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CVI Evolving: What we’re learning from the CVI community

We explore visual-spatial processing, visualization, visual phenomena, migraines, and temperature.

Written by: Rachel Bennett

Centering CVI voices is essential in everything we do to move this field forward. We must come to this work from a disability rights lens. We must empower kids, teenagers, and adults with CVI to continue to find their collective voice to inform research, assessment, education, services, and advocacy. 

We are committed to following current research, learning from people with CVI and their families, and being open to all the ways CVI can manifest. People with CVI are the experts of their own brains. We must lean in and learn, always. 

This is our space to capture emerging topics from the CVI community.

Dive into these current topics:

Exploring more CVI behaviors

People with CVI tend to display key traits and behaviors that reveal how CVI affects the processing of the world around them. CVI manifests in a myriad of diverse ways, where some with CVI might experience some or all of these areas of impact. No one area is separated from the other—the CVI behaviors are highly connected, and all can affect the person with CVI at any time. The list of the CVI visual behaviors found on CVI Now is meant to evolve. 

In this section, we’ll add more examples of CVI behaviors that people with CVI and professionals are reporting. We must all keep our minds open and stay lifelong learners. If you have a student with CVI, believe them. Rely on them to show you how CVI affects them and what they need for access. 

These next three areas—visual-spatial processing, visualization, and visual phenomena—come directly from the collaborative work of Nai Damato, Matt Tietjen, and Rachel Bennett

Difficulty with visual-spatial processing

Visual-spatial processing is the ability to tell where things are in space, comprehend spatial relationships between objects and understand where one’s body is in relation to the environment, and visualize scenarios, maps, images, and scenes. Visual-spatial, or visuo-spatial processing, is a fundamental aspect of how we exist in the world and “one of the building blocks of an individual’s identity and behavior” (Trés & Brucki, 2014).

Visual-spatial skills are foundational to visual processing and are implicated in all of the CVI traits and behaviors. This is an important area to call out and emphasize as a distinct CVI trait that needs more attention, research, and support. 

When I was in high school, I remember being repeatedly late to class because no matter how often I tried to remember what side of the building the stairwell was on I could not remember which side. When I tried to recall it, it would flip back-and-forth in my head, and then turn into a jumbled mess.”

Nai, adult with CVI

Some with CVI report difficulty with visual-spatial processing, which can encompass many kinds of visual tasks, including

People assume I have keen spatial awareness because I am a skilled traveler. They assume I am mental mapping. They don’t realize that I am relying heavily on other cues. I remember and recall routes as body motions. I feel the turns. I sense my limbs in space-time.

Nai, from How CVI is Different from Ocular-Blindness, The CVI Perspective

What is the science telling us about visual-spatial processing?

Difficulty with visualization 

Visualization is the act of creating an internal picture or model in the “mind’s eye” as one reads print or Braille, listens to spoken language, or thinks about past or future events. This mental model or representation is critical in our ability to comprehend or think about the text, lecture, or event. Visualization can be equated to “making a movie in the mind” for thinking and language comprehension.

Mental imagery, our memory, is not only visual. We are able to have mental representations of all senses: tactile, auditory, olfactory, kinesthetic, and visual.

Some with CVI describe their difficulties with visualization and how it impacts their understanding of events, language, and reading comprehension.

“It was the same for the interior decorating – every time he had asked me to make a decision based on what I wanted it to look like, I had been unable to imagine and see the image in my head. All I could see was what was directly in front of me – a blank wall, a concrete floor, bare windows, a pile of dirt.” -Dr. Nicola McDowell, from Nicola McDowell’s Blog (30) – Can’t you just visualise it?

“When I read books, particularly fight scenes, I can never figure out where anybody is or where anything is, even from explicit descriptions. These descriptions are confusing to me because I don’t really have context for them, and I don’t form images in my mind either, so they don’t really serve a purpose to me. I do have, for lack of a better term, ”visualizations,” but they’re not with images.” -Teenager with CVI, from Yellowstone’s Blog (5) Empty Words

“When I am reading a book, the words on the page do not ‘come to life.’ They do not create a movie playing in my head.” Nai, adult with CVI

“I have almost no ability to visualize. The medical term for this is aphantasia. I can visualize if there is a semantic connection — like I can picture spelled words in my mind’s eye. It’s actually more kinesthetic. I would write with my finger on my own thigh when I was learning to write, and the two-way tactile is how I logged the shapes and curves of the letters. I recorded how it felt to write them, not what they looked like. And now that I use braille, I feel the shapes under my fingertip mentally, or I feel my fingers typing braille chords.” -Nai, from How CVI is Different from Ocular-Blindness, The CVI Perspective 

What is the science telling us about visualization?

Visual imagery in the brain: The occipital (primary visual cortex), temporal, and parietal lobes (visual ventral and dorsal streams) are heavily involved in generating internal visual imagery (Keogh, 2021). The dorsal pathway plays a role in generating spatial imagery, while the ventral pathway is involved in creating visual imagery. There is a distinction in what visual information is processed in the ventral stream: “external information (seeing a tree) and the processing of internal information (a mental representation of a tree)” (Blomkvist, 2022; Pearson, 2019). With CVI, both external and internal visual processing may be affected. 

Simultanagnosia (difficulty processing simultaneous visual information) is a common aspect of CVI.  As a result, people with CVI often have difficulty interpreting visual scenes and images. They often catch a detail or two but miss the gestalt of the scene or image. They may focus on individual elements while missing the way that all of the elements relate to each other to form the overall meaning of the image or scene. Research shows that the way a person perceives images is closely related to the way they create internal images. A person who has difficulty seeing and synthesizing all of the elements in a picture to form a gestalt will likely have trouble doing this when creating internal imagery. 

Difficulty visualizing during reading and language listening can result in a person having greater difficulty with the inferential or abstract understanding of the content versus the more concrete aspects (De Koning, 2013). Difficulty visualizing or generating a “movie in the mind” can be a root cause of difficulties with language and reading comprehension (Bell, 2009, 1991). Readers or listeners construct mental models of the situation a writer or speaker is describing, and this can be the basis of language comprehension (Bower and Morrow, 1990).

Aphantasia is difficulty in generating internal images (voluntary or involuntary). Aphantasia is a spectrum. Research on aphantasia shows that while internal visualization is a key component for imagining and comprehending for many people, it is not the only route (Keogh, 2021). We have access to many forms of imagery: auditory, olfactory, tactile, and visual. Visual imagery is not the only representational format in the human brain.

Visual phenomena

People with CVI and their families report certain visual phenomena they experience day to day. Some examples include:

In Heisenberg Vision: A Paradoxical Existence from The CVI Perspective, Nai describes what it’s like not to be able to fully rely on vision or be certain of what you are seeing: “With CVI, there is no singular state or definite outcome. Everything is constantly in flux and remains ambiguous… The world is a constant sea of shifting possibilities. You have to regard everything as a matter of high probability at best. You never know for certain or even with confidence where an object is, or how fast it’s moving, and you definitely can never know both. You are dealing in waves and clouds, and never in absolute points or paths in space-time.”

CVI and Migraines

The frequency and severity of migraines and headaches are a popular topic in the CVI community. Many adults with CVI and families of children with CVI report having migraines that can be caused by any type of overload to the brain: visual fatigue, hunger, overexertion, overheating or too cold, and overstimulation. Some have severe migraines, which can cause nausea, vomiting, extreme pain, total blindness, and loss of motor control and speech. This is a big chronic health issue for some with CVI.

“I have severe chronic migraines. I lose vision completely and can’t talk or walk. Sometimes I have no voluntary muscle control. It almost always starts with visual overstimulation. I feel strongly that there is a connection [between CVI and migraines]. The vision loss sometimes lasts hours.” -Adult with CVI

“My son has severe migraines 1-2 times per week. He gets extremely tired and doesn’t eat. He then has nausea and vomiting for anywhere from 5-12 hours. He’s in so much pain, and it triggers so much health anxiety in me as a parent.” -Rachel, CVI parent

Learn from Dagbört, an adult with CVI, about the effects of visual fatigue.

CVI and environmental temperature

People with CVI and parents of children with CVI report that temperature can be an added sensory overload—when it’s either too hot or too cold. The CVI brain is already an inefficient visual system, so any added stress may make vision use difficult or near impossible. Of course, there are many factors that go into regulating body temperature, so we need to make sure to understand the full profile of the person with CVI. 

Heat waves affect my CVI a lot, and I have been experiencing a lot of zero vision days, or a day when my brain doesn’t want to see. I’m just walking around and getting no visual feedback from my brain.

Tina, adult with CVI

In the CVI Now Parent Group, many families say can’t take their child out on a hot day or sit outside in the cold without it negatively affecting their child. 

“My son has heat intolerance big time. He will positively crumple if it is hot! I actually don’t even plan things for the summer anymore unless we can be in the water or in air conditioning.” -CVI parent

“My son also struggles with temp regulation, both cold and hot but is less tolerant of heat! He won’t stay long outside with the heat and humidity here in the South unless he’s swimming or in the shade. In the winter, he really struggles with hand warmth and isn’t aware that he does. Meltdowns happen quickly also.” -CVI parent

So much can make vision unreliable for people with CVI, including the internal effect of the outside temperature. How does this apply to our students with CVI? If a room is too hot or too cold, this can make attention and focus difficult and cause fatigue. One TVI shared that her high schooler with CVI often wears her winter jacket and hat inside the classroom during the winter months. And when a student comes back inside from recess on a hot day, they may need time to rest and cool down, drink cool liquids, and other protocols that the family uses at home. 

The effect of temperature on vision use is yet another reason why people with CVI need multiple access points to get through their day.

Our hope is that our CVI Evolving page will continue to grow and reflect what the CVI community is talking about right now. Each of these topics will inspire more in-depth articles here on CVI Now and hopefully elsewhere. So stay tuned!


Bell, N. (1991). Gestalt imagery: A critical factor in language comprehension. Annals of Dyslexia, 41(1), 246-260. doi:10.1007/BF02648089

Bell, N., & Bell, N. (2009). On cloud nine: Visualizing and verbalizing for math. San Luis Obispo, CA: Gander Pub.

Blomkvist, A. (2022). Aphantasia: In search of a theory. Mind & Language, 1– 23. https://doi.org/10.1111/mila.12432

Bower, G. H., & Morrow, D. G. (1990). Mental models in narrative comprehension. Science, 247(4938), 44–48. https://doi.org/10.1126/science.2403694

Critten, V., Campbell, E., Farran, E., & Messer, D. (2018). Visual perception, visual-spatial cognition and mathematics: Associations and predictions in children with cerebral palsy. Research in developmental disabilities, 80, 180–191. https://doi.org/10.1016/j.ridd.2018.06.007

Dawes, A. J., Keogh, R., Andrillon, T., & Pearson, J. (2020). A cognitive profile of multi-sensory imagery, memory and dreaming in aphantasia. Scientific Reports, 10(1), 1–10.

Dehaene, S. (2011). The number sense: How the mind creates mathematics. Oxford University Press. 

De Koning, B.B., van der Schoot, M. (2013). Becoming Part of the Story! Refueling the Interest in Visualization Strategies for Reading Comprehension. Educ Psychol Rev 25, 261–287. https://doi.org/10.1007/s10648-013-9222-6

Ferrara, K., Seydell-Greenwald, A., Chambers, C.E., Newport, E.L. and Landau, B. (2021), Development of bilateral parietal activation for complex visual-spatial function: Evidence from a visual-spatial construction task. Dev. Sci., 24: e13067. https://doi.org/10.1111/desc.13067

Gambrell, L. B., & Jawitz, P. B. (1993). Mental imagery, text illustrations, and children’s story comprehension and recall. Reading Research Quarterly, 28(3), 264–276. https://doi.org/10.2307/747998

Gori, S., and Facoetti, A. (2015). How the visual aspects can be crucial in reading acquisition: the intriguing case of crowding and developmental dyslexia. J. Vis. 15, 8. doi: 10.1167/15.1.8

Giovagnoli G, Vicari S, Tomassetti S and Menghini D (2016) The Role of Visual-Spatial Abilities in Dyslexia: Age Differences in Children’s Reading? Front. Psychol. 7:1997. doi: 10.3389/fpsyg.2016.01997

Höhler, C., Rasamoel, N.D., Rohrbach, N. et al. The impact of visuospatial perception on distance judgment and depth perception in an Augmented Reality environment in patients after stroke: an exploratory study. J NeuroEngineering Rehabil 18, 127 (2021). https://doi.org/10.1186/s12984-021-00920-5

Newcombe, N.S. (2022). Three Kinds of Spatial Cognition. In Stevens’ Handbook of Experimental Psychology and Cognitive Neuroscience, J.T. Wixted (Ed.). https://doi.org/10.1002/9781119170174.epcn315

Newcombe, N.S. and Huttenlocher, J. (2007). Development of Spatial Cognition. In Handbook of Child Psychology (eds W. Damon, R.M. Lerner, D. Kuhn and R. Siegler). https://doi.org/10.1002/9780470147658.chpsy0217

Pearson, J. (2019). The human imagination: The cognitive neuroscience of visual mental imagery. Nature Reviews Neuroscience, 20(10), 624–634.

Stein, J. (2014). Dyslexia: the role of vision and visual attention. Curr. Dev. Disord. Rep. 1, 267–280. doi: 10.1007/s40474-014-0030-6

Trés ES, Brucki SMD. Visuospatial processing: A review from basic to current concepts. Dement Neuropsychol. 2014 Apr-Jun;8(2):175-181. 

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