Poster A96, Saturday, March 24, 1:30–3:30 pm, Exhibit Hall C
Where’s my foot? The disappearing ‘foot’ trick in healthy individuals and individuals with Body Integrity Identity Disorder
Kayla D. Stone1, Femke Bullock1, Anouk Keizer1, Rianne Blom2, Manja Engel1, H. Chris Dijkerman1; 1Utrecht University, 2University of Amsterdam
Body ownership (the feeling that my body belongs to me) can be easily perturbed in healthy individuals by inducing bodily illusions. For example, dis-integrating vision, touch, and proprioception can produce the feeling that your limb is ‘lost’ or ‘relocated’, such as in “the disappearing hand trick” (DHT). Following this illusion, participants report that the hand feels as though it is no longer part of the body, that it does not belong to them anymore, and that they do not know its location (Newport and Gilpin, 2011 (Current Biology)). This experience is critically linked to the feeling of body ownership and partly mimics the feelings associated with body ownership disorders. For instance, in body integrity identity disorder (BIID), individuals feel like part of their bodies (usually their legs) do not belong to them or that it should not function, leading to the desire to amputate (amputation-variant) or paralyze (paralysis-variant) that part of the body. Therefore dis-integrating sensory input around the lower body (and thus simulating the desired bodily state) might transiently relieve the feelings associated with BIID. In the current study, we modified the DHT and instead applied it to the feet in a group of healthy controls and in a small sample of individuals with BIID. Results revealed that the illusion can indeed be applied to the feet (measured via a 20-item questionnaire), which was experienced as particularly pleasant for amputation-variant BIID participants as it mimicked the desired state of their bodies/limbs. Inducing bodily illusions might temporarily relieve BIID symptoms.
Topic Area: PERCEPTION & ACTION: Multisensory