Abstract

Peter Brugger, born 1957 in Zurich, Switzerland. Acquired a teacher's Diploma for Elementary and High School levels before studying biology at Zurich University. Dissertation on Subjective Randomness: Implications for Neuropsychology and Parapsychology. Postdoctoral training at UCSD San Diego and University of Victoria (Canada). Currently head of Neuropsychology Unit of University Hospital Zurich. Main research interests: neuropsychology of paranormal beliefs and “schizotypy”; representation of body and space (Pfizer Prize for Medical Research in 2001 for work on phantoms of congenitally missing limbs); simulation of randomness by living organisms.

I will provide an introduction into “phantomology” (Stanislaw Lem) as the science of the virtual reality of body parts and the body as a whole. Phantom limb phenomena comprise a first category to be discussed. Most well-known is the phantom limb after amputation. I will focus on one neglected aspect, that is, the way amputees react when the phenomenal space of their phantom limb is invaded by a solid object. For some, the phantom percept ceases (“obstacle shunning”), some others just experience the phantom in superposition with the object, not mixing physical and virtual realities in their brain. Phenomena like obstacle shunning are important for understanding individual differences in adaptation to a prosthesis.

Phantom sensations are also experienced by a minority of persons born without a limb. These congenital phantom limbs are only briefly touched and described as an “animation without incarnation”.

Conceptualized as such, they help understand a neuropsychiatric condition, which may be conceived of as the mirror image, i.e. an “incarnation with animation”. This alludes to xenomelia (aka body integrity identity disorder), the desire for amputation of a physically normally developed limb. Such an apparently bizarre desire (per definition in the absence of psychosis or other significant psychiatric disorders) can be viewed as arising from a "negative phantom experience". This means that the affected limb has not been properly integrated into the schema of the body as a whole and is thus not experienced as belonging to one's bodily self. I review latest developments in the research in xenomelia, focusing on structural and functional alterations in the sufferers' brain, but emphasizing that an exclusively neurological view cannot explain the full range of symptoms described by xenomelic individuals.

In another category of phantom phenomena one's entire body is experienced as a phantom. After mentioning the hemiplegic twin (MacDonald Critchley) as a transition between phantom limb and phantom body, some variants of autoscopic phenomena are discussed. These involve the feeling of a presence, the experience of seeing a mirror image of oneself (autoscopic hallucination), the experience of a reduplication of body and self (heautoscopy) and out-of-body experiences. The differentiation between different types of autoscopic phenomena is clinically important, as each type is associated with a distinct pattern of lesions in occipito-parieto-insular networks subserving the integration of body and self.