Spontaneous Arousals in "CHIME" Infants at Risk for SIDS

描述(申请人提供)：从睡眠中唤醒是睡眠期间对生理挑战的保护性反应的重要组成部分，有助于保护婴儿免受潜在危险情况的影响，甚至猝死。唤醒机制的失灵可能是小儿麻痹症的病因之一。在人类婴儿中，高碳酸血症、低氧、喉刺激、血压变化、声音或触摸等刺激可能会引起唤醒。很明显，有几种“水平”的唤醒，包括皮质下(脊髓和脑干)和皮质(EEG)的唤醒。然而，关于婴儿自发唤醒的模式和特征的信息有限。事实上，识别婴儿性唤醒的标准仍然存在争议。重要的是，不同程度的唤醒对生存的相对重要性尚不清楚。皮质下觉醒与呼吸、血压、心率和心率变异性的变化有关，这可能对婴儿特别重要。其他与自主活动变化相关的婴儿行为，如喂食，可能对唤醒机制有重要影响。我们对婴儿唤醒的了解主要来自于婴儿暴露在外部刺激下的实验，在这些实验中，观察到的反应是完全的“觉醒”。对于不会导致完全觉醒的自发唤醒，我们所知的要少得多。最后，对婴儿自发唤醒的评估没有标准，对其发育情况也知之甚少。作为协作性家庭婴儿监测评估(CHME)研究的一部分，对634名婴儿进行了夜间多导睡眠图检查。这些婴儿被分成四组进行分析，包括健康的足月儿、患有至少一种ALTE的婴儿、小岛屿发展中国家患者的兄弟姐妹和早产儿。此外，还收集了重要的人口统计数据，包括产妇年龄、吸烟和饮酒情况。庞大的CHIME数据集包含了大量有关婴儿睡眠和唤醒的信息，但尚未分析唤醒的频率、持续时间和水平，或唤醒与自主神经功能或SID风险因素的关系，如持续Alte或早产。这项建议的目的是系统地检查这一大组编钟睡眠录音中的自发唤醒。我们将评估自动唤醒分析的有效性，这将有助于标准化定义。我们还将比较健康的足月儿和有SIDs风险的人(包括足月儿和早产儿)的唤醒特征，包括母亲吸烟的影响。我们还将使用复杂的心率变异性测量方法，重点研究不同唤醒水平(皮质下和皮质下)期间自主神经活动的变化。最后，我们将研究唤醒水平、怀孕后年龄、睡眠状态和其他婴儿行为之间的关系，例如喂养，这些行为也与自主活动的变化有关。

DESCRIPTION (provided by applicant): Arousal from sleep is an important component of the protective responses to physiological challenges during sleep, helping to protect the infant from potentially dangerous situations, even sudden death. Failure of arousal mechanisms may contribute to the etiology of SIDS. In human infants, arousals may be elicited by stimuli such as hypercapnia, hypoxia, laryngeal stimulation, changes in blood pressure, sound, or touch. It is clear that there are several 'levels' of arousal including subcortical (spinal and brainstem) and cortical (EEG) arousals. Information about the patterns and characteristics of spontaneous arousals in infants, however, is limited. Indeed, the criteria for identifying arousals in infants remain controversial. Importantly, the relative importance of the different levels of arousal for survival is unknown. Subcortical arousals associated with changes in breathing, blood pressure, heart rate, and heart rate variability, may be particularly important in infants. Other infant behaviors that are associated with changes in autonomic activity, such as feeding, may have important influences on arousal mechanisms. Our knowledge about arousals in infants has been largely derived from experiments where infants were exposed to external stimuli and where the observed response was a full 'awakening'. Much less is known about spontaneous arousals which do not result in a full awakening. Finally, there are no standards for the evaluation of spontaneous arousals in infants and little is known about their development. As part of the Collaborative Home Infant Monitoring Evaluation (CHIME) study, overnight polysomnograms were performed on 634 infants. These infants were divided into four groups for analysis including healthy term infants, infants suffering from at least one ALTE, siblings of SIDS victims, and premature infants. In addition, important demographic data were collected including maternal age, cigarette smoking, and alcohol use. The large CHIME dataset contains a wealth of information about sleep and arousal in infants at risk for SIDS, but has not been analyzed with regard to the frequency, duration, and level of arousals, or the relationship of arousals with autonomic function or with risk factors for SIDS, such as sustaining an ALTE or prematurity. The purpose of this proposal is to systematically examine spontaneous arousals in this large group of CHIME sleep recordings. We will evaluate the efficacy of an automated arousal analysis that will help standardize definitions. We will also make comparisons between the characteristics of arousals in healthy full term infants and those at risk for SIDS, including full term ALTE and premature infants, including the effects of maternal cigarette smoking. We will also focus on shifts in autonomic activity during different levels (subcortical and cortical) of arousals using sophisticated measures of heart rate variability. Finally, we will examine the relationships among the level of arousal, post-conceptional age, sleep state, and other infant behaviors such as feeding that are also associated with changes in autonomic activity.