Here is a reminder of the Successful Recognition Process with the Westie dogs from a previous section:
If a person had simultanagnosia, as discussed in a previous section the recognition process would look a little different, maybe like this:
With both simultanagnosia and reduced visual acuity, further information about the dog is used to aid recognition, including:
On another day, with the reduced visual information, you may successfully recognise the same dog in the same park with the red collar. You may just as easily mistake another small white dog of a different breed for the Westie, or even a white car with a red collar!
This is a very simple example, but shows how recognition can seem to be affected similarly by both simultanagnosia and reduced visual acuity, however there are important differences, particularly the strategies to support.
With simultanagnosia there may be strategies to aid recognition by, for example building up the whole picture, that can be learnt. With reduced visual acuity, especially in an older child or adult, the best strategy may be learn alternative methods of recognition.
Rather than thinking about the apparent similarities the different visual impairments create in making recognition more challenging, think about the differences in the actual visual experience. Look at the two images above, and how completely different the experience of seeing the dog is.
All cerebral visual impairments create challenges when it comes to recognition. These are often identified in relation to challenges:
Recognising Facial Expressions
Recognising & Remembering Routes
There are other examples, but these four (from the right filing cabinet) are the key areas of recognition that can have a profound impact on the person's day to day life and access to social interactions.
This is Sandra, let us pretend you are friends.
Let us look at how different the experience of seeing Sandra is for people with different CVIs.
These are just a few of examples of many varying degrees and combinations of visual impairments. Note, consider how the same visual impairments might affect a child learning to read. We will be looking at reading and writing in the following sections.
There is another visual impairment affecting facial recognition, called prosopagnosia, or face blindness.
This is a condition where people are not able to recognise faces, and it is not caused by other visual impairments.
Someone with prosopagnosia may be able to explain in great detail every detail of the face they are looking at, down to the colour or eyes and shade of lips, however they are unable to recognise the person. If you look up Prosopagnosia many images demonstrate how people have articulated their experiences.
This image of Sandra has been edited to show how someone with prosopagnosia may explain how they see her.
All these examples assume that Sandra never changes, and we all have the luxury of endless time to consider Sandra's face and recognise her.
Here Sandra is again, she's sitting on the bus and you are walking past her and notice her smiling at you
You have to recognise both her face and expression.
You have around two seconds before it will become awkward and she feels either shunned or ignored.
This exercise demonstrates that a person with CVI may not appear to recognise a face for many different reasons, including:
This explanation of how recognition works is simplified. It is based on what commonly happens when one or other temporal lobe is injured. With these examples the temporal lobes (left and right filing cabinets) may be working well, however they are only as good as the information they receive. If the visual information is affected by a cerebral visual impairment, it is going to affect recognition as has been demonstrated through these examples.
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