Assessment of the emotional responses produced by exposure to real food, virtual food and photographs of food in patients affected by eating disorders

Abstract

Background: Many researchers and clinicians have proposed using virtual reality (VR) in adjunct to in vivo exposure therapy to provide an innovative form of exposure to patients suffering from different psychological disorders. The rationale behind the 'virtual approach' is that real and virtual exposures elicit a comparable emotional reaction in subjects, even if, to date, there are no experimental data that directly compare these two conditions. To test whether virtual stimuli are as effective as real stimuli, and more effective than photographs in the anxiety induction process, we tested the emotional reactions to real food (RF), virtual reality (VR) food and photographs (PH) of food in two samples of patients affected, respectively, by anorexia (AN) and bulimia nervosa (BN) compared to a group of healthy subjects. The two main hypotheses were the following: (a) the virtual exposure elicits emotional responses comparable to those produced by the real exposure; (b) the sense of presence induced by the VR immersion makes the virtual experience more ecological, and consequently more effective than static pictures in producing emotional responses in humans.

Methods: In total, 10 AN, 10 BN and 10 healthy control subjects (CTR) were randomly exposed to three experimental conditions: RF, PH, and VR while their psychological (Stait Anxiety Inventory (STAI-S) and visual analogue scale for anxiety (VAS-A)) and physiological (heart rate, respiration rate, and skin conductance) responses were recorded.

Results: RF and VR induced a comparable emotional reaction in patients higher than the one elicited by the PH condition. We also found a significant effect in the subjects' degree of presence experienced in the VR condition about their level of perceived anxiety (STAI-S and VAS-A): the higher the sense of presence, the stronger the level of anxiety.

Conclusions: Even though preliminary, the present data show that VR is more effective than PH in eliciting emotional responses similar to those expected in real life situations. More generally, the present study suggests the potential of VR in a variety of experimental, training and clinical contexts, being its range of possibilities extremely wide and customizable. In particular, in a psychological perspective based on a cognitive behavioral approach, the use of VR enables the provision of specific contexts to help patients to cope with their diseases thanks to an easily controlled stimulation.

Figure 1

The six high-calorie foods (three savory and three sweet foods) presented to the subjects in the three experimental conditions.

Figure 2

The virtual reality (VR) restaurant. (a) In the VR condition, subjects were asked to move around the room and to stand in front of the six plates covered by the red lids (the same used in the real food (RF) and photograph (PH) conditions) indicated by the yellow arrow on the right side of the figure. (b) Standing in front of the plates, subjects were asked to select them one by one, to virtually remove the lid and to observe the food for 30 s. After this time, the lid was automatically put back on the plate and the subject could do the second selection.

Figure 3

Time schedule of the experiment (repeated for all the three conditions).

Figure 4

Stait Anxiety Inventory (STAI-S) mean scores in anorexia (AN), bulimia nervosa (BN) and control (CTR) groups after the three different food exposures.

Figure 5

Visual Analogue Scale for anxiety (VAS-A) mean scores in anorexia (AN), bulimia nervosa (BN) and control (CTR) groups after the three different food exposures.

Figure 6

Heart rate (HR) mean scores in anorexia (AN), bulimia nervosa (BN) and control (CTR) groups recorded during the three different food exposures.

Figure 7

Skin conductance (SCR) mean scores in anorexia (AN), bulimia nervosa (BN) and control (CTR) groups recorded during the three different food exposures.