On the Evaluation of Engagement in Immersive Applications When Users Are on the Autism Spectrum.

New generation wearable devices allow for the development of interactive environments tailored for Virtual Reality (VR)- and Augmented Reality (AR)-based treatment of Autism Spectrum Disorders (ASD). Experts agree on their potential; however, there is lack of consensus on how to perform trials and the need arises for evaluation frameworks, methods, and techniques appropriate for the ASD population. In this paper, we report on a study conducted with high-functioning ASD people in the 21-23 age range, with the objectives of (1) evaluating the engagement of two headsets offering distinct immersive experiences, (2) reasoning on the interpretation of engagement factors in the case of ASD people, and (3) translating results into general guidelines for the development of VR/AR-based ASD treatment. To this aim, we (1) designed two engagement evaluation frameworks based on behavioral observation measures, (2) set up two packages of reference immersive scenarios, (3) defined the association between metrics and scenarios, and (4) administered the scenarios in distinct sessions for the investigated headsets. Results show that the immersive experiences are engaging and that the apparent lack of success of some evaluation factors can become potential advantages within the framework of VR/AR-based ASD treatment design.