Thursday, 9 February 2012

Cerebral Visual Impairment CVI - A barrier to learning? Part Two

a. Human beings are bombarded constantly by sensory data. The CVI child has a greater difficulty in filtering visual input and cutting out what is not needed.

b. Present things visually in a sequence to the child, one by one, not at all at once.  Choice-making requires the skill of seeing and giving attention to several things at once. 

c. When a person cannot do this they have simultanagnosia, meaning the inability to see two things simultaneously. This may be related to what is sometimes called ‘neglect’.

d. Children up to four and a half cannot parallel process. Their brains can only cope with one piece of  visual input at one time. CVI children usually are developmentally delayed and their brains may  be operating at the level of a very young child.

The world we live in is a place of infinite variety. Daily we are battered by a constant barrage of sensory information; though we become so used to it we barely notice it. The same world however for a child with brain damage and visual impairment is a confusing place, filled with so much contradictory and conflicting data. So many things to distract the senses – sounds, pictures, smells, tastes ... For our CVI child this makes the world a very distracting place. It is difficult for them to concentrate when there is always something else to look at.

If we could only cut out what we don’t want our child to notice and only let them see what we do then we will make it easier for them to pay attention.

So that is precisely our challenge: what we have to do is present one thing, one toy to our child at a time. In other words everything has to be sequential, showing the child one thing after another rather than two or more things at once. Show a picture but only one picture at a time to your child. And the one picture must have only one element in it and a plain background. Don’t show two toys at once or it will only confuse him. Children with CVI have problems making choices. Have you noticed that? And yet we professionals so often put it in the child’s individual education plan: ‘develop choice-making skills’. But they can’t. How can you make a choice if you can only see one thing in front of you (the problem for so many CVI children)? Do not expect your child to make choices if he is not ready. And he is most probably not ready to make choices just yet. It is enough to show your child one toy, point to it and say, do you want this, instead of showing two and saying, which one do you want?

The word ‘simultanagnosia’ I first heard used by Professor Gordon Dutton. It means the inability to pay visual attention to (look at) more than one thing at any one time. Or to put it another way the opposite of attention is neglect, which means that when shown two objects a person will see the one and ‘neglect’ (not notice) the other. So while they can ‘see’ two objects they only really notice one object or worse they are confused by the whole scene.

How does this apply to computer games? I was discussing this with a teacher recently who was trying out switch programmes with a boy with complex needs and visual impairment. She had tried various programmes but only one really worked. One that didn’t work involved switching to add animals to a farm scene. Initially the boy pressed the switch but as soon as two animals appeared on the screen the boy lost interest. The switch operated computer game that was successful however, involved making a light flash on and off in a variety of ways: he really enjoyed this and it kept him focused. The first task presented more than one thing on the screen at once; the second had just one thing. The boy cannot cope with more than one thing at a time being presented to him.

This condition does not automatically depend on the ‘cognitive’ age level of the child. There are some children who are so developmentally delayed that they are operating no higher than the cognitive level of a baby of two to three months old. A child of that age has a very limited amount of 'Ram' in their 'computer' (brain). That is perhaps the best way to see the child's brain. It just can't handle much information. There are on the other hand other children with the same condition who, while still being cognitively delayed, are functioning at a much higher level. Even with these youngsters the ability of the brain to give attention may still be just as limited and we need to be thinking of just these areas as operating at a lower developmental level. As rule children under four years of age are all single processors and cannot cope with dual processing but the situation is just greatly amplified by CVI. As a point of fact there are adults who have suffered stroke who have precisely the same difficulty so it is not only linked with cognitive age.

This difficulty is acknowledged to a degree though actually little understood. The English National Curriculum has now included target setting for children at much lower levels of ability and there is some reference to these issues there. The document on ‘P levels’ was introduced to help teachers set appropriate targets for such children. Insights into this ‘one-at-a-time’ principle at a young developmental age can be gleaned by looking at some of the lower P levels descriptors.

In this extract it points to the difficulty children with complex needs have with sustaining attention: P1(ii) ‘Pupils show emerging awareness ... They may have periods when they appear alert and ready to focus their attention on certain people, events, objects or parts of objects, for example, grasping objects briefly when they are placed in their hand.’

Comparisons have also been with autism (ASD). Though I do not want to draw too many parallels with ASD, some of the approaches used with children on the autistic spectrum are similar to approaches I recommend with CVI children. Many children with ASD have difficulties handling multiple or complex visual information in the same way that children with CVI have. The picture exchange communication system (PECS) for children with autistic spectrum tendencies (ASD) works on a step-by-step (one-at-a-time) visual presentation.

We can also look at the media industry and find examples of this approach in programmes made for children’s television. One of the favourite children’s programmes is the Teletubbies and we can see there a clear one-at-a-time approach used. Events happen one after another not at the same time. The narrator speaks then a Teletubby speaks or moves. Then the narrator speaks again and so on. The characters fill the screen with their big bulgy shapes. The backgrounds are highly simplified. Actions and objects are portrayed so they do not merge into one continuous single action stream. This is great for kids who can’t process information simultaneously.

The above article is a chapter from my handbook for teachers, 'What can I do for my CVI Child?' - Maurice

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