What is Topographic Agnosia?
The term 'topography' is commonly understood in terms of showing hills and mountains on maps.
The topography in topographic agnosia is slightly different, but connected.
Topographic agnosia is an inability or difficulty remembering or recollecting routes, even though they may be well known, and seen clearly.
The confusion is because the terms topography and routes immediately bring up images of maps, so we need to explain some important differences.
Maps come in all shapes and sizes...
You may use a map on your phone to find somewhere local, or a world map to learn about the location of different countries.
In Lesson 1e we explained that the right and left temporal lobes store different types of memories.
Maps, as described above, are diagrams and lines and words, and are left temporal lobe memory processes.
Whilst a map may show you a way to get from one place to another, your experience and memory of the same route is a very different process. That memory of the route is a right temporal lobe process, and it is that process that is impaired with topographic agnosia.
To explain, come on a little journey with us, on Scotland's West Highland Way. Below is a part of the map we have been using, showing the end of the walk, finishing at the town of Fort William.
The map is very detailed, and our ability to follow and understand that map has helped guide us.
Our path and the path marked with a line on the map, whilst accurately matching each other, are not the same. One is a line on a piece of paper, the other a real path.
This is our real path (images above), it has taken us across countryside, through dark woods, over rivers and up steep hills.
The visual memory of the route we have followed can be thought as a bit like video filming the journey, and it is of course tied in with many other sensory experiences and how we are feeling from that journey. That is why it is such a complex memory, and processed for most in the right temporal lobe.
Your memory of that journey is a form of route memory. Having only walked the West Highland Way once, the route memory will probably not be good enough to remember it accurately to be able to walk it again without a map, but if you walked it often, the memory would be reinforced and get stronger, and become a better guide, as is the case with all memories.
Think of routes you know and how you first learnt them. Maybe walking to your local school, or driving to a town centre. Can you remember the first time you did it, when everything was unfamiliar, it probably felt longer.
Think of a local shop and how you get there from home. Go through that journey from home to the shop in your mind. What you are recollecting is the route, that is your route memory. Do you see now, why we say it is a bit like a video film in your mind? Do you see also why your memory of that route is completely different to the lines that indicate the same route on a map?
With topographic agnosia, it is that ability to recollect or remember those routes that is impaired, and it is a right temporal process.
Other issues can affect the route recognition process, particularly where it is not seen clearly enough. We explained this in lesson 8d Impaired Route Recognition.
Topographic agnosia applies when the cause is not because the memory is impaired due to not being seen clearly enough. When the route is not learnt because it is not seen clearly enough, unquestionably this causes an impairment of the route recognition process which in some can be severe, but in terms of the technical definitions, this would not be considered as topographic agnosia.
Topographic agnosia is a right temporal lobe processing issue.
Another right temporal lobe processing condition is prosopagnosia, as explained in lesson 10a. Our memories of faces and routes are both stored in the same part of the brain. This is why it is easier to recognise someone when they are somewhere you expect to see them, and often less easy when they are somewhere unexpected, or 'out of place'. Because faces and places are matched together in the same part of the brain as part of the memory and recognition process.
As with the other forms of agnosia we have explained in this level (prosopagnosia lesson 10a and shape & object agnosia lesson 10b), topographic agnosia can be mild or severe, and from birth or acquired.
In lesson 10b we explained Integrative Agnosia, where both temporal lobes are affected, due to, for example hydrocephalus (also explained in lesson 10b). Topographic agnosia is likely to be a part of these combined recognition difficulties. See 'Visual Behaviours' below for examples of difficulties.
Routes can be short or long, and simple or complex, and everything in between. Going to your kitchen to fetch a cup from the cupboard requires a degree of route memory.
Think of where you are and where the cups are. If you don't have that route to link the two, how do you get to the cups? You can have a perfect picture of the cups in your mind. You may well be able to make an excellent cup of tea or coffee - but you need to get to the cups, and to do that, you need a route memory. The route memory should be an accurate match of the actual route to the cupboard with the cups.
Imagine across your day how many things would be difficult or even impossible if you had topographic agnosia.
Everything that has a 'place', including cups kept in a cupboard and socks kept in a drawer, needs a route to get to it.
At its most severe level, where the ability to recognise routes is completely absent, the person is likely to be often disorientated and struggle with simple tasks, because so much of what we do involves getting something from somewhere, which requires a route.
The person may resort to a lot of guess work, and sometimes get things right, and sometimes not.
Routes may take longer to learn and need to be repeated more often, which can look like a person is a slow learner.
People may not be recognised when somewhere unexpected.
In school, children may struggle to find their classrooms and other rooms like the canteen, toilets, gym etc. It can make a child stressed as they become disorientated. Do you have any memories of really feeling very lost? Maybe as a child? The signals your brain sends are alarm bells, because when disorientated you are not sure where you are, and possibly not safe . So those alarm bells of extreme alert are to make you stop doing whatever you are doing and deal with what you brain has decided is the immediate most important matter - it has overridden everything else and is forcing you to deal with being 'lost'. Recovering from this feeling can take time, meaning that lessons can be affected.
In children this difficulty is likely to be a part of the combined difficulties created by integrative agnosia (see below and explained in lesson 10b).
Topographic Agnosia & Integrative Agnosia
Think about our example of getting a cup from the cupboard to make a drink...
You need both a route to get to the cupboard, and the ability to recognise the shape of the cup, to recognise the object of the cup, to recognise and locate the cup. This requires both left and right recognition processes, working together.
We take very simple tasks like this for granted, but they require multiple synchronised brain processes.
Even if just mildly impaired, what might everyday tasks look like with integrative agnosia?
It can definitely mean tasks are difficult to learn and to do, which can look like a learning difficulty, and certainly create learning difficulties if not identified, understood and appropriately supported.
Use A Map
Using a map when out and about can help, if the difficulty is limited to the right temporal lobe. By using a map or satellite navigation system, you are using the other temporal lobe. If the topographic agnosia is part of an integrative agnosia, this approach may not work so well.
For some where the issues are less severe, routes may just need a little more repetition before they are learnt. Where a route is important to remember, like getting to school, work or the shops independently, you could try:
Some families have found that painting doors different colours has enabled their child to link the colour to the room, and so find their way around the house much more easily.
Use A Rhyme
This might sound odd but we have heard great stories of the success of this approach.
It does not have to be an elaborate rhyme or ever a very good rhyme, and you don't have to say it out lout. It just needs to be easy to remember, so for example to go to the shops...
Outside home is a red post box
Walk towards the door with a fox
Look for the window with curtains blue
The shop's next door, buy something new
The little rhyme is providing a guide using a different part of your brain. It doesn't have to be good - just easy to remember.
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