Spontaneous Arousals in "CHIME" Infants at Risk for SIDS

描述（由申请人提供）：从睡眠中唤醒是对睡眠期间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，甚至猝死。唤醒机制的失败可能导致SIDS的病因。在人类婴儿中，唤醒可由刺激引起，如高碳酸血症、缺氧、喉刺激、血压变化、声音或触摸。很明显，觉醒有几个“层次”，包括皮层下（脊髓和脑干）和皮层（脑电图）觉醒。然而，关于婴儿自发觉醒的模式和特征的信息是有限的。事实上，鉴别婴儿觉醒的标准仍然存在争议。重要的是，不同程度的觉醒对生存的相对重要性是未知的。与呼吸、血压、心率和心率变异性变化相关的皮质下觉醒在婴儿中可能特别重要。其他与自主神经活动变化相关的婴儿行为，如进食，可能对唤醒机制有重要影响。我们对婴儿觉醒的了解主要来源于婴儿暴露于外部刺激的实验，在实验中观察到的反应是完全的“觉醒”。我们对自发觉醒所知甚少，它不会导致完全觉醒。最后，对婴儿自发觉醒的评估没有标准，对其发展也知之甚少。作为协同家庭婴儿监测评估（CHIME）研究的一部分，对634名婴儿进行了夜间多导睡眠图检查。这些婴儿被分为四组进行分析，包括健康足月婴儿、至少患有一例ALTE的婴儿、SIDS受害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、吸烟情况和饮酒情况。庞大的CHIME数据集包含了大量关于SIDS风险婴儿的睡眠和觉醒的信息，但尚未对唤醒的频率、持续时间和水平进行分析，也没有分析唤醒与自主神经功能或SIDS风险因素（如持续ALTE或早产）的关系。本提案的目的是系统地检查大量CHIME睡眠记录中的自发觉醒。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。我们还将比较健康足月婴儿和有SIDS风险的婴儿的觉醒特征，包括足月ALTE和早产儿，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来关注不同水平（皮层下和皮层）唤醒时自主神经活动的变化。最后，我们将研究觉醒水平、受孕后年龄、睡眠状态和其他婴儿行为（如喂养）之间的关系，这些行为也与自主神经活动的变化有关。

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.