Researchers from Brunel University's School of Sport and Education have discovered, after three years of international research, that attention deficit, impulsivity and hyperactivity disorder (ADHD) can be diagnosed in preschool children using a simple but sophisticated biological test. To date, the diagnosis of the condition is made subjectively by the use of questionnaires. This is the first time that such a n 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 op h thalmokinetographic 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 characterised 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 emphasised, "Early diagnosis of these very important hereditary conditions will allow effective intervention (i.e. with personalised multimedia) and proper treatment which in turn will reduce the learning, the behavioural and the painful secondary psychological problems of the children."