So welcome to this Friday's colloquium.
It's a great pleasure to introduce in Chip C, who's today's speaker.
Ian has a distinguished record as an experimental particle physicist.
He's worked on a number of well-known experiments.
He was a very senior member of the CMS collaboration, which discovered the Higgs boson.
He's now moved to Atlas Plus after moving to Oxford.
He's also a senior member of the LHC collaboration.
That's a large synoptic survey telescope. And he has a very, very long reputation in in these areas.
He moved to Oxford a few years ago to occupy what was then known as a professorship of experimental physics.
As those of you who really read your email will see that we finally succeeded in getting this called something sensible.
So in is now the Henry Moseley Centenary Professor of Experimental Physics at the University of Oxford.
And it's great pleasure to introduce him to talk back to us today about something completely different.
I want to carry it. Okay. Thank you for the invitation to speak today.
In October 1989, I had perfect terror.
But by the end of the year, I had no hearing whatsoever.
It began when I could not hear the quiet passages of music on a car radio.
That day. Turning up the volume helped. But soon there was no more music.
At the same time, the voices of friends of the family receded.
And I entered a world of silence. The reason for my deafness.
Was a medically necessary dose of O2 toxic antibiotics.
That destroyed the households of my country.
The reason for the antibiotics was earlier that year I had contracted acute myelogenous leukaemia, a truly terrible form of cancer.
But thanks to friends in Syracuse, Rockefeller and especially Cornell University.
I received first rate medical care at the Cornell University Medical College in New York City.
An industrial strength dose of chemotherapy beat the cancer.
But it left me without an immune system and the antibiotics protected me.
And so my own immune system had virtually. For those that can hear suddenly losing hearing is a terrible disability.
Without an appropriate support network, a person so afflicted can withdraw from society,
can become depressed, can sometimes turn to substance abuse and even to suicide.
For most of us citizens who lose hearing as they age.
Studies show they leave the workforce years earlier than they otherwise would do, and from then on made less fulfilling and productive lives.
Children born deaf was sent to schools with children who can have.
They lack the ability to develop an oral linguistic tradition.
That if school at the age of 18 with the reading age of a 12 year old and that is it got too large, too close.
Fortunately, science and technology are coming to the rescue to treat many difficult conditions in our lives, including deafness.
And in this talk, I want to talk about one of those technologies, the cochlear implant.
And so the outline of the talk will began by looking at the natural physiology of hearing.
And then the causes for deafness, the solutions to hearing loss, in particular the cochlear implant.
I briefly talk about some of the political and social issues that surround this
still somewhat controversial technology and for looking at the future of implants.
So as most of you know, sound is a form of mechanical energy.
When you strike the times of a tuning fork, the oscillatory motion of the times nearby air molecules into oscillatory motion,
and then turns more distant and molecules into oscillatory motion.
And in this way, sound passes through the air as a molecular disturbance until it arrives at piano or airflow.
The events that occur after that are truly remarkable.
And so I'd like to show you that them using a unemotional that's been developed by a friend of mine, Brandon Platt.
She was a young medical illustration test from Georgia. Some years ago, it won first prize in the National Science Foundation,
American Association for Advancement of Science, Science, Engineering Visualisation Challenge.
And in this presentation, it's been heavily edited by one of my graduate students and myself.
Says Sound arrives at the peanut and the peanut collects the salad and follows it down onto the ear canal.
And then it arrives at the tympanic membrane or eardrum, which is about a centimetre across.
And the tympanic membrane vibrates in response to sound.
How is the violin? Can you hear it? No. Good.
So the tympanic membrane is conical in shape, and it is articulated by three small bands collectively called the Usher Cleaves.
The Malleus will hammer the increase or anvil, both about one centimetre in length.
And the staples of the stapes is the smallest bone in the human body.
And it's through these also claims that the vibrations of the tympanic membrane are transmitted to the piece.
Now the stage moves with a piston like action at the oval window of the pony lover.
The body lava instilled with a fluid shown here in purple that similar to cerebral spinal fluid.
Now, fluid is relatively incompressible.
And so the piston like action of the state piece would not be able to transfer energy to this system unless the fluid volume was conserved.
And so this is achieved by a flexible membrane called the round window, which moves in synchrony with the state.
So what about preserving fluid volume and allowing sound energy to enter the body lateral?
Now The Bone elaborates itself is about few centimetres across and has two organs a semicircular organs and balance and ingrain this no shape culture.
Vibrations from the state piece enter into the helical structure.
They rise to its apex and they send the gun to the round window.
In more detail. The court player consists of two principal dogs called Scarlett the Scott of a snippet in which the vibrations rise to the apex.
The Scarlett Symphony, in which they descend to the round window. And each of these dogs is about a millimetre across.
And there's a third duck called the Cochlear Duck shown here in purple, and that's filled with potassium rich solution.
And this cochlea is intricate and it is small.
It's about the size of a chickpea. And the reason that's so small is to enable it to be very light and sensitive to low levels of sound vibration.
And forms earlier.
This is the excited human cook and a child at six months gestation at birth, the cochlea is fully formed and it is fully functional.
Now, if we increase the magnification further,
we see that the skull are separated from each other by two membranes was membrane and the vascular membrane.
These two membranes are flexible. And so when vibrations pass through the fluids of the scarlet, it produces a deflection.
In these membranes. Now in the lower of these two membranes, on the back of the membrane, there's a specialised organ called the organ of Culture.
And when this organ is stimulated by flexing it shown here in green, it produces electricity that passes to the order of and up to the brain,
where the auditory down fills the hollow modulus of the cochlea and innovates to the punch and talk.
35 millimetre helical length. And the origin of these electrical signals of specialised cells called hair cells.
One wrote about a house in a house that was in three rows of out of her cells.
And there's other this house has a built over the muscle membrane and protected and covered by a gelatinous membrane called the tournament.
When the sound causes the mass of the membrane to be displaced, the cilia or has a top to her.
So some actually derives their name are flexed and they cause the cells to trigger and produce electricity that passes to the brain.
And so the house owes on the corner and that trickle transducers and we have about 16,000 of these households in each of our healthy cochlear.
Now the bachelor member itself does not respond simultaneously to sound.
Instead, it responds that the apex of the bass, the membrane, resonates at very low frequencies of sound,
and the base of the bass of the membrane resonates at high frequencies of sound.
And so the bachelor membrane is a frequency analyser.
It's how we know pitch. And we refer to this as a topic organisation.
Well, topic organisation means the relationship between pitch and place,
and you'll see that this is quite important in understanding the cochlear implant.
So what I have here is a ton of topic map of the cochlea showing the frequencies at which it resonates.
Well, the cochlear is very small, less massive, very stiff.
It has a very high resonant frequency, about 20,000 cycles, a second, 20,000 hertz.
And at the base. But it's more massive and less stuff that resonates at around 100 hertz.
And this sets the range of our natural hearing.
Now, some of you know that physicists have played a rather big role in developing this understanding of how we hear.
Helmholtz was the first to recognise that the basilar membrane was a frequency analyser and the brilliant Hungarian biophysicist
George one Becker won the Nobel Prize in 1961 for medicine or physiology for the experimental observation of Sun Atomic Organisation,
which had actually done through years prior.
And so what he actually did was experimentally measured how much of the membrane is displaced and a human cut of it as the pitch is varied.
Now in those days, the 1930s, the technique was rather they only have as a microscope.
So we had to see very big displacement to move to the wavelength of light.
And this meant that we had to have very loud sounds, bigger sounds, bigger displacement.
And so this is some of this data from the 1930s. Well, the Nobel Prize.
This is the base of the base of the membrane. This is the apex, about 35 millimetres in total.
This axis is displacement. And these are extremely loud sounds.
And you can see that as the frequency is reduced, the place that resonates as the most displaced moves gradually towards the apex.
And this was the experimental evidence for turning trophic organisation.
Now it turns out that it's very easy to reproduce the shapes that he saw with mechanical models.
And this was done shortly after the observations are continued for much of the rest of the 20th century.
And so what we have here is the base, and this is the apex right over here and the base of the membrane.
I'm showing just half of it unwrap. This is displacement and that image.
And we're putting it aside the pure tone, which is ten kilohertz, quite a high tone in this case.
And what you can say is quite a lot of the Barcelona and Venice displays.
And if we're not change the input time to 20 kilohertz, doubling the frequency,
they may expect the displacement to move towards the base, which it does.
But you also say that it still overlaps a lot with the Ten Kilohertz Club.
And so what these models actually predict is that the frequency selectivity or pitch perception of the human is rather poor.
We can tell differences between high and low, but it's all kind of mixed together.
And this is in stark contrast with the sacrifices that we actually have.
I see. It's 256 Hertz and C-sharp.
It's like the sublime. Humans can tell 1/10 the difference between C and shot.
That's one hertz 256. So a model like this cannot explain such exceptional ability to recognise pitch.
At the same time, there's a second mystery, and that is how do we actually hear some sound at all?
Think about walking through water and compare it to walking on land.
It's much easier on dry land because the water doesn't resist the ocean.
Here we have a butterfly membrane and it's sitting in fluids.
And so the fluid should damp down the mouth.
Unless there's a significant displacement due to some form of amplifier, something driving the displacement.
And this idea was first suggested by another physicist, the maverick astrophysicist Tommie Gold, in 1945.
And at the time his ideas were ignored. You could say they fell on deaf ears.
And the reason for this was twofold. First, because he was an astrophysicist, not a physiologist.
But the second reason was because his ideas were not really well understood.
Most people got the idea that, okay, there's some kind of amplifier in there driving the displacement.
We don't know what it is, but we can believe that that would hold the sense of sight. What's that got to do with the other problem?
The frequency selectivity and the way to understand that is to simply think of an example of a natural system that has a natural frequency.
So a good example of this is a child in a playground swing. So first, imagine that the child is sitting there passively.
The swing has a natural frequency that's given by the likes of the wrote the mouse to the child itself.
And now the parent comes along and pushes this way. It's very easy to push that swing and it's not for frequency.
If you work harder, you can push the swing of frequencies other than the natural frequency.
And so this system where the the driver is outside the system is a fairly politician system.
A number of frequencies could be sustained. But now remove the mother from the picture to remember your own experience as a child on the playground.
Swing all around when you kick your legs in time with this.
You remember what happened. The amplitude of the swing rises for memory dramatically, and when you kick your legs out the time of the swing,
it stops abruptly when the swing is driven by an internal amplifier.
The child is a much more finely tuned system.
And that was the basic idea. Atomico. Now in the 1980s,
it became possible for the first time to measure with great precision by solar membrane displacements when signs are presented to the solar membrane,
a living out of them. And this is what we see. So that's just the same, Tom, that Rebecca Transposon predicted, but it's quite different.
In reality, there's a much bigger displacement, and that's the amplification, but also there's a much narrower response.
So that's the frequency selectivity. And if I showed you what 20 kilohertz would look like, that would also be like this one.
Would it be white on it? Inside its internal amplifier is responsible.
And that's the evidence for it. So there's an existing amplifier within the organ of Cotai that increases the displacement
of the membrane like this to make soft sounds audible and provide excellent frequency.
So activity. And that's exactly like the actor chart this way.
Now you can look at this data another way and make a plot of the bus with a membrane displacement nanometres.
Thus the loudness of the sound this way.
So loud sounds mean. Lots of displacement that's up here. And soft sounds mean, much less displacement which is done here.
And this is the data from going back to try and extrapolation down to self to sounds.
And this is what's actually said in modern measurements. So it's very different from back office predictions and observations.
And so you could ask should because package have won the Nobel Prize.
To answer that. The first answer that was actually given by a guinea pig, literally a guinea pig.
If you take this this data, it's taken on living guinea pigs.
That species have a particularly easy cochlea to study.
And what happens is this is a very unpleasant operation, Cricket. You have your head opened up.
You're monitoring the motion, the bustle, the membrane, the sounds being played to you.
And sometimes during this operation, the guinea pig dies.
And if the guinea pig dies and you continue to take nature, what happens is the data falls right down onto this line about because you.
So before she got the results,
he did because he performed them on a human cadaver at their cochlear is entirely different to a living call, to a dead copula.
It's like a passive child on the slate. They didn't. Cochlear, as a child, pointed his legs.
The dramatic difference. And so going back to China was a part of physics and definitely deserves a Nobel Prize.
So now what's causing this amplification? And so this is a high magnet edge over basilar membrane.
And these are in rehearsals and these are three rows of outer hazards.
The inner Hassan is about 3500 per ear or afferent highly afferent signals are going through the brain.
The outer vessels, on the other hand, of which there are far more, are rather sparsely innervated.
And this is a typical house. It's another one in this case, study, microbes all about five microns wide.
And you can see the cilia atop it. If you look at a bit more detail, each of these little has this 500 nanometres across.
So that's about a 20th or so the thickness of a hole in your head. And they're joined by fibrous actin strands that are just a few nanometres across.
And when the cell deflected due to the cell causing the basilar membrane to move.
This tip links open truck doors and the walls of the cells.
The potassium rich solution of the complex flows into the cell.
Cells are like batteries are highly polarised. And so the arrival of this car, the polarises, the cell,
and that triggers a sequence of complex chemical steps of at least neurotransmitters at the base of the cell, which pass through the auditory nerve.
And we hear sound. Now both in and hassell's work in that way.
But if these new cells are connected to our brain on a conveying sound to host to it so we can see this with the following movie.
So this is on our side. It's about 70 microns long.
So we take a microphone. We're going to play music through the microphone, the microphone and turn that sound into a cup.
And this current will be modulated by the tempo and the amplitude of the music.
And then we take that current in this and place it into this electrode and the electron goes into the sun.
So now when we start playing, let's watch what happens to the cell. Watch the music starts.
So the current starts. To bring the popular pop, rock and pop, pop, pop.
A lot of the time.
So remember this the next time you dance to the music through. Sure, the Scots like at 16,000 households and it's reality.
So what's happening here is the cars going into the south. The sun is losing its polarisation.
As it polarises, it returns to its natural light. The change length.
Like there's a couple of microns. So the sequence of events as the muscle membrane is displaced due to the presence of sound.
The Protocell flows into the other hair cells, which then contract just like in the movie,
because the other half cells are connected to the base of the membrane.
That increases the displacement of the rest of the membrane so that even the softest sounds will cause Newcastle Centre to be deflected.
Current flows into that neurotransmitters are released at the base, other parts of the brain.
And so to summarise from the motion of our molecules to the vibration of a temperate membrane,
the transmission of vibrations through the oscillators to the piston, like action of the statements to the displacement of the fluids and the sky,
to the reflection of the cilia atop the hearse, others to the opening of truck doors for the floor of the custom car,
and into those cells to a sequence of complex chemical steps that produce
neurotransmitters that produce for countries on the order of the passes to the brain.
It's a sequence of events that have given rise to an auditory perception.
So that's how we hear. Here are five reasons why we don't waste it.
The first is genetic. The second is infections, for example, bacterial meningitis or rubella.
The third is a Q to a chronic exposure to loud sound.
If sound is loud enough, it can produce enormous amounts of vibrational energy and can literally snot herself.
Force causes prescription drugs, certain lots of toxics used in antibiotics and certain chemotherapeutic agents as well.
And the first is hearing loss as we age, which affects most people to some degree more than 10% of our citizens.
And very poorly indeed. And it severely interferes with their normal functions of life.
Now the main types of variables are to the first is called conductive hearing
loss the rarer and it involves the also claims being damaged in some way.
Now the also claims of mechanical. And so you can repair them with surgery.
Most hearing loss, however, is sensorineural.
Sometimes when you see an audiologist who tell you you have nerve deafness, this is not true and nothing wrong with your nerve.
The problem is that your hair cells are not that. Now as we age, we lose vessels.
And in the vast majority of cases, as we age, we lose some of our houses.
And so we lose some of our ability to transduced mechanical energy into electricity.
And the solution to that is a hearing aid. Hearing aid to make sounds loud when a child is loud.
That means that the stapes will move more vigorously. And so more energy will be placed into the bone.
Other.
So even though there's less to transduced that energy, the combination of more energy and less transduction cancel out and you can restore hearing.
It's a very, very effective solution for most people with hearing loss and dramatically changes people's lives.
Unfortunately, there's an enormous stigma associated with wearing hearing aids.
However, 4% of all journalists. The number of households is dramatically reduced or is even absent.
And in those cases, it doesn't matter how loud the signs are, the hearing aid will not help at all because there's no transduction occurring.
And it's in those cases that the cochlear implant is a possible solution.
So it might surprise you to know. The first cochlear implant was developed a couple of hundred years ago.
But this guy, voter and of course, voter, had invented the bachelor, invented battery.
Let's try it out. So let me tell you what he did.
Both are close to metallic probes and both is connected to the ends of the 250 volt battery.
And observe that at the moment when the circuit was completed, I received a shock in the head.
So moments after, I began to hear a sound of other noise in the areas which I cannot well define,
it was a kind of a crackling with shocks, as if some post or tenacious matter had reported.
Notice how beautifully they wrote in those days?
He went on to say, the disturbing sensation, which I believe might be dangerous because of the information, the painting, the experiment.
And if you're saying I just made that up, you can check it for yourself.
So that's the of it is actually true. A wonderful example of experimental physics.
Okay. So now let's move 200 years forward to the very end of the last century, the modern cochlear implant.
So the most important thing to remember first about a cochlear implant is it's not a hearing and it does not make sounds loud.
It's got nothing to do with that at all. But a cochlear implant is going to do is replace the naturally occurring transduction
of the muscles by providing electricity that can go directly to the auditory dog.
And that's what it is. So I've got one on another.
And they had a set. Can you say set? But my left painter.
I'll take it up so you can get a look. So this is a cochlear implant and obviously it's very hard for somebody to say it for her.
And of course, the longer I keep this off, the more I can't hear what I'm saying.
And so I have to put it back on in a second. But what I'll do now is talk you through the different parts of this device.
So we began with a microphone and that bit, it's like hearing it.
So that's the very front of my voice. And that microphone, of course, is going to transformed into an electrical signal.
And then the second bit is a series of bypass filters and ac, ac integrated circuit,
which is just a silicon chip which you consider to be a computer without an operating system.
And what that's going to do is digitise and sort the sounds in terms of amplitude and in terms of time and in terms of frequency.
And then the next thing that happens.
And that these posters come out of this I and they're sent along the wall to the antenna, which is that thing which in this case is above the left.
My case said it's wrapped around my head. And if you want to know where that is, you can ask it.
Yeah. And so we'll see what things they attend to.
We can now take this right away, very much like that. Right away with all of that digital information, they can pass it through the intact set.
And pick it up at a receiver inside the second here, which is in the mastoid bone, it's about the size of a postage stamp.
And what that thing is going to do is read all that information and turn it into analogue information about his pulses.
And this post is going to pass along electrodes, of which there are many in the cochlear implant, and only one is shown in this picture in right here.
It goes right down into the cochlear. Now the cooker is not literally to the side in here.
It's actually towards the eye. And then the electrical pulses are producing electric fields which are picked up by the auditory nerve.
And that signal that pulses to the brain. And the probe that recognises the signals asset.
And I should say that in this picture the brain is not to scan.
So here again is a schematic of a cochlear implant.
That's the microphone, the speech processor, the transmitter.
That's the skin. And under the skin as a receiver and a stimulator followed by electrodes.
And so the natural hair and your side.
The first part of this talk, you know, high frequency sound stimulates the cochlea and auditory base and low frequency sound stimulates at the apex.
And so the idea of the cochlear implant is it's going to exploit that natural physiology.
What we're going to do is spread electrodes along the cochlea,
and individual electrodes will convey a certain range of frequencies to that part of the cochlear,
which naturally responds to that frequency in our normal physiology.
And so the strange process is continually measuring salt in the sound by pitch and by loudness.
And then takes the high frequency solvents and sends them to electrodes that are right at the cochlear base.
As low frequency sounds go to electrodes that call up 35 millimetres almost to the apex.
So as close as you can get to that. That's the basic idea.
Now this is a modern cochlear implant multi electrode and the scar,
the timpani and light grey and actually auditory nerve and modernists and actually grey rectangles is an
electrode pair and this flash or pulse is when the electrode is actually passed through an electrical signal.
And in my device and in most of the other devices we pass the other trade-off around 20,000 times a second.
Now cochlear implants? Well, the very first ones in the modern modern times through 1980.
Over the course of two years, that performance improved dramatically.
And so this is perception and patience versus time and type of device.
In 1983, corporation developed a single electrode cochlear implant.
What this did was enable patients to perceive sound, but not to comprehend it because there was no information about pitch.
Subsequently these multi electrode devices were developed by Vipit and slowly with time were improved.
So these are different manufacturers in yellow and in blue.
Now using appropriate speech coding strategies, which means the way in which the information is presented to the auditory dog.
By the late 1990s, it was possible in the best cases for a patient to perhaps understand 80% of the sounds that they were hearing
as English and to translate that into words that they could repeat to the audiologist and get it correct.
So that was a dramatic improvement. So 2001, I decided I would look into getting a cochlear implant myself.
I delayed until then because I'd heard that although these devices in the best cases produced a very good result,
there were many, many cases where they didn't produce a very good result at all.
And the reason that 2001 was the moment that I decided to get the implant was because I was at a conference at Caltech and a good friend
of mine undressed one out whose a kicked landscapes there is funny that I was attending the conference with me during a coffee break.
He told me that his brother in law had an implant and his brother was similar age to me and Andress was doing really well with the implant.
And so I decided to learn more about the device at that point. So first, let me tell you who can have a cochlear implant.
Now, this slide is written for the United States audience, but in fact, it's not so very different in the U.K.
I'll talk about small differences as we come along. So the first thing is you have to sort people in terms of, oh, you're an adult, your child.
So let's talk first about adults. That means over the age of 18 in the U.S.
But there's no limitation, by the way, with this technology. You could be 90 to benefit from a cochlear implant.
So you need to have bilateral moderate to profound sensorineural hearing loss.
You need to demonstrate those benefit from the state of the art hearing aids of the six month trial.
Approximately a million citizens in the U.S. qualify.
But only 71,000 had a quote. For the last time,
the Federal Data Administration gave the details of how many people had implants in the U.S. That number is now unofficially about 100,000.
That's much less than the number of people that actually need a cochlear implant and about 10% of the people that need it,
more children are represented. I don't send number.
Now you need to be psychologically suitable. At the time I applied to have the cochlear implant.
I'm lip reading and I was interviewed by the doctor. And the doctor said, no psychotics.
But literally I thought he said, no physicists. Fortunately, no.
I think you mustn't have any anatomic contraindication, for example, bony occlusions in your cochlea because then you couldn't put the electrodes in.
And then if you pass these tests, then you do CT scans and memorise, and then you get to choose what you would like to have implanted.
And there are three main choices. That's Cochlear. But an Australian piano company medal in Europe and clarinet in the US.
I chose the latter. Each of these manufacturers would tell you their device is by far the best.
The truth is they all have very similar performance and it's the patient that's allowed to scribble and the outcome.
And then you have to wait for surgery. And that can be many, many months. And finally, the surgery day arrives.
And this is the surgery. This is the playoffs to me. And opening up the wrong window, the electrode placed into the scar,
the temple there and a postage stamp request is covered in the mastoid bone to hold the receiver stimulator.
And the magnet is a major surgery. 3 to 4 hours under general anaesthesia should be done at a good medical school.
Now what happens afterwards? Well, post-operative complication rate is quite low.
It's less than 5%. Most common problems I listed.
The first is wound infection breakdown that's usually easily recoverable.
The second is rare, but devastating. And that spatial nerve injury classically occurs about a millimetre from the first year of the patient.
This transect does not regrow. This means permanent facial paralysis, which is a tragedy for the patient.
And it's a tragedy for the surgeon as well. The next thing that could happen is vertigo.
Vertigo, because the organs of balance and the bony labyrinth, along with the organ of hearing that usually also resolves.
And then there is the possibility of a traditional hardware failure, which many experimentalists familiar with.
We just try it out and put a new device in and that usually works very well.
I've got people that have had four devices in project, including one of my students that is doing really well now,
but he didn't really like having to have the first three.
And then the other thing you have to do for the rest of your life is avoid MRI because you haven't like it.
And the purpose of that magnet is to hold the transmitter outside the head in close proximity to
the receiver stimulator to ensure an effective and efficient transmission of the information.
And then you have to wait eight weeks for the one to hear. Before you can actually have the device turned off.
And during that time, you wonder how to pay the medical bill, at least in the U.S.
And the reason why you wonder is because this is not cheap. The cost in the U.S. is about $100,000 from here.
That includes everything from the surgery to the post-operative care.
Medicare and Medicaid in the U.S. pay total a partial cost, depending on state.
Some private insurers refuse to cover this device. But over the last ten years, that's radically changed.
And now only 10% to 90% now cover the device.
There's been a big shift in the last four years, which is very welcome.
This is a quote, the reimbursement that wasn't forced hospitals to close programs due to the cost of subsidising the input.
Other hospitals ration services by putting children on waiting lists.
These are the current statistics.
In the US, only about 6% of eligible adults in Western Europe have socialised medicine about twice as doing twice as well.
But that still means that most people would benefit from a cochlear implant to not have.
And you know, this cost looks like a big number here.
But the U.S. government themselves estimates that the cost of going through life just for the hearing world is about $1,000,000 per person.
And that's just the economic cost. Just imagine the personal cost of going through life stuff in a harrowing world.
Incredibly difficult. Another quote.
Ultimately, this is about the way society is hearing. Being deaf is going to kill you.
So some insurance companies see this as necessary and there are still issues now, even with Obamacare.
Some states still same cochlear implant programs closing because the reimbursement levels are not sufficient to support the cost.
So I was one of the lucky ones because the cost of my implant was covered by insurance through Purdue University at the time.
That was the first person to actually receive that coverage. And at the time I was denied coverage.
But then they changed their mind. Since then, several more people have been able to get a cochlear implant as well.
And so finally, about eight weeks after we have had the operation, it's ready to actually turn on the device.
And in my case, the surgery was at the Royal Hospital for Children, which was one of the major centres in the U.S. the cochlear implants,
part of Indiana University Medical College, and a really superb place for the really gifted surgeon.
And the operation had been at the beginning of November. And we hope to go home to Europe, to London and to the Middle East.
Danielle It's wrong to self-harm and as at Christmas and New Year and we hope that they would say someone that could hear it.
But unfortunately, this scheduled activation date was January.
So we're very, very disappointed. But then four days before we would get on a plane to come home for Christmas.
Danielle had a phone call from the hospital, said there's been a cancellation and can't even come down the next day to be activated.
So, of course, she had surgery about it. So the next day I go down to Indianapolis and we walk into a very high tech audiology suite.
Batteries of computers and lots of test kits. And you sit down, you're plugged into a PC and various tests performed upon you.
And I say P.C. advisedly, because I'm not compatible. And this doesn't this crushes in head.
I look like that anyway. So you hear nothing during this time at all.
After about almost an hour of this, the audiologist turned to me and I was lip reading still,
and she said, We're going to turn this device on about five more minutes.
So please understand that you've been dead for 12 years.
The chances that you will hear anything are quite low.
If you're lucky, you'll be able to hear soft sounds, but you won't be able to recognise the speech.
But if you were really, really lucky, you might be able to actually understand speech right away.
So she then turned back to the APC and continued to perform tests. And after about another three or 4 minutes, I became impatient.
I turned to her and I said, Have you tried this device on yet?
And before I got to the end of that sentence, I realised I was hearing my own voice through.
My own is for the first time in 12 years.
Better yet, that evening I got back home to Peru and hurt my wife twice for the first time in 12 years.
And because my daughter was born shortly after I became deaf, I heard my daughter's voice for the very first time.
And there are really no words in the English language to convey to you how marvellous that was.
But this is the power of science and engineering. To improve the human condition.
One of the great reasons to do it. So how does this device work?
This is the kind of audiogram that many of you have had in your lives. This is loud sound here, substance here.
And this is frequency, low frequencies in high frequencies. And this is the normal performance of a healthy adult.
Having threshold around 20 decibels or so. This is both auditory performance before the implant.
And what that means is if you stand on a runway or just about hear the jumbo jet.
And this is six months after that commotion. It's a dramatic improvement.
This is the kind of performance that someone in the early forties would have if they experienced a normal amount of hearing loss.
So this is nothing unusual. So these are speech tests, different types performed before the operation, six months after the operation.
And you can see in some cases I got 0% for the operation and 96% after the operation.
But, you know, it's kind of embarrassing to be a physics professor. You had 0% in a test.
But anyway, at the time 2003, these scores were considered to be exceptional.
There were other examples of exceptional performance, but this was not typical.
The good news is that today 75% raised the possibility that patients have studied the glasses and, you know, visual cues whatsoever.
Just use the phone straight. So the question then becomes, why does this work?
You saw we have 3500 households. This device y device has ten electrodes, of which two broke during the surgery.
So I've got eight. I can understand you. So how can.
The reason is because hearing doesn't end at the cuckoo perception, whether it's visual or auditory.
It's a combination of top down and bottom up processing.
It's really, really, really important to understand that sensory detail, the level of it,
the distinctiveness of the object, playing a very big role in our recognition of the world around us.
For example, if you see a huge grey animal in the distance, you don't need to know much detail to know it's an another.
So I'd like to do is give you some exercises in perception.
And so first, I want to show you a very famous person.
Now, usually I give this talk at the States.
I just say, verify this question because this is the U.K. I actually tell you, this is a very famous American person and it's a historical figure.
And so this election is going to contain very few pixels.
And so it will be difficult for you to use only bottom up information, just the information in those pixels to recognise who this person is.
However, because I've told you that it's a famous American historical figure.
You've also got Top Gun knowledge, which you can use.
And in this particular exercise, what you will probably find is that the top down knowledge is enough to work with
the minimum amount of bottom up information to reconstruct who this person is.
So. Tell me if you recognise who this is. Marijuana.
That's right. So for those that didn't get it. But this paucity of bottom up information, I'm going to add more information to you.
And you gradually say they could come into the. Now the language equivalent of that would be a missing word in a well-known phrase.
For example, I pledge allegiance to the flag of the United States of America.
You do not have to know that red flag. That's obvious.
Is the context that tells you. And so that's the top down, working with the information.
And this is exactly how posting really deaf adults understand the world around them.
This device is not capable of giving me every word that you say.
It gives me a few words, and if I don't know the subject, I can backtrack over the last couple of sentences.
Hope to understand something at the current centre to reconstruct the conversation.
And although this takes time to learn, eventually it becomes very easy to do inventory.
Now I'd like to take away your ability to use top down processing.
So I want to give you another example. In this case, it's an object you've all seen before.
But it's much less distinctive. They're much less familiar with it.
I'm not going to give you any information about what it is ahead of time. So they're going to rely entirely on bottom up information.
So tell me what this is. Good. So I'd add more information and more information, and it's gradually seen as coming into this, a rather famous picture.
Now you see it, right? Disintegration of the Persistence of Memory by Salvador Dali.
No. The audit trail. I don't know that.
Would be missing words in a sentence or phrase you've never heard before.
Or hearing a foreign language. Oh.
Hearing language for the first time through a cochlear implant.
And that's exactly the situation of dealing with it, of course, when they're given a cochlear implant.
So for the adult post language, he does.
Our challenge is to recognise that for the young child who's never experienced the auto audio world before, the challenge is to recognise the picture.
That's much harder thing to do.
And so the question then becomes, is the cochlear implant capable of providing enough information to help a child understand the world around?
So this is a photograph of the word choice. This is frequency versus time and it's colour coded with white being the loudest sound.
That's. Sure. This is the. And that's.
That's at the end. Now if you replace frequency with electrode Doppler and look at what the implant sees, it sees that.
So you can say they are similar, but are they similar enough?
And so there's been a great deal of work on optimising cochlear implants to maximise speech perception.
And so you can ask, what are the things that we've got to actually get right? Is there amplitude?
Well, if I'm speaking relatively softly, relatively loudly, as long as you can hear me, you'll understand.
Plentitude is not very important. How about the temple structure itself?
They're all familiar with the idea that in the movie, old fashioned movie, the film runs slow.
You'll start to see a series of still images instead of a continuous motion.
And this would correlate here with the rate at which you post the order shoot up.
It turns out that we composed the instrument so quickly you're always unaware of the pulsing, so as a continuous sound.
And so the tempo structure was not important either.
It turns out that the most important one is the number of locations that works, the stimulated and the places stimulation.
This is what really matters. So this co-writes the pitch. So I'd like to give you an example of this.
So I'm going to play for you a sentence in English. And this sentence is going to go through a single bound passcode.
In other words, there'll be no frequency information whatsoever. And I'd like you to tell me what this sentence is.
You didn't get it right. Okay. So now let's do the following.
So that was by the way, that was one channel. Right. Well, so it's like one electrode and that's a bit like what Volt would have hoped.
So now let's just try to channels.
Now, two channels means that we're going to take two bypass motors, one for all the low frequencies, one for the high frequencies.
So any more information, but not much. But tell me what this is.
It's the same sentence in English, so probably it's not a different tune to the first one, but it probably was unintelligible.
Right. Okay. So now let's go to four channels. So that's low, medium, low, medium, high, high again.
Tell me if you recognise this. The same sentence. It's beginning to become words, right?
To see the differences. Gradually building up is more like language.
Right now. Let's go to right now. I should tell you how he did electronics, but I can understand this.
So you tell me what this is. I think you can do it, Sir Charles. I would like to point out that.
That's right. I like to play tennis. Right. So that's right.
Now. Not too many of you didn't get it because you're not able to rely only on bottom up because there's not really enough good about.
So only occasion if someone ever got it approximately correct.
So now let me play for you the original.
But before I play for you the original which I think you recognise, I should tell you that for me I never should have said exactly the same to you.
It's not very different. I like to play tennis.
You say no, you heard it right. You all understood original. But everyone understand the original preamble if you did.
I'm just checking because I'm not sure how good the sound is. Because the sound as well. Right.
Okay. So now. Now that you've heard the machine, you can use your top down processing.
To reconstruct the much poorer childhood without trials.
So can I listen to this again? I think to understand it now.
I like to put the. It's dramatically different.
So that's the power of top down processing.
Now, you might be saying that it is in a world of eight channels, and so these voices are horribly robotic, but they actually are not.
And the reason for that is because the brain, if a person would do that, remembers how sounds were before.
And so the information I get in, which did sound horribly, rebuts it.
When I first got by upload, the brain says, no, people don't sound like dialects.
And so it puts memory plus memories of voices onto people.
Now, most of the people I've never met. So I've given you all voices based on my relations.
Yeah, but they're very nice voices. There literally no sources. That's okay.
No, it's not surprising that it's not easy to work with so few channels and understand anything, and so it takes time.
And so this is a quick plot of perception in adults who oppose literally death.
And they had preoperative flair. They couldn't understand sentences. They got the implants.
And over the course of six months, they gradually learnt how to use that implant.
And so this is a lovely demonstration of the plasticity of the adult brain.
But all of these adults were posted pretty tough. And so they used their and knowledge of language.
So it's top down processing and it was powerful. What about the printing with the deaf children?
This is where the device becomes controversial.
And so this slide again is for the U.S. but very similar arguments apply in Western Europe and the U.K.
So the first thing is that most of you probably know that people who live in the deaf community and who lead very fulfilling and productive lives.
Emphasising. Sign language, but no auditory ordinary language or language that we use.
In the 1990s in the United States, there was very strong opposition to paediatric implantation while there was neutrality to adult implantation.
And the argument was that the implant delays a deaf child's acquisition of sign language,
which is the deaf child's natural language and their assimilation into the deaf community.
1991, the National Association for the Deaf, and there were similar statements in the UK and other countries as well deplored the
FDA decision to approve paediatric implantation as being unsound scientifically,
procedurally and ethically.
However, within ten years the situation has changed and the deaf community now tends to regard implantation as a personal decision.
The 2000 statement emphasised taking advantage of technological advances that have the potential to improve the
quality of life for deaf and hard of hearing persons and strongly supports the development of the whole child.
And of language and of literacy. So this is an example of one of the most cited studies of language development and show that with importance.
And so the graph on the left shows language, age versus not.
So hearing children at age 48 months have a language age 48 months.
The children who are the data points here are children that cannot hear.
And so that natural age is much greater than the language.
And now these children are going to be implanted in the dark because of the children that receive the implant.
The white circles of children will control them. They don't. And this is the extrapolation of what we would expect to see.
And on the right. The data point said property play and the person to move afterwards.
Other children have been implanted. And this is their projected performance if they hadn't been employed.
And so to quote from the paper, despite a large amount of individual variability,
the best performers have been plucky group seem to be developing an all linguistic system based largely on auditory input from the cochlear implant.
And that is a truly remarkable result. And it's perhaps the most joyful side of this talk.
Now, cochlear implants are not perfect.
One of the challenges is listening to music with that, because to hear music, one has to convey pitch very accurately.
And so I'd like to play for you a piece of music, and you tell me what this is.
This is how it sounds to me through a cochlear implant.
Wasn't that us? Right. So now let me play the commissioner.
Before I do, let me tell you the original and what you just heard sound exactly the same to me.
So they were dramatically different. But you shouldn't say that.
I therefore can't enjoy music as long as I know what the tune is.
I can remember from the past, or if a lyric is there, I can reconstruct a very pleasant musical experience.
And many countries and countries do exactly the same.
So I'll just take two more minutes to talk about how the devices can be improved further and then wrap up.
The first of them is that many, many people retain good hearing at very low frequencies, but lose hearing at high frequencies as they age.
The low frequency hearing can be brought back with a hearing aid,
and then the high frequency part can be brought back with the cochlear implant in the same area.
A shorter cochlear implant is stimulating the base of the cochlear, and that's shown here.
And in this case, a patient could understand nothing without ever hearing 51% with the cochlear implant only.
But it was a great improvement and both are looking at once. It's a very easy way to improve the cochlear implant.
The second is to have two cochlear implants instead of one.
How do we know where sound comes from? When a sound is close, is produced closer to our left ear than are right here?
It arrives in our left ear before our right to right,
then passes from both Cochlear on long delay lines to common neurones in the medial superior olive.
When signals arrive at a common neurone in synchrony that neurone files have a sound source that moves slightly to the right.
The into all time delay is different, and so the signals arrive at a different common neurone in synchrony.
A lot neurone flies. And in this way humans have built up the ability to tell the direction of sound to one degree.
And the play is, however, with a cochlear implant, you're only getting a signal on one side.
And so these neurones can never fire. And so you have no sense of direction.
And so two cochlear implants can give a cochlear implant to your sense of direction.
The precision is about 16 degrees. And this is an example of seven people that were lucky enough to have two cochlear implants.
It's one of them off and say as the sound on your left or on your right, and they get it right half the time.
But if they have both of them, they got over 100%. The sun is the hearing process.
Once you get to cochlear implants, it's something else you can do as well.
And that is understand speech. In a noisy environment, the world is full of noise environments.
Her speech coming from the noises on the left, cochlear implant is on the left performance is poor.
Move the noise source to the right. The shadow of the head blocks.
This noise got to the cochlear implant so the person does better.
But if you have two cochlear implants and the sound is from the front and the noises on the left or the right,
the cochlear implant, you can score 100% in a test very similar to a hearing person.
And as a second benefit as well, there are people who have a cochlear implant.
They don't do very well with it. You had a second one and their understanding of the world around them is transformed.
So the future of these devices, in addition to the two examples I just talked about,
there is a lot of work ongoing on increasing the number of channels of stimulation along the auditory nerve.
And that would lead to improved speech, performance and better future one stop, pitch and improve music appreciation.
There's also a lot of work ongoing on reducing the power that these devices use so they can be fully implanted instead of being partially external.
And cochlear implant performance in the end also depends on the health of the auditory nerve.
And so there's a great deal of work ongoing on the regeneration of auditory nerve neurones.
So to summarise.
Implants have enabled the post-slavery deaf to hear and have provided sufficient information to support language development in children,
which is a truly remarkable result. Implants were proud of speech recognition.
We now know that exploiting telescopic organisation is the key to the implant success.
The music and speech quality, including differentiating between man and female voices and accents.
The cochlear implant does not yet provide enough information to allow.
This is the natural frontier of cochlear implant research.
But implants was the first prosthesis to successfully restore neural function and become a benchmark in biomedical engineering.
So let me leave you with a couple of final thoughts.
The first is that a cochlear implant is a truly wonderful example of a broad range of science and technologies,
all of the disciplines listed here working together to improve the human condition.
One of the great reasons to do science. Today.
It has around a quarter of a million implants worldwide.
And with the latest devices,
about three quarters of post legally deaf adults can use the telephone and small children can hear their parents voices and learn to understand them,
to hear their parents say to the child, I love you, and that's really priceless.
Sometimes about a year or two. After I give this talk, I receive an email from someone that tells me that they have a cochlear implant.
They're very happy with it. And what began their try to do cochlear implant was someone in the audience of this talk telling them about it.
And that's the reason that I give this talk.
So it is critically important that we work to make this technology more widely known and widely available to all our citizens.
That's more than 20 million people in the world at this minute who would benefit from a cochlear implant in their lives would be transformed.
And if we can make it possible for at least a few more of them to get it every
day they can move to towards a happier and better world for those people.
At a personal level. 11 years ago I had my hearing restored and it's enabled me to teach better and to do better research.
And it also enabled me to hear my wife's voice for the first time in 12 years.
And I do this voice for the very first time. Thank you very much.