(HealthDay News) – Patients with anorexia nervosa (AN) tend to overestimate the size of their body but not the bodies of others, basing their weight and body dimensions on their pre-AN body dimensions.

Dewi Guardia, MD, of the University Hospital of Lille in France, and colleagues conducted a study involving 25 patients with AN and 25 control patients who were shown a door-like aperture and asked whether they felt that the opening was wide enough for them to pass through (first-person perspective [1PP]) and for another person present in the testing room to pass through (third-person perspective [3PP]).

The researchers found that AN patients were able to more accurately judge others’ ability to pass through the opening than their own. This perception was strongly correlated with the patient’s body weight and size before the onset of AN, which suggests that these people continue to think of themselves as their previous size.

“Overall, our findings suggest that the anticipation of body-scaled actions can be strongly disturbed in AN,” the authors write. “The body schema overestimation bias observed in AN seems solely related to the patient’s own body action and may be related to specific brain regions involved in the body schema but perhaps also on [brain] regions underlying judgments at 1PP. A mismatch between the actual sensory feedback and the cortical regions representing the body may lead to the maintenance of an incorrect body representation.”

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