Modulation of a Rubber Hand Illusion by Different Levels of Mental Workload: An EEG Study

The current study aimed to investigate the impact of externally evoked mental workload on the level of an artificial hand ownership sensation, a component of the embodiment phenomenon (feeling an external object, in this case a fake upper limb, as part of one’s body). The process of embodiment is extensively investigated in the literature also to find solutions for promoting the acceptance of prosthetic limbs. Before a traditional procedure for summoning in healthy subjects a Rubber Hand Illusion (RHI), the participants performed memory-related tasks in easy or demanding conditions to generate, respectively, low and high mental workloads. Alongside the behavioral correlates of the body ownership in the form of a proprioceptive drift (the measure of the correspondence between the perceived position of the actual limb and the fake one), EEG data was also collected. The results, both behavioral and neural, suggest that a high mental workload before the RHI experience leads to a low level of body ownership, whereas a low one enhances it. This can be interpreted as a consequence of distracting mental resources (possibly a specific type of them) from the embodiment stimulation session.