5,30 Intact sleep organization is a prognostic factor in preterm infants.…”

Section: E64mentioning

confidence: 99%

Reference Values for Amplitude-Integrated Electroencephalographic Activity in Preterm Infants Younger Than 30 Weeks’ Gestational Age

et al. 2004

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ABSTRACT. Objective. To prospectively investigate the development of amplitude-integrated electroencephalographic (aEEG) activity during the first 2 weeks of life in neurologically normal and clinically stable preterm infants <30 weeks' gestational age (GA).Patients and Methods. Infants with a GA of <30 weeks admitted to the neonatal intensive care unit of the Vienna University Children's Hospital (Vienna, Austria) were studied prospectively by using aEEG and cranial ultrasound. Clinically stable infants without clinical or sonographic evidence of neurologic abnormalities were eligible for inclusion in the reference group. The distribution of 3 background aEEG activity patterns (discontinuous low-voltage, discontinuous high-voltage, and continuous), presence of sleep-wake cycles, and number of bursts per hour in the reference group were determined by visual analysis.Results. Seventy-five infants (median GA: 27 weeks; range: 23-29 weeks) were eligible for inclusion in the reference group and had aEEG recordings during the first 2 weeks of life available. Analysis of aEEG background activity showed that with higher GA the relative amount of continuous activity increased while discontinuous patterns decreased. The number of bursts per hour decreased with increasing GA. Cyclical changes in aEEG background activity resembling early sleep-wake cycles were observed in all infants.Conclusions. Normal values for aEEG background activity were determined in preterm infants <30 weeks' GA. Clinically stable and neurologically normal preterm infants exhibit at least 2 different patterns of aEEG activity. There is a correlation between the GA and the relative duration of continuous aEEG activity. A dvances in neonatal intensive care during the last decades have led to an increased survival rate of extremely low birth weight infants. However, neurologic and developmental disability is still common among survivors. 1 Prevention of brain injury in these patients has become one of the main goals of modern neonatology. Continuous monitoring of neonatal brain function may aid in the identification of risk factors and patients at increased risk for neurologic morbidity. Early recognition and modification of potentially harmful environmental factors may prevent secondary brain injury.Conventional electroencephalography (EEG) is one of the most useful tools for intermittent and continuous assessment of brain function and prediction of neurologic outcome in term infants and children. 2-4 However, conventional EEG has limitations in its application for extremely low birth weight infants. Registration and interpretation of conventional EEG in this age group are difficult because of the electrical interferences on the neonatal intensive care unit, the large volume of data generated during a longer recording, and the need for 24-hour availability of a skilled examiner experienced in EEG of preterm infants. Further, data on normal EEG patterns in extremely premature infants are still limited. 5,6 Recently, amplitude-integrated EEG (aEEG) pro...

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“…Similarly, the period of rapid division of dentate granule cells occurs by 1 month of age in the rat but by 10 days in the guinea pig (Altman and Das 1965, 1967). Also, rapid maturation of EEG activity and traces reflecting active and quiet sleep appear in the guinea pig between day 50-56 of gestation (full gestation ϭ 65-72 days), at 35-37 weeks in the human (full gestation for term infant ϭ 37-41 weeks), and between postnatal days 10-13 in the rat (full gestation ϭ 21-22 days) (Dreyfus-Brisac 1970;Jouvet-Mounier et al 1970;Gramsbergen 1976;Umans et al 1985; see reviews by Prechtl 1974;Romijn et al 1991).…”

Section: Schizophrenia Is Associated With Increased Birth Complicatiomentioning

confidence: 99%

Birth Insult Alters Dopamine-Mediated Behavior in a Precocial Species, the Guinea Pig Implications for Schizophrenia

Vaillancourt

Boksa

2000

Neuropsychopharmacology

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Schizophrenia is associated with increased birth complications, suggesting that birth complications might alter CNS dopaminergic activity later in life. In rats, Caesarean section (C-section) birth can produce long term changes in dopaminergic biochemistry and behavior. However rat brain is somewhat immature compared to human brain at birth. The current study tested if mild birth complications also alter dopamine-mediated function in a species with a more mature CNS at birth, the guinea pig. As adults, guinea pigs born by C-section showed increased amphetamine-induced locomotion and disruption of prepulse inhibition (PPI) of acoustic startle, compared to vaginally born controls. Guinea pigs born by C-section withThere is considerable evidence that enhanced mesolimbic dopaminergic activity plays an important role in some of the symptomatology of schizophrenia (e.g., Laruelle et al. 1996Laruelle et al. , 1999Breier et al. 1997; AbiDargham et al. 1998; see reviews by Seeman 1992; Lieberman et al. 1997). In addition, a large number of epidemiological studies have demonstrated that perinatal complications, often involving fetal or neonatal hypoxia, are associated with increased risk for the development of schizophrenia (e.g., Geddes and Lawrie 1995;Jones et al. 1998;Dalman et al. 1999;Hultman et al. 1999;Zornberg et al. 2000; see review by McNeil 1995).Animal modelling provides the opportunity to directly test if a birth complication, such as hypoxia, can cause long term changes in dopaminergic function. Using a rat model of global hypoxia during Caesarean section (C-section) birth, several laboratories have demonstrated that dopaminergic systems are sensitive to mild birth alterations (Bjelke et al. 1991;Loidl et al. 1994;Chen et al. 1995Chen et al. , 1997 Brake et al. 1997a,b; Boksa 1997, 1998;Vaillancourt and Boksa 1998; Berger et al. 2000a). Specifically, as adults, rats born by C-section, either with or without addition of a period of global hypoxia, show increased nucleus accumbens dopamine (DA) release in response to repeated stress (Brake et al. 1997b) Vaillancourt et al. 1999), similar to the reported increased incidence of mild respiratory distress in humans born by C-section (Hales et al. 1993).In relation to the possible clinical relevance of these results, rat brain is generally believed to be somewhat less mature at birth than is the brain of the human newborn. It has been suggested that, at approximately postnatal day 10, the brain of the rat is at the stage of rapid growth, accelerated synaptogenesis, myelinization, and astrocyte proliferation characteristic of the human newborn at term (see review by Romijn et al. 1991). Thus, the model of birth insult in the rat may relate more to premature than to term human brain. To circumvent this limitation, we initiated the current studies to test if mild birth complications also alter DA mediated function in a species with a more mature CNS at birth. The guinea pig is a precocial species, that is, capable of a high degree of independent activity at birth....

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Ontogenesis of sleep in human prematures after 32 weeks of conceptional age

Cited by 209 publications

References 32 publications

Cyclicity of Neonatal Sleep Behaviors at 25 to 30 Weeks' Postconceptional Age

Cyclicity of Neonatal Sleep Behaviors at 25 to 30 Weeks' Postconceptional Age

Reference Values for Amplitude-Integrated Electroencephalographic Activity in Preterm Infants Younger Than 30 Weeks’ Gestational Age

Birth Insult Alters Dopamine-Mediated Behavior in a Precocial Species, the Guinea Pig Implications for Schizophrenia

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