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Learning difficulties may be centred in the eye, not the brain
14 June 2010
The Norwegian University of Science and Technology (NTNU)
Problems with math? And perhaps with handwriting - and motor skills? Researchers at the Norwegian University of Science and Technology (NTNU) believe that the explanation for your troubles may be that not all of the cells in your eyes work the way they should.
Inside the eye, the retina contains a number of cells that respond to specific types of stimuli. Some react to certain colours, while others react to contrast or movement. These cells individually gather information that combined provides our overall visual experience.
One group of cells is called magno cells. These are the cells that respond to rapid movements, transmitting signals from the eye to the brain. The information they send transforms what we see into live video. Without these cells, our brains would only perceive a series of still photos with no direct relationship, much like a comic book.
NTNU researchers suspect that the failure of magno cells to work the way they should may explain multiple learning disabilities and developmental problems.
From motor skills to math problems
Imagine that you are trying to catch a ball. If you can’t quite perceive how the ball travels in relation to your body, you will be a bit awkward when you try to catch it. Or, as the experts say: Your motor skills are less precise than they should be.
But individuals who suffer from motor skill difficulties often have other problems too: Between three and eight per cent of school children have great difficulty learning mathematics (dyscalculia). About half of these individuals also have reading difficulties (dyslexia), and motor development problems.
It has long been known that several types of learning disabilities often occur together. But the cause for this has not been understood.
Professor Hermundur Sigmundsson studies the general principles behind learning, as well as learning disabilities.
Sigmundsson is the driving force behind a study that shows that children who have great mathematical difficulties also have significantly poorer visual perception associated with rapid changes in the environment. The study was carried out as follows: All of the 10-year-olds from two schools were given a mathematics test. Those with both the highest and lowest scores were given further tests.
These two groups went through two so-called psycho-physical tests, where their visual processing was tested. The first test concerned the ability to follow dots on the screen which moved in different patterns, both predictable and unpredictable. This test revealed how well students were able to follow and anticipate predictable movements in relation to accidental movements. In other words, the test quantified the students’ ability to perceive rapid changes in the environment.
The second test was a control test that examined the ability to perceive form, using circles. This test did not include movement.
The differences between the two groups were quite high in the test with the moving dots. Students with the lowest math skills also scored lowest on this test. But there was no difference between the test scores of the two groups for the control test.
Small dysfunction - big effect
The test is the final confirmation of the mechanism that Sigmundsson and his colleagues believe lies behind the specific learning disabilities. It all relates to how our visual system processes information from the environment, through, among others, magno cells. If something goes a bit wrong here, the consequences are significant and result in different types of learning disabilities.
“This demonstrates that when we find evidence of learning disabilities in children in one area, we should expect to find learning difficulties in other areas, too,” the professor says. “And when we know the source of the problem, it makes it easier to create and adapt programmes so children get the most out of them.”
New teaching techniques
Sigmundsson notes that understanding the underlying causes of learning disabilities can lead to a new approach to pedagogical methods. Children with dysfunctional magno cells probably need more specific tools to help them understand visual information than we previously thought.
“The educational challenge is finding teaching techniques that make it easier for visual information to get to the areas of the brain where it will be processed further,” Sigmundsson says.