A type of brain injury that could be made worse by wearing a bike helmet
04-14-10, 09:18 PM
#51
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If a given impact is severe enough to cause a closed skull brain injury with a helmet, would not the same impact cause a severe skull fracture without a helmet?
04-15-10, 12:48 AM
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I have not read entire thread, no time. But I notice some talk about helmet increasing lever arm and also increasing profile of the head making impact with objects more likely than would be for a lower profile helmetless head.
Maybe it's already been said, but I'll point out that some helmets (Bern Brentwood), have a much lower profile and thinner foam than others. This seems like a good thing, as long as the material is thick enough to absorb impact.
Maybe it's already been said, but I'll point out that some helmets (Bern Brentwood), have a much lower profile and thinner foam than others. This seems like a good thing, as long as the material is thick enough to absorb impact.
04-15-10, 07:03 AM
#53
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It's quite common to have no skull fracture, and still have a brain injury.
The prime problem with a skull fracture with regards to a brain injury, is the bleeding within the skull that the fracture may cause, yet it's quite common to suffer a skull fracture and have little ill effects from it. It's a question of degree.
04-15-10, 12:59 PM
#54
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With the help of her fore arms a helmet saved this American gal from a pretty harsh face plant. All kinds of injuries, many ways to get hurt or die.
https://www.break.com/index/indoor-cy...ke-in-two.html
https://www.break.com/index/indoor-cy...ke-in-two.html
04-15-10, 01:50 PM
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You won't see that kind of event happen on the local bike path, or in the streets will you?
04-15-10, 02:11 PM
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Lets assume that in some situations a helmet can increase the severity of a head injury. What percentage of accidents involving head injuries does helmet use make worse, 0.01%, 2%...?? If the situation exists it has to be small, I'll take my chances wearing a helmet, better odds.
04-15-10, 02:20 PM
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Traffic school is good for something... 2% of cars accidents are made worse by seat belt use.
04-15-10, 02:44 PM
#58
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^ You bring up a good point as its all percentages and odds. Personally I neither care nor advocate for whatever reason whether a man, woman, or child wears a helmet or not. For adults its a personal decision, and I leave it at that. OTOH, the OP's description and analysis of his experience is information that someone might possibly want to make that decision. There's some validity to it, but I wouldn't use it myself.
04-15-10, 03:31 PM
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A few years ago I flew over my handlebars while cruising at about 25 mph. I landed head-first on the road and proceeded to do three cartwheels (per a witness). I was wearing a helmet at the time. It got scuffed up and cracked, but it stayed on, held together, and did its job. Unfortunately, I was knocked out cold and was looking pretty lifeless - other than a few grand mal seizures. I spent three days in a coma and ultimately I was diagnosed with Diffuse Axonal Injury or DAI. Most people with DAI are vegetables until they die. I was lucky.
I had what is called a closed-head traumatic brain injury. My skull was perfectly intact. (I'm still pretty - to quote Ali.) The damage to my brain was the result of rapid angular acceleration. In essence, my head suddenly rotated when my helmet hit the pavement. If you ever watch a plane's wheel make contact with the ground when it's landing, you get an idea how your head would experienced a rapid acceleration in a case like this.
The rotation/acceleration generated shearing forces that tore up bits of my brain. There was bleeding here there and everywhere inside my head.
I'm an engineer, so I've given this a little analysis...
The helmet effectively increased the twisting force that was spun into my brain in two ways:
1) The helmet "grabbed" the pavement better than my scalp would have. (Without the helmet, a piece of my scalp might have been ripped off. Not pretty, but it's better than a large torque causing a TBI and being a vegetable for life.)
2) The helmet increased the length of the moment arm that the friction force acted through. This resulted in a greater torque and an increased angular acceleration of my head.
My helmet resulted in a more severe twisting force being cranked into my head by the impact. I'm very confident that in my case, my helmet exacerbated my injury.
For many or most accidents, it's likely that a helmet reduces the severity of an injury. But there are exceptions.
I would love to know if any of the helmet manufacturers have considered this scenario and if they have determined how frequently this type of injury happens to crashing bike riders wearing helmets.
I had what is called a closed-head traumatic brain injury. My skull was perfectly intact. (I'm still pretty - to quote Ali.) The damage to my brain was the result of rapid angular acceleration. In essence, my head suddenly rotated when my helmet hit the pavement. If you ever watch a plane's wheel make contact with the ground when it's landing, you get an idea how your head would experienced a rapid acceleration in a case like this.
The rotation/acceleration generated shearing forces that tore up bits of my brain. There was bleeding here there and everywhere inside my head.
I'm an engineer, so I've given this a little analysis...
The helmet effectively increased the twisting force that was spun into my brain in two ways:
1) The helmet "grabbed" the pavement better than my scalp would have. (Without the helmet, a piece of my scalp might have been ripped off. Not pretty, but it's better than a large torque causing a TBI and being a vegetable for life.)
2) The helmet increased the length of the moment arm that the friction force acted through. This resulted in a greater torque and an increased angular acceleration of my head.
My helmet resulted in a more severe twisting force being cranked into my head by the impact. I'm very confident that in my case, my helmet exacerbated my injury.
For many or most accidents, it's likely that a helmet reduces the severity of an injury. But there are exceptions.
I would love to know if any of the helmet manufacturers have considered this scenario and if they have determined how frequently this type of injury happens to crashing bike riders wearing helmets.
While I have lived with health problems(that includes Epilepsy) all my life due to a brain injury as a child(which was followed by several corrective surgeries), the helmet I was wearing this past Easter Sunday when I crashed, helped save me from almost certain death. The one blessed detail that definitely made a difference, even before the helmet, was that, I was not standing on the pedals when I ran over a pothole. By not standing on the pedals, my forward momentum upon hitting the pothole was greatly decreased resulting in my hitting my forehead and, not with full force.
So helmets are definitely life savers.
04-15-10, 03:37 PM
#60
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With the help of her fore arms a helmet saved this American gal from a pretty harsh face plant. All kinds of injuries, many ways to get hurt or die.
https://www.break.com/index/indoor-cy...ke-in-two.html
https://www.break.com/index/indoor-cy...ke-in-two.html
I doubt very much weather the cyclist would have had a serious injury had the cyclist had not been wearing a helmet (depending on how you define a serious injury - if we take into consideration the theme of this thread, I'll consider a serious injury, a brain injury) because we know what the past experiences of track riders being injured are. The overwhelming incidences of brain injury and death are caused by collisions with motor vehicles and there are very few cars on the track with those riders.
I find helmeteers often equate any fall with a potential brain injury, when in fact brain injuries occur to cyclists only very rarely. Helmeteers like to spread the insinuation that brain injury happens much more than it really does in order to justify helmet use.
Last edited by closetbiker; 04-15-10 at 04:26 PM.
04-15-10, 04:57 PM
#61
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I had a skull fracture and brain injury (subdural hematoma) during a non-cycling accident, that would have equated to a cyclist moving at 0 mph falling sideways and impacting their head the same way mine had hit. Was in ICU for 3 days and did not remember a thing, loss most of my ability to walk for a month, had a severely dizzying case of Diplopia (which lasted 1.5 months), along with the sundry loss of mental abilities etc. etc. The severity was scary, because in such cases one does not know to what degree one will heal.
I agree with you though, and I'm not trying to insinuate anything. Ten people can experience a head impaction in almost exactly the same way and come out unscathed, but the 11th might not be so lucky. The minute variables that can significantly affect such events are enormous. I put that video there not to push any view or agenda, nor to discuss details of the ways the riders fell, but to let individuals see examples of head impacts and come to their own conclusions whatever that may be.
I agree with you though, and I'm not trying to insinuate anything. Ten people can experience a head impaction in almost exactly the same way and come out unscathed, but the 11th might not be so lucky. The minute variables that can significantly affect such events are enormous. I put that video there not to push any view or agenda, nor to discuss details of the ways the riders fell, but to let individuals see examples of head impacts and come to their own conclusions whatever that may be.
04-15-10, 05:09 PM
#62
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I think the issue here is, would wearing a helmet change the outcomes in these types of rare instances?
People have been wearing helmets for some time. I think the record shows that they do not.
Lots of helmeteers are convinced a helmet has saved them from such an injury, but if you check hospital records, you'll find that these injuries have not decreased. In fact, they have increased.
People have been wearing helmets for some time. I think the record shows that they do not.
Lots of helmeteers are convinced a helmet has saved them from such an injury, but if you check hospital records, you'll find that these injuries have not decreased. In fact, they have increased.
04-15-10, 06:15 PM
#63
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I haven't yet read all the posts. Two years ago I too had a crash at ~ 25 mph (hit a dog). I flipped and basically skidded down the road, arching on my head and my hip. No helmet. I remember thinking as I slid, "I am tearing the hell out of this nice hat." I was wearing a ball cap.
1) I think it's good that my head never "caught" and twisted. I did get road rash on my head.
2) I'm lucky my head didn't impact the pavement with force.
3) Since then I will never ride without a helmet.
1) I think it's good that my head never "caught" and twisted. I did get road rash on my head.
2) I'm lucky my head didn't impact the pavement with force.
3) Since then I will never ride without a helmet.
04-15-10, 08:18 PM
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Closed skull injuries result when your head comes to a sudden stop and your brain does not, causing it to impact against the inside of the skull and swell. Helmets are designed to do one thing, slow your head down so your brain does not slam into your skull and they are designed to do this from a height of about 6 feet, basically the distance from your head to the ground when sitting on a bicycle. https://www.bhsi.org/standard.htm
04-15-10, 08:43 PM
#65
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Diffuse axonal injury isn't a simple as the brain impacting the inside of the skull.
"Unlike brain trauma that occurs due to direct impact and deformation of the brain, DAI is the result of traumatic shearing forces.
The major cause of damage in DAI is the disruption of axons. Acceleration causes shearing injury. When the brain is accelerated, parts of differing densities and distances from the axis of rotation slide over one another, stretching axons. Two thirds of DAI lesions occur in areas where grey and white matter meet."
"Unlike brain trauma that occurs due to direct impact and deformation of the brain, DAI is the result of traumatic shearing forces.
The major cause of damage in DAI is the disruption of axons. Acceleration causes shearing injury. When the brain is accelerated, parts of differing densities and distances from the axis of rotation slide over one another, stretching axons. Two thirds of DAI lesions occur in areas where grey and white matter meet."
04-15-10, 09:24 PM
#67
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Gee, I didn't know having an opinion could be wrong. (And I really don't think my opinion on the topic can be described as ignorant either, yet it seems Chris516 may be guilty of being uninformed - aka, ignorant- of my involvement on the merits of this issue)
Last edited by closetbiker; 04-16-10 at 02:26 PM.
04-15-10, 10:20 PM
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A helmet is a simple device that provides some limited benefit to its user. If that is worth it to you wear one, if not, don't. Bicycle safety is a combination of things - situation awareness, skill, equipment... luck.
What I don't understand is why people who don't wear helmets feel the need to justify it by insinuating that they cause or increase the severity of injuries. Suck it up, say "I don't believe that helmets provide any benefit so I don't wear one". That is a perfectly valid argument.
On the flip side, what do you expect from a 20 dollar piece of equipment (200 dollar helmets aren't any better safety wise), a magic bullet? Educate yourself on what it's really designed to do so you don't go riding around with a false sense of security.
What I don't understand is why people who don't wear helmets feel the need to justify it by insinuating that they cause or increase the severity of injuries. Suck it up, say "I don't believe that helmets provide any benefit so I don't wear one". That is a perfectly valid argument.
On the flip side, what do you expect from a 20 dollar piece of equipment (200 dollar helmets aren't any better safety wise), a magic bullet? Educate yourself on what it's really designed to do so you don't go riding around with a false sense of security.
04-16-10, 07:08 AM
#69
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It's important to understand research is often contradictory, and doesn't necessarily end in a black or white, right or wrong answer. The important thing is to get as much information as possible on the subject in order to develop an informed opinion in order to make an informed choice.
Last edited by closetbiker; 04-16-10 at 08:31 AM.
04-16-10, 07:16 AM
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A helmet is a simple device that provides some limited benefit to its user. If that is worth it to you wear one, if not, don't. Bicycle safety is a combination of things - situation awareness, skill, equipment... luck.
What I don't understand is why people who don't wear helmets feel the need to justify it by insinuating that they cause or increase the severity of injuries. Suck it up, say "I don't believe that helmets provide any benefit so I don't wear one". That is a perfectly valid argument.
What I don't understand is why people who don't wear helmets feel the need to justify it by insinuating that they cause or increase the severity of injuries. Suck it up, say "I don't believe that helmets provide any benefit so I don't wear one". That is a perfectly valid argument.
Your points are valid...but dude, catch up!
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"Let us hope our weapons are never needed --but do not forget what the common people knew when they demanded the Bill of Rights: An armed citizenry is the first defense, the best defense, and the final defense against tyranny. If guns are outlawed, only the government will have guns. Only the police, the secret police, the military, the hired servants of our rulers. Only the government -- and a few outlaws. I intend to be among the outlaws" - Edward Abbey
04-16-10, 10:34 AM
#71
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What I don't understand are noobs that come in here and don't bother to catch up on a long running subject, or even the current thread, so they don't realize that most of us who don't wear helmets have and DO make those perfectly valid points concerning why we prefer not to do so.
Your points are valid...but dude, catch up!
Your points are valid...but dude, catch up!
As far a helmets are concerned, I've been listening to that argument for the last 25 years among motorcyclists. And I've met, in person, many helmetless rider who feel compelled to come up to me and list off the dangers of my choice. I've also cringed at the safetycrat lecture about how you're courting death by going anywhere with out fully gearing up, which as often as not, is issued by someone who doesn't actually ride.
Myself, I've had three accidents in those 25 years, and each time I was really glad to be wearing gloves.
Sorry about the diversion to motorcycles but the arguments among lay people are pretty much the same. My point at the beginning, what percentage of accidents are made worse by helmet use? Unfortunately bike riders don't constitute a large enough percentage of road users to get that kind of study funded. The best we is get static tests in a lab.
Also, if you do a Google search of bikeforums EVERY subject is a long running one.
04-16-10, 10:53 AM
#72
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The helmet industry have funded studies that show benefits because it's good business to associate lower head injuries with their product.
There are some studies that are less biased, but such studies don't have the same kind of funding, and promotion of the findings are even less well funded because there is little financial incentive to inform the public of them.
There are a few studies that have examined what has happened after whole populations switched to helmet use and they aren't too flattering to the helmet industry, so the knowledge of these studies are not as widespread. What happens as a result of this is, lay people aren't as well informed as they could be.
Forewarned is forearmed. Gather as much good information you can to make an informed decision. I think too many people are making decisions on poor information or fear campaigns to entice them to "buy" safety.
Last edited by closetbiker; 04-16-10 at 11:58 AM.
04-16-10, 12:15 PM
#73
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A lot of the anti-helmet arguments here remind me of some of the old ones about seat belts --
"it's better to be thrown free of the wreckage"
"seat belts make it harder to get out of the car when it's about to burst into flames."
"In some crashes, the engine winds up in the front seat, crushing the occupants if they are wearing seat belts."
"it's better to be thrown free of the wreckage"
"seat belts make it harder to get out of the car when it's about to burst into flames."
"In some crashes, the engine winds up in the front seat, crushing the occupants if they are wearing seat belts."
04-16-10, 01:46 PM
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Seatbelts: proven effective measure in large populations
Helmets: proven INEFFECTIVE measure in large populations
Astral crystals: hey, some protection is better than none right? That's common sense. Don't bother me with statistics. I fell while wearing an astral crystal and I'd be dead now if I hadn't had a purple one tucked safely in my pocket. Be safe out there. I worry about you. I would never let my children ride without a crystal. <insert link to Journal of Crystal Studies here>.