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    每个人都需要睡眠，但是在军事行动中会有暂时的睡眠剥夺情况。　

    国防基金部的研究员Sean Drummond博士为了获得军人和平民的睡眠相关问题的正确分析，进行了为期4年的研究，分析了睡眠剥夺对于大脑即决策能力的影响，同时也估测了从睡眠剥夺期恢复到正常状态所需的时间。

   “在我们缺乏睡眠时，不能保证每时每刻都把事情处理得当。睡眠剥夺可以明显的损害注意力、工作记忆力及驾驶的能力，这一点正如酒精所起的作用一样，”Drummond说。Drummond博士正与加利福尼亚州圣地亚哥大学和圣地亚哥老龄健康体系的研究员们一同致力于这项研究。

    在五月期的飞行安全杂志上，Brain Drummond上校，作为伊拉克地区KC-135空中加油机的驾驶员，叙述了三月份的一次加油任务中险些造成的失误事故，由于使燃料从机体中泄漏过多，导致了飞机失衡。他认为这次失误根源于过多的任务和过少的睡眠。他回忆道，在结束了12次6-7个小时的飞行任务，完成了所有的简报、任务报告和起飞前后的准备工作之后，那时的他和战友们就如同“行走的僵尸”一般。

   “我认为直到你最终可以休息的时候，你才会明白身体里面深深的疲劳感，”他说，“即使在有11次的突击任务中，我获得了足够的休息，我的身体和我的感官仍然是麻木的。我坚信，由于在自由伊拉克行动中所行使的任务里，我们的军队疲劳至极忘记的许多琐碎的事情，如果加起来就会是非常大的事情。”

    由于有很多类似Drummond所犯的过错，国防部同行评审医学研究项目基金会对Drummond现象作以研究。国会在1999年设立了促进研究军队所面临的严峻健康问题的法案。从其开始至2005年，这项计划花费了三亿美元，用于一系列医疗项目的200余个研究，包括战斗伤亡的护理和医疗技术及传染病方面的研究。

    研究小组招募了40名有良好睡眠习惯的自愿者，他们同意在实验室居住6天。在这段时间内，自愿者经历了两个正常的白天和夜晚，然后保持清醒64个小时，随后允许恢复睡眠，研究员们充分观测了自愿者整个身体复原的过程。

    在自愿者的清醒时期，他们每两个小时进行一次为时半小时的学习、记忆和决策试验，从而评估其剥夺睡眠不同时期的表现。比如，其中的一个试验是要求自愿者记下一系列的名词。Drummon和研究小组在早晚都为自愿者进行了功能磁共振的扫描，记录了大脑的反应情况。图像可以观测到大脑中的氧耗量，无论使用脑的哪一部分，它都会需求更多的氧气。

    “大脑是一个系统，一个网络区域，各个部分共同运转完成任务。”他说。

    研究员发现，自愿者的记忆力在剥夺睡眠后36小时仍不受影响，这并不是因为他们很健康，亦不是因为他们平均年龄只有24岁，原因是大脑的其他区域都在代偿辅助记忆区。

    “大脑确实可以补偿睡眠剥夺造成的功能减退。在人们获得了充足的睡眠后，代偿区域处于关闭状态，反之，呈现开放状态，”Drummon说，“这部分区域得到越好的利用，它们在剥夺睡眠后的表现会越好。”

    剥夺睡眠后的60个小时，多数的自愿者的测试成绩要差于36小时的成绩。因为在睡眠剥夺的2.5天之后，大脑将不能够获得任何的代偿帮助。

    “我认为运用这些数据来预测和推断哪些人在睡眠剥夺后易于恢复精力，哪些人在睡眠剥夺后难以恢复有着重要意义。” Drummon说，“这样做的好处在于，我们可以更好地了解睡眠剥夺对较复杂认知功能（其不同于简单的注意力）的影响，同时还可以更准确地推测睡眠剥夺后恢复到正常状态所需的时间。”

    Drummon的研究小组也发现了从剥夺睡眠后64个小时后恢复过来，并不像睡几个好觉那么简单。

    “我们发现在执行一些任务之后，即使他们仅仅失去了2个夜晚的睡眠，补充了两整晚的睡眠后，他们的大脑功能仍不能完全恢复，”他说，“如果军队和平民都普遍存在睡眠不足的情况，毫无疑问，我们需要明白会发生什么事情并且来阻止它的发生。”

Researcher studies sleep deprivation's effect on decisions
Everyone needs sleep, but temporary periods with no sleep can be a reality of military operations.

To get answers on sleep questions for the military as well as civilians, for nearly four years Dr. Sean Drummond, a Department of Defense-funded researcher, has studied the effects of sleep deprivation on the brain, namely in decision making, as well as how long it takes to recover from periods of no sleep.
"We can't keep as many things online at any one time when we're sleep deprived. Sleep deprivation significantly impairs attention, working memory performance, our ability to drive. It has the same effect as alcohol does," said Drummond, who works with the University of California San Diego and the Veterans Affairs San Diego Healthcare System.
In the May issue of Flying Safety Magazine, Capt. Brain Drummond, a pilot in a KC-135 air refueling tanker in Iraq recounted a potentially accident-causing mistake he made in March during a refueling mission when he let too much fuel out of a tank, causing an imbalance in the aircraft. He believes the mistake resulted from too many missions with too little sleep. After flying 12 six- to seven-hour missions and fulfilling all the briefing, debriefing and aircraft pre- and post-flight requirements, he recalled that he and the crew looked like "the walking dead."
"I don't think you really know the fatigue that sets into your body until you are finally able to rest," he said. "Even though I was getting enough rest at night during the 11 straight sorties, my body and senses became very numb. I truly believe, because of the demand for the missions in OIF (Operation Iraqi Freedom), our crew had become so tired that we forgot the little things, which can add up to big things."
Because of incidents like Drummond's the DoD's Peer Reviewed Medical Research Program funds research like Drummond's. Congress created the program in 1999 to promote research in health issues the military faces. Since its inception through 2005, the program has spent almost $300 million to fund nearly 200 projects in a range of medical topics, including combat casualty care and technology and infectious disease research.
The researcher and his team recruited 40 volunteers with good sleep habits who agreed to live in a lab for six days. For their stay, volunteers lived two normal days and nights, stayed awake for 64 hours and then were allowed again to sleep so the team could observe the recovery process.
During the volunteers' awake hours, they underwent half-hour long learning, memory and decision-making tests every two hours to see how well they fared at different stages of sleep deprivation. One test, for example, had the volunteers memorize lists of nouns. Drummond and his team also used functional magnetic resonance imaging in the morning and evening to map the brain's reaction. The imaging technique looks at oxygen use in the brain, so whatever part of the brain is being used, it needs more oxygen.
"The brain is a system, a network of areas, all of which work together to get a task done," he said.
The researcher found that volunteers' working memory wasn't affected after 36 hours without sleep, not because they were all healthy and had an average age of 24 years, but because other regions of the brain jumped in to help.
"The brain can actually compensate for this level of sleep deprivation. Areas that don't normally turn on when a person is well rested came online when the person was sleep deprived," Drummond said. "The better they're able to engage them, the better they're able to do after sleep deprivation."
After 60 hours, though, most volunteers didn't fare as well on their tests as they had at the 36-hour mark. After two and a half days without sleep, their brains could not recruit help.
"I think it will be important to use these data to try to better predict and understand who is going to be resilient to sleep loss and who is going to be vulnerable," Drummond said. "The benefits will come in better understanding the consequences of sleep deprivation for more complex types of cognitive functions -- as opposed to simple attention, for example -- as well as better understanding how long the recovery process takes."
Drummond's team also found that recovering from 64 hours of sleep loss wasn't as simple as getting a few good nights' rest. "We found on some tasks that people aren't back at the baseline level even after two full nights of sleep, given that they only lost two nights of sleep," he said. "Given the pervasiveness of inadequate sleep in the military and civilian worlds alike, there is clearly a need to understand what this is doing and can it be counteracted."

For more information on the DoD's Peer Reviewed Medical Research Program, go to http://cdmrp.army.mil.

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