Our next presenter is Aurora detailed
her presentation is unilateral trance

to be only a pretty dynamic stability
margin dream treadmill walking

in the middle but

Hi everyone and welcome again.

My name is Chris Tyrol and I'm going to be
presenting today about unilateral trans

tibial in P.T. and dynamic stability
Marston during treadmill walking and

I did this research under
the guidance of young Chang.

So the story all starts with what we call
a lot of role instability every individual

while you're walking is passively
stable walking forward and backward.

But Media lot are really you need to
stabilize yourself using muscle octaves.

If you're actively stabilizing yourself
consistently from side to side but

there's a real lack of research that
looks at how this media lot are all

instability affects in beauty's while
they're walking a majority of it.

Your research looks at the plane and
how they're walking.

But misses this whole segment of
stability and media LOTRO to mention why

is this important one simple fact
amputees fall they fall a lot and

so we need to understand why they're
falling what's causing this falling and

how can we possibly train them to
walk better fifty two percent of

community to eling lower limb N.P.T.'s
fall at least once a year and

this really means that this is a big
problem for entities and this falling and

fear falling further leads to them
walking one which is a real problem and

decreasing their prosthetic use in
order to understand falling and

understand stability my projects
overarching goal is to quantify

differences in stability between how
trance to feel in the teaser walking and

how able body controls are walking
stability and remaining balance is

a really complex problem and involves the
bunch of different dimensions Lockhart.

Site is for me areas that are used
to stabilize yourself and

balance visual stimuli are per
receptive and muscular skeletal and

these are all related to one another and
they're all compromised with tranche of

Elian piccies who are walking so since we
have such a complex multisystem problem.

How are we going to study stability one
way researchers have really found steady

stability is using kind
of global measures and

these two global measures
are using the center of mass

your center of mass concentrated
about where your belly button is.

And your base that support this is
the distance between your two legs while

you're walking a lot of the previous
background research that is used this

measure has looked at Able bodied amputees
able bodied subjects and they show

them that walking at slower speeds
increases these media a lot of movements.

So we know aren't beauties
tend to walk slower.

So that's going to contribute to
some of the need a lot of movement

still experience and some of the research
that's been done with amputees has been

done mostly standing when
we place a probation or

push them a little harder they restabilize
themselves and the research shows that

they restabilize themselves predominantly
by leaning towards their sound like to

regain their balance in order to
study stability during walking.

I'm looking at something called
the dynamic stability margin.

This was developed by hot at all in two
thousand and five to study dynamics

stability and evil bodied subjects and
some pathological groups so I'm taking

that margin that he's established and
developed and applying it to if you tease.

This is really to explain what equation is
he using to establish dynamic stability

there are two main variables we're looking
at we're looking at the math here of

the bases the port between one life and
the other life shown here.

The difference between that and what we
call the X. center of mass what the X.

center of mass is doing it's taking
the center of mass position and

adding in a component of velocity.

It's adding a more
dynamic element to it to.

Make a more accurate representation
of how center of mass

is being adjusted while you're walking and
this B.

value that I'm looking at is the distance
between the center of mass etc Nothing to

be for I'm going to focus from
here on out on the beam in value.

So when it is minimized.

It's usually at
the beginning of a step and

why is that important because when
viewed zero point beam in is your zero.

You're falling over.

So when you don't have any more distance
between your center of math and

the edge of your pieces or
that's when you're falling and

that's what's interesting and
that's why I'm looking at human

My hypothesis is that you know a lot of
trance to fill every cheese will have

greater beam in values on their prosthetic
side compared to able bodied subjects.

I believe this because I believe they're
trying to protect their prosthetic side

by moving their center of mass away from
it more towards or sound like much of what

was seen in the standing research that's
been done previously in order to do this.

I had five M.P.G. subjects and

seven controls this is a video a living
of one of our data collection.

They did thirty second trials of
instrument a treadmill walking.

I only looked at the one meter per second
speed because I felt as if it was most

relevant for looking at this
particular dimension of Mt walking and

we collected kinematics from
reaction forces and lower Louis and

the folded areas are what I'm really
discussing in this presentation but

we do have this huge database of
data that can be tapped into for

future states after the data
was are collected we

took it into Viacom and created this
nice full body model with markers and

fourth place and I extract all that
data using Matlab in Excel to interpret

the center of math we use the ground
reaction forces and we control for math.

So we took out that element that can
potentially lead to some variability and

the based support I use
the term marker and

all the statistics run
off to a basic snapshot.

What are subjects look like we
basically try to control for

any extraneous variable that may
lead to further instability.

So we had really good walkers patient
models who had spent a lot of time walking

could walk in variable speeds people
who only due to trauma amputation and

had no big systemic problems or
any sort of muscular skeletal disorder.

Other than they had the unilateral
trance to feel in our average age for

our subjects was about thirty one
years old for controls and for

the amputees they're about
forty four store in P.T.

population was a little bit older but
fairly close the results that we found

we did in fact find that even with greater
on the prosthetic side on that it was for

control and
this was statistically significant.

But we found that on the south side there
was no significant difference between

what their beamin was versus what controls
Beeman was so essentially what amputees

are doing is they're minimizing how much
their center of math moves while they're

walking they're bringing it closer to
their sound side and they're holding it

a little more centrally to their sound
side and addition to minimizing the motion

of their center now they're also
increasing their base of support and this

is something that I'm sure every clinician
in the room has objective leave served and

this study currently with that results
that we have increased these as support

for all of the areas that in addition to
comparing our amputees to our controls.

We also looked at one like to the other
how symmetric are that we didn't

find any significant differences from one
line to the other in either group but

what's interesting about that is there is
an order of magnitude greater variance

within our trans T.V.
land he said and you can see this just

visually really quick snapshot there were
some subjects were very easy to measure.

I'm going to talk about some of
those reasons in our discussion.

So some of the reasons
that we believe the huge.

Difference in the theory true even between
the different subjects within the N.T.

Tikker if they have larger standard
deviations they weren't as tightly

compacted between step to step and
we see a lot of almost a trend

Ellenberg with these subjects that
have the larger concentration of their

center mass sure it's there down by so
they're placing their center mass directly

over their sound like they're keeping it
really far away from the press that it

like because they're free to follow some
other subjective considerations are it

would be nice to know a little better
the integrity of this download musculature

some good habits if we had more
information about fall history

we might be able to start to extract
subgroups within the entity population.

So we know N.P.T.
is generally behave this way but

what characterizes the difference
between one of our thugs

that had a much larger difference
between one leg of the other and

one that was more symmetric what me
creates that difference and we talk about

them here if we have but we don't have
enough information to justify any right.

The conclusion with the hypothesis was in
fact conceived confirmed unilateral trance

to be only if you did have greater females
on their prosthetic side there protecting

that side so that their first safety
mechanism keeping their center mass in

the small little area and a second safety
mechanism is increasing their visa support

so they can remain more
stable some clinical

applications this is actually mostly just
correlating what a lot of clinicians

already know with some scientific evidence
which I think is really important as

well in addition to this
is creating a clinical B.S.

practice because now you can
say we know this happens.

And now we have our understanding
of why it's happening.

Also observed gait analysis for
those two subjects that were very

sort of more different from the rest
of the M.P.T. subject group.

You could see it.

So there is an element of
being able to physically see

when there is huge differences in the
center of mass movements Franky sceptic.

But some of the symmetry is normal.

Even our controls favored one
like versus the other but

they favored it by very very small
future directions we have a ton of

data that be great if we can
analyze all that muscle data and

get a better idea of what muscles are
using to actively control like the gluteus

medius is a big muscle and but placement
outcomes measures related to stability

is there a way we can make this
more easy for clinicians to see and

figure out in practice if we can Carlie
these results with an outcomes measure

that clinicians can do in five minutes in
their office then that's really valuable.

I also step activity monitors does
the amount that they walk from day to day

impact these results and by how much.

And maybe even the impact of prosthetic
feet on these different beat out

some of my acknowledgments I would not
have been able to do this project without

every person on this slide making Tony
especially if she did a majority of

the job a collection that I used to do
the analysis in a subject and he changed

advice and guidance was invaluable as well
as just for his amazing man of coding.

I'm sorry.
Now I'm pretty going to hear

my references and
now I will take questions and.

Thank you for

are you moderate when it rest.

The center method.

Well I did OK I did a calculation
using the force plates.

So I integrated the force plates and
they divide by mass and

add a constant just to place it in
the proper spatial frame essentially So

I was using for Slate dot I wasn't
using the other center of mass to have

a valuation which is much more difficult.

Which is kind of like you did
a lake in a bucket figure and

I was using for Slate dot.

Yes So we did not control for that at all.

We didn't change whatever prosthesis
they were walking on with the prosthesis

that they came in on I did look into what
types of foot units the amputees that

we had tended to have and
it was all across the board.

So some Had you heard or
seen inverters and some didn't.

I will tell you that one of
the amputees had the greatest kind of

distance that she kept from her prosthetic
leg was one who had a prosthetic foot

that actually complements for you further
and further so I think it has more to do

with good habits than differences
between prosthetic feet but

but based on one subject and some
subjective analysis question of the room.

What

do you mean integrating instability.

No this was normal walking.

We just wanted to see how unstable
were they were just normal walking at

one meter per second which is pretty
close to the self selected speed.

We don't even want the speed to be too
fast because we can we consider that

a perturbation if it was
walking too quickly.

We didn't introduce anything and

we saw these differences because even
the baseline research isn't there.

Introducing instability and stabilization
would be the next step for sure.

Articles are to be so

that you see the correlation
through most of the OR world.

None of our subjects
had superconscious and

so none of them had that particular
type of socket design and

however they had a very to Greece that
some had Pence's that somehow the ceiling.

Honor.

We basically just use stoplight as
a metric to say how well is their sock

fitting socket fitting and we had them
personally evaluate how well their

sockets fitting we've recognized the best
subjective limitation of the study

that some people might have had better
fitting sockets which led to more stable

walking but there was we tried to
control for as much as possible.

I'm thinking as they came and

that's another we weren't able to
I just feel I never prosthesis.

However I will say that all
the subjects we're using some are here

all the little all the subjects that
we are using are patient models.

These are people who have come in for
several different studies these are good

walkers and they tend to be very well fit.

Just because they come in and
participate in a study if you're

volunteering to do treadmill
walking as an amputee.

You probably have.

Do you think confidence
in your prosthesis or

you wouldn't be OK with just
walking on the treadmill.

One last question.

This was one of those little you
think we'll talk to my little one and

receive these potentially yes
that is a limitation of the study

when you have a split well treadmill
some people might artificially try and

make sure they're on both shelf properly
one way we tried to control for

that is when they were walking we put
her a picture of buzz on the wall and

basically said fix on a picture when
you're walking and we didn't start

collecting the data and mediately when
they started walking we gave them a couple

of seconds of acclimation So the hope is
that they will be paying attention and

they'll just naturally drift
to where their normal basis.

OK thank you very much Christine.