Stone Kayla D, Kornblad Clara A E, Engel Manja M, Dijkerman H Chris, Blom Rianne M, Keizer Anouk
Department of Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, Netherlands.
Department of Psychiatry, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.
Front Psychiatry. 2020 Feb 25;11:15. doi: 10.3389/fpsyt.2020.00015. eCollection 2020.
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.
患有身体完整性认同障碍（BIID）的个体长期（非精神病性）渴望截肢或使一个或多个功能健全的肢体（通常是腿部）瘫痪。这种渴望大概源于个体对身体的感知心理形象与身体本身的物理结构和/或功能边界之间存在不匹配。虽然神经影像学研究表明患有BIID的个体存在身体表征网络紊乱，但很少有行为学研究考察这一人群中这种被破坏的下肢表征的表现。具体而言，患有BIID的人感觉自己在当前身体中是过度完整的。也许在肢体及其周围正常处理的感觉输入无法与大脑中腿部的高阶模型（可能发育不全）进行交流。我们要求那些渴望小腿瘫痪或截肢的个体（以及一组年龄和性别匹配的对照组）在依靠视觉、触觉和本体感觉的同时，对自己腿部的大小和形状做出明确和隐含的判断。我们假设患有BIID的参与者对其受影响腿部大小的误判会比对照组同一腿部的误判更多。通过多单病例分析，我们发现患有BIID的参与者和对照组在下肢表征方面没有整体差异。因此，虽然患有BIID的人感觉身体的一部分是异样的，但他们仍然可以对肢体做出正常的基于感觉引导的隐含和明确判断。此外，这些结果表明，BIID本身并非身体形象障碍，并且对腿部表征的检查并未揭示患有BIID的个体所具有的被扰乱的身体体验。
