Psychological and Psychophysiological Responses to Challenge Variations for Virtual Hand Training in Game-based Smart Rehabilitation System

Abstract

Background: Maintaining motivation is one of the most important characteristics of rehabilitation strategies for successful treatment. Understanding the underlying mechanism of mental state is helpful for developing new therapeutic methods based on virtual reality and serious game technologies. Objective: The present study aims to develop a cost-benefit game-based hand rehabilitation system and assess the influence on the psychological state of subjects when they interact with a virtual reality environment in different task difficulty levels. Methods: First, we introduced a low-cost smart hand rehabilitation system based on the Leap Motion tracker; then, the experimental study was performed with 20 healthy participants. Their mental states were evoked using interaction with two separate games in four different difficulty levels. Three measures from the SAM self-reported test described as a psychological response to this condition, and also four features were extracted from Photoplethysmogram signal in order to quantify psychophysiological responses of Autonomic Nervous System. Results: Comparison of the different difficulty levels revealed significant changes in arousal and dominance correspond to under challenging and over the challenging condition, respectively. The results of psychophysiological feature analysis showed significant differences only for the standard deviation of intervals between consecutive heartbeats. Conclusion: The developed system is a low-cost smart solution that can be useful for upper limb neurological rehabilitation. Regulating difficulty parameters of the implemented game can be used to influence the motivation of users through rehabilitation procedures. It seems Photoplethysmogram is an appropriate psychophysiological indicator of mental states, but further studies are required.