Subjective perceptions when using motion tracking systems. A comparison among healthy subjects, individuals post-stroke, and therapists

Abstract

[EN] Tracking technologies allow users to interact with virtual reality environments. Most research regarding tracking systems has focused on studying their performance parameters. However, even though subjective parameters also determine the responses evoked by the virtual reality experience, little effort has been made to study their influence. The objective of this paper is to determine the subjective perceptions of healthy subjects, individuals poststroke, and physical therapists after using three tracking technologies (optical, electromagnetic, and skeleton tracking) to interact with a virtual rehabilitation exercise. Three groups participated in the experiment, involving healthy subjects (n = 19), individuals with stroke (n = 22), and physical therapists (n = 14). Participants belonging to the healthy and stroke groups interacted with a stepping exercise in three 15-minute trials using the three tracking systems. After each trial, participants filled in an ad-hoc questionnaire to report their subjective experiences. Physical therapists monitored 45 training sessions with the virtual rehabilitation exercise, 15 sessions with each tracking technology in randomized order. After the last session, they evaluated the three tracking systems completing another questionnaire. By and large, results showed that healthy subjects and physical therapists mainly preferred the skeleton tracking solution rather than the optical and electromagnetic solution (in that order). However, individuals post-stroke preferred the optical solution to the other options. In conclusion, subjective perceptions and preferences are far from being constant among different populations, thus suggesting that these considerations, together with the performance parameters, should be taken into account when designing rehabilitation systems.