Blindness and the Brain

Christina Grantham

How Does Blindness Affect the Structure of the Developing Brain?

It has often been thought that people lacking one of their senses, such as blind individuals, compensate for their lack of sight, with other enhanced abilities. However, this thought is no longer an assumption. This is because there is significant evidence that individuals missing one sense don't just learn to use the others better, but the brain actually adapts to the loss (Bates, 2012).


If one sense is lost, the areas of the brain normally devoted to handling that sensory information do not go unused — they get rewired and put to work processing other senses (Bates, 2012). This phenomenon is known as cross-modal neuroplasticity. Neuroplasticity is the capability the brain to change with experience. Brain imaging studies show the visual cortex in the blind is taken over by other senses, such as hearing or touch, and contributes to language processing (Bates, 2012). This helps to explain why blind individuals frequently have enhanced auditory abilities.


Below is a wonderful video that helps to explain this phenomena further using a fun and easy approach. Also, the video discusses how extraordinary the brain is, to such a point, that just simulating blindness could cause you to have better hearing!

Heighten Your Senses By Simulating Blindness!

(D News, 2014).

Brain Development that Occurs with Blindness

Humans are thought to have evolved brain regions in the left frontal and temporal cortex that are uniquely capable of language processing, however, congenitally blind individuals also activate the visual cortex in some verbal tasks (Bedny et al., 2011). Until this finding, it had been suggested that the structure of the human brain is predetermined. However, there is evidence that brain regions have the ability to take over tasks that they were not genetically intended to execute. For example, in a study of people blinded early in their life, neuroscientists showed that the visual cortex could participate in a nonvisual function -- reading Braille (Bedny et al., 2011). This proves that individuals who are born blind still use their visual cortex. The finding suggests that the visual cortex can dramatically change its function, from visual processing to language, and it also appears to overturn the idea that language processing can only occur in highly specialized brain regions that are genetically programmed for language tasks (Bedny et al., 2011). The above information demonstrates the fact that your brain is not predetermined as previously thought. The building process is significantly influenced by the experiences you have during your development (Bedny et al., 2011).


Furthermore, below is a link to a very beneficial site that describes how brain development occurs in a person with blindness. It reviews some of the information that was discussed in the prior paragraph, but more in-depth, and in easy way to fully understand the information provided. Other concepts that are covered are the results of a study on sixteen blind individuals who underwent an fMRI, it answers the questions of "If someone is blind do they not use certain areas of the brain?", "Does the brain have the ability to adapt?", "Are certain areas of the brain used for tasks other than what they were meant for?", and much more (Phillips, 2002). Click on the following link to access the article:

Brain Development of a Sighted Individual Compared to a Blind Individual

Big image

A question that is often asked is “How do blind people view reality?” Sighted individuals are able to envision their surroundings by sensing borders between areas rich in different wavelengths of light, which is how sighted people see different colors, whereas blind people build images based upon sense of touch, and by listening to the echoes of clicks of their tongue and taps of their cane as these sounds bounce off objects in their surroundings, which is a technique called echolocation (Wolchover, 2012). Blind people see, it just isn’t visual.


Related to the brain, interestingly enough, there are many similarities in the development and activity of a sighted person’s brain when compared to a blind person’s brain. For instance, evidence from brain-imaging experiments indicates that blind people's brains harness the same neural circuitry as sighted individuals (Wolchover, 2012). This is because in both sighted and blind individuals, visual information first goes to the visual cortex.


Below is a link to a wonderful website that helps to further explain how blind individuals picture reality, and similarities and differences in blind individuals compared to sighted individuals.

Next, below is a great video about a remarkable man named Mike. Mike lost his sight in one eye at a very young age due to an explosion. Even so, Mike has done amazing things in his lifetime. For example, Mike currently holds the world's record for downhill speed skating (Wandell, 2009). The video goes on to talk about Mike's extraordinary life despite his blindness, how research on Mike's brain shows significant differences from a sighted persons brain, and much more. Watch Mike's amazing story below!

Understanding Blindness and the Brain (Brian Wandell, Stanford University)

(Wandell, 2009).

Assisting the Blind: Tips for Caregivers

Many blind individuals prefer to stay in their own home where they are both comfortable, and able to maintain their independence, as long as possible. There are many ways a caregiver can assist with this. First, personal care usually becomes a challenge. Some ways a caregiver can help with this is by assisting individuals in their activities of daily living or ADLs such as bathing, grooming, dressing, transferring, eating and voiding/toileting (BHC, 2014). Another very important task that caregivers can assist with is transportation. Caregivers can drive and accompany their clients to appointments, on errands, to social events, etc. Next, caregivers can help with cooking, preparing meals, laundry, and other household tasks. Knives with adjustable guides for safely cutting slices and devices that beep when a hot liquid overflows help to make an individual’s kitchen a little safer, but there is no substitute for another pair of eyes to guide the blind person (BHC, 2014). Last, a caregiver can assist with organizing and keeping the house safe for the individuals. Ways this can be done are by eliminating clutter, securing rugs and wires, and keeping stairways and living spaces clean and clear of falling hazards (BHC, 2014).

References

Bates, M. (2012, September 18). Super Powers for the Blind and Deaf. Retrieved from http://www.scientificamerican.com/article/superpowers-for-the-blind-and-deaf/


Bedny, M., Pascual-Leone, A., Dodell-Feder, D., Fedorenko, E., & Saxe, R. (2011). Language processing in the occipital cortex of congenitally blind adults. Proceedings of the National Academy of Sciences, 108(11), 4429-4434. doi:10.1073/pnas.1014818108


BHC. (2014). Home Care Support for the Blind and Visually Impaired. Retrieved from besthomecaremn.com/blog/senior-home-care/home-care-support-for-the-blind-and-visually-impaired

D News. (2014, February 8). Heighten Your Senses By Simulating Blindness! [Video file]. Retrieved from https://www.youtube.com/watch?v=GDlPAQakzo4


Phillips, M. (2002, May 20). Braille and the Brain. Retrieved from https://faculty.washington.edu/chudler/brail.html


Wandell, B. (2009, January 22). Understanding Blindness and the Brain [Video file]. Retrieved from https://www.youtube.com/watch?v=VVgfC_FV2hI


Wolchover, N. (2012, October 4). How Do Blind People Picture Reality?- Blindness & Perception. Retrieved from http://www.livescience.com/23709-blind-people-picture-reality.html