Brain scans may help diagnose dyslexia

Washington: Brain scans may help diagnose people with the common reading disorder dyslexia, a new study suggests.

Dyslexia is usually diagnosed around second grade, but the results of a new study from Massachusetts Institute of Technology (MIT) could help identify those children before they even begin reading, so they can be given extra help earlier.

The study, done with researchers at Boston Children`s Hospital, found a correlation between poor pre-reading skills in kindergartners and the size of a brain structure that connects two language-processing areas.

"We were very interested in looking at children prior to reading instruction and whether you would see these kinds of differences," said John Gabrieli, professor of brain and cognitive sciences.

The new study is part of a larger effort involving approximately 1,000 children at schools throughout Massachusetts and Rhode Island.

"From that, we`re able to provide - at the beginning of kindergarten - a snapshot of how that child`s pre-reading abilities look relative to others in their classroom or other peers, which is a real benefit to the child`s parents and teachers," Norton said.

The study included 40 children who had their brains scanned using a technique known as diffusion-weighted imaging, which is based on magnetic resonance imaging (MRI).
This type of imaging reveals the size and organisation of the brain`s white matter - bundles of nerves that carry information between brain regions, researchers said.

Researchers focused on three white-matter tracts associated with reading skill, all located on the left side of the brain: the arcuate fasciculus, the inferior longitudinal fasciculus (ILF) and the superior longitudinal fasciculus (SLF).

When comparing the brain scans and the results of several different types of pre-reading tests, the researchers found a correlation between the size and organisation of the arcuate fasciculus and performance on tests of phonological awareness - the ability to identify and manipulate the sounds of language.

Phonological awareness can be measured by testing how well children can segment sounds, identify them in isolation, and rearrange them to make new words. Strong phonological skills have previously been linked with ease of learning to read, researchers said.

"The first step in reading is to match the printed letters with the sounds of letters that you know exist in the world," Norton said.

The study was published in the Journal of Neuroscience.