Comparing Touchscreen and Mouse Input Performance by People With and Without Upper Body Motor Impairments

Abstract

Controlled studies of touchscreen input performance for users with upper body motor impairments remain relatively sparse. To address this gap, we present a controlled lab study of mouse vs. touchscreen performance with 32 participants (16 with upper body motor impairments and 16 without). Our study examines: (1) how touch input compares to an indirect pointing device (a mouse); (2) how performance compares across a range of standard interaction techniques; and (3) how these answers differ for users with and without motor impairments. While the touchscreen was faster than the mouse overall, only participants without motor impairments benefited from a lower error rate on the touchscreen. Indeed, participants with motor impairments had a threefold increase in pointing (tapping) errors on the touchscreen compared to the mouse. Our findings also highlight the high frequency of spurious touches for users with motor impairments and update past accessibility recommendations for minimum touchscreen target sizes to at least 18mm.

Designing and implementing accessible wearable interactions for people with motor impairments

“…Irwin et al [61] investigated the use of touchscreen technology by people with gross motor impairments and found that this group exhibits longer dwell times compared to those without. When touchscreen input was compared with mouse input, Findlater et al [35] found that though touchscreen input was faster for people with motor impairments, it also led to a three-fold increase in pointing (tapping) errors on the touchscreen compared to the mouse. Some approaches to address these problems have used the edge of the screen to stabilize gestures [38,140], or a swiping ("swabbing") interaction rather than tapping, which allows the user to stabilize their finger on the screen itself [135].…”

“…But, very few gestures were created on the skin. The wider space of non-touchscreen locations in some cases relieved the need for precise input with small targets, a known problem for users with motor impairments (e.g., [35]).…”

“…Previous work has shown accessibility challenges with touchscreen interaction like performing taps on tablets (e.g., [35]) or multi-touch gestures on smartphones (e.g., [3]). Our work also highlights similar problems with taps and pinch-to-zoom for smartwatches.…”

“…On the other hand, many studies have focused on making these mobile computing devices accessible. Some examples include utilizing the physical edges of the device [38,140] for better gesture stability, or touching and sliding the finger (called swabbing) [135] for target selection or analyzing touchscreen gestures to better understand the input preferences for people with motor impairments [35,45]. Particularly for wheelchair users and more closely related to my dissertation, Carrington et al [21] explored alternative input/output spaces on and around the wheelchair for accessible mobile computing and later, built a pressure-sensitive input technique on the armrest of the wheelchair to help people with motor impairments interact with mobile computing devices [22].…”

“…Building on this body of work, we created an input system that utilizes the smartwatch bezel for interaction while also providing a potential solution to overcome the fat finger problem, a common issue with small interaction spaces (e.g., [5,52]). In this chapter we examine if expanding the interaction space to include the smartwatch bezel could potentially lead to an accessible input compared to the smartwatch touchscreen for people with upper body motor impairments who find precise touchscreen input difficult (e.g., [35,45]). More specifically, we investigated the following research question:…”