The is a short (1.22 minutes) virtual reality film from the Laboratory for Visual Neuroplasticity explaining a test to understand the challenges a child may face when trying to find a toy amongst other objects, called Object Crowding Test.
The child can pick one of three toys, the test puts the toy in the toy box, and the child then has to find it, with different levels of difficulty due to the number of surrounding toys.
Similar to the Crowding VR Film we introduced, this little test can tell us an awful lot about the child's visual challenges (please see Crowding VR Film for more details).
Consider the challenges the child has in finding the toy in this test, and let's split them into two groups:
The child must search for the toy amongst the other toys. If the child has reduced visual attention (due to simultanagnostic vision) this is going to prove difficult. Imagine looking through a colander, but you can only see through one hole at a time, and it is extremely difficult to control which holes you look through in which order. Now try to find the blue truck, imagining you have to look through the colander holes, one at a time, seemingly randomly, hoping to hit the target, and if you do, it is more down to luck than anything else.
The process involves the image, which is created in the occipital lobes, and visual search, which requires visual attention, and this is found in the posterior parietal lobes thus the visual search demands are on the dorsal stream (running from the occipital lobes to the posterior parietal lobes, then onward to the frontal lobes where the choice is made).
The other element to this test involves recognising the car. This recognition process involves being able to 'match' the car once it is seen, with a remembered car, to correctly identify it. This may seem very straightforward for many, but CVI can create considerable challenges to the recognition process (see Recognition sections for more information).
The place we keep all our memories stored, is the great library in our temporal lobes. And our libraries are organised into sections to help with the recognition process. We have a section where we keep all our faces for example, and when looking to recognise someone, a specific area of our brain marking the exact location of the faces section will be activated. Similarly we have section for places and routes and expressions. Our great libraries of knowledge, build up over our lifetimes' experiences, are ordered into sections to help us recognise things.
With CVI however, the information needed to create these clear subsections can be less clear, so the library may be a bit disorganised, or there may be 'shelves of books' missing. Thus searching for the little blue car is not as simple as a match in our blue section and car section - these sections may not exist. To grow and develop, the sections need to be fed repeated consistent information from our experiences, but with CVI the way we perceive what we experience is not always consistent. Things that have been experienced and remembered that are blue, and cars, may be part of a huge disorganised library, with no directions to help find the thing the affected child is looking for.
The pathway from the occipital lobes, once the item has been spotted, to the temporal lobes, where the memories are stored for recognition, is called the ventral stream.
Thus for the child with CVI the combined task of search and recognition can be challenging for both the dorsal and ventral streams, and what happens is they start to compete with each other. The more challenges on the dorsal stream, the less there is for the ventral stream. Please look at the 3D rotating brains we linked to (from the same laboratory) showing the dorsal and ventral streams in a person with and a person without CVI.
If you have CVI or are supporting someone with CVI, and something (anything) is difficult, take a moment to consider the demands being made on the dorsal and ventral streams, and whether you can do anything to reduce them. This is not always obvious, and certainly goes beyond completing specific tasks as with this test. Just existing and being awake we use both our dorsal and ventral streams as key closely linked visual systems.
To reduce the pressure on the dorsal stream, consider:
To reduce pressure on the ventral stream:
Do you notice that the way to support the ventral stream is to reduce the demands on the dorsal stream? When we developed our reading tool Look, the purpose was to remove as much dorsal stream activity from the process of learning to read as possible. Thus learning to read using whole word recognition with the reading tool Look is an almost entirely a ventral stream activity (assuming the person is in uncluttered quiet surroundings).
For further information please visit the Laboratory's website:
Early results of this test have been posted on the Laboratory's Facebook Page.
The Laboratory for Visual Neuroplasticity is seeking participants for their research (USA, Northeast region), click here for more information, copy of leaflet below.
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