You know people are looking at this term
and are these accumulative,
and can these produce long-term problems.
And my first response to that is scientific--
is that I--I don't know.
I don't think so--I don't know.
I don't have any scientific evidence to suggest that that's the case.
It could be the case that--we're missing it
in the clinical realm
because we just don't measure it very often.
I mean I don't know how many times a
4 year old bumps his head on a coffee table or
how many times dad--you know--gets his bell rung--
you know--very lightly when he was playing flag football
when he was in college, and does that make him now
an attorney rather than a doctor or a
republican rather than a democrat or something like that.
You just don't know.
But all teasing aside, I don't think there is such a thing
as a subconcussive event,
and this is from science.
And this was work that was done by Yoichi Katayama.
He was gentleman--director and chairman of neurosurgery now at--
at Nihon University.
And while I was at UCLA, we looked at the different levels
of severity of the injury that we could
induce and tissue and in animals,
and it was--There was not a problem
until you reached a particular threshold.
This wasn't a linear event.
So there wasn't this subconcussive thing and then you get this concussion.
It was--it was either nothing and then
the whole brain went into concussion.
And this is a proposal that has been around
It was originally described by a gentleman by the name of
Earl Walker and Denny-Brown
and a gentleman by the name of Liaw,
and he describes __________.
And so--A) At this point, I do not have any scientific evidence
that there is such a thing as a subconcussive syndrome.
B) If there is, it's probably not global.
One of the things I disagree with the--
some of the Colorado guidelines
and the recent guidelines for the National Football League,
in terms of concussion severity,
is that I really don't think--
I think there is such a thing as severity of concussion,
but I think it's more important
to understand what type of concussions.
And a very good example is perhaps
the blast-type concussions
that you are getting in Iraq and Afghanistan
are different than the type of concussions
that the National Football League are getting.
So you may have these, what you think are
but they really are a concussive event
for a particular part of the brain
where the rest of the brain is not.
And it may be that regional change that occurs over time.
But that's something we need--we would like to learn more about.
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Is a subconcussive event a concussive event that only affects one part of the brain? Learn more about what research is showing, and hopes to show in the future.
Produced by Noel Gunther, Ashley Gilleland, and Brian King, BrainLine.
David A. Hovda, PhD, David Hovda, PhD is the director of the UCLA Brain Injury Research Center. He is past president of the National Neurotrauma Society and past president of the International Neurotrauma Society. He has served as chair of study sections for the National Institute for Neurological Disease and Stroke.
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