The Cognitive Deficit Mechanism Of Comorbidity Of Attention Deficit Disorder And Developmental Dyslexia For School Child

Attention Deficit Disorder and Developmental Dyslexia are2of the most prevalent complex neurologic developmental disorders of childhood. Clinical studies and laboratory studies have found the comorbidity rate can reach15%-50%. Compared to the children with one learning difficulties, the comorbidity children have more serious problems in learning and attention. The two disorder affecting approximately5%of the population. Dyslexia and ADD are different, but there are several common neuro-cognitive deficits. Understanding the mechanism of the comorbidity between the two disorders could lead to a deeper understanding of the genetic and brain mechanisms that cause disability, advances in developmental theory, a more refined diagnostic classification scheme, and new treatments and interventions for children with these disorders. This study investigated the phenotypic relation between the Dyslexia, ADD, the Comorbidity and the Control group in attention and processing speed, to inquiry the factors leading to the comorbidity.This study based on a large school samples of participants between the Grade2to5in Shanghai primary school. We screening out of52children with ADD,48children with dyslexia, a total of48parallel classes of disease in children,150children, a total of298people through the teacher rating, nomination and cognitive ability test. The Test of Everyday Attention (TEA-ch) and processing speed tasks were conducted to children, to test the differences between the three disorder group and parallel classes, and to discusses the different factors and the relationship between the common disease. Results indicated:1、In the selective attention, sustained attention, attention switch and processing speed, the normal students all showed the increasing tendency with grade, and10years old is a turning point of attention, processing speed of children;2、The ADD group, reading disorder group and comorbidity group did significantly worse than normal children in the selective attention, sustained attention, attention switching and processing speed;3、Compared to the pure ADD children and the reading disability children, the comorbid children did the worst in the sustained attention and processing speed tasks, and regression analysis showed the sustained attention deficit is likely to be an important factor which causes the comorbidity, more serious the children did in sustained attention deficit and processing speed, the possibility of the comorbidity was greater.