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
2013-12-14
31
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 NewYork-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 NewYork-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.
Which of the following statement does the author say in the article?
选项
A、It was the consensus of the neurologists in diagnosing the condition of Ms. Schiavo.
B、Researchers may never understand the physiology behind unconscious states.
C、People in comas never move or make sounds.
D、Those who have less severe brain damages may never awaken.
答案
A
解析
从倒数第七段第一句话“Neurologists were all but unanimous in diagnosing the condition of Ms.Schiavo,whose heart stopped temporarily in 1990,depriving her brain of oxygen.”我们得知神经学家在诊断Ms.Schiavo的病情时意见一致,因此A是正确答案。
转载请注明原文地址:https://kaotiyun.com/show/0iU3777K
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
器官移植前,需做的特殊检查是
A、Followinggeneralestimates.B、Upgradingyourqualityoflife.C、Makingasmuchmoneyasyoucan.D、Maintainingyourcurrentl
Twoequallybrilliantscientistsapplyforaprestigiousresearchfellowshipawardedbyatopscientificorganization.Oneiswh
TherewereredfacesatoneofBritain’sbiggestbanksrecently.Theyhadacceptedatelephoneordertobuy$100,000worthof
Readingtooneselfisamodernactivitywhichwasalmostunknowntothescholarsoftheclassicalandmedievalworlds,whiledur
Microsoftisnolongertheworld’sbiggestcompany【C1】______marketcapitalization.ThreeotherU.S.companieshaveovertaken【C
Howmuchpaindoanimalsfeel?Thisisaquestionwhichhascausedendlesscontroversy.Opponentsofbiggameshooting,forexam
DespiteDenmark’smanifestvirtues,DanesnevertalkabouthowproudtheyaretobeDanes.ThiswouldsoundweirdinDanish.Whe
Theelementsotherthanhydrogenandheliumexistinsuchsmallquantitiesthatitisaccuratetosaythattheuniverseissomew
Becauseheworeastrangecollectionofclothesandoftentalkedtohimself,hisneighborconsideredhimeccentric.
随机试题
抗人禽流感病毒药物主要包括()和()两大类。
A、.清热利湿,佐以泻下B、.利湿化浊,佐以清热C、.清热解毒,凉营开窍D、.健脾和胃,温化寒湿E、.解表清热利湿急黄神昏舌绛者,其治法是
《公路桥涵设计通用规范》(JTGD60—2015)规定桥梁吊索的设计使用年限为20年。()
以下属于利润表项目的是()。
Therocketengine,withitssteadyroarlikethatofawaterfallorathunderstorm,isanimpressivesymbolofthenewspaceage.R
企业经营计划包括()。
【金石学】南京师范大学2011年考古学与博物馆学复试真题;福建师范大学2013年中国史综合真题;兰州大学2015年历史学综合真题;内蒙古大学2017年中国史真题
关于SPOOLing技术的说法,以下正确的是()。Ⅰ.SPOOLing系统中不需要独占设备Ⅱ.SPOOLing系统加快了作业完成的速度Ⅲ.当输入设备忙时,SPOOLing系统中的用户程序暂停执行,待I/O空闲时再被唤醒
Somesayitisevidentthatcomputerscandamageaperson’seyesight.Sincethepopularityofcomputersbegantoskyrocket,ther
TheEarthcomprisesthreeprincipallayers:thedense,iron-richcore,themantlemadeofsilicate(硅酸盐)thataresemi-moltenatd
最新回复
(
0
)