CONCLUSIONS: The findings support the validity of Attention Slackline for assessing hyperactivity/impulsivity symptoms in children with ADHD. However, its efficacy decreases in adolescents, potentially due to developmental factors, such as compensatory strategies and ceiling effects in task performance. The gamified nature of the tool enhances engagement, which is crucial for young populations, while maintaining its diagnostic utility in measuring impulsivity. The age-dependent validity aligns…