The specific causes of Attention Deficit Hyperactivity Disorder (ADHD) are unknown, but testing in children has shown a link between working memory and ADHD. Children with ADHD have clear weaknesses in working memory in comparison to children who do not have it. These deficits range from slight to severe.
As yet, there are no medical or clinical tests that can determine whether someone has ADHD or whether a child may develop the disorder. Scientists and researchers, however, have identified it as a complicated neurobiological condition caused by several contributing factors. It is thought that both genes and environment can cause changes in the developing brain. These changes can possibly have an effect on a child’s behavior and ability to learn.
Working memory is considered part of the executive function of the brain. Executive functions are things such as scheduling, planning, time management, and focusing on specific tasks. In working on tasks that require sustained concentration and effort, it is a person's working memory that helps to control attention and resist distraction. It is different from short-term memory, in that short-term memory functions to process information and store it momentarily for immediate use. For example, repeating a telephone number or simple driving directions involves the use of short-term memory.
Working memory is more complex and involves storing, retrieving, and processing information to achieve a specific goal, such as solving a math problem. It can only hold a certain amount of information, however. A child with ADHD experiences cognitive difficulties when there is a lot of information to be stored while completing a task. In effect, a child with ADHD has a smaller mental work space. This restricted work space means that working memory and ADHD have a strong connection in regard to working memory deficits.
In comparison to other children, ADHD children of the same age do more poorly on both verbal and written working memory tasks. The poor performance on these tasks cannot be linked to reading disorders or other learning disorders. Studies have shown that the connection between working memory and ADHD is more related to the inattention aspect of ADHD rather than to hyperactivity.
Children with the inattentive subtype of ADHD have more trouble with tasks that require the use of working memory. Children found to be at risk for numeracy and literacy problems also scored lower on tests designed to gauge working memory levels. These same children showed more behavior problems than their peers, suggesting an early connection between working memory weakness and behavior problems. The relationship between working memory and ADHD has not been found to be affected by ADHD medication or dosage levels. Children with ADHD require additional support at home and school to compensate for working memory deficits.