Implicit Mental Motor Imagery Task Demonstrates a Distortion of the Body Schema in Patients With Eating Disorders

A rich body of literature has established the role of body image distortion and dissatisfaction in the development and maintenance of eating disorders. However, many of the currently used techniques require explicit comparison of the person's body to an external stimulus. As the body schema is a largely unconscious construct, explicit comparison tasks may reflect a proxy, rather than the body schema itself.

Here we use an implicit mental motor imagery (MMI) task to interrogate the body schema in healthy control participants (N=40) and participants at a residential eating disorder treatment center (N=42). By comparing the time it takes to imagine making a movement along a part of the body to the time it takes to actually make the same movement, we were able to assess participants' mental image of their body (i.e., body schema).

We found that participants with eating disorders, but not healthy controls, exhibited distortions of the body schema such that they believed their abdomen, buttocks, and thighs to be larger than they really are. Additionally, the MMI task used here provided information above and beyond traditional self-report measures (i.e., Body Shape Questionnaire). Together the MMI task and traditional measures provide the most information.

Findings using the novel MMI task are in line with the literature; participants with eating disorders consider themselves to be larger than they truly are. Taken together, results of this study suggest that MMI tasks provide complementary information to traditional self-report measures. (JINS, 2018, 24, 715-723).