What is CVI?


Looming & Other Causes of Frights and Disorientation

Looming: Dictionary DefinitionLooming: Dictionary Definition

Whilst sharing stories about our children, several parents have described their child reacting to something in their surroundings in an extreme way, as though they think a moving object that is some distance away is about to hit them.

In discussing these descriptions further, we have used the term looming.

We know the specific definition of looming in relation to CVI is not in the literature, but we wanted to include it because these are difficulties and experiences clearly shared by many with CVI.

Looming may be a possible sensory result of optic ataxia.

One mother explained how her son Greg liked to walk in front of the shopping trolley in the supermarket, but would suddenly stop and brace himself, covering his head and face with his arms, thinking he was about to be hit by someone, even though no one was near enough to be such a threat. It was reasonable and real enough though for Greg's 'fight or flight' reflex to be triggered, and he clearly felt he needed to protect himself.

Greg is known to not be able to use his vision alone to guide his movements well (optic ataxia). Things like reaching for a cup and judging distances are difficult.

  • But what do things coming toward the person with optic ataxia look like?
  • Could it be difficult to know how close or far away they are?
  • Would this sometimes be frightening?
  • Is this what the parents were describing?

One dad explained that when his two older unaffected children were learning to cycle at 5 and 6 years of age, they would often call "get out the way", when there was plenty of space, during the first few weeks. Could this be something similar, something we all learnt through our experiences growing up, however some are unable to develop the skills to judge distances?

If you don't have optic ataxia it is difficult to imagine what it is like. To try to help explain what it may be like, firstly take a look at this picture of pavement art (below).

It is quite difficult to see the flat image, here it is (below).

It is not possible to know exactly how someone else sees, but from some of the accounts parents have shared with us, the short exercise (below) might prove helpful in understanding what the experiences of optic ataxia and the looming effect might be like:

1. Looming & Depth Perception in the Moving World

  • think about this picture (above)
  • rather than seeing the depth in the columns and buildings, imagine it is a giant piece of pavement art, that you could walk over the top of
  • now start again, still thinking you are walking on pavement art
  • go towards the columns on the left
  • as you get closer imagine them starting to rise up towards you
  • closer still, and the columns that were flat are suddenly looming over you
  • as you get closer your surroundings develop more depth
  • if you move closer quickly it may feel like they are being launched at you

2. Looming & Calculating Distances

Connor has optic ataxia, these are some of the things he does:

  • When reaching for his milk cup, he walks across the room with his arm outstretched ready to make contact, from a distance sometimes of several meters away - he created this strategy to get his milk cup, he is unable to calculate the distance between himself and the cup, but knows that at some point as he walks towards it, the cup and his hand will make contact.
  • When in unfamiliar places Connor reaches for things that are far away, recently when horse riding he went past a column that was at least 3 meters away, and reached to touch it.

These behaviours show that Connor has marked optic ataxia. If Connor was looking at the picture (above) how might he see it?

  • how does Connor know that the clock tower on the horizon is big and far away, as opposed to small and within arms reach?
  • he doesn't, Connor's visual memories retain little information
  • standing next to the columns, Connor would probably see the clock tower as a mark on the horizon, yet may well reach out to try to touch it.

Imagine being on a day trip and looking at the above scene.

How do you know that it is life-size and not a miniature village?

You will know from:

  • your ability to judge the distance
  • your memories of how big things are
  • an understanding of where you are and why you are there

Connor, and others like him, with CVI at the marked end of the spectrum, have fewer visual clues like these.

Looking at the image below, do you think it is real or miniature?

How do we know this is a miniature village?

  • the people are disproportionately big
  • based on our knowledge of how big an average person is, we are able to estimate the scale of the miniature village
  • based on an understanding of the new smaller scale, we can very quickly re-calculate how big and how far away things are
  • we take for granted that we can do all these things because they are non-conscious skills
  • some with CVI are unable to make such judgements and calculations

For some with CVI, especially in unfamiliar places, it can be the equivalent of not being able to tell whether they are in a miniature village where everything is small and near, or looking across a city, where everything is big and far away.For some with CVI, especially in unfamiliar places, it can be the equivalent of not being able to tell whether they are in a miniature village where everything is small and near, or looking across a city, where everything is big and far away.

Connor's optic ataxia is severe and unless he is in a familiar place, Connor cannot calculate distances. The flip-side of this is that Connor may think something is far away, when it is very close, and he only realises when he collides with it, or is about to. Another element is when he thinks something is a lot closer than it actually is, and moves or ducks to avoid something that isn't there. This is what Greg does.

Greg has known problems using his vision to move accurately. If he was in the supermarket below, and he reached for one of the tins on the shelf, he may well knock other tins over, because guidance of reach is so challenging for Greg.

From Greg's mother's description, this account (below) might explain his behaviour:

  • Greg is moving, walking slowly in front of the trolley his mother is pushing.
  • people are moving all around him
  • Greg finds it difficult to correctly calculate how big or how far away the other people are
  • due to his problems with depth perception for guiding movement through 3D space, calculating how far away they are is made harder still
  • suddenly, like a character in a pop-up book, someone who seemed a safe distance away has sprung up right in his face and Greg braces himself
  • Greg reacts instinctively to protect himself
  • Greg thinks something (probably someone) is going to collide with him and hurt him

Katherine is a girl with known depth perception and guidance of movement challenges. Katherine's mother explains:

Katherine prefers to be at the back of a shopping trolley. I think she finds it very difficult to judge where people / display stands etc are in relation to her, and the trolley can give her advance warning. What I have discovered, is how large her pupils become in these situations, obviously the effects of being in a fight or flight mode. She has to touch things like bollards, something that could be classed as obsessive behaviour but I think it just helps her to gauge where things are and I suppose if she touches them first, it won't then be a surprise. Double yellow lines on the road, she comes to a halt and treats them as if they were a step.

3. Looming & Movement

With movement, the challenges due to the looming effect are greater. This is the case for all of us - picking up a static glass from a table only requires the guidance of our own hand and arm. If we were picking up the same glass from a tray as a waiter walked past us, the task would be much harder.

4. Looming & Busy Places

The looming effect can help explain many extreme anxieties in very busy places, including:

  • Playgrounds
  • Supermarkets / Markets
  • Airports
  • Busy streets
  • Sports venues
  • Concerts
  • Funfairs / Festivals / Carnivals
  • Parties
  • Team Sports (participating in)

Severely complex children who are unable to articulate their fears, or physically remove themselves from the threat, may become extremely distressed, as Connor regularly did as a young child.

Connor's mother explains:

I once took Connor to an outdoor Christmas market that I thought he would enjoy. He was only a baby and in his pram which was low down. Suddenly the place became packed and we were trapped in this outdoor market. He started screaming, and in the end I left the pram to carry him through the crowd. I'm not sure if that was the best thing to do but we couldn't get out. I became lost from the rest of my family so had to wait on the peripheral edge of the market but found a dark alcove and tried to calm Connor down. He screamed for an hour, sometimes I calmed him, and then, like some awful memory had just returned to his thoughts, he started screaming again.

Connor struggles in cluttered places, but can manage them if it is quiet, like the supermarket very early in the morning. Connor cannot tolerate busy places with lots of people moving around him, it terrifies him, I know that now and we avoid it. This is why he never goes to the multiple Christmas Parties he's invited to every year.

I recently discovered by accident an approach that seems to help. Connor got a new wheelchair that came with a large tray which had a raised metal ring around the circumference. I quickly realised that Connor seemed much calmer when he had his tray on his wheelchair, and I think it was because he felt physically protected. I even managed a short trip to the mall which is normally a total no-go area. I now apply the same principle of creating a physically safe space with known boundaries, in multiple environments. If we are going to the beach for example, which can be busy, I take a pop-up tent where Connor can sit and feel safe.

Another example is travelling on his dad's shoulders where I think the height, above most moving object, protects Connor, combined of course with the feeling of safety because he is being carried by his dad. Interestingly, in unfamiliar places Connor often can become confused and stressed, but when on his dad's shoulders (and on a horse too for that matter) he relaxes and seems to visually explore his environment.

Connor's wheelchair and trayConnor's wheelchair and tray

Connor's view from his wheelchair with the tray connectedConnor's view from his wheelchair with the tray connected

Protected by his pop-up tent, Connor feels safe enough to reach out and start exploring the sand.Protected by his pop-up tent, Connor feels safe enough to reach out and start exploring the sand.

Those caring for either very young people with CVI, those unable to walk or those with limited communication might want to note their behaviours in busy places. If they seem uneasy or distressed, you might want to consider one of the strategies Connor's mother suggested, or avoid such places.

Not everyone who has CVI will suffer from the looming effect, and busy places can make people with CVI feel uneasy for multiple reasons, as we have discussed in the previous chapters.

In more able people, busy places can make them feel uneasy or anxious, sometimes without knowing why, they just feel uncomfortable. Even the anticipation of a busy place can be enough to make a person feel anxious or uncomfortable, and over time they learn just to avoid them.

Mary writes:

Your description of looming has just taught me something! I hadn't really understood what you were meaning with looming, but on reading this, I realise that I often experience looming!

On countless occasions, I have been walking along, when suddenly something seems to loom and I jump in fright, sometimes I have even screamed. It's like someone with a scary mask (think of the movie scream) has just appeared in front of me - even though they haven't. But that's what my response is like, so over dramatic. I normally find this experience extremely embarrassing because there is nothing obvious around me and no one understands my extreme reaction.

Mary gives an example: "The anxiety I had before heading away for a holiday where there was a large group of us staying in one small house made me physically ill. I was very aware that it would be crowded, noisy and overwhelming for me. I worried about how I was going to cope and this worry made me feel nauseous and headachy. Although I tried to come up with strategies to make it easier, a lot of the anxiety was around the unpredictability of everyone else, especially children. They move fast and I knew I couldn't control their movement, which made me anxious. As it turned out, I was right to be anxious, because the environment was as I expected. The 'looming' of everyone around me, children and adults for two days was exhausting. I was constantly in fight or flight mode and got many terrifying frights. This also added to feeling ill and it took me a number of days to recover from just two days in this environment".

5. Looming & Simultanagnosia

The descriptions above have been around trying to explain what we mean by looming in relation to optic ataxia. It is possible that for some with CVI, looming may be a greater challenge due to simultanagnosia, if also present.

Mary and Connor both have a combination of simultanagnosia and optic ataxia. The challenges of the two conditions combined are explained with the following examples:

Connor's mother writes:

Connor is a brilliant map maker, but I don't think he is very good at applying his map-knowledge in the abstract. That is, he knows a chair in our house has depth, and can be something he can sit on and also avoid bumping into. He also knows the two steps going up to a television corner. I don't think he can take this understanding of chairs and steps, in relation to their depth, and understand all things in other environments that look like chairs and steps, have depth and could be collided with.

At home Connor will navigate round his chair to get his milk, because the chair is in his mental map of a room he knows well. Out and about he will walk into a chair and only see the milk, due to his simultanagnosia. This is an unmapped unknown environment, so the potential hazards of obstacles are not considered, because on approach they probably still appear flat.

For this reason, at home Connor appears very able, but his challenges become obvious in unknown environments, or if changes are made within known environments. This is why Connor does not like things to be moved around his home where he feels safe - it is the one place he has perfectly mapped and can navigate with confidence.

Mary (unlike Connor) can apply her understanding in the abstract.

Mary knows that a chair has depth and can be either sat upon or bumped into. Mary doesn't accurately move through depth, Mary has optic ataxia, but she knows from her past experiences that when she sees a chair, it would be expected to have depth.

Like Connor, if Mary is in an unfamiliar environment, the combined effects of her simultanagnosia and optic ataxia prove extremely challenging.

Mary writes:

Last year while out on a walk in our local park, I had a looming experience with a rubbish bin! Obviously the rubbish bin wasn't moving, but it suddenly appeared in front of me and terrified me. I screamed, jumped and almost ran away. A reaction you would expect if confronted by a bear, not a rubbish bin!!

The following images and descriptions have been used to help explain Mary's experience, step by step:

The looming rubbish bin.The looming rubbish bin.

Mary has a right hemianopia, so the top image (as seen without visual field loss) would be seen like this to Mary.Mary has a right hemianopia, so the top image (as seen without visual field loss) would be seen like this to Mary.

Mary also has simultanagnosia, and here she describes her technique for moving around safely:

The strategy I have for walking in busy places (especially airports) is to just concentrate on the space directly in front of me. I don't look straight down at the ground but a probably a few meters ahead, as this gives me the most opportunity to see any hazards. But if I lift my head up and look at eye level I miss things, which is why I only do this when really relaxed (so not in cluttered places). I have found that in cluttered places, if I get distracted by anything and change where I am looking, this is when I am going to get in trouble (lots of experience of this).

However, on the occasion with the bin, although the park was busy it was nothing like an airport. I may have been distracted thinking about something, but I certainly was not stressed as I would be in a cluttered place. I was quite relaxed just going for a walk in the park, which I do quite often.

Mary is relaxed and walking, and focusing ahead of her. Due to Mary's simultanagnosia the image would look something like this, below (if seen without her right hemianopia):

Mary's visual field loss is caused by her brain, not her eyes, so this is what her eyes see when Mary is looking straight ahead...Mary's visual field loss is caused by her brain, not her eyes, so this is what her eyes see when Mary is looking straight ahead...

And this is what Mary sees.And this is what Mary sees.

If we look at the two images side by side is it easy to see how Mary could have bumped into the rubbish bin, because she was not visually aware of it due to her simultanagnosia.

However, Mary thinks it is more likely to be the looming effect as she explains:

It could have been my simultanagnosia because I was distracted thinking about something - but I wasn't using specific strategies because I didn't feel like I needed them. I was just walking as a normal person would (I think!).

It could have been looming due to my optic ataxia because there was nothing interesting about the bin, so it didn't pop out. Interestingly, if you had asked me before how many bins there are at this park - I would have said bins? what bins? Whereas now, thanks to the photos, I know there are quite a few bins at the park!!

This example shows how difficult it can be to understand what is responsible for the different reactions, if you have both simultanagnosia and optic ataxia. Had the bin been painted bright orange, of been illuminated or flashing, it is likely to have had a pop-out effect and Mary would have been aware of it.

Going back two sections to the Simultanagnosia Spectrum, this is the image Mary's occipital lobes created:

The bin is clearly here. However when this visual information travelled along the dorsal stream and reached Mary's posterior parietal lobes, where visual attention is given, the bin is there no more:

This image was created non-consciously, Mary didn't deliberately choose to 'not see' the bin, it was awarded no visual attention because on Mary's radar nothing popped-out as being meaningful or significant. This is personal to Mary. The reason nothing popped-out was possibly because on approaching the bin, Mary was unaware of how big it was or how far away it was, so it wasn't considered a threat. As it was not a threat or particularly interesting Mary's posterior parietal lobes awarded it no attention, until... it suddenly appeared in front of me and terrified me. I screamed, jumped and almost ran away. A reaction you would expect if confronted by a bear, not a rubbish bin!!

6. CVI Frights

Looming can be startling and threatening, as described, but it is not the only reason people with CVI may get a fright. Here are some others:

  • Looming (as described here)
  • Simultanagnosia - someone or something not seen suddenly appears
  • Movement (dyskinetopsia / akinetopsia) - things that may not be seen because they are moving too fast, then may suddenly pop into view when they slow down.
  • Visual Field Loss - things suddenly appear as if out of nowhere. Mary described being startled when a friend greeted her with a kiss on the cheek, but on her right side where she has no image. The first thing she knew about is was as a face appeared literally a centimetre away from her face!

In some people, a combination of the above may be present.

Being frightened is something that should be avoided, and understanding the different reasons will help you learn to ensure the environment will feel safe for the person with CVI. If they do not feel safe and happy, they cannot learn and develop.

In a following section we discuss severe behavioural responses called CVI Meltdowns.

Everything listed above could cause a CVI Meltdown.

We sought the opinion of our professional advisors who suggested:

If you cannot map 3D space accurately for the purposes of movement, then it stands to reason that mapping the location of randomly moving people or objects in your environment must be difficult to work out. Furthermore, if you are unable to see things that move fast, then things may pop into view when you slow down.

Many young people with conditions affecting periventricular white matter* like to play in goal when they play football. They can't cope with the moving players, perhaps because they can't map them, and the ball can disappear when it is moving fast. Goal is the most secure place to be, as the ball doesn't disappear as it approaches, there are fewer players to cope with as they come from fewer directions, and the goal provides something of a 'safe place' in what is otherwise a chaotic situation. *Periventricular White Matter is a known underlying cause of CVI.

An additional element may be the simultanagnosia spectrum. If only a limited proportion of the scene can be appreciated at any one time, then the unpredictable sudden appearance of things may add to the mix.

It should be stressed that these processes are non consciously mapped, so it would follow that the experience of something either appearing to come too close, or seeming to pop out of nowhere would be difficult to describe. The three dimensional conscious perception of depth is referred to as stereopsis, which has been reported as normal in some people with optic ataxia, despite gross inaccuracy of visually guided movement.


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