The two dimensions of the body representation in women suffering from Anorexia Nervosa

A core symptom of Anorexia Nervosa (AN) is a severe alteration of body representations. Evidence from somatoperception studies point to a generic disturbances of somatosensory components of body re- presentations. Here we have investigated whether AN patients (N1⁄418) and controls differed in the perception of tactile stimuli differently oriented along the body axes. We tested the hypothesis that patients perceive and represent their body selectively larger in only one dimension. To this aim we used elementary tactile measures for tactile acuity (Von Frey's test and two-point discrimination thresholds – 2 PD) and tactile discrimination measures. The rationale is based on the assumption that AN patients have a wider body representation, and that tactile body representation tasks (Tactile Distance task) or- iented across the bodies (horizontally) are influenced by distorted body representations compared with tactile stimuli oriented along the bodies (vertically) which should not be influenced by body re- presentations. Results showed that patients judged horizontal tactile stimuli significantly wider than the same stimuli oriented vertically.These results suggest that human brain perceives things differently based on body representations and that the beliefs concerning body size influence the specific soma- tosensory process of tactile experience.