Design and Development of One-Switch Video Games for Children with Severe Motor Disabilities
Sebastián A. López, Fulvio Corno, Luigi De Russis · 2017 · ACM Transactions on Accessible Computing · doi:10.1145/3085957
Summary
This paper addresses a significant gap in accessible gaming: children with severe motor disabilities who rely on single-switch interfaces have limited access to action-oriented video games. While cause-and-effect and scanning-based games exist, dynamic games requiring quick responses and precise timing have been largely inaccessible to this population. The authors developed GNomon (Gaming NOMON), a software framework that adapts the NOMON probabilistic selection system for video game interaction. NOMON uses clock-face widgets where users click when a rotating hand crosses noon to make selections. By attaching these widgets to game elements, GNomon enables children to control fast-paced games using a single switch. The framework was developed through participatory design with speech therapists, physiotherapists, and psychologists from a health agency in Turin, Italy. Three games were created: One Switch Demo (single ladybug jumping), One Switch Ladybugs (selecting from four ladybugs), and One Switch Invaders (a space shooter). The research evaluated these games across two studies: a playability study with eight children ages 4-14 with severe motor disabilities (cerebral palsy, spinal muscular atrophy, Down syndrome), and a focus group with healthcare professionals assessing rehabilitation potential.
Key findings
The playability study demonstrated that GNomon-based games are learnable, effective, and enjoyable for children with severe motor disabilities. Children required on average two switch activations to understand the selection mechanism. Seven of eight participants reported having fun, and five of seven remembered the games and how to play them after one month. Error rates varied significantly based on cognitive abilities: children with only motor disabilities achieved 0% error rates, while those with combined motor and cognitive disabilities had error rates of 50-62%. Click effectiveness ranged from 56% to 100% across participants. The second session showed improvement, with average error rates decreasing from 49.8% to 43.8%. Healthcare professionals identified six rehabilitative benefits: training selective attention, visual scanning between objects, hand-eye coordination, learning to wait and respect timeouts, supporting autonomous play, and teaching educational concepts like colors and numbers. Therapists wanted to extend GNomon games to children's hospitals for both therapy and recreational use.
Relevance
This research demonstrates that action-oriented gaming can be made accessible to children who use single-switch interfaces, expanding entertainment and rehabilitation options for a population typically limited to static, scanning-based games. The GNomon framework, released as open source, enables other developers to create accessible action games. For practitioners, the study provides valuable design guidelines: simplify level structures, reduce error consequences, limit available actions, remove precision requirements, and make full game state visible. The finding that cognitive disabilities significantly impact error rates—more so than motor disabilities—is important for designing accessible games or rehabilitation tools. The research highlights the therapeutic potential of accessible gaming, connecting entertainment with rehabilitation goals. The multiplayer games developed (Balloons, Monster Maze, El GNomo Loco) point toward social inclusion through gaming, allowing children with disabilities to play alongside typically developing peers.
Tags: accessible gaming · one-switch · single-switch · motor disabilities · children · cerebral palsy · spinal muscular atrophy · rehabilitation · participatory design · game framework