Why helmets don't prevent concussions -- and what might | David Camarillo

292,339 views ・ 2016-09-29

TED


Please double-click on the English subtitles below to play the video.

00:12
The word concussion evokes a fear these days more so than it ever has,
0
12440
4656
00:17
and I know this personally.
1
17120
2376
00:19
I played 10 years of football,
2
19520
2656
00:22
was struck in the head thousands of times.
3
22200
2416
00:24
And I have to tell you, though, what was much worse than that
4
24640
3656
00:28
was a pair of bike accidents I had where I suffered concussions,
5
28320
4776
00:33
and I'm still dealing with the effects of the most recent one
6
33120
2936
00:36
today as I stand in front of you.
7
36080
1760
00:39
There is a fear around concussion
8
39640
2456
00:42
that does have some evidence behind it.
9
42120
1960
00:45
There is information that a repeated history of concussion
10
45600
3336
00:48
can lead to early dementia, such as Alzheimer's,
11
48960
3296
00:52
and chronic traumatic encephalopathy.
12
52280
2056
00:54
That was the subject of the Will Smith movie "Concussion."
13
54360
3040
00:58
And so everybody is caught up in football and what they see in the military,
14
58560
3576
01:02
but you may not know
15
62160
1336
01:03
that bike riding is the leading cause of concussion for kids,
16
63520
4296
01:07
sports-related concussion, that is.
17
67840
1667
01:11
And so another thing that I should tell you
18
71040
2576
01:13
that you may not know
19
73640
1216
01:14
is that the helmets that are worn in bicycling and football
20
74880
2936
01:17
and many activities,
21
77840
1656
01:19
they're not designed or tested
22
79520
2576
01:22
for how well they can protect your children against concussion.
23
82120
3480
01:26
They're in fact designed and tested
24
86200
1736
01:27
for their ability to protect against skull fracture.
25
87960
2680
01:31
And so I get this question all the time from parents,
26
91840
5616
01:37
and they ask me,
27
97480
1576
01:39
"Would you let your own child play football?"
28
99080
2296
01:41
Or, "Should I let my child play soccer?"
29
101400
3176
01:44
And I think that as a field,
30
104600
2896
01:47
we're a long way from giving an answer with any kind of confidence there.
31
107520
4400
01:53
So I look at that question from a bit of a different lens,
32
113440
3576
01:57
and I want to know, how can we prevent concussion?
33
117040
3736
02:00
Is that even possible?
34
120800
1656
02:02
And most experts think that it's not,
35
122480
2560
02:06
but the work that we're doing in my lab
36
126520
2216
02:08
is starting to reveal more of the details around concussion
37
128760
4376
02:13
so that we can have a better understanding.
38
133160
2776
02:15
The reason we're able to prevent skull fracture with helmets
39
135960
2856
02:18
is because it's pretty simple. We know how it works.
40
138840
2455
02:21
Concussion has been much more of a mystery.
41
141320
2040
02:24
So to give you a sense of what might be happening in a concussion,
42
144280
3760
02:29
I want to show you the video here
43
149240
1936
02:31
that you see when you type into Google,
44
151200
2536
02:33
"What is a concussion?"
45
153760
1416
02:35
The CDC website comes up,
46
155200
1656
02:36
and this video essentially tells the whole story.
47
156880
3456
02:40
What you see is the head moves forward,
48
160360
2416
02:42
the brain lags behind,
49
162800
2056
02:44
then the brain catches up
50
164880
1416
02:46
and smashes into the skull.
51
166320
2256
02:48
It rebounds off the skull
52
168600
2176
02:50
and then proceeds to run into the other side of the skull.
53
170800
3760
02:55
And what you'll notice is highlighted in this video from the CDC,
54
175320
3616
02:58
which I'll note was funded by the NFL,
55
178960
2456
03:01
is that the outer surface of the brain,
56
181440
2936
03:04
where it was to have smashed into the skull,
57
184400
3296
03:07
looks like it's been damaged or injured, so it's on the outer surface of the brain.
58
187720
3936
03:11
And what I'd like to do with this video
59
191680
1976
03:13
is to tell you that there are some aspects that are probably right,
60
193680
3696
03:17
indicative of what the scientists think happens with concussion,
61
197400
3016
03:20
but there's probably more that's wrong with this video.
62
200440
2616
03:23
So one thing that I do agree with, and I think most experts would,
63
203080
3256
03:26
is that the brain does have these dynamics.
64
206360
2016
03:28
It does lag behind the skull
65
208400
2376
03:30
and then catch up and move back and forth and oscillate.
66
210800
2656
03:33
That we think is true.
67
213480
1240
03:35
However, the amount of motion you see in the brain in this video
68
215760
3296
03:39
is probably not right at all.
69
219080
1576
03:40
There's very little room in the cranial vault,
70
220680
3416
03:44
only a few millimeters,
71
224120
1696
03:45
and it's filled entirely with cerebral spinal fluid,
72
225840
3176
03:49
which acts as a protective layer.
73
229040
2176
03:51
And so the brain as a whole probably moves very little inside the skull.
74
231240
4160
03:56
The other problem with this video
75
236520
2056
03:58
is that the brain is shown
76
238600
1736
04:00
as a kind of rigid whole as it moves around,
77
240360
3096
04:03
and that's not true either.
78
243480
1400
04:05
Your brain is one of the softest substances in your body,
79
245720
3416
04:09
and you can think of it kind of like jello.
80
249160
2016
04:11
So as your head is moving back and forth,
81
251200
2136
04:13
your brain is twisting and turning and contorting,
82
253360
2856
04:16
and the tissue is getting stretched.
83
256240
2216
04:18
And so most experts, I think, would agree
84
258480
3016
04:21
that concussion is not likely to be something that's happening
85
261520
3136
04:24
on this outer surface of the brain,
86
264680
1816
04:26
but rather it's something that's much deeper
87
266520
2096
04:28
towards the center of the brain.
88
268640
1560
04:31
Now, the way that we're approaching this problem
89
271279
2577
04:33
to try to understand the mechanisms of concussion
90
273880
2336
04:36
and to figure out if we can prevent it
91
276240
1856
04:38
is we are using a device like this.
92
278120
2816
04:40
It's a mouthguard.
93
280960
1200
04:42
It has sensors in it that are essentially the same
94
282960
2896
04:45
that are in your cell phone:
95
285880
1336
04:47
accelerometers, gyroscopes,
96
287240
2336
04:49
and when someone is struck in the head,
97
289600
1896
04:51
it can tell you how their head moved
98
291520
2536
04:54
at a thousand samples per second.
99
294080
3120
04:58
The principle behind the mouthguard is this:
100
298760
2696
05:01
it fits onto your teeth.
101
301480
1256
05:02
Your teeth are one of the hardest substances in your body.
102
302760
3056
05:05
So it rigidly couples to your skull
103
305840
2056
05:07
and gives you the most precise possible measurement
104
307920
2416
05:10
of how the skull moves.
105
310360
1936
05:12
People have tried other approaches, with helmets.
106
312320
2536
05:14
We've looked at other sensors that go on your skin,
107
314880
3376
05:18
and they all simply move around too much,
108
318280
2616
05:20
and so we found that this is the only reliable way
109
320920
2696
05:23
to take a good measurement.
110
323640
1360
05:27
So now that we've got this device, we can go beyond studying cadavers,
111
327400
4296
05:31
because you can only learn so much about concussion
112
331720
2416
05:34
from studying a cadaver,
113
334160
1216
05:35
and we want to learn and study live humans.
114
335400
2776
05:38
So where can we find a group of willing volunteers
115
338200
3896
05:42
to go out and smash their heads into each other on a regular basis
116
342120
4256
05:46
and sustain concussion?
117
346400
1216
05:47
Well, I was one of them,
118
347640
1896
05:49
and it's your local friendly Stanford football team.
119
349560
2800
05:53
So this is our laboratory,
120
353640
1616
05:55
and I want to show you
121
355280
1696
05:57
the first concussion we measured with this device.
122
357000
3176
06:00
One of the things that I should point out is the device has this gyroscope in it,
123
360200
4256
06:04
and that allows you to measure the rotation of the head.
124
364480
2736
06:07
Most experts think that that's the critical factor
125
367240
2376
06:09
that might start to tell us what is happening in concussion.
126
369640
2856
06:12
So please watch this video.
127
372520
1360
06:15
Announcer: Cougars bring extra people late, but Luck has time,
128
375280
3416
06:18
and Winslow is crushed.
129
378720
1640
06:22
I hope he's all right.
130
382120
1576
06:23
(Audience roars)
131
383720
1960
06:30
Top of your screen,
132
390560
1456
06:32
you'll see him come on just this little post route,
133
392040
2416
06:34
get separation, safety.
134
394480
1640
06:40
Here it comes at you in real speed. You'll hear this.
135
400240
2560
06:44
The hit delivered by --
136
404640
1880
06:47
David Camarillo: Sorry, three times is probably a little excessive there.
137
407720
3456
06:51
But you get the idea.
138
411200
1256
06:52
So when you look at just the film here,
139
412480
2816
06:55
pretty much the only thing you can see is he got hit really hard and he was hurt.
140
415320
3816
06:59
But when we extract the data
141
419160
1656
07:00
out of the mouthguard that he was wearing,
142
420840
2000
07:02
we can see much more detail, much richer information.
143
422864
2712
07:05
And one of the things that we noticed here
144
425600
2416
07:08
is that he was struck in the lower left side of his face mask.
145
428040
4056
07:12
And so that did something first that was a little counterintuitive.
146
432120
3176
07:15
His head did not move to the right.
147
435320
1696
07:17
In fact, it rotated first to the left.
148
437040
1936
07:19
Then as the neck began to compress,
149
439000
2856
07:21
the force of the blow caused it to whip back to the right.
150
441880
3096
07:25
So this left-right motion was sort of a whiplash-type phenomenon,
151
445000
5856
07:30
and we think that is probably what led to the brain injury.
152
450880
4416
07:35
Now, this device is only limited in such that it can measure the skull motion,
153
455320
3776
07:39
but what we really want to know is what's happening inside of the brain.
154
459120
3416
07:42
So we collaborate with Svein Kleiven's group in Sweden.
155
462560
3496
07:46
They've developed a finite element model of the brain.
156
466080
3576
07:49
And so this is a simulation
157
469680
2096
07:51
using the data from our mouthguard from the injury I just showed you,
158
471800
3336
07:55
and what you see is the brain --
159
475160
2016
07:57
this is a cross-section right in the front
160
477200
2416
07:59
of the brain twisting and contorting as I mentioned.
161
479640
2776
08:02
So you can see this doesn't look a lot like the CDC video.
162
482440
2896
08:05
Now, the colors that you're looking at
163
485360
1856
08:07
are how much the brain tissue is being stretched.
164
487240
4136
08:11
And so the red is 50 percent.
165
491400
1696
08:13
That means the brain has been stretched to 50 percent of its original length,
166
493120
3656
08:16
the tissue in that particular area.
167
496800
1696
08:18
And the main thing I want to draw your attention to is this red spot.
168
498520
3256
08:21
So the red spot is very close to the center of the brain,
169
501800
3456
08:25
and relatively speaking,
170
505280
1256
08:26
you don't see a lot of colors like that on the exterior surface
171
506560
4656
08:31
as the CDC video showed.
172
511240
2360
08:34
Now, to explain a little more detail
173
514960
1736
08:36
about how we think concussion might be happening,
174
516720
3616
08:40
one thing I should mention
175
520360
1296
08:41
is that we and others have observed that a concussion is more likely
176
521680
3215
08:44
when you're struck and your head rotates in this direction.
177
524919
3976
08:48
This is more common in sports like football,
178
528919
2257
08:51
but this seems to be more dangerous. So what might be happening there?
179
531200
3335
08:54
Well, one thing that you'll notice in the human brain
180
534559
3017
08:57
that is different than other animals
181
537600
1736
08:59
is we have these two very large lobes.
182
539360
2456
09:01
We have the right brain and the left brain.
183
541840
2216
09:04
And the key thing to notice in this figure here
184
544080
3056
09:07
is that right down the center of the right brain and the left brain
185
547160
3256
09:10
there's a large fissure that goes deep into the brain.
186
550440
2936
09:13
And in that fissure, what you can't see in this image,
187
553400
2856
09:16
you'll have to trust me,
188
556280
1216
09:17
there is a fibrous sheet of tissue.
189
557520
1696
09:19
It's called the falx,
190
559240
1216
09:20
and it runs from the front of your head all the way to the back of your head,
191
560480
3656
09:24
and it's quite stiff.
192
564160
1216
09:25
And so what that allows for is when you're struck
193
565400
3456
09:28
and your head rotates in this left-right direction,
194
568880
3056
09:31
forces can rapidly transmit right down to the center of your brain.
195
571960
3776
09:35
Now, what's there at the bottom of this fissure?
196
575760
2240
09:39
It's the wiring of your brain,
197
579120
2496
09:41
and in fact this red bundle here at the bottom of that fissure
198
581640
4616
09:46
is the single largest fiber bundle
199
586280
2976
09:49
that is the wiring that connects the right and left sides of your brain.
200
589280
3976
09:53
It's called the corpus callosum.
201
593280
1524
09:55
And we think that this might be
202
595480
1936
09:57
one of the most common mechanisms of concussion,
203
597440
3816
10:01
and as the forces move down, they strike the corpus callosum,
204
601280
4696
10:06
it causes a dissociation between your right and your left brain
205
606000
2976
10:09
and could explain some of the symptoms of concussion.
206
609000
2480
10:12
This finding is also consistent of what we've seen
207
612680
2816
10:15
in this brain disease that I mentioned, chronic traumatic encephalopathy.
208
615520
4016
10:19
So this is an image of a middle-aged ex-professional football player,
209
619560
5536
10:25
and the thing that I want to point out is if you look at the corpus callosum,
210
625120
3976
10:29
and I'll page back here so you can see the size of a normal corpus callosum
211
629120
3936
10:33
and the size of the person here who has chronic traumatic encephalopathy,
212
633080
4416
10:37
it is greatly atrophied.
213
637520
2536
10:40
And the same goes for all of the space in the ventricles.
214
640080
3336
10:43
These ventricles are much larger.
215
643440
1776
10:45
And so all of this tissue near the center of the brain
216
645240
2536
10:47
has died off over time.
217
647800
1216
10:49
So what we're learning is indeed consistent.
218
649040
3560
10:53
Now, there is some good news here,
219
653520
2656
10:56
and I hope to give you a sense of hope by the end of this talk.
220
656200
3456
10:59
One of the things that we've noticed,
221
659680
2096
11:01
specifically about this mechanism of injury,
222
661800
2256
11:04
is although there's a rapid transmission of the forces down this fissure,
223
664080
4056
11:08
it still takes a defined amount of time.
224
668160
3296
11:11
And what we think is that if we can slow the head down just enough
225
671480
4336
11:15
so that the brain does not lag behind the skull
226
675840
3216
11:19
but instead it moves in synchrony with the skull,
227
679080
3576
11:22
then we might be able to prevent this mechanism of concussion.
228
682680
3256
11:25
So how can we slow the head down?
229
685960
2680
11:30
(Laughter)
230
690640
1736
11:32
A gigantic helmet.
231
692400
1960
11:35
So with more space, you have more time,
232
695440
2856
11:38
and this is a bit of a joke, but some of you may have seen this.
233
698320
3096
11:41
This is bubble soccer, and it's a real sport.
234
701440
2296
11:43
In fact, I saw some young adults
235
703760
1656
11:45
playing this sport down the street from my house the other day,
236
705440
2976
11:48
and as far as I know there have been no reported concussions.
237
708440
2896
11:51
(Laughter)
238
711360
1016
11:52
But in all seriousness, this principle does work,
239
712400
4416
11:56
but this has gone too far.
240
716840
1376
11:58
This isn't something that's practical for bike riding or playing football.
241
718240
5256
12:03
And so we are collaborating with a company in Sweden called Hövding.
242
723520
4376
12:07
Some of you may have seen their work,
243
727920
2336
12:10
and they're using the same principle of air to give you some extra space
244
730280
4376
12:14
to prevent concussion.
245
734680
1800
12:17
Kids, don't try this at home please.
246
737320
1760
12:20
This stuntman does not have a helmet.
247
740680
2160
12:24
He instead has a neck collar,
248
744200
2256
12:26
and this neck collar has sensors in it,
249
746480
2576
12:29
the same type of sensors that are in our mouthguard,
250
749080
3576
12:32
and it detects when he's likely to have a fall,
251
752680
3136
12:35
and there's an airbag that explodes and triggers,
252
755840
2336
12:38
the same way that an airbag works in your car, essentially.
253
758200
3776
12:42
And in the experiments we've done in my lab with their device,
254
762000
2936
12:44
we found that it can greatly reduce the risk of concussion in some scenarios
255
764960
3736
12:48
compared to a normal bicycle helmet.
256
768720
2136
12:50
So it's a pretty exciting development.
257
770880
1840
12:53
But in order for us to actually realize the benefits of technology
258
773720
4696
12:58
that can prevent concussion,
259
778440
1856
13:00
it needs to meet regulations.
260
780320
2936
13:03
That's a reality.
261
783280
1696
13:05
And this device is for sale in Europe
262
785000
3136
13:08
but is not for sale in the US, and probably won't be any time soon.
263
788160
3696
13:11
So I wanted to tell you why.
264
791880
1536
13:13
There are some good reasons and then there are some not so good reasons.
265
793440
3776
13:17
Bike helmets are federally regulated.
266
797240
2216
13:19
The Consumer Product Safety Commission has been given jurisdiction
267
799480
3736
13:23
to approve any bike helmet for sale,
268
803240
1856
13:25
and this is the test they use.
269
805120
1456
13:26
This is back to what I was telling you at the beginning about skull fracture.
270
806600
3656
13:30
That's what this test is for.
271
810280
1416
13:31
And that's an important thing to do.
272
811720
1736
13:33
It can save your life, but it's not sufficient, I would say.
273
813480
2856
13:36
So for example, one thing this test doesn't evaluate
274
816360
2736
13:39
is it doesn't tell you is that airbag going to trigger
275
819120
2816
13:41
at the right time and place, and not trigger when it doesn't need to?
276
821960
3896
13:45
Similarly, it's not going to tell you
277
825880
2056
13:47
is this helmet likely to prevent concussion or not?
278
827960
3376
13:51
And if you look at football helmets, which aren't regulated,
279
831360
3736
13:55
they still have a very similar test.
280
835120
2376
13:57
They're not regulated by the government, anyway.
281
837520
2256
13:59
They have an industry body, which is the way most industries work.
282
839800
3136
14:02
But this industry body, I can tell you, has been quite resistant
283
842960
3016
14:06
to updating their standards.
284
846000
1376
14:07
So in my lab, we are working on not only the mechanism of concussion,
285
847400
3256
14:10
but we want to understand how can we have better test standards?
286
850680
3456
14:14
And we hope that the government can use this type of information
287
854160
4536
14:18
to encourage innovation
288
858720
1736
14:20
by letting consumers know
289
860480
1616
14:22
how protected are you with a given helmet.
290
862120
3776
14:25
And I want to bring this back finally to the original question I asked,
291
865920
3376
14:29
which is, would I feel comfortable letting my child play football
292
869320
3336
14:32
or ride a bicycle?
293
872680
1736
14:34
And this might be just a result of my own traumatic experience.
294
874440
3336
14:37
I'm much more nervous about my daughter, Rose, riding a bicycle.
295
877800
4000
14:42
So she's a year and a half old,
296
882920
1656
14:44
and she's already, well, wants to anyway, race down the streets of San Francisco.
297
884600
5456
14:50
This is the bottom of one of these streets.
298
890080
2336
14:52
And so my personal goal is to -- and I believe this is possible --
299
892440
5216
14:57
is to further develop these technologies,
300
897680
2056
14:59
and in fact, we're working on something in my lab in particular
301
899760
2976
15:02
that really makes optimal use of the given space of a helmet.
302
902760
2953
15:05
And I am confident that we will be able to,
303
905737
2479
15:08
before she's ready to ride a two-wheeler,
304
908240
3216
15:11
have something available
305
911480
1376
15:12
that can in fact really reduce the risk of concussion
306
912880
3336
15:16
and comply with regulatory bodies.
307
916240
3136
15:19
And so what I'd like to do --
308
919400
1616
15:21
and I know that this is for some of you of more immediate nature,
309
921040
3376
15:24
I've got a couple years here --
310
924440
1656
15:26
is to be able to tell parents and grandparents when I'm asked,
311
926120
4136
15:30
it is safe and healthy for your children to engage in these activities.
312
930280
4416
15:34
And I'm very fortunate to have a wonderful team at Stanford
313
934720
2816
15:37
that's working hard on this.
314
937560
1896
15:39
So I hope to come back in a few years with the final story,
315
939480
4096
15:43
but for now I will tell you,
316
943600
1976
15:45
please don't just be afraid when you hear the word concussion.
317
945600
2936
15:48
There is hope.
318
948560
1216
15:49
Thank you.
319
949800
1216
15:51
(Applause)
320
951040
4503
About this website

This site will introduce you to YouTube videos that are useful for learning English. You will see English lessons taught by top-notch teachers from around the world. Double-click on the English subtitles displayed on each video page to play the video from there. The subtitles scroll in sync with the video playback. If you have any comments or requests, please contact us using this contact form.

https://forms.gle/WvT1wiN1qDtmnspy7