Disruption of spatial task performance in anorexia nervosa.

Dewi Guardia,Olivier Cottencin,Aurélie Carey,Marion Luyat,Pierre Thomas,Alessio Avenanti

doi:10.1371/journal.pone.0054928

Abstract

In anorexia nervosa (AN), body distortions have been associated with parietal cortex (PC) dysfunction. The PC is the anatomical substrate for a supramodal reference framework involved in spatial orientation constancy. Here, we sought to evaluate spatial orientation constancy and the perception of body orientation in AN patients. In the present study, we investigated the effect of passive lateral body inclination on the visual and tactile subjective vertical (SV) and body Z-axis in 25 AN patients and 25 healthy controls. Subjects performed visual- and tactile-spatial judgments of axis orientations in an upright position and tilted 90° clockwise or counterclockwise. We observed a significant deviation of the tactile and visual SV towards the body (an A-effect) under tilted conditions, suggesting a multisensory impairment in spatial orientation. Deviation of the Z-axis in the direction of the tilt was also observed in the AN group. The greater A-effect in AN patients may reflect reduced interoceptive awareness and thus inadequate consideration of gravitational inflow. Furthermore, marked body weight loss could decrease the somatosensory inputs required for spatial orientation. Our study results suggest that spatial references are impaired in AN. This may be due to particular integration of visual, tactile and gravitational information (e.g. vestibular and proprioceptive cues) in the PC.

Highlights

Key symptoms of anorexia nervosa (AN) include (i) disturbance in the way in which one’s body weight or shape is experienced, (ii) an undue influence of body weight or shape on self-evaluation and (iii) a persistent lack of recognition of the seriousness of low body weight; AN patients perceive themselves to be larger than they really are [1]
The AN patients’ greater sensitivity to visual information in this task somewhat contradicts their greater sensitivity to proprioceptive information in the sizeweight illusion (SWI) paradigm found by Case et al [23], these results generally suggest that multisensory integration in AN is different from healthy subjects
Spatial cognition was analyzed in patients with AN and healthy control participant by using tasks involving the manual adjustment of a rod to the vertical or the body midline when the body was upright and when it was tilted

Summary

Introduction

Key symptoms of anorexia nervosa (AN) include (i) disturbance in the way in which one’s body weight or shape is experienced, (ii) an undue influence of body weight or shape on self-evaluation and (iii) a persistent lack of recognition of the seriousness of low body weight; AN patients perceive themselves to be larger than they really are [1]. The AN patients’ greater sensitivity to visual information in this task somewhat contradicts their greater sensitivity to proprioceptive information in the SWI paradigm found by Case et al [23], these results generally suggest that multisensory integration in AN is different from healthy subjects. The latter may be related to overestimation of the body schema

Objectives

Results

Conclusion