Why helmets don't prevent concussions -- and what might
-
0:00 - 0:05The word concussion evokes a fear
these days more so than it ever has, -
0:05 - 0:07and I know this personally.
-
0:08 - 0:10I played 10 years of football,
-
0:10 - 0:13was struck in the head thousands of times.
-
0:13 - 0:16And I have to tell you, though,
what was much worse than that -
0:16 - 0:21was a pair of bike accidents I had
where I suffered concussions, -
0:21 - 0:24and I'm still dealing with the effects
of the most recent one -
0:24 - 0:26today as I stand in front of you.
-
0:28 - 0:30There is a fear around concussion
-
0:30 - 0:32that does have some evidence behind it.
-
0:34 - 0:37There is information
that a repeated history of concussion -
0:37 - 0:40can lead to early dementia,
such as Alzheimer's, -
0:40 - 0:42and chronic traumatic encephalopathy.
-
0:42 - 0:45That was the subject
of the Will Smith movie "Concussion." -
0:47 - 0:50And so everybody is caught up in football
and what they see in the military, -
0:50 - 0:51but you may not know
-
0:52 - 0:56that bike riding is the leading cause
of concussion for kids, -
0:56 - 0:58sports-related concussion, that is.
-
0:59 - 1:02And so another thing
that I should tell you -
1:02 - 1:03that you may not know
-
1:03 - 1:06is that the helmets that are worn
in bicycling and football -
1:06 - 1:07and many activities,
-
1:08 - 1:10they're not designed or tested
-
1:10 - 1:14for how well they can protect
your children against concussion. -
1:14 - 1:16They're in fact designed and tested
-
1:16 - 1:19for their ability to protect
against skull fracture. -
1:20 - 1:25And so I get this question
all the time from parents, -
1:25 - 1:27and they ask me,
-
1:27 - 1:29"Would you let your own child
play football?" -
1:29 - 1:33Or, "Should I let my child play soccer?"
-
1:33 - 1:35And I think that as a field,
-
1:36 - 1:40we're a long way from giving an answer
with any kind of confidence there. -
1:41 - 1:45So I look at that question
from a bit of a different lens, -
1:45 - 1:49and I want to know,
how can we prevent concussion? -
1:49 - 1:50Is that even possible?
-
1:50 - 1:53And most experts think that it's not,
-
1:55 - 1:57but the work that we're doing in my lab
-
1:57 - 2:01is starting to reveal more
of the details around concussion -
2:01 - 2:04so that we can have
a better understanding. -
2:04 - 2:07The reason we're able
to prevent skull fracture with helmets -
2:07 - 2:09is because it's pretty simple.
We know how it works. -
2:09 - 2:11Concussion has been
much more of a mystery. -
2:12 - 2:16So to give you a sense of what might
be happening in a concussion, -
2:17 - 2:19I want to show you the video here
-
2:19 - 2:22that you see when you type into Google,
-
2:22 - 2:23"What is a concussion?"
-
2:23 - 2:25The CDC website comes up,
-
2:25 - 2:28and this video essentially
tells the whole story. -
2:28 - 2:31What you see is the head moves forward,
-
2:31 - 2:33the brain lags behind,
-
2:33 - 2:34then the brain catches up
-
2:34 - 2:37and smashes into the skull.
-
2:37 - 2:39It rebounds off the skull
-
2:39 - 2:43and then proceeds to run
into the other side of the skull. -
2:43 - 2:47And what you'll notice is highlighted
in this video from the CDC, -
2:47 - 2:49which I'll note was funded by the NFL,
-
2:49 - 2:52is that the outer surface of the brain,
-
2:52 - 2:56where it was to have
smashed into the skull, -
2:56 - 3:00looks like it's been damaged or injured,
so it's on the outer surface of the brain. -
3:00 - 3:02And what I'd like to do with this video
-
3:02 - 3:05is to tell you that there are
some aspects that are probably right, -
3:05 - 3:08indicative of what the scientists
think happens with concussion, -
3:08 - 3:11but there's probably more
that's wrong with this video. -
3:11 - 3:14So one thing that I do agree with,
and I think most experts would, -
3:14 - 3:16is that the brain
does have these dynamics. -
3:16 - 3:19It does lag behind the skull
-
3:19 - 3:21and then catch up and move
back and forth and oscillate. -
3:21 - 3:23That we think is true.
-
3:24 - 3:27However, the amount of motion
you see in the brain in this video -
3:27 - 3:29is probably not right at all.
-
3:29 - 3:32There's very little room
in the cranial vault, -
3:32 - 3:34only a few millimeters,
-
3:34 - 3:37and it's filled entirely
with cerebral spinal fluid, -
3:37 - 3:39which acts as a protective layer.
-
3:39 - 3:43And so the brain as a whole probably
moves very little inside the skull. -
3:45 - 3:47The other problem with this video
-
3:47 - 3:48is that the brain is shown
-
3:48 - 3:51as a kind of rigid whole
as it moves around, -
3:51 - 3:53and that's not true either.
-
3:54 - 3:57Your brain is one of the softest
substances in your body, -
3:57 - 3:59and you can think of it
kind of like jello. -
3:59 - 4:01So as your head is moving back and forth,
-
4:01 - 4:04your brain is twisting
and turning and contorting, -
4:04 - 4:06and the tissue is getting stretched.
-
4:06 - 4:09And so most experts, I think, would agree
-
4:10 - 4:13that concussion is not likely
to be something that's happening -
4:13 - 4:14on this outer surface of the brain,
-
4:15 - 4:17but rather it's something
that's much deeper -
4:17 - 4:18towards the center of the brain.
-
4:19 - 4:22Now, the way that we're
approaching this problem -
4:22 - 4:24to try to understand
the mechanisms of concussion -
4:24 - 4:26and to figure out if we can prevent it
-
4:26 - 4:29is we are using a device like this.
-
4:29 - 4:30It's a mouthguard.
-
4:31 - 4:34It has sensors in it
that are essentially the same -
4:34 - 4:35that are in your cell phone:
-
4:35 - 4:38accelerometers, gyroscopes,
-
4:38 - 4:39and when someone is struck in the head,
-
4:40 - 4:42it can tell you how their head moved
-
4:42 - 4:45at a thousand samples per second.
-
4:47 - 4:49The principle behind
the mouthguard is this: -
4:49 - 4:51it fits onto your teeth.
-
4:51 - 4:54Your teeth are one of the hardest
substances in your body. -
4:54 - 4:56So it rigidly couples to your skull
-
4:56 - 4:58and gives you the most precise
possible measurement -
4:58 - 5:00of how the skull moves.
-
5:00 - 5:03People have tried
other approaches, with helmets. -
5:03 - 5:06We've looked at other sensors
that go on your skin, -
5:06 - 5:09and they all simply move around too much,
-
5:09 - 5:12and so we found that this
is the only reliable way -
5:12 - 5:13to take a good measurement.
-
5:15 - 5:20So now that we've got this device,
we can go beyond studying cadavers, -
5:20 - 5:22because you can only
learn so much about concussion -
5:22 - 5:23from studying a cadaver,
-
5:23 - 5:26and we want to learn
and study live humans. -
5:26 - 5:30So where can we find
a group of willing volunteers -
5:30 - 5:34to go out and smash their heads
into each other on a regular basis -
5:34 - 5:36and sustain concussion?
-
5:36 - 5:38Well, I was one of them,
-
5:38 - 5:40and it's your local friendly
Stanford football team. -
5:42 - 5:43So this is our laboratory,
-
5:43 - 5:45and I want to show you
-
5:45 - 5:48the first concussion
we measured with this device. -
5:48 - 5:52One of the things that I should point out
is the device has this gyroscope in it, -
5:52 - 5:55and that allows you
to measure the rotation of the head. -
5:55 - 5:58Most experts think
that that's the critical factor -
5:58 - 6:00that might start to tell us
what is happening in concussion. -
6:01 - 6:02So please watch this video.
-
6:03 - 6:07Announcer: Cougars bring
extra people late, but Luck has time, -
6:07 - 6:08and Winslow is crushed.
-
6:10 - 6:12I hope he's all right.
-
6:12 - 6:14(Audience roars)
-
6:19 - 6:20Top of your screen,
-
6:20 - 6:22you'll see him come on
just this little post route, -
6:22 - 6:24get separation, safety.
-
6:28 - 6:31Here it comes at you in real speed.
You'll hear this. -
6:33 - 6:35The hit delivered by --
-
6:36 - 6:39David Camarillo: Sorry, three times
is probably a little excessive there. -
6:39 - 6:40But you get the idea.
-
6:40 - 6:43So when you look at just the film here,
-
6:43 - 6:47pretty much the only thing you can see
is he got hit really hard and he was hurt. -
6:47 - 6:49But when we extract the data
-
6:49 - 6:51out of the mouthguard that he was wearing,
-
6:51 - 6:54we can see much more detail,
much richer information. -
6:54 - 6:56And one of the things that we noticed here
-
6:56 - 7:00is that he was struck
in the lower left side of his face mask. -
7:00 - 7:03And so that did something first
that was a little counterintuitive. -
7:03 - 7:05His head did not move to the right.
-
7:05 - 7:07In fact, it rotated first to the left.
-
7:07 - 7:10Then as the neck began to compress,
-
7:10 - 7:13the force of the blow caused it
to whip back to the right. -
7:13 - 7:19So this left-right motion
was sort of a whiplash-type phenomenon, -
7:19 - 7:23and we think that is probably
what led to the brain injury. -
7:23 - 7:27Now, this device is only limited in such
that it can measure the skull motion, -
7:27 - 7:31but what we really want to know
is what's happening inside of the brain. -
7:31 - 7:34So we collaborate with
Svein Kleiven's group in Sweden. -
7:34 - 7:38They've developed a finite element
model of the brain. -
7:38 - 7:40And so this is a simulation
-
7:40 - 7:43using the data from our mouthguard
from the injury I just showed you, -
7:43 - 7:45and what you see is the brain --
-
7:45 - 7:48this is a cross-section right in the front
-
7:48 - 7:50of the brain twisting
and contorting as I mentioned. -
7:50 - 7:53So you can see this doesn't
look a lot like the CDC video. -
7:53 - 7:55Now, the colors that you're looking at
-
7:55 - 7:59are how much the brain tissue
is being stretched. -
7:59 - 8:01And so the red is 50 percent.
-
8:01 - 8:05That means the brain has been stretched
to 50 percent of its original length, -
8:05 - 8:06the tissue in that particular area.
-
8:07 - 8:10And the main thing I want to draw
your attention to is this red spot. -
8:10 - 8:13So the red spot is very close
to the center of the brain, -
8:13 - 8:15and relatively speaking,
-
8:15 - 8:19you don't see a lot of colors like that
on the exterior surface -
8:19 - 8:22as the CDC video showed.
-
8:23 - 8:25Now, to explain a little more detail
-
8:25 - 8:28about how we think
concussion might be happening, -
8:28 - 8:30one thing I should mention
-
8:30 - 8:33is that we and others have observed
that a concussion is more likely -
8:33 - 8:37when you're struck and your head
rotates in this direction. -
8:37 - 8:39This is more common
in sports like football, -
8:39 - 8:43but this seems to be more dangerous.
So what might be happening there? -
8:43 - 8:46Well, one thing that you'll notice
in the human brain -
8:46 - 8:47that is different than other animals
-
8:47 - 8:50is we have these two very large lobes.
-
8:50 - 8:52We have the right brain
and the left brain. -
8:52 - 8:55And the key thing
to notice in this figure here -
8:55 - 8:58is that right down the center
of the right brain and the left brain -
8:58 - 9:01there's a large fissure
that goes deep into the brain. -
9:01 - 9:04And in that fissure,
what you can't see in this image, -
9:04 - 9:05you'll have to trust me,
-
9:06 - 9:07there is a fibrous sheet of tissue.
-
9:07 - 9:08It's called the falx,
-
9:08 - 9:12and it runs from the front of your head
all the way to the back of your head, -
9:12 - 9:13and it's quite stiff.
-
9:13 - 9:17And so what that allows for
is when you're struck -
9:17 - 9:20and your head rotates
in this left-right direction, -
9:20 - 9:24forces can rapidly transmit
right down to the center of your brain. -
9:24 - 9:26Now, what's there
at the bottom of this fissure? -
9:27 - 9:30It's the wiring of your brain,
-
9:30 - 9:34and in fact this red bundle
here at the bottom of that fissure -
9:34 - 9:37is the single largest fiber bundle
-
9:37 - 9:41that is the wiring that connects
the right and left sides of your brain. -
9:41 - 9:43It's called the corpus callosum.
-
9:43 - 9:45And we think that this might be
-
9:45 - 9:49one of the most common
mechanisms of concussion, -
9:49 - 9:54and as the forces move down,
they strike the corpus callosum, -
9:54 - 9:57it causes a dissociation
between your right and your left brain -
9:57 - 9:59and could explain some
of the symptoms of concussion. -
10:01 - 10:03This finding is also consistent
of what we've seen -
10:04 - 10:08in this brain disease that I mentioned,
chronic traumatic encephalopathy. -
10:08 - 10:13So this is an image of a middle-aged
ex-professional football player, -
10:13 - 10:17and the thing that I want to point out
is if you look at the corpus callosum, -
10:17 - 10:21and I'll page back here so you can see
the size of a normal corpus callosum -
10:21 - 10:25and the size of the person here
who has chronic traumatic encephalopathy, -
10:26 - 10:28it is greatly atrophied.
-
10:28 - 10:31And the same goes
for all of the space in the ventricles. -
10:31 - 10:33These ventricles are much larger.
-
10:33 - 10:36And so all of this tissue
near the center of the brain -
10:36 - 10:37has died off over time.
-
10:37 - 10:41So what we're learning
is indeed consistent. -
10:42 - 10:44Now, there is some good news here,
-
10:44 - 10:48and I hope to give you a sense
of hope by the end of this talk. -
10:48 - 10:50One of the things that we've noticed,
-
10:50 - 10:52specifically about
this mechanism of injury, -
10:52 - 10:56is although there's a rapid transmission
of the forces down this fissure, -
10:56 - 10:59it still takes a defined amount of time.
-
10:59 - 11:04And what we think is that if we can
slow the head down just enough -
11:04 - 11:07so that the brain
does not lag behind the skull -
11:07 - 11:11but instead it moves
in synchrony with the skull, -
11:11 - 11:14then we might be able to prevent
this mechanism of concussion. -
11:14 - 11:17So how can we slow the head down?
-
11:19 - 11:20(Laughter)
-
11:20 - 11:22A gigantic helmet.
-
11:23 - 11:26So with more space, you have more time,
-
11:26 - 11:29and this is a bit of a joke,
but some of you may have seen this. -
11:29 - 11:32This is bubble soccer,
and it's a real sport. -
11:32 - 11:33In fact, I saw some young adults
-
11:33 - 11:36playing this sport down the street
from my house the other day, -
11:36 - 11:39and as far as I know
there have been no reported concussions. -
11:39 - 11:40(Laughter)
-
11:40 - 11:45But in all seriousness,
this principle does work, -
11:45 - 11:46but this has gone too far.
-
11:46 - 11:51This isn't something that's practical
for bike riding or playing football. -
11:52 - 11:56And so we are collaborating
with a company in Sweden called Hövding. -
11:56 - 11:58Some of you may have seen their work,
-
11:58 - 12:03and they're using the same principle
of air to give you some extra space -
12:03 - 12:04to prevent concussion.
-
12:05 - 12:07Kids, don't try this at home please.
-
12:09 - 12:11This stuntman does not have a helmet.
-
12:12 - 12:14He instead has a neck collar,
-
12:14 - 12:17and this neck collar has sensors in it,
-
12:17 - 12:21the same type of sensors
that are in our mouthguard, -
12:21 - 12:24and it detects when he's likely
to have a fall, -
12:24 - 12:26and there's an airbag
that explodes and triggers, -
12:26 - 12:30the same way that an airbag
works in your car, essentially. -
12:30 - 12:33And in the experiments
we've done in my lab with their device, -
12:33 - 12:37we found that it can greatly reduce
the risk of concussion in some scenarios -
12:37 - 12:39compared to a normal bicycle helmet.
-
12:39 - 12:41So it's a pretty exciting development.
-
12:42 - 12:46But in order for us to actually realize
the benefits of technology -
12:46 - 12:48that can prevent concussion,
-
12:48 - 12:51it needs to meet regulations.
-
12:51 - 12:53That's a reality.
-
12:53 - 12:56And this device is for sale in Europe
-
12:56 - 13:00but is not for sale in the US,
and probably won't be any time soon. -
13:00 - 13:01So I wanted to tell you why.
-
13:01 - 13:05There are some good reasons and then
there are some not so good reasons. -
13:05 - 13:07Bike helmets are federally regulated.
-
13:07 - 13:11The Consumer Product Safety Commission
has been given jurisdiction -
13:11 - 13:13to approve any bike helmet for sale,
-
13:13 - 13:15and this is the test they use.
-
13:15 - 13:18This is back to what I was telling you
at the beginning about skull fracture. -
13:18 - 13:20That's what this test is for.
-
13:20 - 13:21And that's an important thing to do.
-
13:21 - 13:24It can save your life,
but it's not sufficient, I would say. -
13:24 - 13:27So for example, one thing
this test doesn't evaluate -
13:27 - 13:30is it doesn't tell you
is that airbag going to trigger -
13:30 - 13:34at the right time and place,
and not trigger when it doesn't need to? -
13:34 - 13:36Similarly, it's not going to tell you
-
13:36 - 13:39is this helmet likely
to prevent concussion or not? -
13:39 - 13:43And if you look at football helmets,
which aren't regulated, -
13:43 - 13:45they still have a very similar test.
-
13:46 - 13:48They're not regulated
by the government, anyway. -
13:48 - 13:51They have an industry body,
which is the way most industries work. -
13:51 - 13:54But this industry body, I can tell you,
has been quite resistant -
13:54 - 13:55to updating their standards.
-
13:55 - 13:59So in my lab, we are working on not only
the mechanism of concussion, -
13:59 - 14:02but we want to understand
how can we have better test standards? -
14:02 - 14:07And we hope that the government
can use this type of information -
14:07 - 14:08to encourage innovation
-
14:08 - 14:10by letting consumers know
-
14:10 - 14:14how protected are you with a given helmet.
-
14:14 - 14:17And I want to bring this back finally
to the original question I asked, -
14:17 - 14:21which is, would I feel comfortable
letting my child play football -
14:21 - 14:22or ride a bicycle?
-
14:22 - 14:26And this might be just a result
of my own traumatic experience. -
14:26 - 14:30I'm much more nervous
about my daughter, Rose, riding a bicycle. -
14:31 - 14:33So she's a year and a half old,
-
14:33 - 14:38and she's already, well, wants to anyway,
race down the streets of San Francisco. -
14:38 - 14:40This is the bottom
of one of these streets. -
14:40 - 14:46And so my personal goal
is to -- and I believe this is possible -- -
14:46 - 14:48is to further develop these technologies,
-
14:48 - 14:51and in fact, we're working
on something in my lab in particular -
14:51 - 14:54that really makes optimal use
of the given space of a helmet. -
14:54 - 14:56And I am confident
that we will be able to, -
14:56 - 14:59before she's ready to ride a two-wheeler,
-
14:59 - 15:01have something available
-
15:01 - 15:04that can in fact really reduce
the risk of concussion -
15:04 - 15:07and comply with regulatory bodies.
-
15:07 - 15:09And so what I'd like to do --
-
15:09 - 15:12and I know that this is for some of you
of more immediate nature, -
15:12 - 15:14I've got a couple years here --
-
15:14 - 15:18is to be able to tell parents
and grandparents when I'm asked, -
15:18 - 15:23it is safe and healthy for your children
to engage in these activities. -
15:23 - 15:26And I'm very fortunate
to have a wonderful team at Stanford -
15:26 - 15:27that's working hard on this.
-
15:27 - 15:32So I hope to come back in a few years
with the final story, -
15:32 - 15:34but for now I will tell you,
-
15:34 - 15:37please don't just be afraid
when you hear the word concussion. -
15:37 - 15:38There is hope.
-
15:38 - 15:39Thank you.
-
15:39 - 15:44(Applause)
- Title:
- Why helmets don't prevent concussions -- and what might
- Speaker:
- David Camarillo
- Description:
-
What is a concussion? Probably not what you think it is. In this talk from the cutting edge of research, bioengineer (and former football player) David Camarillo shows what really happens during concussion -- and why standard sports helmets don't prevent it. Here's what the future of concussion prevention looks like.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDTalks
- Duration:
- 15:56
Brian Greene edited English subtitles for Why helmets don't prevent concussions -- and what might | ||
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Brian Greene edited English subtitles for Why helmets don't prevent concussions -- and what might | ||
Brian Greene accepted English subtitles for Why helmets don't prevent concussions -- and what might | ||
Brian Greene edited English subtitles for Why helmets don't prevent concussions -- and what might | ||
Joseph Geni edited English subtitles for Why helmets don't prevent concussions -- and what might | ||
Joseph Geni edited English subtitles for Why helmets don't prevent concussions -- and what might | ||
Joseph Geni edited English subtitles for Why helmets don't prevent concussions -- and what might |