American scientists claim that early MRI brain scans on pre-school children could provide detection of dyslexia in children as young as four.

Researchers from the Children’s Hospital Boston, led by the Laboratories of Cognitive Neuroscience, suggest that children at risk of dyslexia show differences in the brain before they begin learning to read.

Although common diagnosis of dyslexia usually takes place when the child is around seven or 8 years old, the team of American scientists believe that MRI scans could show signs of the learning disease in children as young as four.

Since developmental dyslexia responds to early intervention, diagnosing children before they reach school age could prove successful and avoid them experiencing difficulties and frustration in school.

"We call it the dyslexia paradox," says Nadine Gaab, a researcher from the study. "Often, by the time they get to diagnosis, they usually have experienced three years of peers telling them they are stupid, parents telling them they are lazy. We know they have reduced self-esteem," Gaab adds.

According the research, published in the Proceedings of the National Academy of Sciences, developmental dyslexia affects 5 to 17% of all children and one in two children with a family history of dyslexia will struggle to read and have problems with spelling and word recognition.

Researchers performed a functional MRI imaging on 36 pre-school children (average age 5 ½) while they performed tasks asking them to decide whether two words started with the same speech sound.

During the phonological tests, which recognises and manipulates individual sounds that form words, children with a family history of dyslexia had reduced metabolic activity in certain areas of the brain.

Children with high activity in these bran areas had better pre-reading skills, such as rhyming, knowing letters and letter sounds, knowing when two words start with the same sound and being able to separate sounds within a word.

Those at risk of dyslexia showed no increase of this type of activation in the brain and suggest that children predisposed to dyslexia struggle to activate the brain area, typically used for processing this kind of information and that these brain regions only become active when children begin reading.

"We hope that identifying children at risk of dyslexia around pre-school or even earlier may help reduce the negative social and psychological consequences these children often face," explains Nora Raschle, from the study.

Dr Barry Johnson, Head of Assessment Services & Principal Educational Psychologist and Dr John Rack, Head of Research, Development and Policy both at Dyslexia Action told The Huffington Post: "The term developmental dyslexia ("specific reading retardation") has often being defined as an unexpected difficulty in reading in children and adults who otherwise possess the intelligence, motivation, and schooling considered necessary for accurate and fluent reading."

"Over recent years, there has been an increase in research at looking for possible physiological underpinnings to the condition, and in this, brain imaging has come to make a major contribution.

"Initially the focus was on adults with acquired dyslexia, but attention has now turned to studies in children to see how far such findings may already be present during the period of, or before, literacy acquisition.

"This study gives strong support for the validity of the concept of developmental dyslexia along with evidence of its neurobiological base. Dyslexia Action welcomes this research and fully supports the assertion that early identification of dyslexia is extremely important, particularly on the future learning those with dyslexia have access to.

"However it should also be noted that if you wanted to find out if a person may be dyslexic, you could just give them the reading-related tasks to do - more easily than the brain scanning tasks in fact. However studies like this, showing that brain patterns are different in people with dyslexia when they are doing reading and reading-related tasks are hugely interesting. Demonstrating that the connections between the difficulties and the brain processes can be seen.

"But we have a long way to go before measurements of brain pattern at an individual level can replace assessment of what a child or adult can do. Therefore we recognise that whilst research of this kind is important, in order for it to serve its purpose it needs to be supported by other forms of early identification that are fundamentally linked to teaching, training and monitoring."