Gordon_Dutton_Webinar
Good day to you. My name is Gordon Dutton. I am a retired pediatric ophthalmologist who has taken an interest in the subject of cerebral, or brain, visual impairment. Also known as cortical visual impairment.
And the topic that I'm going to talk to you today is about understanding what children with CVI, or cerebral or cortical vision impairments, see. And using this knowledge to help affected children.
The key fact is that children can only learn from what they can see, what they can hear, and what they can understand. And if we present information to them in a way that they cannot see, or cannot hear, or understand, they cannot learn from it. And this is being missed all the time.
I've seen many situations where children have at last been given a chance to learn by being given the opportunity to see, hear, and understand when previously they couldn't. And, of course, they need to be happy whilst doing this to optimize their learning.
So what I would like to share with you, first, is how the brain sees. Seeing from inside to out, not outside to in. What I mean by that is the brain is where the picture is formed. And this is what I want to show you. The picture is not out in front of us. The picture is in our minds. We create what we see in our minds. And then we endow that picture onto our surroundings. And assume the picture is in the right place. And contains all the information and all the detail.
I want to then go onto the profile of seeing when the brain sees differently. Those of us who have cerebral visual impairment are normal. Normal is what I am. Normal is what children with cerebral vision impairment are.
And then we need to find and know the limits of vision in children with cerebral visual impairment, so that we can stay within them. And if we can't stay within them, because whatever we show can't be seen, that we can use alternatives. And through training we can extend the limits for children as they grow, and develop, and their vision continues to improve.
So first, how does the brain see from inside to out? The classical picture, of course, is that an image of what we are looking at is formed clearly as an inverted image of the object on the back of the eye, on the retina. The retina is an amazing structure made up, just as the computer screen you are looking at, of pixels. Little dots. Except those pixels comprise the rods and cones.
The rods seeing in darkened conditions. The cones seeing in light conditions. Present throughout the retina. And these individual elements create the individual image details. Which add up to the electrical signals that are passed down the 1.2 million fibers that pass from each eye into the brain as a fully, created, electrical representation of what light creates in our eyes.
Light, of course, is that part of the electromagnetic spectrum for which man has been endowed perception through the eyes. Light is therefore truly defined biologically. Because ultraviolet is just off the light spectrum. We cannot see it. And so is infrared. But these again are defined by the human eye, and what it can detect.
Once the image has been created into its component parts, then the next process is for the picture to pass down the optic nerves into where they meet up and crossover in the optic chasm. Then, behind that, along the optic tracks to the lateral geniculate nucleus where they form into new pathways. Down to the back of the brain along the optic radiations to the occipital lobes, the back of the brain. And the part that does the principal, initial processing is called the primary visual cortex.
In this diagram I've drawn the eyes as if this picture were a cyclops. Because both eyes feed equally to the brain at the back. And if you look at the clock on this picture, you'll see that in a sense it is upside down and horizontally inverted. As if it were plastered onto the back of the head. So that the top right quarter of the back of your head sees in the bottom left quarter of the visual scene for both eyes equally.
What those sinuous, white lined arrows represent is the fact that the actual pathways within the optic radiations, the pathways passing through to brain, from the lateral geniculate nuclei. What those pathways pass around the water spaces in the brain. With the upper pathways going over the top of the water spaces. And the lower pathways to the temporal lobes passing around them, through the temporal lobes to the occipital lobes. So they are susceptible to different damage in different locations in the brain.
As one can see on the diagram on the right side if there is an injury to the brain on the right side then one will not see on the left. Whereas, if there's an injury to the brain on the left side one will not see on the right, as shown in the top of the diagram.
Similarly, if there is an injury to the top of the brain towards the back in the parietal lobes then one will not see in the lower visual field. And if there's a subtle injury, one will not see a more peripheral, lower, visual field. Which means that one may not see one's feet when walking or climbing down the stairs. Because of the peripheral, lower, visual field impairment. Which is rarely detected by eye professionals. Because they do not look, when they are assessing, the area over which we can see the visual field into the far periphery. But we'll come back to seeing about that later.
Moreover, one can have a lesion or injury, for example, in the right, temporal lobe leading to a left, upper quadrant visual field defect. Or one in the left, parietal lobe leading to a right, lower quadrant visual field impairment. And if everything's impaired maybe there'll be a small amount of vision in the center with the visual field constriction which has been caused.
So let's move on to the next area. And that is once the picture has come into the back of the brain, the primary, visual cortex denoted by the red oval or the computer, the image is computed. And then it's computed in two ways to be passed to the library. Which is the complete library of pictures that we've ever seen in our lives before, held within the temporal lobes which are just behind the ears.
And the map, a separate pathway in green arrows, in the parietal lobes. Which are responsible for mapping the scene that we see. To enable us to both move through it, move around obstacles. And, of course, each obstacle, each element that we may wish to move around or pick up is individually and separately mapped. But let's go into the detail of that next.
The computer. What does the computer of the occipital lobes do? Well first, it sees over a wide area. Approximately 60 degrees on the side of the nose. And out to 100 degrees. We see slightly behind ourselves because the light is bent as it comes into the eye. So that's a wide, horizontal, visual field.
We also see vertically up by about 60 degrees. And down by 75 degrees. Or even a little bit further down. Because when looking straight ahead most of us can see our extended foot. Although we aren't really conscious of doing so, most of the time. When we stride out and know that we're putting our foot down on a irregular piece of ground, and modifying the position of our foot to match that. Miraculous, isn't it?
The other element, or function, of the primary visual cortex within the back of the brain, the occipital lobes, is the ability to see clearly. Here is an accurate simulation of what 20/200 vision looks like as compared with the clear vision a London bus. The London bus on the right, one can see the number, the detail, the headlines. But the London buses on the left, we can see them as buses. We can see the windows. But the detail is missing when it is blurred by tenfold.
And then there is contrast. Contrast sensitivity is the capacity of the mind to differentiate shades of gray from one another. And so somebody with normal contrast sensitivity would see the mouse on the left. But reduced contrast sensitivity would accord the image as seen on the right. Because it would look washed out with lesser ability to differentiate the shades of gray.
The primary visual cortex also processes color slightly further forward than those other two elements. And this shows a picture of the Mona Lisa looking washed out in a way in which the red part of the spectrum is not seen. And so essential color deficiency can occur, rarely, in those who have problems due to seeing in a way which has been affected by the occipital lobes.
Now moving forward again. In the brain there is an area called the middle temporal lobes, just in front of the occipital lobes, where the moving information is sent. It's quite extraordinary. Inside your eyes there are two types of nerve fiber and cell body called the ganglion cells. Big ones, magnocellular cells. And little ones, parvocellular cells.
The parvocellular cells are little. They're compact. They have a lot of detail. And they are responsible for being able to analyze the inner elements of the picture with great detail. The magnocellular cells, on the other hand, serve the more peripheral visual field. And what do we do with our more peripheral visual field? We handle movement. We move through the visual scene. And the visual scene moves in the equal and opposite direction to our movement. We process that. And then that enables us to move accurately.
And it is the data from those big cells, which are coming from the peripheral vision, which are so important to enable us to move freely through the world, and to see moving targets.
So that information is also handled distinctly and separately in the middle temporal lobes. Now each one of these elements can be interfered with either, separately or together, if there is brain injury. Depending upon the location, extent, degree, and severity of the injury. And the pattern of it. Any single one of the elements I referred to can be impaired, and not work as well.
So what happens to the picture which has been processed by the computer? It's passed into the library. Those blue arrows represent the pathway, which is called the ventral stream. Ventral means at the front. Your chest is at the front. And that's the ventral part of your body. And that is because anatomical description is described with the head and as if the eyes were looking at the ceiling. And then, of course, that pathway becomes ventral.
And what does the ventral stream do? Well in the temporal lobes, as I've explained, the complete world as we see it, and have seen it, is stored. So that the information is being compared with our library store. And that is how we recognize what we see.
The model that I'm sharing with you is one where we talk about injury to the brain. And when the left temporal lobe is injured, then it tends to be geometric shapes and forms that are not seen so well. So that if someone has a specific, focal, left temporal lobe injury they may find it difficult to differentiate the scissors from the keys, et cetera.
By contrast, in the next slide, which is a photograph of a group of people. One can see that they have smiling faces looking at us. And it is face recognition which is served in the right temporal lobe. Along with the capacity to interpret the language of facial expression, and pass that to the language brain on the left side. So that we can understand what facial expressions mean.
Moreover-- moving to the next slide, which is showing a street in London-- the ability to find our way around. Whether we are finding our way around a street. Finding our way around inside of a building. Or even finding your way around the elements that we've laid around on our desk. That is mapped in the temporal lobes, too. So that we can find our way back to where we were. Remember where we've put things. And find our way through buildings, too.
So an injury in the right temporal lobe, as I've already shown you, would give rise to two things. It will give rise to lack of the left, upper quadrant of the visual field of both eyes. And it will give rise to an impairment of the ability to recognize faces, and to find our way about. That's if it's a large injury.
But lack of ability to recognize faces has recently been found to be fairly common. Affecting, perhaps, up to 3% of the whole population. Not because of injury, just because of a different, normal kind of brain.
So let's move to the green arrows which go to the part responsible for seeing in the posterior parietal lobes. Indeed. If you place your hands over your ears, perhaps you'd like to do that now, with your thumbs pointing backwards they cover over the oval, red part, the occipital lobes, with your thumbs. The palms of your hands are covering the temporal lobes. Whereas the fingers are covering the posterior parietal lobes. Which is where the map of what we see is.
It is the work of a Goodale and Milner, whose textbooks are really worth reading, which have shown us that this map through which we move-- assuming it to be coincident with reality, so that we are endowing our maps upon the outside world-- this map is totally nonconscious. We do not know we have it. Their work on people who have lost the capacity to see clearly but can move freely through the world they cannot see has demonstrated this.
The video of the woman who could see rain is really worth watching on YouTube to explain all this. And, in essence, we move through the map which includes all the elements of detail. So that we can reach out for things. That we can move around things. And the map is then endowed by the information in the temporal lobes. As shown by the picture of the building itself.
It's a bit like the invisible man. It's a bit like the story of the invisible man by Robert Louis Stevenson. In which the man was wrapped in bandages. He was invisible until the scene was covered. This is what the temporal lobes do. They cover the nonconscious, three dimensional map in the parietal lobes with meaning. And they endow the conscious picture.
But it is not until someone has an injury to their temporal lobes, and is able to strangely move through the world that they cannot see-- as in the video on YouTube of the woman who could see rain-- that we begin to understand that these two elements are dissociated.
So somebody who has a severe injury of the temporal lobes, partly affected the occipital lobes, can move. And these may be children who tend to rock. Or to have to move to be able to see. But not able to identify anything they're looking at.
By contrast if there is an injury to the parietal lobes then, of course, the mapping becomes less accurate. And we become more clumsy.
So when it comes to going in the cinema, of the 3D cinema, then the audience may see the rocket, the dinosaur, and the turtle coming out at them. Because it has been mapped by the engineers as to create a three dimensional image in 3-D space. Feeding into our two eyes but by having created those three dimensional pixels in space. Which are volumetric pixels or voxels.
So the engineers have, in a sense, engineered the same concept as our own posterior parietal lobe visual systems that map our three dimensional space for us by voxels. If you look at the center of the screen, then you can point to it. And touch it accurately.
But the top, right hand corner, when you reach for it, if you try a few times, you'll find that occasionally you miss it. That is because the voxels of our visual scene are small in the center and larger to the side. So what happens when we map a complex scene like the inside of a supermarket. The detail of what we are looking at can overwhelm our visual system. And indeed, if I were to ask you to point to a specific element in the scene, such as the little boy wearing blue, that's something you'd find almost impossible to do without spending a long time searching.
So what this map also allows us to do is to reach out and grab something. As this baby is reaching out for an apple. Or, if you want another picture, to reach out for something that one wishes to hold. Moreover, it enables us to move accurately down steps and stairs. To move freely through our visual worlds. Through the map in our minds assuming it to be coincident with what we deem to be our reality.
So, in summary, the computer analyzes the information. The information is unconsciously mapped for all senses. Not just vision, but for sound and touch as well. As a 3-D mental copy of the surroundings. And the images are compared with the library and painted onto the map. So sight is inside to out. Not outside to in. Our minds create the image in themselves. And therefore, this is our true reality. And everybody's reality is, of course, different to everybody else's. All depending upon our previous life experiences.
So, let's consider what the limits of seeing are when the brain sees differently. First, taking into account that we need to ensure that the optimum picture is presented to it by wearing spectacles, if necessary. Every, single child with cerebral or cortical visual impairment must be tested to see if they need to wear spectacles for their optics. And they must be tested for the possibility of lack of focusing. Something which is often not done because both, of which, are common.
So let's go back to the computer and seeing. The computing profile is to deal with each element. Now here is an image, an MRI scan, of a child's brain where the child had a difficult delivery. And there was poor oxygen supply to the brain. The back of the brain has got a Swiss cheese appearance to it. Whereas the front is entirely normal. The front is at top and the back is at the bottom.
So this is hypoxic-ischemic encephalopathy of the occipital lobes in a child who actually has remarkably clear vision. Somewhat similar to the images shown, where the low contrast means that the eyes are missing in the mouse.
As does the low clarity. So one can see that both clarity and contrast, when reduced, can impair perception. Here we need to introduce color, too. So that color and contrast are combined in the real world. Because imagine you go to a paint store. And you get the gray paint to which you add green. A little more green, bit more green until it's totally green on the outside. A little more red, more red until it's totally red on the outside.
So these are hues. And each hue is becoming more and more colored until it can't become more colorful. So a color is a fully, saturated hue. Now if we add white to our paint then we get pastel shades. And whereas we add black we get dark shades. So a pastel shade is called a tint, and a dark shade, a shade.
So if you add black then you get a navy blue or brown. And as you add white you get pink, or light green, or light yellow. And to make things visible, optimally visible, this idea of this picture-- which is an imagined picture of how we process color in our minds, called the color solid-- then we can think that the best way of presenting information to those who do not see so well is to present either from around the color circle. Such as yellow contrasting with blue. Not so much green with red because, remember, that 8% of men have impaired color vision for green and red. And also with white added or dark added. And therefore optimizing the color boundaries to render them perceptible.
So what we must always do is to watch for what is seen and what is not. And to ensure what can be seen.
Let's move on to the visual field. And here we are looking at the Simpsons. But if one has a lack of vision on the right side, right hemianopia, then one would miss the Simpsons. But hemianopia moves with a head turn. So let's say I want to look at Homer, and Homer's changer for the television. Look what disappears. And now I want to look across to his son. And look what re-appears.
Visual fields move with the head and eyes. But watch this space. There's more to say about this. Because when it comes to the posterior parietal lobes, the visual fields that they serve move with the body.
Another example, which is to take us back to 1918 for a particular reason. This is Sergeant K, who was reported by Gordon Holmes in the British Journal of Ophthalmology in 1918. You can find this article for yourself, if you want, simply by typing Gordon Holmes BJO 1918 onto PubMed and you'll find it. He described six soldiers, and Sergeant K is one of them, whose shrapnel wounds of the First World War went through the top of the brain at the back. And led, as here, to a complete, lower visual field impairment.
But this soldier also lost his mapping, and his vision for movement, and his vision for searching. So that, too, is something we need to discuss later.
For movement perception, when do propellers disappear? Well for a number of children I've seen with brain injuries they disappear, as do bulls or other moving targets, when they move quickly. A number of children have said to me-- when you ask them what does a ball look like when it's kicked?-- the response is, it disappears, of course. And then it comes back when it slows down.
So such children see rotating propellers to disappear earlier than those of us who do not have this impairment of perception of movement. Which goes by the long name of dyskinetopsia. Or if one has absent perception of movement, akinetopsia.
Let's move to the library. What problems can arise if the library is not working well? Well, in particular difficulty with faces. Being able to tell, whether one can tell a face or not, to recognize a face. And to recognize facial expressions. As well as, possibly, having difficulty recognizing shapes, or letters, or numbers, or objects.
It's more common for both temporal lobes to be affected and therefore for there to be an inability to cement the image detail to create meaning for all aspects of the picture. Including, of course, the ability to remember where we are, and find our way about. For the long words, the ability not recognize a face, or the impairment in recognizing faces is called prosopagnosia. Prosopos, Greek for face. A, not to. Gnosis, know or have knowledge. Not to have knowledge of faces, prosopagnosia.
Whereas not finding your way about, due to not being able to map things properly, is called topographic agnosia. Whereas impaired letter reading is literal alexia. Shape problems. Shape agnosia. And when is dyscalculia due to difficulty recognizing numbers. And not recognizing objects is called object agnosia. All of which have been described in adults with focal damage in specific parts of the temporal lobe.
And then what happens if the map is impaired? Now this is the commonest type of disorder of vision that I've seen in my career. And yet it is being missed all the time in my experience. And why? Well because, first of all, how do we understand the loss of a non-conscious function? First, we have difficulty understanding it. Secondly, people who have lost it don't know that they have lost it. Because how can you know that you've lost an unconscious function? You simply know that the environment feels strange. It feels odd. It feels difficult to see within.
And one seems to be missing things, not finding things, bumping into people, being clumsy. Clumsy is the wrong word. Impaired visual guidance of movement is the correct term.
So let's move on. This picture of a concert in New Zealand was taken by a friend and colleague who herself has an inability to see more than one thing clearly at any one time. As one can see, one person with his hat on is seen. The rest is a blur. We've blurred it and left a little bit in the middle visible. And then showing this to my colleague, who is a teacher of visual impairment in New Zealand, and she says that the picture is identical when affected like this, when compared with the actual picture.
So she has an inability to map more than one thing or one item in the scene. And this is called simultanagnosia. Simultanagnosia is very common at various degrees. So some people have just difficulty copying print of a blackboard. Because how can you find the requisite letters and words from a model, and then look down at your own model, find where you writing and write? And go back and forth doing so. It takes ages. So simultanagnosia is the word to remember.
And then action with a less accurate map, such as reaching for a glass, affects all the body or part of the body. For example, the legs. So in this picture for the hand. The reaching hand in A has matched to the width of the glass. Whereas the reaching hand in B, as it moves out, is wider than the glass, the reaching hand in C is naturally compensating for reaching for the glass by putting the hand on top of it. And in D naturally compensating by reaching beyond it, and gathering up.
Do this yourself. Place a glass on a table and look further and further away from it. And reach out for it. And you'll be surprised. You do exactly the same thing with all three compensations, of B,C and D, as the glass is further out in your peripheral visual field. So these are natural reactions for lack of voxels of the peripheral field.
So you can actually work out what it's like to see. If you emulate that hand movement and find out why you do it when you copy the movement of a child doing the same thing. Similarly, for moving the legs. How many of us have come across children who have difficulty climbing steps, or going down steps, because they may have a lower visual field impairment? But even when they look at those steps they may probe the ground ahead to feel whether it's flat or not. Because they're not sure. And indeed, in Gordon Holme's paper there is the description of one soldier who said, I can see that step in front of me. But my foot doesn't know where that step is.
So that's dealt with the limits of visual function. We clearly need to find and know those limits. And therefore we need to assess acuity, contrast, visual field, the ability to see color, the ability to see movement. We need to assess the temporal lobe functions of recognition of objects letters, words, people, facial expressions. And we need to assess the capacity to move accurately through 3-D space. And to be able to find things. And to know what the limits are. So that we can stay within them, use alternatives, and potentially extend those limits.
So, for example, for lack of vision on one side if doors or door posts are bumped into a colored marker at a child's eye level draws attention and has proved effective. Crossing roads, even at safe places, needs a head and a body turn. Why a body turn?
Well, the kind of anomaly you saw in the head scan, due to hypoxic-ischemic, encephalopathy, for example, can extend from the occipital lobes into the posterior parietal lobes. And as I've said, the posterior parietal lobes guide our movements by remapping the field of view to the body. And it's been remarkable to have the privilege to watch people who have had a focal lesion, for example, in the right , posterior parietal lobe. And when they look at a scene the left half is missing.
You might think that was hemianopia. But when they look and search with their head and eyes, the left half is equally missing. Their eyes and head don't pick up the picture on the left. But when they turn their body to the left, the picture appears. Affected children tend to compensate with a slight body turn when they are sitting at table. So that they can, for example in that circumstance, see the fork and know that it is there.
Such children, obviously, need to sit on one side of the classroom. And to be taught from the good side. While being encouraged to find favorite food on the hemianopic side. For example, this enhances education whilst motivating visual search on the other hand.
Children with acquired hemianopia have found that if one cannot see on the right side, the words on the right side of the page may not come into view. So that they are missed. However, when the text is rotated through 90 degrees so that it can be read vertically downwards, the area that is not seen simply covers over the text which has been read . So that it does not get in the way.
All those people that read Chinese know that it's normal to read vertically downwards. So it may seem counter-intuitive. But remarkably, it was an 8-year-old girl who had discovered that vertical reading for her lack of vision on the right would help her. And who was actually tilting her head by 45 degrees and the text by 45 degrees in the other direction. And reading vertically downwards in a way that nobody would notice.
She taught me this. As have other children who have spontaneously discovered it. It doesn't take all that long to read, just a few hours, and then it's mastered.
So what approaches can be used for lower visual field impairment, often with lack of attention for the lower visual field, as well?
Well, when feeding the approaching spoon is moved through the upper visual field before it reaches the mouth. And then the mouth opens. In children in whom the mouth does not open, have a go and see what happens. It can be quite remarkable.
Then, of course, keep the floorspace clear of obstacles. Especially if they are of low contrast. The belt, clothing, pocket, or elbow of an accompanying adult tends to be held onto for tactile guidance of the height of the ground ahead. So in the picture here clothing or elbow are being held.
In the past I've met families where the parents have, said stop pulling my clothes down. Until they've recognized that there is a function in doing so. White shoes can aid walking by being rendered more visible. With a little black part which helps contrast against a lighter floor surface.
Telescopic hiking poles supplement vision with tactile guidance and have proved very popular amongst children that I've seen. Especially if they're spring loaded so they don't jar when they hit the ground ahead which isn't seen. And provide this knowledge of where to place the foot.
An adjustable reading stand makes the lower part of the page accessible. And eye contact is an important issue. Because how can one give eye contact and cope with the ability to see a lot of things at once? Or hear a lot at once? So some children may not be able to give eye contact. And mustn't be told, look at me when I'm talking to you. Because to do so might make it impossible to listen.
An important issue, also, is the maximum eye contact distance. Because eye contact cannot be adopted if one can't see the eyes. These figures come from a research project that we did. In which we estimated how far it was before children lost interest in their own reflections in a mirror. But, also, when you reverse the concept, you can see that if a maximum eye contact distance is 1.5 meters then that vision is 6/60 or 20/200.
Whereas if the maximum eye contact distance is six meters that is normal vision. So you can see what we've plotted in this table is the child's age, and the normal levels of vision by age and developmental age. The maximum eye contact distance. And the approximate Smellen acuity using the six notation. So that one can use this table in different ways. Both to estimate vision, and to understand the normal development of vision.
So your eyes cannot be seen. What about enlarging facial features? It's quite remarkable what happens when you get a smile for the very first time because the facial features have been rendered visible. Important parts include the eyes and the nose. So this dog has a visible eyes and nose. By contrast is this an eyeless toy? One in which the eyes are little dots?
Well, if we move on to the next picture one can see that one clearly, of course, needs to provide a pen for a child so they can see their own handwriting. So a felt tip drawing becomes visible. But a pencil image may not be easily visible as this simulation for 20/200 vision shows.
So clearly, a very effective way of ensuring that a child's books has been properly checked to ensure that all the key elements can be seen, is to prescribe the pen. The pen whose line widths have already been shown to be visible by visual acuity testing. And then using that pen to enhance the eyes and other elements within the books that the child is using, if the eyes are smaller than the thickness of the pen.
Similarly, the gaps between the lines are just as important as the line thickness. So wide gaps are also needed because insufficient gaps blur the overall image, as well. So the text needs to match the functional visual acuity. Whilst being san serif. The little bits, extra bits that are on times romans should not be there. Because they confuse with visual acuity being poor. San serif, like this. And well separated, like this. Because the gaps need to separate the words into entities. With clear separation of lines, like this. To separate the words into entities, too. So these approaches are all crucial.
For lower visual field impairment, or for impaired visual guidance of movement of the feet, the stairs can be colored. Or they can have contrast or focal lighting. If there's an absent facial expression then, of course, they may need to be amplified. And, indeed, the spoken word to explain how one feels. Here's me being happy or sad.
What about color? Well, watch what is seen. The commonest feature is a problem with color naming. When children are unable to see things and name their colors then use the color for a few weeks by putting it after the appropriate noun. Such as sky blue and grass green.
And in many conditions, this condition of not being able to name colors, called color anomia, resolves within a few weeks. Indeed, for my children, I taught them colors this way. And they were early in learning their colors. Because, of course, color words are abstract. And the concrete word coming first gives the label.
So for impaired perception of movement think about whether and which moving things are seen and at what speed. And play with balloons and beach balls. Giving progressive training in processing faster movement. And slow ones facial expressions for inability to see fast movement. And consider slowing one's speech. This is an important issue which is outside my particular expertise. But we have found that by slowing one's voice, like this, for children who have not adopted language and have cerebral palsy, for example, some of them will give sudden attention to the slow voice.
Because this dyskinetopsia, in our experience, also is analogous within sound and prolongation of language. Including the consonants, as you could hear, can render those sounds audible and hearable. And it was the work of Merzenich and Tallal, m-e-r-z-e-n-i-c-h and Tallal t-a double l a-l, that has shown us that sound prolongation makes a difference for this group of children. Who even I've been able to help from my clinical experience.
So what about if there's impaired recognition despite good acuties. The sound of the footfall, the voice recognition, the shoes worn, an obvious skin blemishes can aid identification. While a colored hat or scarf can be seen from all directions. And a flag can help identify the family car.
For impaired orientation, colored door and floor markers can prove useful. As can coloring the doors themselves. And composing songs that describe routes.
For visual overload, one dimensional search is helped by vertical and horizontal array. While impaired reading can be helped by good horizontal and vertical spacing. Or using a typoscope. A slot in a black plastic. One can search for typoscopes on the internet, and purchase them. And, or, a bar magnifier. In which the magnification takes place both in the vertical and horizontal dimensions.
Not insisting on eye contact during a conversation. But, instead, teaching to look between sentences helps a child to attend and listen this. UK classroom is overwhelming. While this Japanese classroom is relaxing. And removing clutter in classrooms not only helps children with visual disability, it helps teachers, and it helps all children. The Japanese are right. They understand Feng Shui.
So this uncluttered bedroom, the act of de-cluttering at home in school, can greatly enhance performance. While this country scene is relaxing as a place to go out to for getting a sense of calm. For mathematics, presenting and writing single calculations on visible graph paper, or squared paper, helps prevent numbers in columns and rows from becoming jumbled. While creating ones own geometric figures using string tied between chair legs has helped with geometry.
I've done that with a number of young people who once they've actually created their three dimensional imagery can then imagine it.
Arriving early at a children's party, when it is quiet, allows the clutter to build up. And it's OK to leave early, too. Listening through to music through headphones can provide distraction. While wrap around sunglasses may diminish complexity and can be relaxing, especially on long car journeys.
Impaired visual guidance of movement, or optic ataxia, can be helped for the child who cannot reach out because of lack of visual guidance of movement, is helped by tactile bridging along a parent's static or moving arm and hand. This helps avert the development of tactile defensiveness by preventing accidents, injury, and pain. And promotes learning and independence, probably through neuroplastic development.
Teaching older children with impaired visual guidance of movement, or optical ataxia, can include using an extended little finger to identify the position of a surface when putting down a glass. Or touching the table, the chessboard, or pegboard with part of the body to locate it, or even holding the thumb is against the piano is done for the same reason. But touching the piano the legs prevents the need to do this.
A brick trolley designed not to run away nor fall over backwards provides a tactile guide to the height of the ground, and by banging into them, the location of obstacles. It has a shape that helps viewing the ground ahead, as well.
One needs radio, not TV communication, all the time for scenes and emotions. Close your eyes and listen to the television. It makes no sense. But close your eyes and listen to the radio. The scripting is different. We all must always be radio communicators for every element of vision that is non informative. So if it's emotions, explaining how you feel. If it's distant objects, explaining what is ahead. But not in a way of look at that. Because, of course, that is not there.
One needs to be inside the mind of the observer to understand and know what is seen and what is not. To be able to ensure that everything used to motivate and enhance skills and knowledge is perceptible and accessible. To know what is exciting interesting and fun. To bring about motivation. To facilitate plastic brain development. And to always work within all visual perceptual and intellectual limitations to ensure that no effort on the part of either teacher, parent, or child is redundant. But, in particular, that nothing is lost in translation.
And to make things accessible to drive attention, motivation, and learning. To gain happiness, independence, and fulfillment.
So in conclusion, the brain sees from inside to out. The limits of seeing need to be identified, known, and understood. To stay within them, to use alternatives, and to extend the limits. Some interesting information you might find is that the site simulation picture that you saw is available on your Android phone on this website.
And if you would like a free textbook, that we wrote a number of years ago, about all impairing conditions of vision for children is available on this next website; At the Scottish Sensory Centre education center.
Thank you. I hope you found this lecture to be helpful.