Lessons

10b - Shape & Object Agnosia

Posted by Helen St Clair Tracy in Level 10 - Temporal Lobe
Published: 25/09/2021, 12:00am | Updated: 19/10/2021, 11:14am

Video Link: https://vimeo.com/589921090

What is a shape?

Most of us first learn about shapes in school, starting with the basic shapes like squares, circles, triangles and rectangles. These shapes are two dimensional, they have no depth.

A cube is a square with added depth.

We can only show you things on a screen (or paper if you have printed this lesson off), so even illustrating depth like the picture of the cubes (above) can only be representations of three dimensional shapes, so let's do a little exercise...

Please get something that is cube shaped, it could be a food box, or a dice, or a stock cube - it doesn't have to be a perfect cube, and hold it and feel it and look at it.

Now, thinking about the cube you are holding, what is its 'cubeness'?

For most, through seeing and feeling it, your systems of recognition (explained in lesson 2h) have performed a correct identification process and resulted with you knowing, or believing you are holding a cube.

We have been very careful to avoid using a word in the above sentence, and that word is 'object'.

Let us imagine the cube we are all holding is a sugar cube.

There is a substance that has been shaped into a cube and been given a name - sugar cube.

So we have three elements:

  • The 'thing', in this case sugar
  • The shape, in this case a cube, and
  • The name, a sugar cube.

Those three elements together are the object.

So, the shape and name are properties of the object.

The reason we are making this point is to show that shapes and objects are completely connected, in the real world, but also in the brain where they are processed for you to see and understand them.

Some objects have simple shapes, like a sugar cube, or spherical balls (sphere is the three dimensional shape of a circle).

Other objects have much more complex shapes and in these cases the name of the shape is often also the name of the object...

Like 'car shape' or bicycle shape' or 'computer shape'.

Shape is a property of an object.

Objects and shapes, as explained in lesson 3i Visual Recognition are for most people mainly stored and processed in the left temporal lobe.

Left temporal lobe, coloured red.Left temporal lobe, coloured red.

Now take a moment to look around. Everything has form. So, everything you can see including people, has shape, but objects refer to inanimate objects. People, and with increasing evidence animals, particularly the faces of animals, maybe your pet cat or dog, are processed in the right temporal lobe, because they are much more complex memories, compared to objects which are inanimate.

This lesson is about objects and the shapes of objects, largely processed for most in the left temporal lobe.

How do you imagine the world would look different if your brain did not process shapes, typically meaning shapes are not seen or recognised?

Recognising shapes is a key part of how our brain helps us make sense of what we are looking at.

It is a process, and going back to the earlier lessons 3j Visual Pathways, a ventral stream process. The ventral stream is sometimes called the 'what' pathways, so you know what you are looking at.

Shape recognition is a key part of the recognition process.

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What might life be like if you couldn't recognise shapes?

Sight Unseen by M Goodale & D MilnerSight Unseen by M Goodale & D Milner

The book 'Sight Unseen' by Melvyn Goodale and David Milner has a brilliant account of just that. The researchers met a woman they called Dee who had lost the ability to recognise shapes after a brain injury. She could see clearly, there was nothing wrong with her visual acuity or contrast sensitivity and she had full visual fields.

Dee could see the colours of things, and fine detail, but not the shapes. For example, when presented with a torchlight (flashlight), she could see the surface area in great detail, but could not identify the object as a torch, even though she knew what a torch was.

Dee could see the torch, but she could not recognise the torch.

Dee could describe in great detail the surface area of what she was looking at, including the colours and what it was made of, but not recognise it as a torch.Dee could describe in great detail the surface area of what she was looking at, including the colours and what it was made of, but not recognise it as a torch.

Look around you, and imagine you can see all the colours and fine details but not recognise the shapes of the objects in the room.

It is very tricky to describe, because what comes to mind is a big blur, but it was not like that. Dee could see the fine detail of surfaces, so when shown a torch she could correctly identify part of the material as plastic, (image of the actual torch Figure 1.1 on Page 4 of Sight Unseen) but not recognise what it was she was looking at as a torch.

Dee, following a brain injury, could not recognise shapes and so could not recognise objects, as explained, one is the property of the other. This is called Shape & Object Agnosia. Agnosia means to not know something, or be ignorant of it.

Shape & Object Agnosia relates to not being able to recognise shapes visually.

Because Dee couldn't recognise shapes, she couldn't recognise objects and therefore couldn't name what she was looking at. Dee had to adapt and find other ways of recognising things to get by.

Helpful adaptations included:

  • remembering what was where by keeping things in the same place
  • using colours to identify objects, with...
  • touch and the memory of what the object felt like.

So there are other ways to recognise shapes and objects where vision is not effective.

Dee had a severe form of acquired shape and object agnosia.

Shape and object agnosia it is not necessarily this severe and can be present from birth or acquired any time.

It can be difficult to identify, especially if from birth.

Dee was an adult when she had her brain injury and had stores in her brain from a lifetime of experiences of what things looked like, leading to her learning and understanding. An example might be that Dee when looking for the kettle in her kitchen, would look for the silver colour in the corner where the kettle was kept. Once she touched the silver colour, her pre-injury touch or haptic memories (lesson 2g) would confirm she was indeed touching the kettle and let her identify it. Dee also maybe had further memories of the different hot drinks she can make, and when looking in the cupboard for the coffee jar, would initially identify it visually by the dark brown colour she recognised as the jar, again confirmed, or not, once she touched it.

Now imagine a new born baby destined to develop shape and object agnosia. What might their difficulties present as? None of those memories exist, they need to be built, but how in a visual world that lacks shape can the identify and meaning of objects be learned?

How, in a visual world that lacks shape, can the identity and meaning of objects be learned?

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Hydrocephalus

The term hydrocephalus refers to an increase of fluid in the water chambers (or ventricles) in the brain.

If you have seen MRI images, you may recognise areas that are very dark in the centre of the brain (see image below). These dark areas are chambers where the cerebral spinal fluid is made and flows through and out into all the space around the brain and spinal cord so that they are surrounded and protected by water.

MRI image of the left side of a brain with the ventricle area marked with a red arrow.MRI image of the left side of a brain with the ventricle area marked with a red arrow.

When fluid increases in volume in the brain, it is here, in the ventricle chamber, that this happens.

With the increase of fluid, the chamber can expand.

If we look at the left side of the brain on the image above, the area coloured red is called a lateral ventricle, there are two, one on each side of the brain. The blue area marks two more ventricles, that feed the lateral ventricles, a bit like canals feeding a lake. The lateral ventricles cover a large area, starting with the temporal lobes, and curving in a 'c' shape to extend to the regions of the parietal lobes and frontal lobes.

If we look at the left side of the brain (image above), if the ventricles expand due to increased fluid, the brain they are expanding into includes the temporal lobes.

As the ventricles expand, it is not just to one side though.

Looking at the lateral ventricles (in red) in relation to the temporal lobes from the left, right and back view of the brain, we can see that the lower part is inside the temporal lobe on each side.

Any increase in the size of the ventricles can then impact on the temporal lobes, particularly the white matter (lesson 1a) of the temporal lobes, because the ventricles are located deep in the white matter, compared to the grey matter (cortex) which covers the outer area of the cerebrum.

The temporal lobe white matter contains the pathways that takes the information of what you are looking at to different parts of the brain for recognition and understanding.

For this reason, people affected by hydrocephalus may be at increased risk of having not just shape and object agnosia, but also agnosia affecting the right side of the brain where people and places are processed, creating a form of Integrative Agnosia for which the incoming information cannot be integrated into pictures with meaning.

Integrative Agnosia

Research has shown that over half of children affected hydrocephalus treated with a shunt (a small tube inserted into the lateral ventricles to drain the excess of cerebral spinal fluid) have CVI and part of their CVI profile is integrative agnosia. So difficulties recognising both faces, and shapes and objects, likely mean that the temporal lobes have been affected on both sides.

When severe and from birth or in young children, we think it is likely such children may go on to develop significant learning difficulties. Vision may be considered a cause as the child is unlikely to meaningfully reach for things even though their visual acuity has been measured as with a normal range. Dee could see tiny details on a surface like the hairs on the back of a hand, and tell apart fine shades of colours...she could see very clearly. A child may evidence good clarity of vision in a sight test, yet be unable to recognise shapes. This may mean their difficulties may instead be attributed to one of the many generic labels like profound learning difficulties.

Where a child has reduced visual acuity from birth, this can mean shapes and objects are not learnt because they have not been experienced in a way the child can understand what they are. This leads to what might be considered a form of developmental integrative agnosia. It is not caused by temporal lobe issues, but the child's knowledge of shapes and objects is impaired, in some profoundly, causing integrative agnosia. A child can have both reduced visual acuity and temporal lobe issues, combined contributing to their integrative agnosia.

In milder cases, both from birth (congenital) or acquired, the cause of shape and object agnosia is likely to be extremely difficult to establish.

Our team are not aware of any validated and standardised tests for shape and object agnosia in young children, to either confirm or eliminate it as a cause of difficulties. It is not known how common it is and it is likely that the difficulties caused, or partly caused by shape and object agnosia are attributed to many other labels.

Isolated shape and object agnosia is rare in children, and where present, from the small numbers of cases we are aware of, each person is uniquely affected. An integrative form of agnosia, is likely to be more common than thought, especially in children with considerable learning challenges.

Integrative agnosia, combining difficulties recognising faces, facial expressions, routes, places, objects and shapes.Integrative agnosia, combining difficulties recognising faces, facial expressions, routes, places, objects and shapes.

Visual Behaviours

Difficulties may appear to have a visual cause where objects are missed or not seen, but vision may have been inappropriately ruled out as a cause because only standard sight tests were used.

Language may well be affected, as the names of objects are difficult to learn unless they are taught while the child is experiencing them in a meaningful way (see lessons 2b, 2c & 2d).

Sometimes a person might make what looks like little errors with object recognition, for example mistaking a jug for a cup. This could be an indication of someone more mildly affected, or possibly more severely affected and showing the limits of their adaptive strategies to work out what things are, meaning small mistakes are made.

A person may regularly make small errors recognising things, for example mistaking a jug for a cup, or watch for a bracelet.A person may regularly make small errors recognising things, for example mistaking a jug for a cup, or watch for a bracelet.

Targeted Support

If the shape and object agnosia was acquired, as with Dee, then using a combination of routine (keeping things in the same place) with colour for visual identification, then touch and consistently naming of things as they are being picked up or played with, can help reinforce existing knowledge and learn how to recognise new objects.

Use Words / Names

The naming of objects can be particularly helpful. A name can evoke multiple memories. Think of a simple word... coat. What comes in to your mind? Right now, thinking of a coat or coats, it is likely to be coats you own and wear, maybe previously owned or on other people. That one little word naming an object has the power to activate a lifetime of memories in your brain, of what 'coat' means to you.

Using a name (word) can help a person with recognition difficulties 'see' through language.

If thought to be present from birth, we recommend developing a system of learning using 'language as a label'. We explain this in the short section under the paragraph title The Label in lesson 2h.

Why Words?

If there is a difficulty caused in one part of the brain, then one approach is to try shifting the activity to another part of the brain that may be working more effectively, the language centres. Even if the person has very little language or is non-verbal (example below), it does not mean language can't be learnt, understood and used to identify objects. When objects can't be recognised, so not learnt for different reasons, they can be learnt by a name when they are experienced. That experience may involve how they feel through touch, and their purpose, and what they feel, smell and taste like. So a coat is worn on the outside of clothes and makes you feel warm. The word 'coat' can be taught, and used to learn to recognise the object, using the combined approaches of consistent repetition, recognising the colour, the feel of the object and knowing what it is by the label (name).

One child we know has learnt the name of many objects she is unable to recognise visually. By learning the names, she was able to attribute meaning to the object, for example her mother may say 'shower' and she will know it is shower time and go to the bathroom. She does not speak, but by learning the names of objects around her, she has been able to add meaning to something in her world that used to make no sense, through the word. Now her learning across all areas has progressed considerably, as has her behaviour.

Think of the brain like a city of roads and lights. The part of the brain largely responsible for processing shapes and objects is likely to be mainly the left temporal lobe. Let us imagine there are some road closures and power supply issues to this area, so by using language we are taking a different route.

In a profoundly learning disabled child where shape and object agnosia have not been identified as the cause but could be, using simple language to label the child's experiences as they happen can be extremely effective. In our team we have found that the use of language to aid the recognition process in profoundly learning disabled children to be enormously helpful.

Checklist:

Before moving on please check you have understood:

  • What a shape is
  • That shape is a property of the object
  • By objects we mean inanimate objects and why in relation to regions of the brain
  • The importance of recognising shapes
  • Shape and object agnosia can be from birth or acquired
  • Shape and object agnosia can be mild or severe
  • What hydrocephalus is
  • Why hydrocephalus can lead to shape and object agnosia
  • What integrated agnosia is
  • Why shape and object agnosia is easily missed
  • Why shape and object agnosia can cause profound learning difficulties
  • Ways to adapt when affected by shape and object agnosia
  • Why language can be a useful adaptive strategy

Next lesson Level 10c Temporal Lobe Topographic Agnosia

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