Head Injuries. Am I right, or have I suffered a few too many

Discussion in 'UK and Europe' started by Mark Thompson, Apr 24, 2004.

  1. While reading through The Effectiveness of Bicycle Helmets:A
    Review[1] in section 2.3 paragraph 3, it quotes a study by
    Piggott et al, 1994[2] as saying that

    "The prevalence of head injuries among hospital admissions
    was 32 per cent .... although for only 5 per cent was the
    head injury categorised as being more than minor"

    Sorry, what was that again?

    "for only 5 per cent was the head injury categorised as
    being more than minor"

    So unless my brain is failing me again[3], and if this study
    is right and the results are comparable across all
    hospitals:

    1. 95% of the head injuries in hospital admissions in this
    study are minor.
    2. With plenty of exceptions, it is a broad rule that the
    harder the impact, the more the damage.
    3. Helmets protect better against impacts of a smaller force
    than of a larger force.
    4. So if x% of head injuries are prevented by wearing a
    helmet, then that will generally be the least serious x%
    5. So to start preventing significant amounts of serious
    head injuries cycle helmets would have to reduce head
    injuries by more than 95% - and that's just the ones
    serious enough to make people pop into the hospital!

    I have two questions.

    A) Is there a flaw in my logic?
    B) Is the 5% figure valid for UK hospitals?

    [1]Revised Edition Prepared by Dr. Michael Henderson for the
    Motor Accidents Authority of New South Wales, Australia.
    1995 http://www.helmets.org/henderso.htm

    [2] Piggott P, Knuiman M W and Rosman D L, Rates and pattern
    of injuries from bicycle crashes based on population:
    police and hospital data, Rood and Transport Research,
    3:64-74, 1994.

    [3]Postage and packaging free...
     
    Tags:


  2. Just Zis Guy

    Just Zis Guy Guest

    On 24 Apr 2004 21:25:33 GMT, Mark Thompson
    <[email protected]> wrote in message
    <[email protected]>:

    >A) Is there a flaw in my logic?

    No, there is a large heap of flaws in Henderson's ;-)

    >B) Is the 5% figure valid for UK hospitals?

    90,210 admissions 5,804 cyclist admissions 2,183 cyclist
    head injury admissions Under 400 known serious cycling head
    injuries Unknown number of the above to areas covered by the
    helmet, studies suggest around half.

    According to the Government's figures around one in ten of
    these serious injuries might be preventable by a helmet.

    I wonder what the injury reductions in Hull's home zones
    have been like?

    --
    Guy
    ===
    May contain traces of irony. Contents liable to settle after
    posting. http://www.chapmancentral.co.uk

    88% of helmet statistics are made up, 65% of them at
    Washington University
     
  3. Simon Mason

    Simon Mason Guest

    "Just zis Guy, you know?" <[email protected]> wrote in message
    news:[email protected]...

    >
    > I wonder what the injury reductions in Hull's home zones
    > have been like?

    I don't think they break down the figures for individual
    homezones, all I know is that since the 20 mph limits were
    introduced to now 25% of the city, injuries to cyclist and
    peds are at an all time low. This piece was from last
    November 03.

    http://www.thisishull.co.uk/displayNode.jsp?nodeId=136265&c-
    ommand=displayContent&sourceNode=136248&contentPK=7675956

    If Proof was ever needed about the effectiveness of Hull's
    20mph zones, it has finally been delivered.

    New statistics reveal 300 accidents involving children have
    been prevented since the lower speed limits were introduced
    eight years ago in residential areas.

    But the £4m success story making our roads safer doesn't
    end there.

    Hull now leads the country in its pioneering work cutting
    speed limits.

    The city now boasts more 20mph zones than any other local
    authority, with more than one quarter of Hull now covered.

    Such progress has quite rightly earned praise from the
    Government's Health Development Agency.

    However, it is vital the work on road safety does not
    end there.

    Areas which do not already benefit from 20mph limits need to
    be included as soon as possible.

    It is crucial police continue to make the resources
    available to enforce the restrictions.

    And it is also vital innovative new ways are found to make
    accident-prone roads more pedestrian-friendly.

    If motorists feel they are being unfairly victimised, then
    they should think again.

    Up to 13,000 children could be saved from death or serious
    injury each year if speed limits on all residential roads
    nationwide were cut to 20mph.

    It is a small price to pay if slowing down helps save a
    child's life.

    --
    Simon M.
     
  4. Mark Thompson wrote:
    >3. Helmets protect better against impacts of a smaller
    > force than of a larger force.
    >4. So if x% of head injuries are prevented by wearing a
    > helmet, then that will generally be the least serious x%
    >5. So to start preventing significant amounts of serious
    > head injuries cycle helmets would have to reduce head
    > injuries by more than 95% - and that's just the ones
    > serious enough to make people pop into the hospital!
    >
    >I have two questions.
    >
    >A) Is there a flaw in my logic?

    Helmets could plausibly prevent (i.e. make non-injuries)
    only 5% of injuries and still reduce some serious
    injuries to not-serious. You only have to prevent over
    95% of injuries to make some of the serious injuries into
    non-injuries.

    Now other figures suggest that helmets don't actually
    provide that benefit, or only to a very small extent, but I
    don't think the argument above is enough to show that, at
    least without some elaboration of 4. (And if that
    elaboration turns into "helmets are, on the whole, useless
    in serious impacts", you can omit the other steps.)
     
  5. Simon Brooke

    Simon Brooke Guest

    in message <[email protected]>, Alan Braggins
    ('[email protected]') wrote:

    > Now other figures suggest that helmets don't actually
    > provide that benefit, or only to a very small extent, but
    > I don't think the argument above is enough to show that,
    > at least without some elaboration of 4. (And if that
    > elaboration turns into "helmets are, on the whole, useless
    > in serious impacts", you can omit the other steps.)

    It may be worse than that. It may well be 'helmets mitigate
    injury in minor impacts but agravate injury in
    [some|many|most|all] major impacts'. Someone with serious
    research funding needs to do a study on the rotational
    acceleration effects of glancing blows on helmets. It may be
    that on investigation this turns out to be not serious and
    not likely to cause severe injury - and it may not. It
    urgently needs serious investigation.

    --
    [email protected] (Simon Brooke)
    http://www.jasmine.org.uk/~simon/

    ;; I'd rather live in sybar-space
     
  6. > minor impacts but agravate injury in [some|many|most|all]
    > major impacts'.

    The only reports on it I've seen said it was likely to
    happen in only a very few cases.

    It also said that a major impact was not needed for injury
    to occur, as even minor impacts could cause the effect (but
    presumably were less likely to injure).

    On the other hand, it also said that serious brain
    damage/death only hapened in a very few cases.

    But it went on to say that as rotational thingummies are
    more likely to cause severe brain damage/death, then it's
    likely to be over-represented in the more serious cases.

    So yeah, more research needed!
     
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