What happens when you have a concussion? - Clifford Robbins

譯者: Szu-Wen Kung 審譯者: Ann Chen

Each year in the United States,

每年在美國

players of sports and recreational activities

體育和休閒活動的運動員

receive between 2.5 and 4 million concussions.

會發生兩百五十萬到 四百萬次的腦震盪

How dangerous are all those concussions?

腦震盪到底有多危險？

The answer is complicated,

答案頗為複雜

and lies in how the brain responds when something strikes it.

取決於腦部如何回應撞擊

The brain is made of soft fatty tissue, with a consistency something like jello.

腦部是由柔軟的脂肪組織組成

質地近似果凍

Inside its protective membranes and the skull's hard casing,

因位於多層保護膜 和堅硬顱骨的內部

this delicate organ is usually well-shielded.

這脆弱的器官通常被妥善保護著

But a sudden jolt can make the brain shift

但突如其來的搖晃會使腦位移

and bump against the skull's hard interior,

重擊堅硬顱骨的內側

and unlike jello, the brain's tissue isn't uniform.

與果凍不同的是 腦組織並不一致

It's made of a vast network of 90 billion neurons,

它是由九百億個神經元 所組成的巨大網絡

which relay signals through their long axons to communicate throughout the brain

神經元透過其細長的軸突 在腦內傳達訊息

and control our bodies.

並控制身體運作

This spindly structure makes them very fragile

如此細薄的結構 使得神經元極為易脆

so that when impacted, neurons will stretch and even tear.

因此每當受到撞擊 神經元會伸展甚至撕裂

That not only disrupts their ability to communicate

這不但會中斷神經元 傳遞訊息的能力

but as destroyed axons begin to degenerate,

當受損的軸突開始退化時

they also release toxins causing the death of other neurons, too.

它們也會釋放毒素 導致其他神經元死亡

This combination of events causes a concussion.

這一連串的事件造成腦震盪

The damage can manifest in many different ways

腦震盪會產生不同的症狀

including blackout,

包括昏厥

headache,

頭痛

blurry vision,

視力模糊

balance problems,

平衡問題

altered mood and behavior,

情緒和行為的改變

problems with memory, thinking, and sleeping,

有記憶、思考和睡眠的問題

and the onset of anxiety and depression.

並引發焦慮和憂鬱

Every brain is different,

每個腦並不相同

which explains why people's experiences of concussions vary so widely.

這也說明為何人們產生 腦震盪的情況大相逕庭

Luckily, the majority of concussions fully heal

好在絕大多數的腦震盪都會痊癒

and symptoms disappear within a matter of days or weeks.

症狀在幾天或幾週內就會消失

Lots of rest and a gradual return to activity

大量的休養和漸進式恢復日常活動

allows the brain to heal itself.

能讓腦部自行療癒

On the subject of rest,

至於休養

many people have heard that you're not supposed to sleep

最常聽到的說法是

不該在腦震盪後立即睡覺 因為有可能會陷入昏迷

shortly after receiving a concussion because you might slip into a coma.

That's a myth.

這是無稽之談

So long as doctors aren't concerned there may also be a more severe brain injury,

只要醫生不認為 會有更嚴重的腦部創傷就可以

like a brain bleed,

例如腦出血

there's no documented problem with going to sleep after a concussion.

並無前例顯示 腦震盪後睡覺會產生問題

Sometimes, victims of concussion can experience something

有時候腦震盪傷者

會出現「腦震盪症候群」 也就是 PCS

called post-concussion syndrome, or PCS.

People with PCS may experience constant headaches,

腦震盪症候群的病患 會有持續頭痛的狀況

learning difficulties,

學習障礙

and behavioral symptoms that even affect their personal relationships

及影響到人際關係的行為症狀

for months or years after the injury.

於傷後持續數月或數年

Trying to play through a concussion, even for only a few minutes,

若腦震盪後繼續活動 就算只有幾分鐘的時間

or returning to sports too soon after a concussion,

或沒多久後立刻進行運動活動

makes it more likely to develop PCS.

很容易形成腦震盪症候群

In some cases, a concussion can be hard to diagnose

有些案例不易診斷出腦震盪

because the symptoms unfold slowly over time.

因為相關症狀後來才慢慢出現

That's often true of subconcussive impacts

這尤其常見於輕微腦部撞擊

which result from lower impact jolts to the head

相較於腦震盪 這種是比較輕微的撞擊

than those that cause concussions.

This category of injury doesn't cause noticable symptoms right away,

這種傷害不會立即產生明顯的症狀

but can lead to severe degenerative brain diseases over time

但一段時間後 也可能造成嚴重的腦部退化疾病

if it happens repeatedly.

尤其是重複發生的話

Take soccer players, who are known for repeatedly heading soccer balls.

以足球員為例，他們需重複頂球

Using a technique called Diffusion Tensor Imaging,

利用「擴散張量影像」的技術

we're beginning to find out what effect that has on the brain.

我們便能瞭解 這對腦部會產生何種影響

This method allows scientists to find large axon bundles

科學家能透過此技術 找出大型軸突束

and see how milder blows might alter them structurally.

並觀察當輕度撞擊時 其結構上會如何改變

In 2013, researchers using this technique discovered

2013 年 研究人員利用此技術發現

that athletes who had headed the ball most,

最常以頭頂球的運動員

about 1,800 times a year,

大約每年頂球一千八百次

had damaged the structural integrity of their axon bundles.

其軸突束的整體結構已受到損害

The damage was similar to how a rope will fail

這樣的損傷就像

when the individual fibers start to fray.

當繩子的纖維開始磨損後 繩子就會斷裂

Those players also performed worse on short-term memory tests,

這些球員在 短期記憶測試的表現也較差

so even though no one suffered full-blown concussions,

所以儘管沒有真正的腦震盪

these subconcussive hits added up to measurable damage over time.

輕微的腦部撞擊 長久累積造成的傷害也不容小覷

In fact, researchers know that an overload of subconcussive hits

研究人員了解到 過多的輕微腦部撞擊

is linked to a degenerative brain disease known as Chronic Traumatic Encephalopathy,

與一種退化性腦部疾病有關聯 ── 即「慢性創傷性腦病變」

or CTE.

或簡稱 CTE

People with CTE suffer from changes in their mood and behavior

慢性創傷性腦病變的患者 在情緒和行為上會出現變化

that begin appearing in their 30s or 40s

於 30 或 40 多歲開始顯現

followed by problems with thinking and memory

接著會有思考與記憶力的問題

that can, in some cases, even result in dementia.

有些人甚至可能產生癡呆

The culprit is a protein called tau.

罪魁禍首是 Tau 濤蛋白

Usually, tau proteins support tiny tubes inside our axons called microtubules.

正常下濤蛋白 可支持軸突內部的微管

It's thought that repeated subconcussive hits damage the microtubules,

研究人員認為反覆頭部的 輕微撞擊會損害微管

causing the tau proteins to dislodge and clump together.

導致濤蛋白脫離原位並結塊

The clumps disrupt transport and communication along the neuron

結塊阻礙神經元的訊息傳導

and drive the breakdown of connections within the brain.

也會破壞腦內部神經元之間的連結

Once the tau proteins start clumping together,

一旦濤蛋白開始結塊

they cause more clumps to form

會因此愈積愈多

and continue to spread throughout the brain,

且繼續蔓延整個腦部

even after head impacts have stopped.

此現象在頭部撞擊停止後 仍舊持續著

The data show that at least among football players,

資料顯示，至少對美式足球球員來說

between 50 and 80% of concussions go unreported and untreated.

有 50% 到 80% 的腦震盪 並未回報也未接受治療

Sometimes that's because it's hard to tell

有時候是因為

腦震盪剛發生時難以覺察

a concussion has occurred in the first place.

But it's also often due to pressure or a desire to keep going

但也多半是受到不想 中斷活動的壓力和意念所驅使

despite the fact that something's wrong.

儘管情況已經不對

This doesn't just undermine recovery.

這樣不只會破壞復原效果

It's also dangerous.

同時也很危險

Our brains aren't invincible.

人腦並非所向無敵

They still need us to shield them from harm

我們仍需善加保護腦部 使之不受傷害

and help them undo damage once it's been done.

並幫助受傷的腦部復原