What is CVI?


Combined Hemianopia and Visual Inattention or Neglect

Mary, as we have previously explained, has a right hemianopia, meaning that her occipital lobes create only the left side of the image.

what Mary's eyes see

what Mary's brain seeswhat Mary's brain sees

what Mary sees

If Mary turn's just her body to the right, to move her body-centric attention (as Lucy did in the previous section to see more of her dinner), it would make no difference.

With hemianopia, to see in her right visual field, Mary needs to move her head, so that what is on her right, has moved to her left, where the occipital lobes create an image she can see.

turning her head to the right, new information is sent to the occipital lobes, with the right hand page now on the left

the image Mary's occipital lobes have created

what Mary sees

Now Mary can read the right hand page because she has moved it onto her left visual field where the occipital lobes create an image.

If Mary only had a right hemianopia the process of learning to turn to her right to check for missing pages, the other half of her dinner or obstacles to avoid would be comparatively straight forward. However, Mary also has inattention on her right hand side (right hemi-inattention). Unlike Lucy, for Mary turning her body will not reveal the right side of the image.

Think of the pathway we are following; the image goes to the occipital lobes first - whatever image is created here cannot be added to further along the pathway (aside from through blindsight). If half of the image is missing, as with Mary, it stays missing.

Mary has the same problems with attention, and once went out having only brushed one side of her hair, whilst looking in the mirror. This example demonstrates Mary's allocentric hemi-inattention, in that she is unaware of the right hand side of the image in the mirror. And Mary's egocentric hemi-inattention, by not being aware of the right side of her head to brush her hair.

Mary has kindly shared some of her other experiences:

"I could give you so many examples of 'hemi attention attacks'! They happen every day. In fact, after trying to cut my thumb off yesterday morning, I then tried to knock myself out by banging my face on the corner of the table when I bent down too close to the table. I caught myself right on my right eyebrow, very painful.

Anyway, my all-time favourite hemi inattention story is the day my own hand gave me a fright! It's pretty special to be able to do that! I was sitting on the couch watching TV with my right elbow propped up in the couch arm rest with my hand in the air. My hand moved (I didn't remember moving it, but obviously I did) and I saw the movement on my right side. I didn't realise it was my own hand and I got a real fright and jumped off the couch. I thought something had suddenly come in really close to me and was frightened by it! It was quite hard explaining to my family what was wrong!

This morning I accused the rest of my family of eating my avocado that I had put in the fridge for my lunch. Of course no one had, it was just on the right hand side of the fridge and I didn't scan to look for it.

I have been known to leave washing hanging on the line after thinking I have collected it all in, only to find items still hanging on the right hand side!


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At CVI Scotland we are devoted to helping people understand cerebral visual impairments, and together working towards developing the understanding of this complex condition.