CVI: Sensory integration and its impact on vision

Written by: Rachel Bennett

At Perkins, we are a gathering place of ideas. The CVI visual behaviors synthesize current research and build on the work of leading theorists in the field. CVI is a lifelong disability, and we want to ensure that all individuals with CVI are fully understood. The CVI visual behaviors are an ongoing need, they can change and improve for some, but the need never goes away. No area is separated from the other—the CVI visual behaviors are highly connected, and all can impact the individual with CVI at any time.

What is Sensory Integration and its Impact on Vision?

Sensory integration refers to the processing, integrating, and organizing of sensory information from the body and the environment. For people with CVI, it can be difficult to use (and/or have a preference not to use) vision simultaneously with other sensory inputs (sound, touch, gross/fine motor activities, distracting lights and motion, temperature, and internal stimuli). The ability to maintain visual skills, and other sensory streams of input, can change based on the task, situation, or activity.

People with CVI may have difficulty using vision (and/or prefer not to use) when:

in noisy, crowded, and cluttered environments
listening to auditory input
there is a familiar/unfamiliar sound in the environment
they are physically challenged
being touched or moved
feeling motion, vibration
touching materials with different textures
the outside temperature is too hot or too cold
internal stimuli are not okay: when they are sick, pre or post-seizure, stressed, fatigued, overheated, too cold, have a headache, and so on

Some with CVI require that only one sense is challenged at a time. Otherwise, they can demonstrate:

reduced eye-to-object contact when looking or listening
having meltdowns in busy/loud/novel environments
repeatedly asking to leave the area
Increased time for processing and responding to information/requests
frequently startled
visual fatigue

When a task required my vision, it stole all cognitive resources for all other senses. In other words, I could either see and do nothing else, or I could do other things and not see. Doing both at the same time was not an option. Vision was an app or webpage that would use up all the RAM on a computer or smartphone.
-Nai, adult with CVI, creator of The CVI Perspective

What are some compensatory strategies related to Sensory Integration?

People with CVI have strategies and workarounds for so much in their daily lives. When processing multiple sensory inputs, many with CVI rely on their compensatory skills. Some with CVI report that vision is often the first to go when the brain is bombarded with simultaneous multisensory input.

Some people with CVI may:

Rely on tactile skills for navigation or to complete a task
Rely on auditory skills (if there isn’t too much noise or any unfamiliar sounds)
Rely on memory
Remove themselves from the environment, space, and task
Take a break in a quiet and dark space
Need kinesthetic input or output; need a movement break
Require the support of a trusted adult or guide
Advocate for themselves using the way they prefer to communicate (and yes, this includes any type of noticeable behavior: hand over ears or eyes, head down, vocalizations, running away, screaming, crying, holding onto an adult, repetitive motions of the body, and so on)

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

CVI Perspective

Nicola McDowell, Ph.D., researcher and lecturer at the Institute of Education at Massey University and an adult with CVI, describes how multiple sensory inputs from the “unruly” hustle and bustle of the start of class led to her brain being overloaded. She compares this to too many applications open causing a computer to freeze and need a reboot. Read more at her blog, Nicola McDowell’s Blog (9) Accessing classroom material

“This constant movement, overload of visual information, and noise all conspired to cause my brain to shut down even further. It was simply too much for me to process… Think of it like the older computer systems. The more windows or applications you had open, the slower and slower the overall system became. Until finally it would get to the stage where you had too much open and it could not cope anymore so the computer would freeze. At this point, the only thing you could do was reboot the computer and give it some time to start up all over again. When I was trying to visually map the classroom environment so that I could walk safely to a desk, avoiding other students, desks, chairs, and school bags, at the same time as trying to concentrate on what the person beside me was saying, listening to the teacher’s instructions, all while blocking out everyone else’s conversations and trying to think logically about where I should sit taking into account my right-side hemianopia – I had too many applications open.”

Dr. McDowell described how it took nearly half the class for her brain to reboot, which caused the stress of needing to catch up, and this stress triggered overload and shutdown all over again. The shutdown and reboot cycle went on all day, every day.

Yet another example of how, when it comes to CVI, it’s not simply about seeing or not seeing, it’s about the profound effect of CVI on the ability to function and engage in the everyday.

I had a five-minute breakdown during my rehearsal as the lead role in an operetta show. If I have to use all of my senses at the exact same time, one will have to back off. With CVI, it is ALWAYS vision. Using my whole body to dance, my ears to listen to the micro details in the music, my memory to start singing in the exact nanosecond, and my vision to not to bump into anyone—something has to back off… and it’s always my vision.
Dagbjört, adult with CVI

What are some look fors/questions when observing your child with CVI?

Does the person with CVI prefer to use alternate sensory channels to explore learning materials?
How do noisy environments affect visual attention and recognition (increase, decrease, or have no impact)?
How do noisy environments affect the ability to navigate effectively? How is the ability to navigate impacted by motion in the environment?
To what extent is vision disturbed by common sounds in the environment (air conditioners, fans, etc.)?
Is the person with CVI able to look at a familiar object that also has sound? Are they able to simultaneously look at and listen to something? Can they simultaneously look at and listen to something that has motion? Are they able to look at and hold an object that has vibration?
When listening to someone speaking, to music, an audiobook, or a video, does the person with CVI look away or appear not to see when using their auditory skills?
To what extent does familiarity with the environment impact integration of vision, touch, or sound?
To what extent does being physically challenged (i.e., any sort of movement or position) affect vision use? Is there a specific body position that supports visual attention and recognition?
To what extent does the temperature in an environment impact vision use?

What people without CVI don’t realize, is that I only look at things when I absolutely need to… I don’t like looking. It’s taxing. Most of the time, I can get the same information from my other senses. When I don’t look at things because I’m using my other senses, it’s not because the other senses are blocking out my ability to look, it’s because I don’t need to look anymore, so I don’t.
-Teenager with CVI, The Yellowstone Blog

What are some examples of adaptations and accommodations?

All accommodations must be based on individual assessment. The following are meant to inspire and provide a general idea. Accommodations and instructional approaches must be student-specific. Access is individual.

Your child should be fully physically supported for learning tasks and activities. This may include a wheelchair, stander, or other equipment adaptations required (armrests, footrests, stool) and in any other position deemed safe by your physical therapist and occupational therapist.
Your child’s learning environment may need to be quiet with low background noise levels.
Your child may benefit from separate/early arrival to destinations when environments are quieter. They might consider visiting busy places at quieter times and transitioning between classes shortly before or following the bell to avoid navigation in highly busy environments.
Your child’s school team may need to:
- Be flexible in scheduling and instruction. Be proactive and responsive!
- allow your child to focus on one task at a time (i.e., writing, listening, or speaking).
- incorporate learning activities that allow for variety in participation (standing, moving, listening, touching, speaking, looking).
- allow for frequent movement breaks or gross motor activities.
- pace instruction to provide multisensory learning with one sense challenged at a time.
- allow for use of non-visual sensory channels to support learning and concept attainment.
Respect the need of the person with CVI to listen only and turn off visual attention.
Allow the person with CVI to look and orient wherever needed during presentations to the class or a group.
If the student is in a new environment, a cluttered and busy environment, or they are tired, expect that they may be more tactile, kinesthetic, or use their auditory skills. Allow space for the student to do what they need for access.
If they have central auditory processing disorder (APD) or are Deaf or hard of hearing, know the supports and adaptations needed for processing what you are communicating.
Know their reliable responses to ensure they understand the information you share—verbal, gestures, AAC device, body language, or symbols, for example.
Be aware of the environment. If you need to convey information, but it’s too noisy, cluttered, and busy, move to a quieter and less cluttered space. Perhaps step out into the hallway or a quieter corner of the room.

Find more examples from a guide to common CVI IEP accommodations in the CVI Now IEP Guide. Then review how to rethink four social and environmental norms to fully include individuals with CVI.

I hate parades. They are very loud and hurt my ears. I can’t tell where to go. I can’t tell where the noise is coming from.
Albie, adult with CVI from Albie’s CVI Perspective

Following the science

Connecting current research of the brain, our visual system, and CVI to better understand the CVI visual behaviors.

Dorsal stream dysfunction contributes to difficulty with visual attention in the presence of competing stimuli which leads to distress in crowded and noisy locations, inability to find an object in clutter, a friend in a group, or to read unless the peripheral text is masked. Also common is for the person to look away from a face into an uncluttered area when listening to someone speaking to facilitate auditory attention (Chokron, Klara, & Dutton, 2021).
Research shows that some with CVI have difficulty using vision in noisy, crowded, and cluttered environments, while listening and simultaneously implementing motor movements, and while walking and talking (Phillip and Dutton, 2014; Leuck and Dutton, 2015). People with CVI may get easily distracted by sounds, movement, and other people (Pilling, 2022).
Serial processing is scrutinizing one piece of information at a time when there is more sensory information to take in, while parallel processing is being able to process many elements of a visual scene at the same time. Serial processing is a less efficient form of visual search. Dr. Lotfi Merabet discusses that with an increased visual load, individuals with CVI have to grind it out (serial processing), as opposed to having that instantaneous capture of information we see with an efficient visual system. How does this relate to difficulty with sensory integration? When additional sensory input is added to an already overloaded and overtaxed visual system, things will start to shut down.
Pilling (2022) surveyed people with CVI about 3-word phrases to indicate a simple strategy to support common visual dysfunctions seen in CVI. For sensory integration (difficulty seeing and hearing at the same time), “Eyes or Ears” was the most popular, and others included “See or Hear, One Sense Only, Keep it Quiet.” For other CVI areas: Difficulty maintaining visual attention: “Keep It Short,” Difficulty with busy visual scenes: “Clear the Clutter,” and Variable visual function: “My Vision Varies.”
Research on Central Auditory Processing (CAPD) disorder is one place to explore to better understand how our sensory systems are interconnected and the difficulty with sensory integration with a brain-based sensory disorder. Some with CVI also have CAPD, and are on the deafblind spectrum. Maurice Belote, a retired project coordinator from the California Deafblind Services, summarizes research on CAPD and CVI in his article, “Central Auditory Processing Disorder – The Hearing Equivalent of CVI: Risk Factors, Features, and Strategies.” Belote shares potential considerations that can support both CVI and CAPD:
- “Consider the limits of simultaneous multi-sensory input. There may be times when it is not advisable to require multi-sensory participation. If a student with CAPD is listening very carefully, at that moment they may not be as available for visual and tactile input as they might otherwise be. This is similar to the way that children with CVI can sometimes seem more visually impaired when they are listening carefully or exploring tactile objects, especially objects that are new to them.”
- “Use a multisensory approach. Even though a student may not be able to access auditory, visual, and tactile information simultaneously, a multisensory approach is still important. In some cases, you may want to provide sensory input through one sense at a time. For example, when presenting a novel item, you may want to wait for the student to tactually explore the object before providing auditory information about what the object is called, its purpose or use, etc.

References

Belote, M. (2020). Central Auditory Processing Disorder – The Hearing Equivalent of CVI: Risk Factors, Features, and Strategies. reSources: Vol. 25, No. 1
Bennett, C., Bauer, C., Bailin, E., & Merabet, L. (2020). Neuroplasticity in cerebral visual impairment (CVI): Assessing functional vision and the neurophysiological correlates of dorsal stream dysfunction. Neuroscience and Biobehavioral Reviews, 108, 171-181
Chokron, S., Klara, K., & Gordon D. (2021). Cortical Visual Impairments and Learning Disabilities. Frontiers in Human Neuroscience 15, 573.
Dutton, G. (2015). “The brain and vision.” In: A. H. Lueck & G. N. Dutton (eds). Vision and the Brain: Understanding Cerebral Visual Impairment in Children (pp. 21-38). American Foundation for the Blind Press. New York, New York: American Foundation for the Blind Press.
Lueck, A. H., & Dutton, G. N. (2015). “Intervention Methods: Overview and Principles.” A. H. Lueck & G. N. Dutton (eds). Vision and the Brain: Understanding Cerebral Visual Impairment in Children (pp. 497-536). New York, New York: American Foundation for the Blind Press.
Merabet, L. B., Mayer, D. L., Bauer, C. M., Wright, D., & Kran, B. S. (2017). Disentangling how the brain is ‘wired’ in Cortical (Cerebral) visual impairment. Seminars in Pediatric Neurology 24, 83-91.
McDowell, N., & Budd, J. (2018). The Perspectives of Teachers and Paraeducators on the Relationship between Classroom Clutter and Learning Experiences for Students with Cerebral Visual Impairment. Journal of Visual Impairment & Blindness, 112(3), 248–260.
Philip, S.S. and Dutton, G.N. (2014), Cerebral visual impairment in children: a review. Clin Exp Optom, 97: 196-208.
Pilling, R.F. (2022) Make it easier: 3-word strategies to help children with cerebral visual impairment use their vision more effectively. Eye.
Roman-Lantzy, C. (2018). Cortical Visual Impairment: An Approach to Assessment and Intervention. 2nd ed., New York, NY: AFB Press.
McDowell, N. & Budd, J. The perspectives of teachers and paraeducators on the relationship between classroom clutter and learning experiences for students with cerebral visual impairment (2018). Journal of Visual Impairment and Blindness 248-260.