DoD Biotechnology High-Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, US Army Medical Research and Materiel Command, Fort Detrick, MD 21702, USA.
J Sleep Res. 2012 Dec;21(6):659-74. doi: 10.1111/j.1365-2869.2012.01008.x. Epub 2012 Mar 21.
We have developed a new psychomotor vigilance test (PVT) metric for quantifying the effects of sleep loss on performance impairment. The new metric quantifies performance impairment by estimating the probability density of response times (RTs) in a PVT session, and then considering deviations of the density relative to that of a baseline-session density. Results from a controlled laboratory study involving 12 healthy adults subjected to 85 h of extended wakefulness, followed by 12 h of recovery sleep, revealed that the group performance variability based on the new metric remained relatively uniform throughout wakefulness. In contrast, the variability of PVT lapses, mean RT, median RT and (to a lesser extent) mean speed showed strong time-of-day effects, with the PVT lapse variability changing with time of day depending on the selected threshold. Our analysis suggests that the new metric captures more effectively the homeostatic and circadian process underlying sleep regulation than the other metrics, both directly in terms of larger effect sizes (4-61% larger) and indirectly through improved fits to the two-process model (9-67% larger coefficient of determination). Although the trend of the mean speed results followed those of the new metric, we found that mean speed yields significantly smaller (∼50%) intersubject performance variance than the other metrics. Based on these findings, and that the new metric considers performance changes based on the entire set of responses relative to a baseline, we conclude that it provides a number of potential advantages over the traditional PVT metrics.
我们开发了一种新的精神运动警觉测试（PVT）指标，用于量化睡眠剥夺对表现损伤的影响。新指标通过估计 PVT 测试过程中反应时间（RT）的概率密度来量化表现损伤，然后考虑相对于基线测试过程的密度偏差。一项涉及 12 名健康成年人的对照实验室研究的结果表明，这些成年人经历了 85 小时的延长清醒，随后进行了 12 小时的恢复性睡眠，新指标的组表现变异性在整个清醒过程中保持相对均匀。相比之下，PVT 失误、平均 RT、中位数 RT 和（在较小程度上）平均速度的变异性表现出强烈的时间效应，PVT 失误变异性随时间而变化，具体取决于所选的阈值。我们的分析表明，新指标比其他指标更有效地捕捉到睡眠调节的内稳态和生物钟过程，这不仅直接体现在更大的效应大小（4-61%更大）上，而且还通过对双过程模型的拟合更好（9-67%更大的决定系数）。尽管平均速度结果的趋势与新指标一致，但我们发现平均速度产生的受试者间表现变异性明显小于其他指标（约 50%）。基于这些发现，以及新指标考虑了相对于基线的整个反应集的表现变化，我们得出结论，与传统的 PVT 指标相比，它提供了一些潜在的优势。
