Anne Fleur Kortekaas-Rijlaarsdam

CHAPTER 6 114 ABS T RAC T Objectives ADHD treatment with stimulant medication is common in regular classrooms. Previous research implies that stimulants may affect the ability to profit from feedback and reward on cognitive and academic tasks. In order to determine the most effective approach to optimize school performance in children with ADHD, the current study investigated the interplay between the effects of stimulant medication and rewarded feedback using a novel motivated math task. Children with ADHD were hypothesized to be impaired in math performance compared to typically developing controls, and MPH was expected to improve the ability to profit from rewarded feedback on math performance in children with ADHD. Materials and methods Sixty-three children with ADHD (age 8-13, IQ>70) were randomly allocated to a 7 day-methylphenidate (MPH) or placebo treatment and were compared to 67 typically developing children. The motivated math task required children to solve calculations (addition) of increasing difficulty level. Difficulty level was adapted to performance. Performance was either coupled to feedback that was coupled to reward (motivation condition) or no feedback (neutral condition). Achieved difficulty level at the end of the task was the dependent variable. Data were analyzed using mixed-model analysis. Results Children with ADHD were impaired on the math task compared to typically developing children. Both groups profited equally from the motivation condition ( d =.17), resulting in better math performance. MPH improved math performance ( d =.27) but did not interact with the motivation condition. Independently, both rewarded feedback and MPH treatment resulted in normalization of math performance of children with ADHD to the level of typically developing peers. Conclusions The effects of rewarded feedback and MPH treatment on math are independent and additive. Our results emphasize the importance of rewarded feedback to improve math performance in both children with and without ADHD. Keywords: ADHD, methylphenidate, motivation, reward, feedback, math