CheerBrush: A Novel Interactive Augmented Reality Coaching System for Toothbrushing Skills in Children with Autism Spectrum Disorder
Z. Kevin Zheng, Nandan Sarkar, Amy Swanson, Amy Weitlauf, Zachary Warren, Nilanjan Sarkar · 2021 · ACM Transactions on Accessible Computing · doi:10.1145/3481642
Summary
CheerBrush is an augmented reality system designed to teach toothbrushing skills to children with autism spectrum disorder (ASD). Many children with ASD struggle with toothbrushing due to differences in motor dexterity, learning styles, and sensory sensitivity—leading to poor oral health, increased dental visits, and negative social consequences from breath odor. The system combines several components: a Microsoft Kinect V2 camera that tracks children's movements and projects them onto a 40-inch display (functioning like a mirror), a virtual avatar that demonstrates brushing steps with multimodal cues (visual arrows, audio instructions like "Grab the brush"), and a custom 3D-printed mechatronic toothbrush with embedded sensors to measure actual brushing motion during assessment. An E4 wristband monitors physiological stress indicators (heart rate, skin conductance) throughout the session. The coaching breaks toothbrushing into subtasks across four difficulty levels (beginner, simple, medium, hard), progressively adding complexity. Children manipulate virtual objects by moving their hands in the air—the system maps their real movements onto virtual toothbrush and toothpaste objects. A finite state machine controls the progression, providing real-time feedback and adjusting difficulty based on performance.
Key findings
A feasibility study with 12 children (6 with ASD, 6 typically developing, ages 3-6) showed promising results. Both groups completed the coaching and showed improvement in brushing skills as measured by the mechatronic toothbrush. The ASD group showed statistically significant improvement in brushing distance (p=0.03), with brushing patterns becoming closer to adult benchmarks after just one 30-minute session. Physiological monitoring revealed reduced stress during coaching compared to baseline: heart rate decreased 11.15% for children with ASD and skin conductance decreased 26.76%. This suggests the AR environment created a low-stress learning context—important because anxiety often interferes with skill acquisition. Engagement was high: children with ASD looked at relevant regions of interest (face, brush, avatar) 66% of the time, while typically developing children looked 82% of the time. Parent questionnaires showed strong approval, with high ratings for enjoyment (4.42/5), instructional helpfulness (4.25/5), and increased interest in toothbrushing (4.67/5). The hard difficulty level revealed significant differences—children with ASD spent 24.69% longer than TD children—reflecting the known challenges with fine motor coordination in this population.
Relevance
This research demonstrates how AR can provide accessible, engaging coaching for daily living skills that children with ASD typically struggle to learn through conventional instruction. The closed-loop, adaptive system responds to each child's performance in real-time, unlike traditional open-loop approaches (videos, picture cards) that cannot adjust to individual needs. For accessibility practitioners, the multimodal approach is notable: visual cues (arrows, color-coded targets), audio instructions, avatar demonstrations, and gamification (coin rewards, scores) work together to accommodate different learning styles. The stress monitoring component highlights the importance of creating low-anxiety learning environments for effective skill transfer. The relatively low prototype cost (~$71 for the mechatronic brush, plus Kinect hardware) suggests potential for accessible deployment. Limitations include the current focus only on mesial and facial tooth surfaces, the need for children to sit 1.5 meters from the Kinect, and the single-session study design. Future work should establish whether skills transfer to real-world toothbrushing over time.
Tags: autism spectrum disorder · augmented reality · daily living skills · children · motor skills · behavioral coaching · assistive technology