A ansiedade na perceção de ilusões corporais

: insights a partir do paradigma clássico da Rubber Hand Illusion

Abstract

Introduction: The Rubber Hand Illusion paradigm (RHI) is a bodily illusion that
induces the sensation that a rubber hand is actually one's own hand through synchronous stimulation and manipulation of neuronal processes that underlie exteroceptive visuotactile intergration. The task measures, essentially, two quantitative metrics with their own variables that indicate whether the illusion was succesfully assimilated: sense of belonging (SP) and the proprioceptive drift (PD) that occurs as a product of the illusion. To date, it is believed that the illusion is the end result of the integration of ascending neural signals of three main sensory modalities: proprioceptive, visual, and tactile pathways. Because of the cross modal congruency effect (CCE), the processing of these same ascending neural signals are more strongly integrated, especially since the
field of stimulation (CCE) is within the subject's visuotactile field. To this extent, it is expected that the subjects experiencing the illusion that present a diminished capacity to distuingish, detect, and interpret bodily signals, are more vulnerable to the illusion. Objective: The present study's directive and purpose is to investigate whether the individual differences in subject's anxiety, which is known to affect bodily interoceptive and exteroceptive processes and signals, are associated to the bodily illusion's experience and resulting vulnerability. The investigation's main hypothesis pertains to the individual anxiety difference in subjects that do not have a clinical diagnostic. Methodology: 83 subjects participated in the present study and completed the classical Rubber Hand Illusion paradigm (RHI) of synchronous and asynchronous stimulation, that is a good indicator of assessment of vulnerability to external cues according to
subjective metrics (Sense of belonging questionnaire) and behavioural metrics
(proprioceptive drift). The State-Trait Anxiety Inventory (STAI) was also administered in order to evaluate subject's anxiety and anxiety-trait.
4 Results: As expected, we observed Sense of Belonging scores that were significantly higher in the synchronous condition than those of the asynchronous condition, as well as higher scores in the experimental items than the control ones. The deviations in the proprioceptive drifts were also higher in the synchronous condition than in the asynchronous one, even though differences were not statistically significative. A statistically significative correlation was found between STAI scores, experimental items and control items of the Sense of belonging questionnaire in the asynchronous condition. Conclusion/Discussion: The results seem to suggest that particpants who suffer more from anxiety are indeed more vulnerable to the perceptive illusion. This manifests itself as an increased sense of belonging under conditions of absence of reinforcement of tactile information and through unexpected sensations when exposed to those same conditions. These results support the idea that anxiety, even in non-clinical levels, is associated to an increase in difficulty in dealing with proprioceptive signals predisposing individuals to atypical multisensory integration processes.

Date of Award	7 Dec 2023
Original language	Portuguese
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Rita Canaipa (Supervisor)