Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Feb 25;11:15.
doi: 10.3389/fpsyt.2020.00015. eCollection 2020.

An Investigation of Lower Limb Representations Underlying Vision, Touch, and Proprioception in Body Integrity Identity Disorder

Affiliations
Free PMC article

An Investigation of Lower Limb Representations Underlying Vision, Touch, and Proprioception in Body Integrity Identity Disorder

Kayla D Stone et al. Front Psychiatry. .
Free PMC article

Abstract

Individuals with Body Integrity Identity Disorder (BIID) have a (non-psychotic) longstanding desire to amputate or paralyze one or more fully-functioning limbs, often the legs. This desire presumably arises from experiencing a mismatch between one's perceived mental image of the body and the physical structural and/or functional boundaries of the body itself. While neuroimaging studies suggest a disturbed body representation network in individuals with BIID, few behavioral studies have looked at the manifestation of this disrupted lower limb representations in this population. Specifically, people with BIID feel like they are overcomplete in their current body. Perhaps sensory input, processed normally on and about the limb, cannot communicate with a higher-order model of the leg in the brain (which might be underdeveloped). We asked individuals who desire paralysis or amputation of the lower legs (and a group of age- and sex-matched controls) to make explicit and implicit judgments about the size and shape of their legs while relying on vision, touch, and proprioception. We hypothesized that BIID participants would mis-estimate the size of their affected leg(s) more than the same leg of controls. Using a multiple single-case analysis, we found no global differences in lower limb representations between BIID participants and controls. Thus, while people with BIID feel that part of the body is foreign, they can still make normal sensory-guided implicit and explicit judgments about the limb. Moreover, these results suggest that BIID is not a body image disorder, per se, and that an examination of leg representation does not uncover the disturbed bodily experience that individuals with BIID have.

Keywords: body integrity dysphoria; body ownership; body perception; lower limbs; multisensory; xenomelia.

Figures

Figure 1
Figure 1
(A) Image showing an example trial from the Template Matching Task. Participants were presented with distorted images of their own legs and asked to judge whether the leg was wider/slender (or longer/shorter, not pictured here) than their own leg by clicking one of the buttons on either side of the image. (B) Image showing setup for localization task, in an example trial of the Real condition. Participants placed their legs under a television screen and were asked to click-to-indicate (using a mouse in their right hand, not pictured here) the position of different leg landmarks. (C) Image showing an example trial from the tactile distance estimation task. Two unseen points were applied to the leg in the vertical (pictured here) or horizontal direction. (D) Image showing example response for the tactile distance estimation task. While blindfolded, participants judged the distanced between the two applied points (e.g. as shown in C.) using their thumb and index finger on a touchscreen tablet.
Figure 2
Figure 2
Bar graph showing proportion mis-estimation (1 is veridical) for judgments of images distorted width-wise or length-wise in the Template Matching Task. The white bars represent estimates of the right leg in controls. The grey bars represent estimates of the left leg in controls. Error bars represent standard deviation. The horizontal line positioned at y = 1 denotes veridical performance on this task. Each colored point represents a BIID participant. RA, right amputation; LA, left amputation; BA, bilateral amputation; P, paralysis in the legend. The preceding numbers denotes participant number.
Figure 3
Figure 3
Bar graph showing percent mis-estimation of distances applied horizontally (width-wise) and vertically (length-wise) to the shins. The white bars represent percent mis-estimation for the right shin in controls. The grey bars represent percent mis-estimation for the left shin in controls. Error bars represent standard deviation. Negative values suggest under-estimation of distances applied and positive values suggest over-estimation of distances applied. Individual colored point represents percent mis-estimations for each BIID participant. RA, right amputation; LA, left amputation; BA, bilateral amputation; P, paralysis in the legend. The preceding numbers denotes participant number. Note that some estimations were so similar in BIID participants that their points overlapped. **p < 0.001 and denotes that control participants overestimated more for distances applied horizontally versus vertically.
Figure 4
Figure 4
Bar graph showing percent mis-estimation of distances applied horizontally (width-wise) and vertically (length-wise) to the forearms. The white bars represent percent mis-estimation for the right forearm in controls. The grey bars represent percent mis-estimation for the left forearm in controls. Error bars represent standard deviation. Negative values suggest under-estimation of distances applied and positive values suggest over-estimation of distances applied. Individual colored point represents percent mis-estimations for each BIID participant. P = paralysis in the legend. The preceding numbers denotes participant number. Note that some estimations were so similar in BIID participants that their points overlapped. **p < 0.001 and denotes that control participants overestimated more for distances applied horizontally versus vertically.
Figure 5
Figure 5
Bar graph showing lower leg normalized shape indices (NSI). The white bars represent NSIs for the right shin in controls. The grey bars represent NSIs for the left shin in controls. Error bars represent standard deviation. The grey horizontal bar at y = 1 denotes veridical shape perception of the lower leg. Individual colored point represents lower leg NSIs for each BIID participant. RA, right amputation; LA, left amputation; BA, bilateral amputation; P, paralysis in the legend. The preceding numbers denotes participant number. Note that some estimations were so similar in BIID participants that their points overlapped. *p < 0.05 and denotes that, for control participants, NSIs in the Real condition were significantly higher than NSIs in the Imagine condition, and NSIs in the Mannequin condition were significantly higher than NSIS in the Imagine condition (regardless of leg). Note: miniature y-ticks following NSI of 5 each correspond to a value of 5 in order to display extremely high NSIs from participant 1 (i.e. NSI Right leg Imagine = 86.9; NSI Left leg Imagine = 20.8).

Similar articles

See all similar articles

References

    1. First MB, Fisher C. Body integrity identity disorder: the persistent desire to acquire a physical disability. Psychopathology (2012) 45:3–14. 10.1159/000330503 - DOI - PubMed
    1. Veale D. A compelling desire for deafness. J Deaf Stud Deaf Educ (2006) 11:369–72. 10.1093/deafed/enj043 - DOI - PubMed
    1. Gutschke K, Stirn A, Kasten E. An overwhelming desire to be blind: similarities and differences between body integrity identity disorder and the wish for blindness. Case Rep Ophthalmol (2017) 8:124–36. 10.1159/000456709 - DOI - PMC - PubMed
    1. Blom RM, Hennekam RC, Denys D. Body integrity identity disorder. PloS One (2012) 7:E34702. 10.1371/journal.pone.0034702 - DOI - PMC - PubMed
    1. Aoyama A, Krummenacher P, Palla A, Hilti LM, Brugger P. Impaired spatial-temporal integration of touch in Xenomelia (Body Integrity Identity Disorder). Spat Cognit Comput (2012) 12:96–110. 10.1080/13875868.2011.603773 - DOI

LinkOut - more resources

Feedback