A Performance Evaluation of Nomon: A Flexible Interface for Noisy Single-Switch Users

TL;DR

This study compares Nomon, a probabilistic single-switch interface, to traditional row-column scanning, demonstrating Nomon's superior speed and ease of use over extended periods and in diverse tasks, including with motor-impaired users.

Contribution

The paper introduces a webcam-based switch to simulate motor-impaired user responses and provides a comprehensive performance evaluation of Nomon versus row-column scanning.

Findings

Users typed faster with Nomon than with row-column scanning.

Nomon improved performance in picture-selection tasks.

Motor-impaired user feedback supports Nomon's effectiveness.

Abstract

Some individuals with motor impairments communicate using a single switch -- such as a button click, air puff, or blink. Row-column scanning provides a method for choosing items arranged in a grid using a single switch. An alternative, Nomon, allows potential selections to be arranged arbitrarily rather than requiring a grid (as desired for gaming, drawing, etc.) -- and provides an alternative probabilistic selection method. While past results suggest that Nomon may be faster and easier to use than row-column scanning, no work has yet quantified performance of the two methods over longer time periods or in tasks beyond writing. In this paper, we also develop and validate a webcam-based switch that allows a user without a motor impairment to approximate the response times of a motor-impaired single switch user; although the approximation is not a replacement for testing with single-switch users, it allows us to better initialize, calibrate, and evaluate our method. Over 10 sessions with the webcam switch, we found users typed faster and more easily with Nomon than with row-column scanning. The benefits of Nomon were even more pronounced in a picture-selection task. Evaluation and feedback from a motor-impaired switch user further supports the promise of Nomon.