GS Paper - III

Dyslexia occurs in about 5%-10% of people worldwide, making it the most common learning disorder. The symptoms can present as early as in infancy. Boys are affected two to three times more often than girls.

Kids with dyslexia

• At school, kids with dyslexia may find it difficult to reproduce or describe the content of texts in a language class — such as a text they have just read.
• The difficulties can occur in any school subject, where reading and writing are required, including in mathematics, or when an exercise is presented as a text.
• However, dyslexia says nothing about the intellect (or creative talent) of the people who have it.
• Famous dyslexics include Albert Einstein, Ludwig van Beethoven, Charles Darwin, Ernest Hemingway, Agatha Christie and Whoopi Goldberg… and the list goes on.

Researchers locate the cause of dyslexia

• The causes of dyslexia are not yet fully understood. However, researchers based in Dresden, Germany, say they have been able to show, for the first time, that dyslexia is linked to changes in the function and structure of a specific part of the human brain called the visual thalamus.
• The visual thalamus is a key brain region that connects the eyes with the cerebral cortex, which is important to our ability for reasoning, emotion, thought, memory, language and consciousness.
• Visual information from the eyes is processed in two separate parts with different tasks: One part is larger than the other and primarily processes colors. The other, smaller part recognizes movements and rapidly changing images.
• Structures in the visual thalamus are very difficult to examine using conventional magnetic resonance imaging (MRI) because the visual thalamus lies deep in the brain and is tiny. Its smaller part, the one described above, is the size of a peppercorn.

How researchers spotted changes in the visual thalamus

• Thanks to a special MRI system at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, researchers were able to study the visual thalamus in unprecedented detail in living humans.
• The researchers found that people with dyslexia show changes in the function and structure of the movement-sensitive part of the visual thalamus. These changes are particularly evident in male dyslexics.
• Their study, which was published in the journal Brain, involved 25 people with dyslexia and 24 control subjects. The researchers say it’s given them a better understanding of this key brain region.
• [It] paves the way for further research aimed at gaining a more comprehensive understanding of the brain mechanisms underlying dyslexia.