The Gest-Rest Family: Exploring Input Possibilities for Wheelchair Armrests
Patrick Carrington, Jian-Ming Chang, Kevin Chang, Catherine Hornback, Amy Hurst, Shaun K. Kane · 2016 · ACM Transactions on Accessible Computing (TACCESS) · doi:10.1145/2873062
Summary
This paper introduces the Gest-Rest Family, a suite of gesture-based input devices designed to fit over standard power wheelchair armrests, enabling users with upper body motor impairments to interact with computing devices without needing to reach for or hold separate input devices. The concept of "chairable" computing — input devices integrated into the wheelchair form factor, analogous to wearable technology fitted to clothing — addresses the reality that power wheelchair users often have limited range of motion obstructed by the wheelchair frame itself. Four Gest-Rest prototypes were developed with different sensing technologies: a single large button (one binary sensor), a D-Pad (four directional buttons), an FSR-16 (a 4x4 grid of 16 force-sensitive resistors detecting pressure levels), and a touchscreen (a capacitive touch surface with hundreds of sensing points). All were built to clip onto or wrap around existing armrests without permanent modification. Two studies were conducted: a formative study with 3 power wheelchair users and 3 occupational/physical therapists evaluating the FSR-12 (an earlier prototype), followed by a comparative study with 4 wheelchair users and 4 therapists evaluating all four Gest-Rest prototypes. Participants performed standardized gestures — press, double press, triple press, swipe in four directions, and flick — on each device and rated them on ease of use, responsiveness, versatility, and preference.
Key findings
The FSR-16 and touchscreen Gest-Rests were rated highest overall, though wheelchair users and therapists preferred them for different reasons. Wheelchair users ranked the touchscreen first due to familiarity from smartphone use, while therapists ranked the FSR-16 first because of its versatility across patients with varying abilities — it could be used with any body part (fingers, palm, elbow, fist), through gloves or foam, and did not require capacitive skin contact. The integrated armrest form factor was universally valued: all participants reported an increased sense of independence since no caregiver assistance was needed for device positioning, and the always-available nature eliminated risks of dropping or losing devices. Force-sensitive input emerged as particularly promising because it combines touchscreen-like continuous surface interaction with the ability to work through materials and with non-standard body parts, overcoming capacitive touchscreen limitations for users with sensory deficits or prosthetics. Therapists noted that patients with sensory deficits might not feel button presses, suggesting additional audio or visual feedback. The single button was seen as useful for scanning interfaces and for users with the most limited dexterity, demonstrating that the family approach — offering devices at different complexity levels — addresses the wide variability within the wheelchair user population.
Relevance
This research introduces a valuable design paradigm for accessible computing: embedding input devices into the objects people already use rather than requiring them to interact with separate devices. For power wheelchair users, the armrest is always within reach and provides physical support for the arm during interaction — advantages that external devices like phones or switches cannot match. The finding that wheelchair users and therapists have different but complementary perspectives on device selection (personal preference vs. clinical versatility) reinforces the importance of including both stakeholder groups in accessible technology design. For the assistive technology industry, the Gest-Rest concept suggests that wheelchair manufacturers should consider integrating computing input capabilities into armrests as standard features. The force-sensing approach is particularly noteworthy as it addresses a gap between physical buttons (accessible but limited gestures) and touchscreens (rich gestures but require capacitive contact), offering a middle ground that accommodates the widest range of motor abilities.
Tags: wheelchair · motor impairment · input device · chairable computing · assistive technology · force sensing · touchscreen · gesture interaction · alternative input device