Rebecca Atkinson published an essay on July 17, 2007, in the Guardian newspaper about her gradual loss of sight from a condition called Leber's congenital amaurosis. Atkinson states, "Suddenly you can smell the world and sense when someone is standing out of your line of vision. Your brain grows on the inside, and things on the outside start to matter less." Researchers who study the human brain and sensory compensation because of blindness come to much the same conclusions as Atkinson, who goes on to say that, "while a blind life is different from a sighted life, it is not lesser."
The Adaptable Brain
At birth, the portions of the brain that deal with vision, hearing and all other senses are connected, according to Pascal Belin of the University of Montreal. As a sighted child grows, these connections begin to separate from one another until independent centers in the brain control each of the senses. In a blind infant, Belin says, these connections might remain, and the job of processing sound might be shared by both the visual cortex and auditory processing centers. If a person loses his sight during childhood or adulthood, the connections might have already separated because myelin, the fatty sheath surrounding affected nerves, develops rapidly in the very young.
Using neuroimaging tools, researchers have found that while regions in the brain that deal with vision are smaller in blind individuals than in those of sighted, other nonvisual areas were larger. In a 2007 article discussing the brain's potential to adapt after blindness, The Science Daily website states that, "blindness causes structural changes in the brain, indicating that the brain may reorganize itself functionally in order to adapt to a loss in sensory input." Areas in the brain that dealt with memory, hearing and the remaining senses were all enlarged. "It appears the brain will attempt to compensate for the fact that a person can no longer see," says postgraduate researcher, Natasha Leporé, at UCLA's Laboratory of Neuro Imaging.
A blind person can become quite adept at using echolocation--identifying an object by the sound or echo it makes--while moving through the world around her. Babies or children born blind use extra hand movements as they crawl, slapping the floor to create a kind of auditory and sensory feedback. According to the Blind Children's Resource Center, the use of reflected sound by blind children helps them explore and manipulate aspects of the sound world. Other visually impaired individuals may make clicking noises to note the changes in sound as the distance between them and obstacles shifts.
Using Touch to Explore the World
“The largest area of the brain's surface is devoted to the hand. The skin is the largest organ of the body. The blind child is a 'sensation' of information," according to the Blind Children's Resource Center. Many blind individuals feel changes in temperature as they near a window or wall and rely on their enhanced senses of touch.
A Deeper Vision
Before the invention of non-invasive neuroimaging tools, people could only speculate and look in awe on the increased abilities of the blind. Well-known painter Pablo Picasso explored the nature of blindness during his Blue Period, states the Archives of Ophthalmology website. The website mentions that some art critics saw “spiritual inner vision” in Picasso’s Blue Period portraits, and that he "found an intensity of other senses in his depiction of the blind." In her Guardian essay, Atkinson states, "what you lose in one place, you gain elsewhere," reinforcing the idea that other senses are not only affected but enhanced by blindness.
- Science Daily: Blindness Causes Structural Brain Changes
- National Federation for the Blind: Reflections on Becoming Blind
- Blind Children's Resource Center: A Process Towards Independence
- Archives of Opthalmology: Representations of Blindness in Picasso's Blue Period
- BioEd Online: Tone Task Proves Blind Hear Better