Piece by Piece: A Puzzle-Based Serious Game for Engaging Children with ADHD (Preprint)

BACKGROUND Abstract Background: Attention-Deficit/Hyperactivity Disorder, predominantly inattentive presentation (ADHD-I), is characterized by persistent difficulties in sustaining attention, organizing tasks, and resisting distractions. Recent research indicates that serious games offer a motivating and ecologically valid platform for cognitive training, particularly for neurodiverse populations such as those with ADHD. OBJECTIVE Objective: This paper presents Piece by Piece, a novel puzzle-based serious game designed to address attentional deficits in individuals with ADHD, specifically targeting visual attention, sustained focus, and task adherence in children with ADHD predominantly inattentive presentation (ADHD-I) and combined presentation (ADHD-C). The game aims to provide optimal challenge levels and reward-driven motivation for continued engagement and task completion. METHODS Methods: Piece by Piece comprises five levels of increasing difficulty, each an n×n image-based puzzle where players rotate pieces to correct orientation. Successful completion rewards players with a short video thematically linked to the puzzle image, increasing in length with difficulty to enhance engagement and motivation. The design is informed by cognitive load theory, reinforcement learning, and flow theory. Preliminary usability testing was conducted with male students aged 6 to 12 who had been pre-identified by teachers as inattentive and clinically evaluated using the Integrated Visual and Auditory Continuous Performance Test (IVA-2). Study approval was granted by the Research Ethics Committee of Faculty of Psychology and Education at the University of Tehran (Approval Code: IR.UT.PSYEDU.REC.1403.127). RESULTS Results: Preliminary usability testing revealed high engagement and low dropout rates, suggesting the game's effectiveness in promoting sustained attention in children with ADHD-I and ADHD-C. Most participants showed strong persistence, with 6 of 9 severe ADHD students completing all levels. The game maintained a high success rate across all difficulty levels for both groups (Group 0: No/Mild ADHD; Group 1: Severe/Moderate/Invalid ADHD), supporting its engagement potential and effectiveness in minimizing avoidance behaviors. An analytical engagement score () quantified productive engagement, showing similar average scores for Group 0 (mean 67.65, SD 5.06) and Group 1 (mean 65.96, SD 9.65), though Group 1 exhibited greater variability. While overall classification models showed modest performance (), they provided preliminary evidence that behavioral metrics like duration and extra clicks can distinguish ADHD severity levels. CONCLUSIONS Conclusions: The puzzle-based serious game successfully promotes sustained visual attention, persistence, and task adherence in children with predominantly inattentive and combined ADHD presentations. Observed variability in engagement highlights individual differences and supports the game's broad suitability for neurodiverse populations. Future work will aim to enhance behavioral modeling by incorporating multimodal data such as facial expressions and gaze patterns. CLINICALTRIAL Trial Registration: The study protocol was approved by the Research Ethics Committee of Faculty of Psychology and Education at the University of Tehran (Approval Code: IR.UT.PSYEDU.REC.1403.127).