Astonishing discovery that could change our understanding of attention deficit disorders

Jan 18 2005

British researchers from Brunel University have made an astonishing discovery that could change our understanding of attention deficit, impulsivity and hyperactivity disorder (ADHD).

The researchers found that ADHD could be diagnosed in preschool children using a simple biological test.

“The estimated prevalence of all ADHD is around 5% of school-aged children. Not all children who might meet the diagnostic criteria for ADHD are diagnosed. It has been estimated that approximately 1% of school-aged children meet the diagnostic criteria for severe combined type ADHD. An estimated 2 million children in the United States have ADHD, this means that in a typical U.S. classroom of 25 to 30 children, it is likely that at least one will have ADHD.

To date, the diagnosis of the condition is made subjectively by the use of questionnaires. This is the first time that such an objective and biological test- discovery has been made, worldwide.

The fully automated, inexpensive test can be completed within ten minutes. The children just have to look at a spot of light on a computer screen and follow it with their eyes as it moves across the screen.

ADHD is a common disorder, estimated to affect approximately three to seven per cent of school-age children. The diagnosis of ADHD is difficult in preschool ages, as many normally active children are overactive and exuberant.

Professor George Th. Pavlidis and Panagiotis Samaras from Brunel University examined whether there was a significant correlation between the eye movements of preschool children (4-6 year olds) and ADHD symptomatology. They also examined whether eye movements could be used to objectively identify preschool children at high-risk for ADHD, by the use of a reliable biological test ( Pavlidis Test ).

Four eye movement tasks were run - (non-guided saccades, fixation, guided saccades and smooth pursuit) - each lasting 30 seconds. A fully automated ophthalmokinetographic system, developed by Professor Pavlidis , measured and analysed the results. Statistically highly significant differences were found between normal and ADHD children, especially in the smooth pursuit and saccadic eye movement tasks. The test correctly classified 93.1% of preschoolers into normal and ADHD.

It was also established that the ADHD group was characterized by erratic or differential patterns of eye movement to the non-ADHD group and that a high correlation existed between ADHD symptomatology and the eye movement patterns of preschoolers.

Professor George Th. Pavlidis commented: "This biological test proved to be objective, and highly accurate, and can be used at preschool age. The discovery is also important internationally as the test operates equally effectively regardless of language, race, culture and I.Q."

The ' Pavlidis Test' - the test that was used in this research - was initially developed to prognose dyslexia in pre-school children, and it proved to be 91.5% accurate as it objectively predicted at the age of six who developed dyslexia two years later.

Professor Pavlidis emphasized, "Early diagnosis of these very important hereditary conditions will allow effective intervention (i.e. with personalized multimedia) and proper treatment which in turn will reduce the learning, the behavioral and the painful secondary psychological problems of the children."