首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
医学
Neuroscientists now understand at least some of the physiology behind a wide range of unconscious states, from deep sleep to com
Neuroscientists now understand at least some of the physiology behind a wide range of unconscious states, from deep sleep to com
admin
2013-12-06
62
问题
Neuroscientists now understand at least some of the physiology behind a wide range of unconscious states, from deep sleep to coma, from partially conscious conditions to a persistent vegetative state, the condition diagnosed in Ms. Schiavo.
New research, by laboratories in New York and Europe, has allowed for much clearer distinctions to be made between the uncounted number of people who at some time become comatose, the 10,000 to 15,000 Americans who subsist in vegetative states and the estimated 100,000 or more who exist in states of partial consciousness.
This emerging picture should make it easier for doctors to judge which brain-damaged patients have some hope of recovering awareness, experts say, and already it is providing clues to the specific brain processes that sustain conscious awareness.
"Understanding what these processes are will give us a better sense of how to help the whole range of people living with brain injuries," said Dr. Nicholas Schiff, an assistant professor of neurology and neuroscience at New York-Presbyterian/ Weill Cornell hospital. "That is where this field is ultimately headed: toward a better understanding of what consciousness is."
The most familiar unconscious state is sleep, which in its deepest phases is characterized by little electrical activity in the brain and almost complete unresponsiveness. Coma, the most widely known state of impaired unconsciousness, is in fact a continuum. Doctors rate the extent to which a comatose person shows pain responses and reactions to verbal sounds on a scale from 3, for no response, to 13, for consistent responses.
As in sleep, people in comas may move or make sounds and typically have no memory of either. But they almost always emerge from this state in two to three weeks, doctors say, when the eyes open spontaneously. What follows is critical for the person’s recovery.
Those who are lucky, or who have less severe injuries, gradually awaken. "The first thing I remember was telling my ex-boyfriend, who was at the foot of the bed, to shut up," said Trisha Meili, who fell into a coma after being beaten and raped in 1990, and wrote about the experience in the book, I Am the Central Park Jogger.
In the days after this memory, Ms. Meili said, she slipped in and out of conscious awareness, "as if my body was taking care of the most important things first, and leaving my moment to moment awareness for last."
In fact, researchers say, this is precisely what happens. The primitive brain stem, which controls sleep-wake cycles as well as reflexes, asserts itself first, as the eyes open. Ideally, areas of the cerebral cortex, the seat of conscious thought, soon follow, like lights flicking on in the upper rooms of a darkened house.
But in some cases—Ms. Schiavo’s was one of them—the cortical areas fail to engage, and the patient’s prognosis becomes dire.
Neurologists were all but unanimous in diagnosing the condition of Ms. Schiavo, whose heart stopped temporarily in 1990, depriving her brain of oxygen. Brain cells and neural connections wither and die without oxygen, like marine life in a drained lake, leaving virtually nothing unharmed.
People with these kinds of injuries—Nancy Cruzan, whose case reached the Supreme Court in 1990 is an example—almost always remain unresponsive if they have not regained awareness in the first months after the injury.
In medical terms, they become persistently vegetative, a diagnosis first described in 1972 by Dr. Fred Plum of Cornell University and Dr. Bryan Jennett, a neurosurgeon at Glasgow University in Scotland. In a sense, the description of the diagnosis began the modern study of disorders of consciousness. "Before 1972 people talked about permanent comas, or irrecoverable comas, but we defined a different state altogether, with the eyes open, some reflex activity, but no sign of meaningful psychological responsiveness," Dr. Jennett, now a professor emeritus, said in an interview.
In an exhaustive review of the medical histories of more than 700 persistently vegetative patients, a team of doctors in 1994 reported that about 15 percent of those who suffered brain damage from oxygen deprivation, like Ms. Schiavo, recovered some awareness within three months. After that, however, very few recovered and none did so after two years.
About 52 percent of people with traumatic wounds to the head, often from car accidents, recovered some awareness in the first year after the injury, the study found; very few recovered after that. "It’s the difference between taking a blow to the brain, which affects a local area—and taking this global, whole-brain hit," said Dr. Joseph Fins, chief of the medical ethics division of New York-Presbyterian / Weill Cornell hospital.
Yet these statistics cannot explain the stories of remarkable recovery that surfaced during the debate over Ms. Schiavo’s fate. There was Terry Wallis, a mechanic in Arkansas who regained awareness in 2003, more than 18 years after he fell into unconsciousness from a car accident; Sarah Scantlin, a Kansas woman who, also a victim of a car accident, emerged from a similar state after 19 years; and several others, whose collective human spirit seemed to defy the experts, and trump science.
Researchers say these cases can be accounted for by recent studies that indicate the existence of yet another state of subdued responsiveness, one that represents a clear break from the vegetative.
It is suggested in the passage that______.
选项
A、no unconscious patients can emerge from their states
B、there exists another state of subdued responsiveness
C、all brain damages are caused by a persistent vegetative state
D、it was in 1994 when the modern study of disorders of consciousness began
答案
B
解析
文章最后一段是全文的概括总结,指出:最近的研究表明存在有另外一种受到抑制的反应状态,这种状态代表一种与植物人状态完全不相干的状态。因此正确答案是B。
转载请注明原文地址:https://kaotiyun.com/show/eSU3777K
本试题收录于:
医学博士外语题库考研分类
0
医学博士外语
考研
相关试题推荐
Despitegrowingnumbersofjoggers,CanadaFitnessSurveysacrossthecountrydemonstratethatCanadiansarelessphysicallyfit
Despitegrowingnumbersofjoggers,CanadaFitnessSurveysacrossthecountrydemonstratethatCanadiansarelessphysicallyfit
Osteoporosisusedtobecalled"thesilentdisease"becauseitsvictimsdidn’tknowtheyhadituntilitwastoolateandthey
ManyCanadiansenjoytheluxuryofalargeamountoflivingspace.Canadaisvast,andthehomesarelargeaccordingtothestan
Thebiggestengineeringprojectthattheyundertookwasencumberedbylackoffunds.
A、Thepatientisringingabell.B、Hernamesoundsbeautiful.C、NancyJohnsonisringingthebellnow.D、Hernamesoundsfamilia
Everyonehasseenithappen.Acolleaguewhohasbeenexcited,involved,andproductiveslowlybeginstopullback,loseenergy
Shyness,themostcommonformofsocialanxiety,occurswhenaperson’sapprehensionsaresogreatthattheyinhibithismaking
Thereiscurrentlyabroadanewwaveofappreciationforbreadthofknowledge.Curriculaatuniversalitiesandcollegesandprog
Skippersmustmakeareporttocustomseitherinpersonorbytelephone,iftheyhaveanydutyfreegoodsonboard,orarecarryi
随机试题
对于科学文化领域的人民内部矛盾,需要实行的方针是()
能够治疗疮疡,湿疹,水火烫伤的药物是
有支持作用的卡环是
《中华人民共和国劳动法》于1994年7月5日由中华人民共和国第八届全国人民代表大会常务委员会第八次会议通过,自1995年1月1日起施行。旨在保护劳动者的合法权益,调整劳动关系,建立和维护适应社会主义市场经济的劳动制度,促进经济发展和社会进步。《中华人民共和
科学知识的再生产有多种途径,而_______是科学知识再生产最主要的途径。
从头开始是人生经常可能遇到的境况。大至地震,战争,国破家亡,死里逃生,事业一败涂地。小至丧偶,失恋,经济破产,钱财被窃,身上一文不名。凡此种种,皆会使你不同程度地产生一种废墟感。当此之时,最健康的心态便是忘掉你曾经拥有的一切,忘掉你所遭受的损失,就当你是赤
在飘来飘去的朋友圈谣言面前,我们需要对传统的治理模式进行反思。一个更公开的、更亲民的政府,一个更克制的、更有限的市场,一个更平和的、更理想的社会,都是文明开放的舆论生态场不可或缺的。坦率而言,无论在哪一个方面,距离这个状态都还有很长的路要走,而在当下,也许
一个学校在新学年招收了120名学生而使在校生总数增了15%,新学年在校生总数为多少?()
Eventhoughcurrenttechnologiesmaketheultimatesegmentednetworkimpractical,newtechnologiesandproductsholdthepromise
A、Hesoldhisinventiontomakemoney.B、Hepreferredinventiontoteaching.C、Hewashonoredwithanawardforhisteachingmet
最新回复
(
0
)