Children suffering from ADHD may be ignoring visual information to their left

Feb 27 2005

Children suffering from Attention Deficit Hyperactivity Disorder (ADHD) may be ignoring visual information to their left and being diagnosed mistakenly as having dyslexia, according to new research by Dr Tom Manly and colleagues at the Medical Research Council (MRC) Cognition and Brain Sciences Unit in Cambridge and published in Journal of Child Psychology and Psychiatry and Brain and Cognition.

The latest of three recent papers on the subject, published today, shows that this ‘left neglect’ phenomenon is more widespread in children than previously thought.

The research, conducted by Dr Manly and colleagues Dr Veronika Dobler and Melanie George, showed that children with ADHD might simply stop noticing things to their left, particularly when they are doing boring or unstimulating tasks. The phenomenon of ‘left neglect’ is well-known in adults who have suffered right-sided brain injury, who can act as if half the world has simply disappeared. Some children with ADHD, who had no brain damage and perfectly normal intelligence, showed ‘left neglect’ quite as severe as that seen in some adults with substantial damage to the right side of the brain. Remarkably, the studies show that most children’s awareness of things to their left - but not their right – significantly declines if they are asked to perform a boring task for about 40 minutes.

The research published today shows that even perfectly healthy children can begin to lose some awareness of information on the left with boredom. Dr Manly said, “The right side of our brain seems to be heavily involved in keeping us awake and alert, particularly when we are bored. Because the right side of the brain is interested in what is going on to our left and vice versa, as this alertness declines over time or with boredom, it takes some of our awareness of the left with it. All children lose information disproportionately from the left, but children with ADHD appear to reach this point more quickly and to a greater extent than other children unless they are given stimulant medication.

Dr Manly highlighted the phenomenon in his earlier studies, “One boy with ADHD we worked with tended to ignore the first letters in words, reading ‘TRAIN’ as ‘RAIN’ and ‘FLOAT’ as ‘OAT’. Another boy would miss details from the left in his drawing and compress his writing or drawing only into the right hand side of the page.”

Dr Manly claims that this difficulty with noticing things on the left has often gone undiscovered because it is not routinely assessed. The problems may be attributed incorrectly to dyslexia or clumsiness.

He concludes, “We have no idea how many children are affected, or if they grow out of it or if it is permanent. However, there are some effective treatments for this problem in adults and our early studies suggest they may work for children, but more research is needed. Nevertheless, improving early assessment in children should be a priority.”