The dorsal stream is the pathway in the brain that deals with “where” things are in space as well as the perception of movement. Therefore, dorsal stream dysfunction in children with CVI (Cerebral Visual Impairment) may have serious impacts on orientation and mobility tasks in the areas of visual attention, perception, and guidance of motion. This is especially true in complex environments with lots of visual clutter and movement (Lueck, 2015, Ch. 17). It can literally turn an ordinary journey across a school campus from one class to the next into an exhausting trial with danger around every corner and down every hallway.
The inaccurate visual guidance of reach present in many with CVI results from a condition known as Optic Ataxia. In essence, this condition occurs when the visual depth map of the world inside a person’s mind is not in line with where things really are. It only has to be “off” by a small margin to cause problems for the individual. When students are unable to judge depth accurately, they will not have a clear idea of when they will come in contact with something in their environment (St Clair Tracy, 2019). Common navigational hazards include tripping over objects in their path, knocking things over that they reach for, falling from curbs or stairs, bumping into walls or other people, etc. These incidents occur because the student can see something is there, but not how far or near, high or low it is from them, meaning they constantly have a much greater risk of injury when navigating by sight alone. This is why even if the student’s acuity and field are clinically measured to be close to normal, they should still be encouraged to use a white cane to protect themselves when traveling (Nai, 2021).
In addition to navigational concerns, Optic Ataxia also causes emotional damage. Peers and other observers will perceive the student as very clumsy, inattentive, or even unthinking because of the way they appear when stumbling their way around or because they have a tendency to spill things and make messes when nobody else is. Emotional consequences for the effected student include feelings of embarrassment, frustration, confusion, anger, disliked, and even depressed. The perceived or actual social abuse can be worse if the student is unaware of why they have so much more trouble than others because they haven’t been diagnosed with CVI or don’t know about Optic Ataxia. These negative feelings cause the student to withdraw from and avoid social situations, preferring to stick to quieter, calmer environments that are more predictable (CVI Scotland, 2021).
Unfortunately, the effects of Optic Ataxia can get even worse than this. Not only do students with this condition feel ostracized and isolated, but they often feel physically threatened as they attempt to move through the world, whether or not there is any actual threat present. They may perceive far away targets as very close by or vice versa. A moving target can therefore trigger intense fright of being hit, even though it is too far away to cause harm. The student may exhibit looming behavior such as shrinking back and covering their head, run away, withdraw into themselves, or lose control and become overwhelmed resulting in physical aggression, screaming, or crying. Looming does not always escalate into a full-blown meltdown if the situation resolves quickly. Even so, crowded places like grocery stores, shopping plazas, festivals, concerts, airports, or busy hallways with lots of activity will still be quite stressful and frightening for them through no fault of their own (CVI Scotland, 2021).
It is key for teachers who work with these students to take the time to understand why these behaviors are occurring. If they do not, the behaviors will likely get worse. Thus, leading to the increased social isolation from peers and teachers alike who misinterpret them. Many children in this situation have ended up being diagnosed with autism by professionals who don’t see the reasons behind the behaviors. However, when teachers do understand what is causing the problem and choose to respond with respectful compassion, they can help other adults and peers to begin to understand also so they can see past the behaviors to the individual, thus decreasing social isolation (CVI Scotland, 2021). Environmental changes and accommodations can then be implemented to minimize the fear response triggered by everyday situations for those living with Optic Ataxia.
References
CVI Scotland. (2021, July 13). Optic ataxia. Optic Ataxia. Retrieved March 30, 2022, from https://cviscotland.org/documents.php?did=1&sid=39&kws=motion
Lueck, A. H., & Dutton, G. (2015, Ch. 17). Vision and the brain: Understanding cerebral visual impairment in children. AFB Press.
Nai. (2021, September 7). Nai’s CVI perspective: “you’re seeing but you’re not”. Perkins School for the Blind. Retrieved March 30, 2022, from https://www.perkins.org/resource/nais-cvi-perspective-youre-seeing-but-youre-not/
St Clair Tracy, H. (2019, March 15). Lessons. Retrieved March 30, 2022, from https://cviscotland.org/lessons/7b-optic-ataxia-28-01-2020