A Virtual Reality Full Body Illusion Improves Body Image Disturbance in Anorexia Nervosa.

BACKGROUND:Patients with anorexia nervosa (AN) have a persistent distorted experience of the size of their body. Previously we found that the Rubber Hand Illusion improves hand size estimation in this group. Here we investigated whether a Full Body Illusion (FBI) affects body size estimation of body parts more emotionally salient than the hand. In the FBI, analogue to the RHI, participants experience ownership over an entire virtual body in VR after synchronous visuo-tactile stimulation of the actual and virtual body. METHODS AND RESULTS:We asked participants to estimate their body size (shoulders, abdomen, hips) before the FBI was induced, directly after induction and at ~2 hour 45 minutes follow-up. The results showed that AN patients (N = 30) decrease the overestimation of their shoulders, abdomen and hips directly after the FBI was induced. This effect was strongest for estimates of circumference, and also observed in the asynchronous control condition of the illusion. Moreover, at follow-up, the improvements in body size estimation could still be observed in the AN group. Notably, the HC group (N = 29) also showed changes in body size estimation after the FBI, but the effect showed a different pattern than that of the AN group. CONCLUSION:The results lead us to conclude that the disturbed experience of body size in AN is flexible and can be changed, even for highly emotional body parts. As such this study offers novel starting points from which new interventions for body image disturbance in AN can be developed

A Virtual Reality Full Body Illusion Improves Body Image Disturbance in Anorexia Nervosa

BACKGROUND: Patients with anorexia nervosa (AN) have a persistent distorted experience of the size of their body. Previously we found that the Rubber Hand Illusion improves hand size estimation in this group. Here we investigated whether a Full Body Illusion (FBI) affects body size estimation of body parts more emotionally salient than the hand. In the FBI, analogue to the RHI, participants experience ownership over an entire virtual body in VR after synchronous visuo-tactile stimulation of the actual and virtual body. METHODS AND RESULTS: We asked participants to estimate their body size (shoulders, abdomen, hips) before the FBI was induced, directly after induction and at ~2 hour 45 minutes follow-up. The results showed that AN patients (N = 30) decrease the overestimation of their shoulders, abdomen and hips directly after the FBI was induced. This effect was strongest for estimates of circumference, and also observed in the asynchronous control condition of the illusion. Moreover, at follow-up, the improvements in body size estimation could still be observed in the AN group. Notably, the HC group (N = 29) also showed changes in body size estimation after the FBI, but the effect showed a different pattern than that of the AN group. CONCLUSION: The results lead us to conclude that the disturbed experience of body size in AN is flexible and can be changed, even for highly emotional body parts. As such this study offers novel starting points from which new interventions for body image disturbance in AN can be developed

A Virtual Reality Full Body Illusion Improves Body Image Disturbance in Anorexia Nervosa

BACKGROUND: Patients with anorexia nervosa (AN) have a persistent distorted experience of the size of their body. Previously we found that the Rubber Hand Illusion improves hand size estimation in this group. Here we investigated whether a Full Body Illusion (FBI) affects body size estimation of body parts more emotionally salient than the hand. In the FBI, analogue to the RHI, participants experience ownership over an entire virtual body in VR after synchronous visuo-tactile stimulation of the actual and virtual body. METHODS AND RESULTS: We asked participants to estimate their body size (shoulders, abdomen, hips) before the FBI was induced, directly after induction and at ~2 hour 45 minutes follow-up. The results showed that AN patients (N = 30) decrease the overestimation of their shoulders, abdomen and hips directly after the FBI was induced. This effect was strongest for estimates of circumference, and also observed in the asynchronous control condition of the illusion. Moreover, at follow-up, the improvements in body size estimation could still be observed in the AN group. Notably, the HC group (N = 29) also showed changes in body size estimation after the FBI, but the effect showed a different pattern than that of the AN group. CONCLUSION: The results lead us to conclude that the disturbed experience of body size in AN is flexible and can be changed, even for highly emotional body parts. As such this study offers novel starting points from which new interventions for body image disturbance in AN can be developed

Means and SD’s for actual body size by group, and comparisons between AN and HC group.

<p>Means and SD’s for actual body size by group, and comparisons between AN and HC group.</p

Experimental set up.

<p>Experimenter touching participants’ actual abdomen with a movement sensor, stroking movements are displayed in VR (inlay).</p

Front, side and back view of the avatar from a third person perspective.

<p>Front, side and back view of the avatar from a third person perspective.</p

Embodiment Questionnaire (EQ, based on [45]) assessing the strength of the illusion on three subscales.

<p>Embodiment Questionnaire (EQ, based on [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0163921#pone.0163921.ref045" target="_blank">45</a>]) assessing the strength of the illusion on three subscales.</p

Results of repeated measures ANOVA’s for within and between group differences in percentage of misestimation of body size.

<p>Results of repeated measures ANOVA’s for within and between group differences in percentage of misestimation of body size.</p

Means and SD’s of pre-illusion, post-illusion (synchronous and asynchronous condition), and follow-up illusion percentage of misestimation of body size by group.

<p>Means and SD’s of pre-illusion, post-illusion (synchronous and asynchronous condition), and follow-up illusion percentage of misestimation of body size by group.</p