Influence on the user's emotional state of the graphic complexity level in virtual therapies based on a robot-assisted neuro-rehabilitation platform

•In this study we've tried to analyze the influence of using different levels of graphic detail on virtual rehabilitation environments with the same physical workload, on an ADL simulated task-environment.•From the GSR parameters we have detected significant differences between the basal values and those corresponding to both therapeutic stages.•The only index who presents a different behavior is the pNN50 which does not show significant differences in the comparison between the different stages.•The amount of detail of the graphic interface used in RSG environments of neuro-assisted rehabilitation influences the subjective perception of the user, who finds a detailed environment more pleasant and attractive than a schematic one. In recent years, a remarkable trend in neurorehabilitation is the combination of conventional methods and emerging technologies, such as robotic platforms with virtual reality (VR), Serious Games (SG) and other types of sophisticated graphic interfaces. The aim of the present study is to evaluate the influence on the user's mental workload of the degree of graphic detail present in this kind of environments, comparing the experience of subjects working with two graphical environments with the same physical load but radically different graphic detail levels. The same therapy is performed by 52 healthy subjects in two totally different graphic environments, one rich in details and visual stimuli, and its schematic version focusing just in the target graphic elements. Autonomic Nervous System (ANS) activity, related to emotional state, is analyzed through the capture and processing of associated physiological signals. The SAM test is used to assess the subjective perception of the participants in order to establish a relationship with the calculated physiological parameters. Indexes calculated from the ANS physiological signals show significant differences between the basal state and those corresponding to the performance of the therapies but do not allow discriminating between the effects of performing a therapy based on an environment rich in stimuli and an austere one. In the case of subjective perceptions, based on the results of the SAM test, the subjects perceive significant differences between the basal stage and the therapies, and also between each of the two graphic environments. Users reflected that a graphic environment rich in detail was more pleasant and attractive than a schematic one. However, this is not reflected in