Avaliação da percepção de usabilidade de um sistema de feedback visual em espelhamento baseado em realidade virtual (Mirror-Up) para a reabilitação do membro superior pós-acidente vascular cerebral

Abstract

Stroke is the main cause of disability in the adult population in Brazil. Unfortunately, the functional recovery of the upper limb (UL) is fully completed only in 5% of the stroke survivors. In this context, mirror therapy (MT) has been used as an intervention to help rehabilitation process in stroke survivors and the effectiveness of the technique is likely due to the activation / plasticity in mirror neurons. However, the practice of MT has several limitations, either due to the low attractiveness / monotony of the proposed activities or the person’s difficulty in performing tasks looking exclusively at the mirror-based feedback. Thus, we developed a mobile phone system that provides a mirror-up visual feedback (Mirror-Up) to be used as low-cost virtual reality (VR) glasses / helmets. This, theoretically, minimizes such problems and enhances the illusion of mirroring. In this way, Mirror-Up inverts the individual's body image, promoting a greater sensation of being using the stroke-affected UL during the sensorimotor tasks. The goal of this study was to evaluate the usability perception of the Mirror-Up system in comparison with the traditional MT. A total of 15 participants with a history of stroke and UL disability were studied. In addition, elderly (n = 15) and young groups (n = 15) without a history of stroke were also assessed, since the age could be a confounding variable in the usability perception metrics. All 45 participants performed two identical tasks using the traditional MT and Mirror-Up system, in a random order, totaling 20 minutes of experience. At the end of the tasks, System Usability Scale (SUS) and NASA Task Load Index (NASA-TLX) as well as some opened questions regarding usability perception were applied. The frequency of complains and participant’s performance on tasks were also assessed. The study was approved by the Ethics Committee (CEP-PUCRS). The results showed both the MT and Mirror-Up did not present satisfactory levels of usability perception, without superiority of any of the experiences. In addition, Mirror-Up was found to be inferior to MT in terms of self-referred discomfort. However, the Mirror-Up prevented cheating during the tasks, which probably generated more difficulty to the participants when performing the tasks. To test new interfaces / helmets is suggested to provide greater visual comfort before conducting randomized clinical trials to determine the Mirror-Up effectiveness.