Robin Bekrater-Bodmann

The amputation of a limb requires substantial physical and psychosocial adjustment to a changed life situation. As a prosthesis often facilitates this process, its integration into one’s body representation, referred to as prosthesis embodiment, has been proposed as a marker of adjustment. Building on previous evidence that negative consequences of limb amputation are reflected in how the own body is experienced in dreams, this study examined whether prosthesis embodiment mitigates such effects. In 192 prosthesis-using individuals with acquired lower limb amputation, dream recall frequency, recalled body appearance in dreams (impaired, intact, or not remembered), and indicators of psychosocial adjustment were assessed. Dreams most frequently featured an intact body. In 113 dream recallers, higher prosthesis embodiment, unlike other psychosocial indicators, was significantly associated with a lower likelihood of recalling an impaired body. No association emerged for recalling an intact body or for absent body recall. This asymmetric pattern supports the continuity hypothesis of dreaming, suggesting that an embodied prosthesis loses salience as an amputation cue, thereby reducing waking concerns about impairment reflected in dreams. The findings provide empirical evidence that prosthesis embodiment represents cognitive integration of the device into the self-model, marking the transition from salient foreign-body representation to non-salient self-representation.

Patients with borderline personality disorder (BPD) suffer from severe emotional dysregulation and disturbances in body image and self-perception. Interoception, the processing and perception of internal body signals, is closely linked to emotional processing, but it remains unclear whether BPD impairs specific interoceptive facets and how these deficits respond to treatment. We investigated two key interoceptive facets, accuracy and attention, in BPD patients and healthy controls (HC) using self-report and objective measures before (n _BPD =55,n _HC = 31) and after (n _BPD =37,n _HC = 31) four-week residential Dialectical Behavior Therapy (DBT)/a waiting interval. Interoceptive accuracy and its metacognitive awareness were evaluated using a heartbeat discrimination task, while interoceptive attention was measured through questionnaires, intensity ratings, and uni- and multivariate neural responses during a functional magnetic resonance imaging (fMRI) interoceptive attention task. Before DBT, BPD patients showed reduced self-reported interoceptive attention, which was associated with more interpersonal problems. Patients further exhibited higher similarity in activity patterns evoked by cardiac interoceptive and exteroceptive attention in the insular and dorsal anterior cingulate cortex. There were no significant group differences in behavioral or self-reported interoceptive accuracy or metacognitive awareness. However, behavioral interoceptive accuracy was impaired in BPD patients with more severe symptoms. After four-week residential DBT, self-reported interoceptive attention significantly improved, while other interoceptive facets showed no significant changes. Our findings indicate that BPD involves selective interoceptive attention disturbances, with only self-reported measures responding to treatment. These results support multifaceted assessments of interoception and the potential benefit of interoceptive attention training for all BPD patients, with additional accuracy training in more severe cases.

Looking at one’s own body has been shown to exert analgesic effects on experimental pain stimulation. This study investigated the potential involvement of descending pain modulation and the role of body experience in this phenomenon. Non-clinical participants completed four experimental conditions with either a glass or mirror partition placed sagittally between their hands, which were either visible or covered with wooden boxes. This allowed participants to view either their left hand or the reflection of their right hand (each visible or covered), while they underwent a conditioned pain modulation (CPM) protocol with the test stimulus applied to their left hand. Disembodiment experiences regarding the left hand were additionally recorded using a questionnaire. Looking at the mirrored right hand significantly induced disembodiment experiences of the hidden left hand, even in the absence of explicit multisensory conflict. Across all conditions, significant CPM responses were observed. Although CPM responses were not modulated by mere vision of the left hand, their magnitude was significantly negatively correlated with disembodiment ratings. These results suggest that states of body experience modulate nociceptive processing through descending pathways. The findings are discussed within a body salience framework.

Background: The amputation of a limb constitutes one of the most severe disruptions of body integrity. Nevertheless, many individuals with limb amputation report a restored sense of integrity when wearing a prosthesis. The rubber limb illusion (RLI) has been proposed as an experimental model to study such experiences. In this paradigm, correlated visuo-tactile stimulation of the residual limb and an artificial limb can induce amputated individuals to experience ownership of the latter one which is then perceived as a counterpart of the missing limb. However, due to methodical limitations in previous setups, the neural processes underlying alterations in the sense of body integrity remain insufficiently understood. Methods: In this cross-sectional study, we developed a novel RLI setup to systematically manipulate the sense of body integrity in a sample of N = 34 individuals with unilateral lower limb amputation. Participants completed six randomized trials across two experiments. In Experiment 1, we varied artificial limb appearance (intact vs. impaired) and visuo-tactile stimulation (synchronous vs. asynchronous) on the residual limb. In Experiment 2, we manipulated artificial limb appearance and induced the RLI on both the residual and the non-amputated limb. Neural activity was assessed using functional magnetic resonance imaging. Results: Synchronous visuo-tactile stimulation of the residual limb and an intact artificial counterpart induced artificial limb ownership and was associated with improvements in perceived body integrity. Neuroimaging revealed specific activation in the left superior parietal lobule associated with dynamic changes in the sense of body integrity. Neural activity underlying RLI processing did not significantly differ between the residual limb and the non-amputated limb. Conclusion: Appropriate multimodal sensory stimulation can strengthen the sense of body integrity in most individuals with lower limb amputation. This effect appears to be mediated by the brain’s capacity for sensory integration within the body representation network. These insights advance our understanding of prosthesis-related experiences and may inform the development of improved prosthetic devices that employ non-invasive somatosensory feedback, thereby promoting positive rehabilitative outcomes through enhanced prosthesis embodiment.

Background: Patients with borderline personality disorder (BPD) suffer from severe emotional dysregulation and disturbances in body image and self-perception. Interoception, the processing and perception of internal body signals, is closely linked to emotional processing, but it remains unclear whether BPD impairs specific interoceptive facets and how these deficits respond to treatment. Methods: We investigated the two key interoceptive facets, accuracy and attention, in 55 BPD patients and 31 healthy controls (HC) using self-report and objective measures before and after four-week residential Dialectical Behavior Therapy (DBT). Interoceptive accuracy and its metacognitive awareness were evaluated using a heartbeat discrimination task, while interoceptive attention was measured through questionnaires, intensity ratings, and both uni- and multivariate neural responses during a functional magnetic resonance imaging (fMRI) interoceptive attention task. Results: Before DBT, BPD patients showed reduced self-reported interoceptive attention, which was associated with more interpersonal problems. Patients further exhibited higher similarity in activity patterns evoked by cardiac interoceptive and exteroceptive attention in the insular and dorsal anterior cingulate cortex. There were no significant group differences in behavioral or self-reported interoceptive accuracy or metacognitive awareness. However, behavioral interoceptive accuracy was impaired in BPD patients with more severe symptoms. After four-week residential DBT, self-reported interoceptive attention significantly improved, while other interoceptive facets showed no significant changes. Conclusions: BPD involves disturbances in specific interoceptive facets that respond differently to treatment. Our findings support multifaceted assessments of interoception and the potential benefit of interoceptive attention training for all BPD patients, with additional accuracy training in more severe cases.

Negative cognitions related to one’s own body, here referred to as body image disturbances (BID), are common after lower limb amputation and correlate with weak psychological functioning. The Amputee Body Image Scale (ABIS) is internationally used to assess BID in persons with lower limb amputation. However, there is no psychometrically evaluated German adaptation available. Including a sample of 191 individuals with lower limb amputation, the present study developed and psychometrically evaluated the German ABIS. Results suggest high reliability in terms of internal consistency and stability of the measure over two years. Meaningful and significant relationships to sex, amputation level, post-amputation pain, mobility, and psychopathology indicate validity of the instrument. Multivariate analyses emphasize a specific and inverse relationship between BID and psychosocial adaptation to the prosthesis including its embodiment. Focussing on ABIS items that are independent of the type of amputation or rehabilitation experiences resulted in an ABIS short form with psychometric properties comparable to the long form. This instrument could be prospectively used in diverse limb loss populations, such as individuals with upper limb amputation or persons not using a prosthesis. The present results thus crucially contribute to the repertoire of patient-reported outcome measures in the context of post-amputation rehabilitation.