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CYBERPSYCHOLOGY, BEHAVIOR, AND SOCIAL NETWORKING Volume 19, Number 2, 2016 ª Mary Ann Liebert, Inc. DOI: 10.1089/cyber.2015.0235
Testing Augmented Reality for Cue Exposure in Obese Patients: An Exploratory Study Federica Pallavicini, PhD,1 Silvia Serino, PhD,1 Pietro Cipresso, PhD,1 Elisa Pedroli, PSYD,1 Irene Alice Chicchi Giglioli, MA,1 Alice Chirico, MA,1 Gian Mauro Manzoni, PhD,2,3,* Gianluca Castelnuovo, PhD,2,3 Enrico Molinari, PhD,2,3 and Giuseppe Riva, PhD1,3
Abstract
Binge eating is one of the key behaviors in relation to the etiology and severity of obesity. Cue exposure with response prevention consists of exposing patients to binge foods while actual eating is not allowed. Augmented reality (AR) has the potential to change the way cue exposure is administered, but very few prior studies have been conducted so far. Starting from these premises, this study was aimed to (a) investigate whether AR foods elicit emotional responses comparable to those produced by the real stimuli, (b) study differences between obese and control participants in terms of emotional responses to food, and (c) compare emotional responses to different categories of foods. To reach these goals, we assess in 15 obese (age, 44.6 – 13 years; body mass index [BMI], 44.2 – 8.1) and 15 control participants (age, 43.7 – 12.8 years; BMI, 21.2 – 1.4) the emotional responses to high-calorie (savory and sweet) and low-calorie food stimuli, presented through different exposure conditions (real, photographic, and AR). The State-Trait Anxiety Inventory was used for the assessment of state anxiety, and it was administered at the beginning and after the exposure to foods, along with the Visual Analog Scale (VAS) for Hunger and Happiness. To assess the perceived pleasantness, the VAS for Palatability was administered after the exposure to food stimuli. Heart rate, skin conductance response, and facial corrugator supercilii muscle activation were recorded. Although preliminary, the results showed that (a) AR food stimuli were perceived to be as palatable as real stimuli, and they also triggered a similar arousal response; (b) obese individuals showed lower happiness after the exposure to food compared to control participants, with regard to both psychological and physiological responses; and (c) high-calorie savory (vs. low-calorie) food stimuli were perceived by all the participants to be more palatable, and they triggered a greater arousal response.
Introduction
O
besity is a major public health problem worldwide, and its prevalence in the world population is dramatically increasing.1 Numerous studies have pointed out that obesity is a multifactorial disorder, including psychological factors, such as anxiety and distress, that involve individuals in a variety of behaviors that serve to regulate their emotions.2 A key behavior in relation to the etiology and severity of obesity is binge eating (BE),3,4 a dysfunctional behavior that can be triggered by food craving,5 which is an appetitive motivational–emotional state that triggers the search for food and the consequent intake behaviors even in a state of satiety.
The conditioning model of BE postulates that, in addition to internal states (e.g., psychological emotional states), exposure to certain stimuli associated with BE (e.g., the presence of high-calorie meals) provokes physiological responses and subjective craving. Cue exposure with response prevention of binge eating (ERP-B) is a type of treatment derived from this model, which consists of exposing patients to binge-triggering foods and preventing BE while the food is present and can be smelled.6–9 The main objective of ERP-B is to extinguish food craving by breaking the link between the conditioned and the unconditioned stimulus (for a recent review, see Ref.10). While the cue exposure approach has been proven to be an effective
1
Applied Technology for Neuro-Psychology Lab, IRCCS Istituto Auxologico Italiano, Milan, Italy. Psychology Research Laboratory, Ospedale San Giuseppe, Istituto Auxologico Italiano, Verbania, Italy. Department of Psychology, Catholic University of the Sacred Heart, Milan, Italy. *Current affiliation: Faculty of Psychology, eCampus University, Novedrate, Como, Italy.
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treatment of BE behaviors,8,9 it has important constraints that make its implementation difficult, such as logistical difficulties, the time required to carry out the treatment, and the need for natural environments adapted to the requirements of each patient.10 Among the technologies that have emerged in more recent years, augmented reality (AR) represents an innovative tool that has the potential to dramatically change the way psychological treatments are administered,11 including cue exposure treatments.12 Essentially, the concept of AR is that synthetic objects can be added to the real world in real time, enriching reality with helpful and relevant information.13–17 Despite the opportunities that AR could offer in the administration of cue exposure, including the prevention of BE behavior in obesity, very few prior studies have compared emotional reactions to AR and real stimuli. Nevertheless, a necessary condition for the successful use of AR in cue exposure is that it must elicit roughly the same emotional reaction as a real-life stimulus. In particular, the studies conducted so far have mainly investigated the level of presence, defined as ‘‘the feeling of being in a world that exists outside of the self,’’18,19 as experienced in AR systems, compared to that experienced in a real environment20 and virtual reality (VR) environments.21 To our knowledge, only one previous study has investigated the differences in terms of emotional responses to stimuli presented through AR compared to other exposure methods—particularly VR21—while no study has yet compared the responses with respect to those shown in response to realworld stimuli. Moreover, previous studies have focused on AR only in terms of exposure to phobic stimuli, showing the usefulness of AR in the treatment of a specific phobia, such as cockroach and spider phobias,15,22–25 and acrophobia20,21 (for a recent review, see Ref.11). As yet, nothing is known about its possible application of AR for cue exposure in the treatment of other conditions, including obesity. Starting from these premises, the first goal of this study was to investigate whether AR food stimuli elicit emotional responses comparable to those produced by real exposure stimuli. The second aim of this study was to investigate differences between obese and control group participants in terms of emotional responses to food stimuli. Finally, the third aim was to compare emotional responses to the different categories of food stimuli adopted to extend to which the effects of cue exposure are related to a specific category of food. Materials and Methods Subjects
The experimental sample included 15 obese (OB) patients (7 males and 8 females), as well as a control group (CTR) of 15 individuals (7 males and 8 females). OB patients were recruited from the inpatient units of a public hospital in Verbania (Italy), while CTR subjects were recruited through local advertisements among college students and administrative and workers’ staff at the hospitals. The mean body mass index (BMI)26 was 44.2 – 8.1 in the OB group (frequency of OB Class II = 33.3%; Class III = 66.7%) and 21.2 – 1.4 in the CTR group. The mean age and years of education were 44.6 – 13 and 11 – 3.83 in the OB group and 43.7 – 12.8 and 15.7 – 2.43 in the CTR group, respectively.
PALLAVICINI ET AL.
To be included in the study, individuals were required to meet the following criteria: (a) no Axis I disorders as defined in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV-TR)27; (b) age between 18 and 60 years; (c) not to be presently using pharmacotherapy; (d) no history of neurological diseases, psychosis, alcohol, or drug dependence; (e) no migraine, headache, or vestibular abnormalities; (f) no food allergies or intolerances; (g) not currently dieting for weight loss or in any dietary restrictions; and (h) no BMI less than 18.5. A semistructured clinical interview and the Mini International Neuropsychiatric Interview Plus (MINI)28,29 were used to exclude the presence of any psychiatric diseases, including actual or past eating disorders, according to the DSM-IV-TR.27 Before participating in the study, each participant was provided with written information about the study and required to give written consent for inclusion in the study. The study received ethical approval by the Ethical Committee of the Istituto Auxologico Italiano.
Psychological assessment
The following questionnaires were administered to each participant: State-Trait Anxiety Inventory, Form Y-1 (STAIY1):30,31 The STAI-Y1 is a validated and widely used measure of state anxiety. Visual Analog Scale (VAS):32 The VAS is a horizontal line, 100 mm in length, anchored by word descriptors at each end. The participants mark on the line the point that they feel represents their perception of their current state. Participants’ level of hunger was measured using Visual Analog Scale for Hunger (VAS-H), a rating scale headed ‘‘How strong is your hunger right now?’’ A similar scale, the Visual Analog Scale for Happiness (VAS-HP), was also used. All the scales were anchored by the phrases ‘‘Not at all’’ and ‘‘Extremely.’’ Moreover, since the hedonic component of sensation (or the ‘‘pleasantness’’) of food stimuli is an integral part of their sensory profile and it can influence appetite and eating rate,33–36 the Visual Analog Scale for Palatability (VAS-P) was administered.
Physiological assessment
At the beginning of the experiment and during the laboratory session, skin conductance response (SCR), heart rate (HR; in particular, NN50 values), and facial corrugator supercilii muscle electromyography (fEMG) were recorded to obtain participants’ physiological responses to food stimuli. While SCR37 and NN5038 are considered indexes of arousal responses, fEMG is considered a good measure of negative emotional state.39,40 The physiological signals were acquired using a ProComp Infiniti device from Thought Technology, including Biograph Infiniti 5.0.2 software to record and export all raw signals. Every signal was synchronously acquired at 2,048 Hz and exported at a minimum of a 256 Hz sampling rate (every 3.9 ms). Amplitude is measured in microvolts.
AUGMENTED REALITY AND CUE EXPOSURE IN OBESE PATIENTS Food stimuli and exposure conditions
We selected nine food items—three in each of the three categories—based on nutritional estimates (i.e., total fat and saturated fat): high-calorie savory foods (HC-SAVs) included three salty foods (salami, potato chips, and crackers) relatively high in total fat (>20 g/100 g) and saturated fat (>6.25 g/100 g), high-calorie sweet foods (HC-SW) consisted of three sweets (chocolates, cookies, and muffins) containing at least moderate levels of total fats (>10 g/100 g) and saturated fats (>5 g/100 g), and low-calorie (LC) foods were three food stimuli (pears, tomatoes, and carrots) containing low total fats (
