STUDY OBJECTIVES To compare delta spectral power (delta) and odds ratio product (ORP) as measures of sleep depth during sleep restriction with placebo or a drug that increases delta. METHODS This is a secondary analysis of data from a study of 41 healthy participants randomized to receive placebo or gaboxadol 15 mg during sleep restriction. Participants underwent in-laboratory sleep studies on two baseline, four sleep restriction (5-h), and two recovery nights. Relation between delta or ORP and sleep depth was operationally defined as the degree of association of each metric to the probability of arousal or awakening occurring during the next 30 s (arousability). RESULTS ORP values in wake, N1, N2, N3, and REM were significantly different. Delta differed between both N2 and N3 and other sleep stages but not between wake and N1 or N1 and REM. Epoch-by-epoch and individual correlations between ORP and delta power were modest or insignificant. The relation between ORP and arousability was linear across the entire ORP range. Delta also changed with arousability but only when delta values were less than 300 μV2. Receiver-operating-characteristic analysis found the ability to predict imminent arousal to be significantly greater with ORP than with log delta power for all experimental conditions. Changes in ORP, but not log delta, across the night correlated with next-day physiologic sleep tendency. CONCLUSIONS Compared to delta power, ORP is more discriminating among sleep stages, more sensitive to sleep restriction, and more closely associated with arousability. This evidence supports ORP as a measure of sleep depth/intensity.

中文翻译：

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比较两种睡眠深度/强度的测量值

研究目标 比较 delta 光谱功率 (delta) 和优势比乘积 (ORP) 作为睡眠限制期间睡眠深度的测量值与安慰剂或增加 delta 的药物。方法 这是对 41 名健康参与者在睡眠限制期间随机接受安慰剂或 15 mg 加波沙朵的研究数据的二次分析。参与者在两个基线、四个睡眠限制（5 小时）和两个恢复之夜进行了实验室内睡眠研究。delta 或 ORP 与睡眠深度之间的关系在操作上被定义为每个指标与在接下来的 30 秒内发生的觉醒或觉醒概率（觉醒度）的关联程度。结果唤醒、N1、N2、N3 和 REM 的 ORP 值显着不同。Delta 在 N2 和 N3 以及其他睡眠阶段之间存在差异，但在清醒和 N1 或 N1 和 REM 之间没有差异。ORP 和 delta 功率之间的逐个时代和个体相关性是适度的或不显着的。在整个 ORP 范围内，ORP 和可唤醒性之间的关系是线性的。Delta 也随可唤醒性而变化，但仅在 Delta 值小于 300 μV2 时才会发生变化。接收器操作特征分析发现，在所有实验条件下，ORP 预测即将唤醒的能力显着高于 log delta 功率。整夜的 ORP 变化，但不是 log delta，与第二天的生理睡眠趋势相关。结论 与 delta 功率相比，ORP 更能区分睡眠阶段，对睡眠限制更敏感，并且与觉醒度更密切相关。该证据支持 ORP 作为睡眠深度/强度的衡量标准。