ADHD and DCD: a relationship in need of research.

Although the connection between attention deficit hyperactivity disorder (ADHD) and developmental coordination disorder (DCD) has been recognized for several decades, little research has examined the relationship between these two disorders. This paper draws attention to the contribution the cognitive-energetic model (CEM) can make in determining the specific nature of these two disorders. An information processing approach such as the CEM is a useful model to identify specific and overlapping mechanisms that are disrupted in these two disorders. This paper describes the CEM and reviews the research so-far in relation to the model. The CEM has several advantages over other models: First, it predicts which task variables will be independent or may interact, thus enabling the investigator to determine the success/failure of the task manipulation(s) and identify spurious findings. Second, the CEM links energetic factors to task variables and predicts both additive and interactive effects. Third, the CEM enables executive processes such as selective attention, working memory and inhibition to be related to both energetic and lower level processes. Fourth, by employing the CEM in clinical research, taxonomy of deficits can be derived enabling further insight into the nature of the disorders and their specific neuropsychological dysfunction. Suggestions are made for future research into the neuropsychological deficits associated with ADHD and DCD.