Trackball text entry for people with motor impairments

We present a new gestural text entry method for trackballs. The method uses the mouse cursor and relies on crossing instead of pointing. A user writes in fluid Roman-like unistrokes by "pulsing" the trackball in desired letter patterns. We examine this method both theoretically using the Steering Law and empirically in two studies. Our studies show that able-bodied users who were unfamiliar with trackballs could write at about 10 wpm with <4% total errors after 45 minutes. In eight sessions, a motor-impaired trackball user peaked at 7.11 wpm with 0% uncorrected errors, compared to 5.95 wpm with 0% uncorrected errors with an on-screen keyboard. Over sessions, his speeds were significantly faster with our gestural method than with an on-screen keyboard. A former 15-year veteran of on-screen keyboards, he now uses our gestural method instead. ACM Classification Keywords H.5.2. Information interfaces and presentation: User interfaces -- Input devices and strategies. K.4.2. Co...

• Type: Conference
• Year: 2006
• Where: CHI
• Authors: Jacob O. Wobbrock, Brad A. Myers
• Keywords: CHI 2006, Gestural Method, Gestural Text Entry, Human Computer Interaction, Uncorrected Errors