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Lessons

7d - Apraxia of Gaze

Posted by Helen St Clair Tracy in Level 7 - CVIs Movement and Dorsal
Published: 28/01/2020, 12:00am | Updated: 24/02/2020, 7:37am

Video Link: https://vimeo.com/392274172

Apraxia of Gaze is a condition that is diagnosed if a person is unable to consistently look at particular targets when asked.

For example, in the image below, look at the red peppers:

To look at the red peppers, a number of things have to have happened, starting with reading the words 'red peppers', matching them with the image of what red peppers look like in your mind, looking at the picture, and when your mind finds a match for red peppers it sends a message to the eye movement centre in the pons at the back of your brain (marked on the image below) which sends the signal to move your eyes to look at the red peppers.

The pons, an area at the back of the brain just above the spinal cord, responsible for sending the eye-movement signals needed to look at things.The pons, an area at the back of the brain just above the spinal cord, responsible for sending the eye-movement signals needed to look at things.

The tests are simple, they are not designed to test general knowledge, just the person's ability to move their eyes to look at a particular target. Note, any ocular disorders affecting eye movements would need to have been ruled out as a cause before apraxia of gaze could be diagnosed.

Whilst not a general knowledge test, language is required to undertake the test. The instruction to 'look at..." requires an understanding of what is being asked, so by definition, those with extremely limited or no language, cannot be diagnosed with apraxia of gaze, because they are unable to undertake the diagnostic test, even though, many may struggle with the same condition.

What a diagnosis of apraxia of gaze does not include is why?

Why, when asked to look at the red peppers, is it that some people can't move their eyes to look at the red peppers, even if they know full-well what red peppers look like, and their eyes movements are otherwise normal?

Could it be, maybe, that they can't move their eyes because they can't see the target?

 look at the red peppers - what red peppers? look at the red peppers - what red peppers?

In this image (below) look at the keys...

Did you find them? They aren't actually there, we were playing a bit of a trick, but think about your searching for them, where your eyes would have been looking all over the image searching for them, just like the visual search patterns described in the previous lesson (lesson 7c).

This seems to be what people with apraxia of gaze do, as their inability to move their eyes to look at a target (despite otherwsie normal eye movements), like the red peppers, seems to be directly linked to their inability to find it, which is directly linked to their visual search challenges which can be caused by simultanagnostic vision (lesson 7c).

Checklist: Before moving on, please check you understand:

  • What Apraxia of Gaze means
  • That ocular disorders affecting eye movements need to be considered and ruled out for a diagnosis of apraxia of gaze
  • The testing conditions are only suitable for those who understand language
  • Why this means non-verbal people technically can't have apraxia of gaze, whilst being affected by the same problem
  • Suggested reasons for apraxia of gaze.

Next lesson Level 8a CVIs Ventral - CVIs and Recognition Introduction

Level 7 Full Checklist

You should understand...

  • What the word dyskinetopsia means
  • How the vision of those affected by dyskinetopsia is different to the vision of those not affected.
  • That dyskinetopsia varies from person to person, from mild to severe.
  • Ways to measure the severity of dyskinetopsia.
  • The need to slow things down.
  • That sounds may also need to be slowed down.
  • That things need to be slow enough to see and hear clearly, to learn effectively.
  • What Akinetopsia is, and how it is different from dyskinetopsia.
  • What the mapping process is
  • Where in the brain the mapping process takes part
  • How the map is different from the picture
  • That there is an order, and the picture feeds to the map (not the other way around)
  • One part of the mapping process involves giving depth to the visual information in the picture
  • What optic ataxia means
  • Why optic ataxia is different if from birth or acquired.
  • The role of visual memories
  • How optic ataxia is different from DCD
  • Why optic ataxia can cause confusion, anxiety or even frights.
  • The difference between looking and seeing
  • Why we use the term simultanagnostic vision rather than simultanagnosia
  • How simultanagnostic vision affects searching visually for things
  • That simultanagnostic vision can range between being very limited to only somewhat limited
  • What that change in 'range' entails for the affected person
  • Factors that affect the range of simultanagnostic vision
  • Different non-visual difficulties simultanagnostic vision can look like
  • Different approaches to help
  • What Apraxia of Gaze means
  • That ocular disorders affecting eye movements need to be considered and ruled out for a diagnosis of apraxia of gaze
  • The testing conditions are only suitable for those who understand language
  • Why this means non-verbal people technically can't have apraxia of gaze, whilst being affected by the same problem
  • Suggested reasons for apraxia of gaze.

Congratulations on completing Level 7!Congratulations on completing Level 7!

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