The Senses of Agency and Ownership in Patients With Borderline Personality Disorder

Abstract

Patients with borderline personality disorder (BPD) not only experience a strong instability in their affect and interpersonal relations but also disturbances in their self-experience, including dissociation and body-alienation symptoms. It is not yet understood whether an altered sense of ownership (SoO) or sense of agency (SoA) may contribute to these disturbances. One recent hypothesis is that patients with BPD have a reduced sense of self and are therefore more likely to misattribute external objects or actions to their own self than healthy individuals. The present study followed up this hypothesis by investigating whether BPD patients have a more flexible body representation than healthy participants. More specifically, the active rubber hand illusion (aRHI) was applied to 21 patients with BPD and the same number of healthy participants. Using established subjective, electrodermal, and behavioral measures, the participants' SoO and SoA were assessed during the aRHI. The findings show self-reported evidence for higher SoO under anatomical hand congruency as compared to anatomical incongruency, but no evidence for group differences between BPD patients and healthy participants. This finding is inconsistent with previous findings of an enhanced SoO-related body plasticity in BPD patients. Regarding SoA, the findings show self-report evidence of higher SoA in BPD patients versus healthy participants, although this group difference was not evident in the implicit SoA measure (intentional binding). In summary, the present study only reveals partial evidence for a higher body plasticity in BPD patients. Instead, the observed variability in results appears better explainable by some generally elevated perceptual suggestibility of BPD individuals.

Experimental Induction of Micro- and Macrosomatognosia: A Virtual Hand Illusion Study

“…Regarding our correlation analysis, we found a weak positive correlation (r = 0.318) between SoO and SoA across conditions. This finding is in line with previous studies (Kalckert and Ehrsson, 2012;Braun et al, 2014;Möller et al, 2020;Spychala et al, 2020) and suggests that both subjective measures do not assess completely distinct, but rather overlapping aspects of selfexperience, or that SoO and SoA promote each other (Braun et al, 2018).…”

“…This spatial constraint falls in line with several other identified top-down constraints that a perceptual object has to fulfil to become embodiable and identified as "mine" (Braun et al, 2018). A RHI is typically not inducible, for example, if the artificial hand is placed in an anatomically-implausible position (Ehrsson et al, 2005a;Kalckert and Ehrsson, 2012;Braun et al, 2014;Möller et al, 2020), or if a non-hand object is used instead of an artificial hand (Haans et al, 2008;Tsakiris et al, 2010). Following Tsakiris (2010) classification, according to which most SoO theories can be situated in a continuum ranging from bottom-up to top-down accounts, the present results rather support top-down theories of SoO.…”

“…In accordance with previous studies (Armel and Ramachandran, 2003;Alimardani et al, 2013;Braun et al, 2020;Möller et al, 2020), EDA was recorded during the syringe applications to implicitly assess the participants' level of embodiment over the virtual hand. Following the previous studies, we expected that in the case of a successful integration of the virtual hand into one's own body scheme, a fear-evoking stimulus such as a syringe would trigger a physiologically-measurable fear response.…”

The Cognitive, Ecological, and Developmental Origins of Self-Disturbance in Borderline Personality Disorder

“…Two recent experiments in BPD show contrasting results: an experiment using the Sensory Attenuation paradigm suggest that this implicit measure of SoA is abnormally decreased in a subgroup of BPD patients without non-suicidal self-injury ( 96 ). Another experiment using an intentional binding paradigm incorporated into a modified RHI paradigm provided evidence for higher self-reported SoA, but no conclusive evidence of an impaired implicit measure of SoA ( 45 ). However, these preliminary results should be interpreted with caution given their methodological limitations and lack of statistical power.…”

“…Two studies report an increased illusory limb ownership in adult women with BPD compared to healthy controls ( 43 , 44 ). A third study using a modified version of the RHI did not replicate this finding ( 45 ). Interestingly, one of these studies showed that this increased illusion occurred not only in the synchronous condition, but also in the asynchronous condition ( 44 ).…”