Patients with anorexia nervosa may be using an “obsolete” body schema to judge whether or not they can walk through a doorway, but they are still able to assess other people’s capability to pass through normally, finds a French study.
Although people with anorexia have long been known to have a distorted body image, these new experiments looked at a different aspect of self-image – the body schema – the sensorimotor representation of the body used when moving about.
Building on their previous work which showed that people with the eating disorder overestimated their size when imagining walking through a doorway, the current study of 25 women with
anorexia and 25 healthy controls confirmed the earlier findings and demonstrated that the effect did not occur when judging whether a person standing next to them could get through the doorway.
“These data [are] concordant with the patients’ clinical complaints that they feel larger than they really are,” the authors wrote in PLoS one. There was also a significant positive correlation between the
overestimation of their own size and scores on the EDI-2 “drive for thinness” scale, and analysis of a subgroup of patients who had lost weight over the preceding 6 months showed the greater the weight loss, the more difficult they perceived getting through the door, they wrote.
The finding provided a possible explanation for the disruption of body-scaled actions in anorexic people, they said: “the body schema modified by the rapid weight loss may not have been updated by the CNS.”
Patients would find themselves “locked into a larger body”, they suggested, although they were hopeful that the virtual reality ‘full-body illusion paradigm’ might help with treatment of the distortions.
As first appeared in Psychiatry Update, 30 August 2012. Source:PLoS one, 2012: doi: 10.1371/journal.pone.0043241