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Recognition & CVI

Here is a reminder of the Successful Recognition Process with the Westie dogs from a previous section:

Experience - I stroke a cute and friendly dog in the park.  The owner tells me the dog is a Westie.

Memory - I remembered the breed name, the softness, the friendliness of both the dog and owner

Recognition - Another day in a different park I saw a different dog. It was a close enough match for me to correctly recognise the dog as another Westie.Recognition - Another day in a different park I saw a different dog. It was a close enough match for me to correctly recognise the dog as another Westie.

If a person had simultanagnosia, as discussed in a previous section the recognition process would look a little different, maybe like this:

Recognition Process with Simultanagnosia

Experience - I am in the park and am drawn to the red collar.  I feel around it and it is soft and fluffy.  The owner tells me the dog is a Westie.

Memory - I remembered the breed name, the softness, the red collar and the friendliness of both the dog and owner.

Recognition - Another day in a different park I saw this different dog.  There is nota visual match so I don't recognise it as a Westie.  Note, without the red collar to hold my visual attention, I can see the whole dog much more clearly.Recognition - Another day in a different park I saw this different dog. There is nota visual match so I don't recognise it as a Westie. Note, without the red collar to hold my visual attention, I can see the whole dog much more clearly.

Experience - I am in the park and I come across what I assume is a little dog.  I stroke the dog and it is soft and fluffy.  The owner tells me the dog is a Westie.

Memory - I remembered the breed name, thesoftness and friendliness of both the dog and owner.

Recognition - Another day in a different park I saw this different dog.  I would probably suggest it was a Westie, but would not be surprised if I got it wrong.Recognition - Another day in a different park I saw this different dog. I would probably suggest it was a Westie, but would not be surprised if I got it wrong.

With both simultanagnosia and reduced visual acuity, further information about the dog is used to aid recognition, including:

  • the texture of the dogs coat, soft and fluffy
  • the location - both in parks
  • the emotion - the friendliness of the dog and owner created a positive feeling

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.

Example of recognition challenges with simultanagnosia.Example of recognition challenges with simultanagnosia.

Example of recognition challenges with reduced visual acuity.Example of recognition challenges with reduced visual acuity.

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 Faces

Recognising Facial Expressions

Recognising & Remembering Routes

Locating things

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.

SandraSandra

Sandra with reduced visual acuitySandra with reduced visual acuity

Sandra with reduced colour contrast sensitivity.Sandra with reduced colour contrast sensitivity.

Sandra with right visual field lossSandra with right visual field loss

Sandra with left visual field loss.Sandra with left visual field loss.

Sandra with simultanagnosia.Sandra with simultanagnosia.

Sandra with a lower visual field impairment.Sandra with a lower visual field impairment.

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.

Face Blindness / Prosopagnosia

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.

Sandra on a bus.Sandra on a bus.

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.

How easy is it to recognise Sandra as the same person with:

SandraSandra

Sandra with slightly visual acuitySandra with slightly visual acuity

Sandra with further reduced visual acuitySandra with further reduced visual acuity

Sandra with lower contrast sensitivitySandra with lower contrast sensitivity

Right Visual Field LossRight Visual Field Loss

Left visual field lossLeft visual field loss

SimultanagnosiaSimultanagnosia

Lower Visual Field ImpairmentLower Visual Field Impairment

Face Blindness (Prosopagnosia)Face Blindness (Prosopagnosia)

This exercise demonstrates that a person with CVI may not appear to recognise a face for many different reasons, including:

  • their acuity is too low
  • they have a visual field 'loss'
  • they can't find the face due to simultanagnosia
  • They have face blindness

but the outcome is the same:

the person they would like to greet has not been greeted.

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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