A prosthetic arm that feels Todd Kuiken

so today I would like to talk with you

about bionics which is the popular term

for the science of replacing part of a

living organism with a mechatronic

device or a robot it is essentially the

the stuff of life meets machine and

specifically I’d like to talk with you

about how bionics is evolving for people

with our man pute Asians this is our

motivation our man tation causes a huge

disability I mean the functional

impairment is clear our hands or amazing

instruments and we lose one far less

both it’s a lot harder to do the things

we physically need to do there’s also a

huge emotional impact and actually I

spent as much of my time in clinic

dealing with the emotional adjustment of

patients as with the physical disability

and finally there’s a profound social

impact we talk with our hands we greet

with our hands and we interact with the

physical world with our hands and when

they’re missing it’s a barrier arm

amputation is usually caused by trauma

with things like industrial accidents

motor vehicle collisions or very

poignant Lee War there are also some

children who are born without arms

called contingent limb deficiency

unfortunately we don’t do great with

upper limb prosthetics there are two

general types they’re called body

powered prosthesis which were invented

just after the Civil War refined in

World War one in World War two here you

see a patent for an arm in 1912

it’s not a lot different than the one

you see on my patient they work by

harnessing shoulder power so when you

squish your shoulders they pull on a

bicycle cable and that bicycle cable can

open or close a hand or hook or Bend an

elbow and we still use them commonly

because they’re very robust and

relatively simple devices the state of

the art is what we call mile electric

pressed

these are motorized devices that are

controlled by little electrical signals

from your muscle every time you contract

a muscle it emits a little electricity

that you can record with antenna or

electrodes and use that to operate the

motorized prosthesis they work pretty

well for people who’ve just lost their

hand because your hand muscles are still

there you squeeze your hand these

muscles contract you open it these

muscles contract so it’s intuitive and

it works pretty well

but how about with higher levels of an

amputation now you’ve lost your arm

above the elbow you’re missing not only

these muscles but your hand in your

elbow too what do you do well our

patients have to use very kody systems

of using just their arm muscles to

operate robotic limbs

we have robotic limbs there are several

available on the market here you see a

few they contain just a hand that’ll

open and close a wrist rotator and an

elbow there’s no other functions if they

did how would we tell them what to do

we’ve built our own arm at the rehab

Institute of Chicago where we’ve added

some wrist flexion and shoulder joints

to get up to six motors or six degrees

of freedom and we’ve had the opportunity

to work with some very advanced arms

that were funded by the US military

using these prototypes that had up to 10

different degrees of freedom including

moveable hands but at the end of the day

how do we tell these robotic arms what

to do how do we control them well we

need a neural interface a way to connect

to our nervous system or our thought

processes so that it’s Intuit if it’s

natural like for you and I well the body

works by starting Akimoto command in

your brain going down your spinal cord

out the nerves into your periphery I’m

cutting and your sensations exact

opposite you touch yourself there’s a

stimulus that comes up those very same

nerves back up to your brain when you

lose your arm that nervous system still

works those nerves can put out command

signals and if I tap the nerve ending on

a World War 2 vet he’ll still feel is

missing hand so you might say let’s

let’s go to the brain and put put

something in the brain

record signals or into the end of the

peripheral nerve record him there and

these are very exciting research areas

that’s really really hard you have to

put in hundreds of microscopic wires to

record from little tiny individual

neurons or nerve fibers that put out

tiny signals that are there micro volts

and it was just it’s just too hard to

use now and for my patients today so we

developed a different approach we’re

using a biological amplifier to amplify

these nerve signals muscles muscles will

amplify the nerve signals about a

thousandfold so that we can record them

from on top of the skin like you saw

earlier so our approach is something we

call targeted reinnervation imagine with

somebody who’s lost their whole arm we

still have four major nerves that go

down your arm and we take the nerve away

from your chest muscle and let these

nerves grow into it now you think closed

hand and a little section of your chest

contracts you think bend elbow a

different section contracts and we can

use electrodes or antennas to pick that

up and tell the arm to move that’s the

idea so this is the first man that we

tried it on his name is Jesse Sullivan

he’s just a saint of a man 54 year old

lineman who touched the wrong wire and

had both of his arms burnt so badly they

had to be amputated at the shoulder

Jesse came to us at the RIC to be fit

with the state-of-the-art devices and

here you see them I’m still using that

old technology with a bicycle cable on

his right side and he picks which joint

he wants to move with those chin

switches on the left side he’s got a

modern motorized prosthesis with those

three joints and he operates little pads

in his shoulder that he touches to make

the arm go and Jesse’s a good crane

operator and he did okay by our

standards he also required a revision

surgery on his chest and that regain us

the opportunity to do targeted

reinnervation so my colleague dr. Greg

damayan

did the surgery first we cut away the

nerve to his own muscle then we took the

arm nerves and just kind of had him

shift down onto

chest and closed him up and after about

three months the nerves grew in a little

bit and we could get a twitch and after

six months the nerves grew in well and

you could see strong contractions and

this is what it looks like this is what

happens when Jesse thinks open and close

his hand or bend or straighten your

elbow you can see the movements on his

chest and those little hash marks are

where we put our antennas or electrodes

and I challenge anybody in the room to

make their chest go like this his brain

is thinking about his arm he’s not

learned how to do this with the chest

there is not a learning process that’s

why it’s intuitive so here’s Jesse in

our first little test with him on the

left-hand side you see his original

prosthesis and he’s using those switches

to move little blocks from one box to

the other had that arm for about 20

months so he’s pretty good with it on

the right side two months after we fit

him with his target Adrina vation

prosthesis which by the way is the same

physical arm just programmed a little

different you can see that he’s much

faster and much smoother as he moves

these little blocks and we’re only able

to use three of the signals at this time

then we had one of those little

surprises and science

okay so we’re all motivated to get motor

commands to drive robotic arms and after

a few months you touch Jesse on his

chest and he felt his missing hand his

hands sensation grew into his chest skin

probably because we had also taken away

a lot of fat so the scanner is right

down on the muscle and D nerve ated if

you would his skin so you touch Jesse

here he feels his thumb you touch it

here he feels his pinky

he feels light touch down to one gram of

force

he feels hot cold sharp dull all in his

missing hand or both his hand and his

chest but he can attend to either so

this is really exciting for us because

now we have a portal a portal or a way

to potentially give back sensation so

that he might feel what he touches with

his prosthetic an imagined sensors in

the hand coming up and pressing on this

new hand skin so it’s very exciting

we’ve also gone on with what was

initially our

primary population of people with above

the elbow amputations and here we D

nerve 8 or cut the nerve away just from

little segments of muscle and leave

others alone that give us our up-down

signals and to others that will give us

a hand open closed signal this was one

of our first patients Chris you see him

with his original device on left there

after 8 months of use and on the right

in just 2 months he’s about I don’t know

four or five times as fast with this

simple little performance metric I don’t

write so one of the best parts of my job

is working with really great patients

who are also our research collaborators

and we’re fortunate today to have Amanda

Kitts come and join us please welcome

Amanda Kitts

so Amanda would you please tell us how

you lost your arm

sure in 2006 I had a car accident and I

was driving home from work and a truck

was coming the opposite direction came

over into my lane ran over the top of my

car and his axle tore my arm off okay so

after your amputation you healed up and

you’ve got one of these conventional

arms can you tell me tell us how it

worked well it was a little difficult

because all I had to work with was a

bicep and a tricep so for the simple

little things like picking something up

I would have to bend my elbow and then I

won’t have to co contract'

to get it to change modes when I did

that I had to use my bicep to get the

hand to close use my tricep to get it to

open

kokin tracked again to get the elbow to

work again so it’s a little slow a

little slow and it was very it was it

was just hard to work you had to

concentrate a whole lot okay so I think

was about nine months later that you had

the target reinnervation surgery took

another six months to have all the

reinnervation then we fit her with a

prosthesis and how did that work for you

it worked

good I was able to use my elbow and my

hand simultaneously I could work them

just by my thoughts so I didn’t have to

do any of the coking tracting and all

that little faster it was a little

faster much more easy much more natural

okay this was my goal okay for 20 years

my goal was to let somebody able to use

their elbow and hand in an intuitive way

and at the same time and we now have

over 50 patients around the world who

have had this surgery including over a

dozen of our wounded warriors in the US

Armed Services the success rate of the

nerve transfers is very high it’s like

96 percent because we’re putting a big

fat nerve onto a little piece

muscle and it provides intuitive control

our functional testing those little

tests all show that they’re a lot

quicker and a lot easier and the most

important thing is our patients have

appreciated it so that was all very

exciting but we want to do better okay

there’s a lot of information in those

nerve signals and we wanted to get more

you can move each finger you can move

your thumb your wrist can we get more

out of it so we did some experiments

where we saturated our poor patients

with zillions of electrodes and then

have them tried to do two dozen

different tasks okay from wiggling a

finger to moving a whole arm to reaching

for something and recorded this data and

then we use some algorithms that are a

lot like speech recognition outcomes

algorithms called pattern recognition

see and here you can see on Jesse’s

chest when you just tried to do three

different things you can see three

different patterns okay but I can’t I

can’t put an electrode to say go there

so we collaborated with our colleagues

in University New Brunswick came up with

this algorithm control which a mannequin

now demonstrate so I have the elbow it

goes up and down I have the wrist

rotation that goes and they can go all

the way around and I have the wrist

flexion and extension and also have the

hand close and open Thank You minna no

this is this is a research arm but it’s

made out of commercial components from

here down and a few that I’ve borrowed

from around the world it’s about seven

pounds which is probably what about what

my arm would weigh if I lost it right

here

obviously that’s heavy for Amanda and in

fact it feels even heavier because it’s

not glued on the same she’s carrying all

that weight through harnesses so the

exciting part isn’t so much the the

mechatronics but the control and so

we’ve developed a small micro computer

that is blinking somewhere behind her

back and is operating this all by the

way she trains it to

use her individual muscle signal so

Amanda when you first started using this

arm how long did it take to use it I

took just about probably three to four

hours to get it to train I had to hook

it up to a computer so I couldn’t just

train it anywhere so like if it stopped

working I just had to take it off so now

it’s able to train with just this little

piece on the back I can wear it around

if it stops working for some reason you

can retrain it takes about a minute so

we’re really excited because now we’re

getting to a clinically practical device

and that’s that’s where our goal is to

have something clinically pragmatic to

where we’ve also had Amanda able to use

some of our more advanced arms that I

showed you earlier here’s Amanda using

an arm made by Decca Research

Corporation and I believe Dean came and

presented it at Tech a few years ago so

Amanda you can see has really good

control it’s all the pattern recognition

and it now has a hand that can do

different grass what we do is have the

patient go all the way open and think

what hand grass pattern do I want it

goes into that mode and then you can do

up to five or six different hand grasps

with this hand Amanda how many were you

able to do with the DECA arm I was able

to get four I had the key grip

I had a Chuck grip I had a power grass

and I had a find pinch but my favorite

one was just when the hand was open

because I work with kids and so all the

time you’re clapping and singing so I

was able to do that again which was

really good that hands not so good for

clapping can’t clap what those are so

that’s exciting on where we may go with

the better mechatronics if we make them

good enough to put out on the market and

use in a field trial once you watch

closely

that’s Claudia and that was the first

time she got to feel sensation through a

prosthetic she had a little sensor at

the end of her prosthesis that then she

rubbed over different surfaces and she

could feel different textures of

sandpaper different grits ribbon cable

as it pushed on her renovated hand skin

she said that when she just ran it

across the table it felt like her finger

was rocking so that’s an exciting

laboratory experiment on how to give

back potentially some skin sensation but

here’s another video that shows some of

our challenges this is Jesse and he’s

squeezing a foam toy and the harder he

squeezes you see a little black thing in

the middle that’s pushing on his skin

proportional to how hard he squeezes but

look at all the electrodes around it I

got a real estate problem I’m supposed

to put a bunch of these things on there

but our little motors making all kinds

of noise right next to my electrodes so

we’re really challenged on what we’re

doing there the future is bright we’re

excited where we are and a lot of things

we want to do so for example one is to

get rid of my real-estate problem and

get better signals we want to develop

these little tiny capsules about the

size of a piece of risotto that we can

put into the mussels and tool eMeter out

the mg signals so that it’s not worrying

about electrode contact and we can have

the real estate open to try more

sensation feedback we want to build a

better arm

okay this arm the are they’re always

made for the 50th percentile male which

means they’re too big for 5/8 of the

world so rather than a super strong or

super fast arm we’re making an arm that

is we’re starting with the 20th 25th

percentile female okay

that will have a hand that wraps around

opens all the way to degrees of freedom

and a wrist and an elbow so it’ll be the

smallest and lightest and the smartest

arm ever made once if we can do it that

small it’s a lot easier making them

bigger so those are just some of our

goals and we really appreciate all being

here today I’d like to tell you a little

bit about the dark side with yesterday’s

theme

so Amanda came jet lag she’s using the

arm and everything goes wrong idea there

was a computer spook a broken wire a

converter that sparked we took out a

whole circuit in the hotel and just

about put on the fire alarm and none of

those problems could I have dealt with

but I have a really bright research team

and thankfully dr. Annie Simon was with

us and worked really hard yesterday to

fix it that’s science unfortunately the

work today

so thank you very much