New Clues to Understanding Attention Deficit Hyperactivity Disorder in Children

Main Category: ADHD
Article Date: 28 Feb 2005 - 0:00 PDT

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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."

ENDS

For further information, or to arrange an interview, contact Adrian Penrose, MRC Regional Communications Manager, Cambridge, on (01223) 748179 or mobile 07990 541520

Notes to Editors

The Medical Research Council (MRC) is a national organisation funded by the UK tax-payer. Its business is medical research aimed at improving human health; everyone stands to benefit from the outputs. The research it supports and the scientists it trains meet the needs of the health services, the pharmaceutical and other health-related industries and the academic world. MRC has funded work which has led to some of the most significant discoveries and achievements in medicine in the UK. About half of the MRC's expenditure of £450 million is invested in its 40 Institutes, Units and Centres. The remaining half goes in the form of grant support and training awards to individuals and teams in universities and medical schools. Web site at: http://www.mrc.ac.uk.

The MRC Cognition and Brain Sciences Unit in Cambridge investigates fundamental human mental processes such as attention, memory, communication and emotion. It conducts behavioural experiments to see how these processes work, builds computer models of their operation, studies how they could arise from the neural mechanisms of the brain, and explores the clinical implications for patient therapy and rehabilitation.

'Left spatial neglect' is the term used to describe a phenomenon whereby the eyes can still move to the left but the brain ceases to be alert to the visual signals. Visual awareness is controlled by opposite sides of the brain - the right hand side of the brain controls what we see to our left and vice-versa. For example, in the case of adults who have suffered brain injury, such as a stroke to the right hand side of the brain, they may ignore people approaching from the left, leave untouched food on the left side of the plate or even ignore their own left arm.

The paper published today may be accessed if you click HERE in the 'online early' articles

The other recent papers on this subject published by Dr Manly and colleagues are currently cited electronically (without page numbers) as:

Dobler, V. B., Manly, T., Anker, S., Gilmore, J., Dezeryu, A. M., & Atkinson, J. (in press). Asymmetric deterioration of spatial awareness with diminishing levels of alertness in normal children and children with ADHD. Journal of Child Psychology and Psychiatry.

George, M., Dobler, V. B., Nicholls, E., & Manly, T. (in press). Spatial awareness, alertness and ADHD: The re-emergence of unilateral neglect with time-on-task. Brain and Cognition.

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