Relationship Between Cerebral Blood Flow Velocities and Cerebral Electrical Activity in Sleep

Hajak, Göran; Klingelhöfer, Jürgen; Schulz-Varszegi, M.; Matzander, G.; Sander, Dirk; Conrad, Bastian; Rüther, Eckart

doi:10.1093/sleep/17.1.11

Cited by 81 publications

(71 citation statements)

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“…Interestingly, in the current study using a more sensitive multiple regression analysis, a small decrement in PCD (0.36 s) was identified in AS. We are unsure why this small decrement occurs, but it may mirror the effect of an increased cerebral blood velocity during AS (15,16) leading to a small reduction in lung-chemoreceptor delay and PCD. In addition, we found that SP had no effect on PCD maturation, suggesting that the respiratory control system and circulation delay are not influenced by whether the infant is prone or supine; this finding argues against a role for vestibular processes in the declining trend in PCD.…”

Section: Discussionmentioning

confidence: 97%

Postnatal Development of Periodic Breathing Cycle Duration in Term and Preterm Infants

Wilkinson

Skuza

Rennie³

et al. 2007

Pediatr Res

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Previous studies of the maturation of periodic breathing cycle duration (PCD) with postnatal age in infants have yielded conflicting results. PCD is reported to fall in term infants over the first 6 mo postnatally, whereas in preterm infants PCD is reported either not to change or to fall. Contrary to measured values, use of a theoretical respiratory control model predicts PCD should increase with postnatal age. We re-examined this issue in a longitudinal study of 17 term and 22 preterm infants. PCD decreased exponentially from birth in both groups, reaching a plateau between 4 and 6 mo of age. In preterm infants, PCD fell from a mean of 18.3 s to 9.8 s [95% confidence interval (CI) is Ϯ 3.2 s]. In term infants, PCD fell from 15.4 s to 10.1 s (95% CI is Ϯ 3.1 s). The higher PCD at birth in preterm infants, and the similar PCD value at 6 mo in the two groups, suggest a more rapid maturation of PCD in preterm infants. This study confirms that PCD declines after birth. The disagreement between our data and theoretical predictions of PCD may point to important differences between the respiratory controller of the infant and adult. E xperimental evidence is accumulating that PB in the infant, as in the adult, is caused by instability in the respiratory control system, possibly mediated by increased hypoxic stimulation of the peripheral chemoreflex feedback loop during the early postnatal period (1,2). Furthermore, math modeling studies of respiratory control based on a downscaling of adult cardiorespiratory time constants to the infant (3,4) support such a conclusion. Of interest, the theoretical model of Khoo et al. (3) predicts that the PCD should increase progressively with age from approximately 18 s at birth to an adult value in excess of 30 s.Surprisingly, most infant data contradict this model prediction, with three longitudinal studies in term infants (5-7) and one small study in preterm infants (1) reporting that PCD decreases significantly from birth to 6 mo postnatally. However, another cross-sectional study of selected long epochs of PB in a larger group of preterm infants studied just before discharge from the nursery reported that PCD showed no trend or a weakly increasing trend over the first 3 mo postnatally (8); while the results of this study could be interpreted as conforming with the predictions of the Khoo model scaled to the infant, we have argued previously that the study design may have biased the outcome (1).To resolve the issue as to whether PCD decreases or increases with postnatal age, further longitudinal studies were warranted in a larger population of term and preterm infants. Based on our earlier studies, and consistent with recent findings that the ventilatory response to CO 2 becomes brisker with age (9), we hypothesized that the reduction in PCD commencing at birth and completed by 6 mo postnatally in both term and preterm infants represents a similar adaptation to air breathing and is mediated principally by changes in the response time of the peripheral chemoreceptors. ...

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Section: Discussionmentioning

confidence: 97%

Postnatal Development of Periodic Breathing Cycle Duration in Term and Preterm Infants

Wilkinson

Skuza

Rennie³

et al. 2007

Pediatr Res

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“…The diversity of species investigated and the techniques used are certainly part of the answer. However, other factors are less understood, such as the intriguing possibility of sleep-independent across-night CBF decreases (Hajak et al 1994) or the possible confounding eect of circadian rhythms, which may also be involved. A better knowledge of CBF regulation during sleep is certainly needed at this stage.…”

Section: Application Of Spm In Sleepmentioning

confidence: 99%

Functional neuroimaging of normal human sleep by positron emission tomography

Maquet

2000

Journal of Sleep Research

562

312

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Functional neuroimaging using positron emission tomography has recently yielded original data on the functional neuroanatomy of human sleep. This paper attempts to describe the possibilities and limitations of the technique and clarify its usefulness in sleep research. A short overview of the methods of acquisition and statistical analysis (statistical parametric mapping, SPM) is presented before the results of PET sleep studies are reviewed. The discussion attempts to integrate the functional neuroimaging data into the body of knowledge already acquired on sleep in animals and humans using various other techniques (intracellular recordings, in situ neurophysiology, lesional and pharmacological trials, scalp EEG recordings, behavioural or psychological description). The published PET data describe a very reproducible functional neuroanatomy in sleep. The core characteristics of this ‘canonical’ sleep may be summarized as follows. In slow‐wave sleep, most deactivated areas are located in the dorsal pons and mesencephalon, cerebellum, thalami, basal ganglia, basal forebrain/hypothalamus, prefrontal cortex, anterior cingulate cortex, precuneus and in the mesial aspect of the temporal lobe. During rapid‐eye movement sleep, significant activations were found in the pontine tegmentum, thalamic nuclei, limbic areas (amygdaloid complexes, hippocampal formation, anterior cingulate cortex) and in the posterior cortices (temporo‐occipital areas). In contrast, the dorso‐lateral prefrontal cortex, parietal cortex, as well as the posterior cingulate cortex and precuneus, were the least active brain regions. These preliminary studies open up a whole field in sleep research. More detailed explorations of sleep in humans are now accessible to experimental challenges using PET and other neuroimaging techniques. These new methods will contribute to a better understanding of sleep functions.

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“…Coupling between CBF and EEG features has been observed during sleep (13,14), seizures (15,16), electrical stimulation (17), and cerebral ischemia (18), but thresholds of CBF and cerebral O 2 supply below which electrical brain dysfunction occurs during hemorrhagic hypotension have not yet been defined in near-term-born humans and animals. Therefore, the aim of this study was to determine the effect of gestational age (GA) on the cerebral O 2 supply threshold level for the preservation of ECBA during hemorrhagic hypotension in near-termborn lambs.…”

mentioning

confidence: 99%

Cerebral O2 Supply Thresholds for the Preservation of Electrocortical Brain Activity During Hypotension in Near-Term-Born Lambs

Os¹,

Liem²,

Hopman³

et al. 2005

Pediatr Res

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The fetal brain develops rapidly during the last trimester of pregnancy. Therefore, the brain of infants who are born preterm is vulnerable to changes in oxygen and nutrient supply in the neonatal period. The objective was to determine the effect of gestational age (GA) on the cerebral O 2 supply threshold level for preservation of brain function during hypotension in nearterm-born lambs. Lambs were delivered at 141 or 127 d of gestation Approximately 2% of all newborns in the Netherlands are born before 32 completed weeks of gestation. Although mortality rates have decreased over the past 15 y, long-term morbidity has not changed (1). Because the fetal brain develops very rapidly during the last trimester of pregnancy, the brain of infants who are born preterm is very vulnerable to changes in oxygen and nutrient supply in the neonatal period.Brain cells need a sufficient amount of oxygen for function, growth, and development. Cerebral O 2 supply is determined by the arterial oxygen content (CaO 2 ) and cerebral blood flow (CBF). If cerebral autoregulation is impaired, then hypotension results in low CBF and leads to decreases in cerebral O 2 supply. When cerebral O 2 supply becomes insufficient to meet the cellular demand for oxygen, a sequence of events will be triggered, eventually leading to neonatal brain cell dysfunction or damage.EEG features provide information on brain cell function (2). Energy failure in the brain, e.g. as a result of reduced cerebral O 2 supply during hemorrhagic hypotension, leads to a blockade of neuronal synaptic function and reduced electrical firing of neurons. A disadvantage of conventional EEG is that it requires the presence of an expert to interpret the large volumes of data. In an effort to solve this problem, various methods of compressing the EEG signal have been developed, the cerebral function monitor (CFM) being one of them. CFM correlates well with conventional multichannel EEG evaluation of cortical neuronal activity in neonates, except for the recognition of very short seizure activity patterns (3-8). Noninvasive recording of electrocortical brain activity (ECBA) by means of CFM-like signals can be used as a measure for brain cell function in the newborn period (2). Abnormal tracings are indicative of the risk for neonatal death and in the survivors to neurodevelopmental outcome (3,9 -12).

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Relationship Between Cerebral Blood Flow Velocities and Cerebral Electrical Activity in Sleep

Cited by 81 publications

References 0 publications

Postnatal Development of Periodic Breathing Cycle Duration in Term and Preterm Infants

Postnatal Development of Periodic Breathing Cycle Duration in Term and Preterm Infants

Functional neuroimaging of normal human sleep by positron emission tomography

Cerebral O2 Supply Thresholds for the Preservation of Electrocortical Brain Activity During Hypotension in Near-Term-Born Lambs

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