Is executive function specifically impaired in children with neurofibromatosis type 1? A neuropsychological investigation of cognitive flexibility.

Our study investigated spontaneous versus reactive cognitive flexibility in children with neurofibromatosis type 1 (NF1) and their comorbidity with attention-deficit hyperactivity disorder (ADHD). Thirty children with NF1 aged 7 to 12 years old were compared to 60 healthy controls matched by age, gender, and parental education. On the basis of Eslinger and Grattan's definition ( 1993 ), spontaneous shifting was assessed using fluency tests, whereas reactive flexibility was measured by a child adaptation of the Modified Card-Sorting Test and the Brixton Test. IQ and basic skills were taken into account as confounding variables that might influence executive measures. NF1 children performed below the level of healthy children on both reactive flexibility tasks, even when intelligence and basic skills were partialled out, but ADHD symptomatology was not found to adversely affect the performance of patients. Our findings support the hypothesis of a specific executive impairment in NF1, uncovering a dissociation between (impaired) reactive flexibility and (preserved) spontaneous shifting, with no impact of ADHD on executive performance.