Enhancing Android accessibility for users with hand tremor by reducing fine pointing and steady tapping

Smartphones and tablets with touchscreen have demonstrated potential to support the needs of individuals with motor impairments such as hand tremor. However, those users still face major challenges with conventional touchscreen gestures. These challenges are mostly caused by the fine precision requirement to disambiguate between targets on small screens. To reduce the difficulty caused by hand tremor in combination with small touch targets on the screen, we developed an experimental system-wide assistive service called Touch Guard. It enables enhanced area touch and a series of complementary features. This service provides the enhanced area touch feature through two possible disambiguation modes: magnification and descriptive targets list. In a laboratory study with motor-impaired users, we compared both modes to conventional tapping and tested Touch Guard with real-world applications. Targets list based disambiguation was more successful, reducing the error rate by 65% compared to conventional tapping. In addition, several challenges and design implications were discovered when presenting new touchscreen interaction techniques to users with motor impairments. As the experimental product of an intern research project at Google, Touch Guard demonstrates broad potential for solving accessibility issues for people with hand tremor using their familiar mobile devices, instead of high-cost hardware.