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Miracle Recovery
2006/07/04 10:17:26瀏覽864|回應0|推薦1

By Dr. SCOTT TERRANELLA, ABC News Medical Unit

July 3, 2006 —

Now, researchers believe the "miracle" that allowed the 42-year-old to rejoin the world was actually a very slow process in which his brain grew new connections to heal its injured parts.

What is remarkable about this is that up until now, brain experts did not know to what extent the brain could still heal itself so many years after an injury.

"In essence, Terry's brain may have been seeking out new pathways to re-establish functional connections to areas involved in speech and motor control — to compensate for those lost due to damage," said Nicholas Schiff, the senior author of a study on brain damage published in the July 1 issue of The Journal of Clinical Investigation.

The study used a combination of new and standard brain imaging techniques to look at the state of Wallis' brain at various points after he became fully conscious.

While technically conscious, he still suffers from complete amnesia. He's convinced that it's still the 1980s, and he can't walk and needs helps eating.

"High-tech brain imaging is suggesting that cells in the relatively undamaged areas of Terry's brain slowly grew important, novel connections over a period of years," said Schiff, who is also the director of the Laboratory of Cognitive Neuromodulation at Weill Cornell Medical College in New York City.

Not too many years ago, conventional wisdom said that the nervous system — and certainly the brain — stopped growing once it fully developed during childhood and that it did not regenerate or repair itself.

However, this study confirms there is still a lot to be learned about the brain and its cells, known as neurons.

"Currently, there is very little known about this process," said Joy Hirsch, professor of radiology and psychology in the Center for Neurobiology and Behavior at Columbia University Medical Center in New York City. "This study is a landmark study because of its potential clinical relevance."

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Although the goal is to eventually be able to predict which patients have the best chance of recovering consciousness, experts warn that this research is only one step in that direction.

"The brain is the most complicated organ, and trauma is the most complicated injury," said David Hovda, director of the UCLA Brain Injury Research Center. "We need to study multiple patients over time and the same patients at different times in their recovery before we'll be able to predict which patients have the best chance of recovery."

Wallis' Long Ordeal

Wallis was 19 when he was severely injured in an automobile crash. After emerging from a coma — meaning he had been unresponsive to stimuli — in the early months following his accident, his doctors determined he would likely spend the rest of his life in a vegetative state. His eyes had opened but he was still unresponsive.

When his parents were told nothing more could be done, they took him back to a nursing home near their Arkansas home, where they helped care for him. His ordeal was showcased in the documentary "The Man Who Slept for 19 Years."

Everyone, to say the least, was utterly surprised when Wallis awoke three years ago and called out the word "mom," asking for the woman who had spent the previous two decades at his bedside.

A New Diagnosis: 'Minimally Conscious State'

When Wallis suffered his injury, the diagnosis "minimally conscious state" did not exist. Experts say it is a fairly new category of consciousness.

"It is defined by evidence at the bedside of some awareness of the environment or self-awareness," Schiff said.

"Patients will respond to sensory stimuli. They may track objects in the room, reliably fixate their eye or respond to auditory stimuli. On the higher end, [they] will respond to commands. [They] may even verbalize or intermittently communicate. But … although they show evidence of conscious awareness, patients are unable to reliably communicate."

 

 In 2003, almost 20 years after suffering a severe brain injury during a car accident, Terry Wallis suddenly emerged from what doctors call a "minimally conscious state" — somewhere between being awake and being in a vegetative state.
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美國廣播公司(ABC)3日報導,現年42歲的沃利斯曾因車禍腦部受重傷,在昏迷將近20年後,2003年突然從介於清醒和植物人之間的「最低意識狀態」醒過來。  @ http://udn.com  

研究人員現在相信沃利斯恢復知覺,是因為他的腦部在非常緩慢的程序中,長出新的神經連結修復受傷的部分。在此之前,專家並不知道腦部受傷這麼多年後能夠自我修復到何種程度。

最新一期「臨床調查期刊」發表的研究報告表示,沃利斯的腦部可能一直在尋找新的通道,以與控制言語和運動的部分重新建立連繫,以彌補因腦部受傷失去的功能。

這項研究利用腦部造影技術,探究沃利斯完全清醒後不同階段的腦部狀況。雖然他已清醒過來,可是仍有記憶缺失問題,他認為現在仍是1980年代,他也不能走路,進食仍需別人協助。

主持這項研究的康乃爾醫學院認知神經調適實驗室主任席夫說,腦部顯影顯示,沃利斯的腦部沒有受損部分,在過去幾年期間慢慢長出重要的新神經連結。專家幾年前認為包括腦部在內的神經系統,一旦在童年階段發育完成,就停止生長,也不會自我更新或修補。但是新研究證實人類對腦部及其神經仍缺乏瞭解。

專家希望這種研究日後能夠協助判斷哪些病人可能恢復意識,以免使他們太早失去恢復清醒的機會、資源和治療。

陷於昏迷與處於最低意識或植物人狀態,有重要差別。「昏迷」被鬆散的用於形容病人對外界沒有反應的狀態,可是在臨床上只出現在腦部受損初期,病人毫無反應,眼睛緊閉之時。

一旦眼睛爭開,就算脫離昏迷狀態,這時醫生必須決定病人究竟進入最低意識狀態,還是成為植物人。

處於最低意識狀態的病人對感官刺激會有反應,他們可能追蹤房間裡的物體,眼睛跟著移動,或是對聽覺刺激有反應。在較高層次,他們可能接受指令,甚至發出聲音或做不連貫的溝通。但是,他們無法做可靠的溝通。一些專家相信這可能是從無意識過渡到有意識的程序。植物人就像昏迷的病人一樣,對四周環境毫無反應,但可能對非常強烈的刺激出現反射動作,也可能偶爾張開眼睛。

【2006/07/04 聯合晚報】

( 知識學習健康 )
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