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| Q&A: Dr David Hartman on Head Injuries (824 Posts)
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Gloves with wristguards
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On 5/29/2002
Sparker
wrote in from
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I'm currently using an old pair of Level "Superpipe" snowboarding gloves as slider gloves. These feature a kevlar and rubber reinforced palm and fingers.
As well as the reinforcement, these gloves feature a built in semi-flexible wristguard.
They offer good support without being totally rigid.
They work for me (if a bit hot and sweaty sometimes).
Cheers
Sparker
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Kanufi's new business. . .
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On 5/28/2002
Dr Dave
wrote in from
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I'm not aware of any slide glove/wrist guard combo. I think it would be a fantastic product for boarders. Anyone into making specialty apparel?
drD
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Wrist guards
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On 5/28/2002 kanufi
wrote in from
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Is there a wrist guard/slide glove combo.I have noticed that a slide glove will give you protection from wearing away your hand but impact forces like your talking about its useless.My main sliding wrist is 10mm thicker from falls of this nature.When it happened i saw a doc and he said there is damage there but he could do nothing .Now i put some high density foam behind the slide puck just to take out the jaring effect of falls.
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No Risk Wrist (try repeating *that fast)
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On 5/26/2002
Dave H.
wrote in from
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Henry,
Wrist guards that have a plastic spring will absorb the landing of the most common fall - that of splaying out your arms in front of you. You land directly on the wrist bone without a guard and your wrist, which is composed of many tiny little bones that are not skateboard-approved, is toast. Yes, if you're good, you can Coleman slide or other maneuver, but for an unexpected fall, put your wrist on springs.
drD
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wrist guards
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On 5/26/2002
Henry J
wrote in from
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Doc-
How do wrist guards prevent injury? I know that they basically absorb the shock from a fall, but in my quest for enlightenment I'd like to know more.
Thanks,
hj
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The Helmet that keeps on giving - KMG's note
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On 5/25/2002
Dr. Dave
wrote in from
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KMG,
The shell of the helmet doesn't have to be soft also because impact slams your head against the *inside of the helmet. As you suggest, this crumples/crushes the foam and disipates the force of the impact. The shell is hard, so a random rock, girder, etc, doesn't impale your head on the way down and so the foam remains intact in its original shape to cradle your skull.
drD
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my point
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On 5/25/2002 P@io
wrote in from
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a helmet is better than the body's natural padding.
there are many levels of helmets/padding.
every level has SOME benefit. even a ballcap can prevent chunks of scalp lost in a SLIDE situation, but for a WHACK, fergit it!
my invisible point was that everyone should wear the best helmet that they can(within reality...I won't wear a NASCAR fullface for slalom).
and yes, helmet manufacturers should do more than just produce "all sport" helmets. and several are getting more "sport specific", but there's still a way to go.
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Go to the link
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On 5/24/2002
Dr. Dave
wrote in from
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The chart below didn't format properly, but the link http://www.bhsi.org/stdchart.htm should show the comparisons between standards. CPSC is a good standard, and almost as strict as Snell.
drD
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Helmet standard comparison
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On 5/24/2002
Dr. Dave
wrote in from
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Don't know if this will come out but if it doesn't, go to the link: http://www.bhsi.org/stdchart.htm
CPSC ASTM Snell Snell ANSI 1984
F1447 B-90S B-95 (withdrawn)
Drop height on 2.0 m 2.0 m 2.0 m 2.2 m* 1.0 m
flat anvil 2.0 m
Drop height on 1.2 m 1.2 m 1.3 m 1.5 m* 1.0 m
hemispherical 1.3 m
anvil
Drop height on 1.2 m 1.2 m None 1.5 m* None
curbstone anvil 1.3 m
Headform weight 5 kg 5 kg 5 kg 5 kg 5 kg
for adult tests
Headform weight 5 kg 3.2 or 5 kg 5 kg 5 kg
for child tests 4.0 kg
(pending)
Total energy: 98 J 98 J 98 J 110 J* 49 J
adult test 100 J
medium headform
flat anvil
Failure
threshold 300 g 300 g 300 g 300 g 300g
Coverage vs. Same Less Same More Same
CPSC 1999
Strap jerk 24 J 24 J 24 J 24 J 24 J
(joules)
Rolloff test Yes Yes Yes Yes None
*Snell B-95 uses a more severe impact for initial certification than for
follow-up performance testing. Snell considers the B-95 strap jerk test
to be roughly equivalent to the B-90 test, although parameters have changed.
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Jonathan's Head
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On 5/24/2002
Dr. Dave
wrote in from
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Jon,
Pre-frontal head injuries can disrupt attention and so-called "executive" processes -basically, how to direct all the other parts of the brain in an orderly, systematic manner. That often shows up as problems with attention and being overloaded trying to make sense of complex information.
The people to see for possible help on this would be anyone doing "cognitive rehabilitation" on an outpatient basis. This is basically a lot of systematic practice and learning of work-arounds for such difficulties. The adage "use it or lose it" applies. The more practice, the better.
The second source of information would be a neurologist who provides pharmacotherapy for enhancing cognitive function in brain injured patients. He or she would also likely be working at a rehabilitation center or the neurology wing of a university hospital. Best of luck. Write again and let us know what happens or if you have other questions.
drD
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The Egg and I
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On 5/24/2002
Dr. Dave
wrote in from
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Wes,
A couple of limitations in your egg analogy: Dropping an egg surrounded by a thin shell and a large amount of egg white doesn't keep the yolk together. The "vitelline membrane" does. It's a sac that covers the yolk and keeps it from leaking.
Also the analogy doesn't really hold, because the brain is composed of trillions of synapses that can be broken or disrupted by the kinetic energy of the fall. Even if the brain looks OK on observation, the outer shape is an inaccurate guide to the amount of damage caused by the fall.
But let's say you wanted a helmet like an egg. You'd have to have a think shell surrounding a very large amount of viscous gel, giving you a look a little like the gremlin in old Bugs Bunny cartoons. It would be pretty heavy and would make current helmets look really good by comparison.
It's an interesting idea though. . . drD
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Hey Patio
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On 5/24/2002
Wesley Tucker
wrote in from
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And your point is?
Have I at anytime advocated riding without a helmet? Or even suggested anyone should consider riding without a helmet? Of course not. Your "thought experiment" proves beyond a shadow of a doubt that an argument between your skull and concrete will always have a pre-determined outcome.
Does that mean, though, that helmet design, versatility, materials, construction and fit should come to a standstill? Have we learned all there is to learn about head protection and we should stop looking into new ways? Is foam rubber then end-all in padding? Is Kevlar the final word in shell materials?
I don't think so. What I do believe is that helmet design (or any safety equipment for that matter,) is a lot like skateboard racing: the sooner you realize we have our own needs and requirements, the sooner manufacturers will stop making motorcycle helmets for us to wear. I don't play hockey, I don't do BMX, I don't whitewater, I don't even ride a skateboard on a plywood ramp. I ride a skateboard on concrete and asphalt as fast as I can. I want a SKATE RACING helmet. I see nothing insensitive about proposing that we as skaters demand the best product for OUR sport.
I now yield the soap box to the next loud mouth who wants to let out a good rant!
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hey wes...
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On 5/24/2002 Patio...
wrote in from
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for a real experiment, stand flat footed on a sidewalk, driveway, whatever.
fall backwards with your arms folded in front of you.
at this low altitude, and zero speed, you'll hear a nice whack as your head hits.
do you trust your "natural padding" to protect you? I hope not.
I hit my head in a similar manner(board shot out from under me, taking my feet with it, and the back of my head went WHACK. luckily, I only damaged my cerebellum, and was in a wheelchair and then had to re-learn walking and everything.
this is the same injury that you see hockey players get all the time, their feet go out from under them and they whack the back of their heads.
some of them aren't lucky enough to re-learn anything.
The old Tour de France riders would use those "leather strap" helmets. those would let you skid on the leather rather than your scalp, and incase of a good impact, it kepe your head parts in the same general area until they came with a mop and bucket to get you.
Those nutty Harley helmets are the same...skid lids to slide on, but no real padding for impact.
oh wait, you don't have helmet laws in south carolina anyways...It scares me when some dude blows by on his hog at 80mph with no helmet, but the "innocent" helmetless wife/girlfriend on back is who I feel REALLY sorry for.
a skateboard helmet is as comfy as a baseball cap.
wheelchairs suck.
re-learning to walk sucks.
it's better to have one and never have it touch the ground, than to be riding in a chair thinking you shoulda' had one...
off my soapbox and back to slalom practice.
bottom line is that "I LOVE Y'ALL, MAN!", and I want to skate with you untill we are REALLY old.
p
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VANS helmet or CPCS certified Helmets
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On 5/24/2002
Leo
wrote in from
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Dr dave, have u seen tis helmet?
are the cpsc certified helmets good for anything besides puting it upside down and plant a flower?
oppinions wanted
leo
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replacing helmet
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On 5/24/2002
Paul K
wrote in from
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With any helmet constructed with a foam core, its 1 hit & replace it, as the foam has already compressed, leaving further Shock dampening qualities as zero.
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replacing skate helmets
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On 5/24/2002 66.
wrote in from
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dr. dave,
at what point should you replace a skate helmet?
would a glancing blow be enough?
i took a pretty hard slam (momentary blurred vision) on the vert ramp at the xgames skatepark in atlanta. the helmet obviously saved me, but showed absolutely no signs of damage.
66.
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Reading
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On 5/24/2002 Jonathan
wrote in from
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Dr. Dave - I recieved a head injury some years ago - doctors at the time diagnosed a tiny amount of frontal lobe damage...
Im fully functioning in most departments, but have difficulty concerntrating enough to read a book. Pre injury I could read a book a day (!) post injury I'm struggling to read a page... Is it attention span stuff? No problems with reading short articles in magazines and so forth, but large scale just eludes me.
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off topic
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On 5/23/2002
Kaylee
wrote in from
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Sitting at home and watching TV is not good for your head either.
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More thinking experiments
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On 5/23/2002
Wesley Tucker
wrote in from
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Dr. Dave, I follow your Jello experiment with no problem. Only one issue to address. You forgot to wrap the jello in a "liquid" shell (my silicon cells.) So there is one layer of impact-absorbing material missing from your process.
I have another thought experiment to consider: drop an EGG from your 10 foot ladder. The shell breaks, the white splatters BUT the yolk remains intact (usually until you try and clean it up.) Why? I'm assuming because the concussion of the impact was transferred through the shell and DISSIPATED by the egg white. Thus, the yolk (brain) survives.
Of course, I realize that you could drop an egg from such a height as to ensure complete destruction. The same is true of helmets. As my father explained to me one time, "a hard hat doesn't protect you from a falling I-beam. But if some nimrod on the third floor drops a 2" screw, it won't plow through you all the way to you feet!"
The same is true when considering helmet design. We have to be reasonable. (Which in a society filled with litigious attorneys is almost impossible!) NOTHING is going to protect a wearer from all injury. The idea is to reduce the severity of injury while allowing a certain freedom of movement to enjoy our sport. Otherwise, we could all practice the safest head protection of all: sitting at home watching TV.
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Helmet design
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On 5/23/2002
kmg
wrote in from
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Dr. Dave,
Correct me if I'm wrong, but I'm thinking that a good helmet slowly crushes/collapses kinda like crumple zones in automobiles, to gradually decellerate (sp) the skull in an impact with the ground. This reduces the G-forces encountered by the brain, thereby reducing the impact of the brain against the interior of the skull. Shouldn't the shell of the helmet have a little "give" instead of being hard and rigid?
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A thought experiment for Wes involving Jello
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On 5/23/2002
Dr. Dave
wrote in from
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Wes,
Here's a picture for you: Imagine a hemisphere of jello (pick the flavor (g)), that is set in one of your kevlar helmets with a little bit of padding. Got it? O.K. Now go up on a 10 foot ladder and drop the kevlar-helmetted-jello onto the concrete. What will happen?
Answ: The Kevlar will be undamaged - the jello will be internally fissured, if not actually broken into pieces.
Anyway, your brain has the consistency of jello. If the shock of impact is transferred directly into a gelatinous medium (e.g., brain tissue) the shock will fissure and tear the medium. Since the kevlar does not absorb the shock, it just gets passed into the next layer. In high impact collisions you can have cavitations (holes) produced, or broken axons (shearing) from the stretching and deforming of brain tissue on impact. In some cases, having your skull fracture is actually associated with a *better outcome. Why? Because it means that your skull absorbed enough of the shock to crack, rather than remaining intact and transferring the shock directly into the brain tissue.
The risk for real brain tissue is worse, because there are knife-like bony projections (sphenoid wings) in the frontotemporal region, and portions of the frontal bone are rougher than a surform file. So the brain can get cut on its own bony casing.
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Greatful Heads helmet
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On 5/23/2002
Kaylee
wrote in from
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I'd like to report that although my Hawg helmet is in desparate need of some ventilation, it is not nearly as heavy as a motorcycle helmet or the like. It doesn't seem heavy at all, and is in fact much more comfortable than your standard $30 skate helmet. The extra foam padding I added in the back helps keep it locked on my head, and the main stock foam is supposed to be multi-impact. I reallu just wanted to chime in and say that "heavy" is not a term I'd use to describe this helmet at all.
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Snell RS98 Standard
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On 5/22/2002
Dr Dave
wrote in from
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Check the Snell site. It has a complete description of what this helmet standard will tolerate in terms of shock etc.
http://www.smf.org
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Wes the Centurian or Crushing is Better than Hard
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On 5/22/2002
Dr. Dave
wrote in from
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Wes,
Helmets need the padding more than the shell. It's the padding that reduces g forces to manageable levels. Without it, you just have a hard shell that transmits all the force of impact directly into the brain. This is bad. This is why old cars like those tank-like Mercedes that are relatively undamaged in accidents can pulp their occupants, while people can walk away from cars that crumple up like a wad of paper on impact. You want a helmet where the padding crushes, crunches, etc., because it's the crunch/crush which absorbs the impact. I'm not sure that silicon would be very "crunchable" with very rapid impact collisions. Plus it's heavy and hot.
One last thing,to Vasocreta - a 40 mph boarding impact is much worse than falling off a rail because the acceleration physics are much more severe the faster you're going.
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Subduing Friends of Wes
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On 5/22/2002
Dr Dave
wrote in from
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If someone is irrational or belligerent after a head injury or wants to drive in that condition, you are not going to argue them out of it. Unless you are a paramedic trained in subduing intoxicated or delerious patients, don't even try it yourself. Call 911, your local police or FD paramedics. If your irrational buddy drives away, sic the cops after him or her. You're doing them a favor. If you were delerious, you'd want the same from your friends.
drD
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