What happens when you have a concussion? - Clifford Robbins

翻译人员: 芷蘅 张 校对人员: Lipeng Chen

Each year in the United States,

每年在美国，

players of sports and recreational activities

参加体育或者娱乐性活动的运动员中

receive between 2.5 and 4 million concussions.

有250-400万的人会经历脑震荡。

How dangerous are all those concussions?

脑震荡有多大危险？

The answer is complicated,

答案很复杂，

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

而且取决于你的大脑对撞击作出的反应。

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

大脑由一些像果冻粘度一样的 柔软的脂肪组织构成。

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

在保护性的薄膜和坚硬的颅骨内部，

this delicate organ is usually well-shielded.

这一脆弱的器官可以被很好的保护。

But a sudden jolt can make the brain shift

但是突然的撞击会让大脑变化，

and bump against the skull's hard interior,

对着头颅内部撞击，

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

而且不像果冻，大脑组织并不是完全一样。

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

它巨大的网络由900亿神经元构成，

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

神经元通过轴突传递信号并在大脑中交流，

and control our bodies.

并控制我们整个身体。

This spindly structure makes them very fragile

细长的结构使他们非常脆弱，

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

所以当受到影响时，神经元会伸长甚至撕裂。

That not only disrupts their ability to communicate

这不仅扰乱他们交流的能力，

but as destroyed axons begin to degenerate,

而且受损的轴突开始退化，

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

并且释放毒素使其他神经元死亡。

This combination of events causes a concussion.

这一系列事件会引起脑震荡。

The damage can manifest in many different ways

损伤会表现在很多地方，

including blackout,

包括暂时失忆，

headache,

头痛，

blurry vision,

视线模糊，

balance problems,

平衡问题，

altered mood and behavior,

情绪和行为转化，

problems with memory, thinking, and sleeping,

记忆、思考以及睡眠问题，

and the onset of anxiety and depression.

还有焦虑和抑郁的开始。

Every brain is different,

每个大脑都是不一样的，

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

也解释了人们脑震荡后不同的结果。

Luckily, the majority of concussions fully heal

幸运的是大多数脑震荡是可以痊愈的，

and symptoms disappear within a matter of days or weeks.

在几天或者几周之后症状就会消失。

Lots of rest and a gradual return to activity

充足的休息和逐渐运动

allows the brain to heal itself.

会让大脑自己痊愈。

On the subject of rest,

对于休息这一说，

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

很多人听说在脑震荡对之后一段时间，

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

由于容易昏迷，最好不要睡觉。

That's a myth.

这是虚构的。

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

只要医生没说有更严重的大脑损伤，

like a brain bleed,

比如脑溢血，

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

脑震荡之后睡觉就是没问题的。

Sometimes, victims of concussion can experience something

有时，脑震荡患者会经历

called post-concussion syndrome, or PCS.

脑震荡后综合症，或PCS。

People with PCS may experience constant headaches,

这样的患者在伤后几个月甚至几年会

出现持续头痛，

learning difficulties,

学习障碍，

and behavioral symptoms that even affect their personal relationships

和一些甚至影响到他们个人关系的行为问题。

for months or years after the injury.

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

在脑震荡期间想要运动，即使是几分钟，

or returning to sports too soon after a concussion,

或者想立刻重回运动场，

makes it more likely to develop PCS.

会更容易产生PCS。

In some cases, a concussion can be hard to diagnose

有些情况，脑震荡会很难诊断，

because the symptoms unfold slowly over time.

因为他们的症状出现的太慢。

That's often true of subconcussive impacts

这种震荡影响时常发生，

which result from lower impact jolts to the head

并且大多来自的头部撞击相对产生脑震荡的撞击

than those that cause concussions.

影响较小。

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

这样的伤不会立刻产生明显的症状，

but can lead to severe degenerative brain diseases over time

但是如果经常发生，

if it happens repeatedly.

时间久了会产生退行性的大脑疾病。

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

就比方说头部经常遭球撞击的足球运动员。

Using a technique called Diffusion Tensor Imaging,

用一项叫弥散张量成像的技术，

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

我们可以知道对它大脑的影响。

This method allows scientists to find large axon bundles

这个方法可以让科学家看到大束轴突

and see how milder blows might alter them structurally.

以及轻微的波动会如何改变它们。

In 2013, researchers using this technique discovered

2013年，研究人员用这项技术发现

that athletes who had headed the ball most,

一年被球撞过约1800次的

about 1,800 times a year,

运动员，

had damaged the structural integrity of their axon bundles.

大脑中轴突束已经完全被损坏。

The damage was similar to how a rope will fail

这种损伤就好比一根

when the individual fibers start to fray.

所有纤维都开始磨损的绳子。

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

这些运动员在短期记忆测试中表现得也不好，

so even though no one suffered full-blown concussions,

即使现在没人有完全型脑震荡，

these subconcussive hits added up to measurable damage over time.

但是一直以来的撞击也会积累损伤。

In fact, researchers know that an overload of subconcussive hits

事实上，研究发现过多震荡型撞击

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

和退行性脑疾病即慢性创伤脑疾病，或CTE

or CTE.

有很大联系。

People with CTE suffer from changes in their mood and behavior

患有CTE的人

在30或40岁开始会出现情绪和行为变化，

that begin appearing in their 30s or 40s

followed by problems with thinking and memory

紧接着就是思考和记忆问题，

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

很多情况下，甚至导致痴呆。

The culprit is a protein called tau.

这个起因就是一种叫tau的蛋白。

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

通常，tau蛋白要支撑称为微管 即存在于轴突中的小管。

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

我们认为重复性震荡撞击会损伤微管，

causing the tau proteins to dislodge and clump together.

致使tau蛋白聚成一起。

The clumps disrupt transport and communication along the neuron

这中断了沿着神经元的运输和交流，

and drive the breakdown of connections within the brain.

也驱使中断大脑内部的联系。

Once the tau proteins start clumping together,

一旦tau蛋白开始聚集成簇，

they cause more clumps to form

将会引起更多簇的形成，

and continue to spread throughout the brain,

并且延伸致整个大脑，

even after head impacts have stopped.

即使头部影响已经停止。

The data show that at least among football players,

数据显示在足球运动员中，

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

至少50%-80%的脑震荡没有上报或者治疗。

Sometimes that's because it's hard to tell

有时因为脑震荡发生的第一时间，

a concussion has occurred in the first place.

很难分辨出。

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

但也由于运动员的压力或者想继续前进的欲望，

despite the fact that something's wrong.

而忽略了受伤的事实。

This doesn't just undermine recovery.

这不仅减慢了恢复，

It's also dangerous.

而且很危险。

Our brains aren't invincible.

我们的大脑并不是无敌的。

They still need us to shield them from harm

它们需要我们保护它不受伤害，

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

如果受伤就需要我们帮助它进行恢复。