Study Objectives Within-subject stability of certain sleep features across multiple nights is thought to reflect the trait-like behavior of sleep. However, to be considered a trait, a parameter must be both stable and robust. Here, we examined the stability (i.e. across the same sleep opportunity periods) and robustness (i.e. across sleep opportunity periods that varied in duration and timing) of different sleep parameters. Methods Sixty-eight military personnel (14 W) spent 5 nights in the sleep laboratory during a simulated military operational stress protocol. After an adaptation night, participants had an 8-hour sleep opportunity (23:00–07:00) followed by 2 consecutive nights of sleep restriction and disruption which included two 2-hour sleep opportunities (01:00–03:00; 05:00–07:00) and, lastly, another 8-hour sleep opportunity (23:00–07:00). Intra-class correlation coefficients were calculated to examine differences in stability and robustness across different sleep parameters. Results Sleep architecture parameters were less stable and robust than absolute and relative spectral activity parameters. Further, relative spectral activity parameters were less robust than absolute spectral activity. Absolute alpha and sigma activity demonstrated the highest levels of stability that were also robust across sleep opportunities of varying duration and timing. Conclusions Stability and robustness varied across different sleep parameters, but absolute NREM alpha and sigma activity demonstrated robust trait-like behavior across variable sleep opportunities. Reduced stability of other sleep architecture and spectral parameters during shorter sleep episodes as well as across different sleep opportunities has important implications for study design and interpretation.

中文翻译：

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心理特征：模拟军事作战压力期间睡眠机会操纵的稳定性和稳定性

研究目标 在多个晚上的某些睡眠特征的受试者内稳定性被认为反映了睡眠的特征样行为。但是，要被视为特征，参数必须既稳定又稳健。在这里，我们检查了不同睡眠参数的稳定性（即跨越相同的睡眠机会期）和稳健性（即跨越持续时间和时间不同的睡眠机会期）。方法 68 名军事人员 (14 W) 在模拟军事操作压力协议期间在睡眠实验室度过了 5 个晚上。适应之夜后，参与者有 8 小时的睡眠机会（23:00-07:00），随后连续 2 晚睡眠限制和中断，其中包括两次 2 小时的睡眠机会（01:00-03:00；05 :00–07:00)，最后还有 8 小时的睡眠机会 (23:00–07:00)。计算组内相关系数以检查不同睡眠参数的稳定性和鲁棒性差异。结果睡眠结构参数不如绝对和相对频谱活动参数稳定和稳健。此外，相对光谱活动参数不如绝对光谱活动稳健。绝对 alpha 和 sigma 活动表现出最高水平的稳定性，在不同持续时间和时间的睡眠机会中也很稳定。结论 稳定性和稳健性因不同的睡眠参数而异，但绝对 NREM α 和 sigma 活动在不同的睡眠机会中表现出稳健的特征样行为。