“…The main result of this research was the confirmation of a close relationship between ADHD and the components of comprehension and metacognition that form part of RD. On another note, the repeated finding that there is strong comorbidity between the two disorders (August & Garfinkel, 1990;Semrud-Clikeman et al, 1992;Willcutt, Pennington, Olson, Chhabildas, & Hulslander, 2005) makes it necessary to investigate the nature of this relationship that, according to recent studies, denotes an influential genetic component (Miranda, Grau, Rosel, & Meliá, 2009;Pennington et al, 2009;Willcutt, Pennington, Olson, & DeFries, 2007), calling into question the thesis that the two disorders have different cognitive and behavioral profiles, a notion that is defended by developmental psychologists (Bonafina, Newcon, McKay, Koda, & Halperin, 2000;Felton, & Wood, 1989). According to Pennington, Groisser, and Welsh (1993), the phonological processing of children with RD is affected, while their executive functions remain intact.…”