Julia Diemer

The impact of perception and presence on emotional reactions: a review of research in virtual reality

Virtual reality (VR) has made its way into mainstream psychological research in the last two decades. This technology, with its unique ability to simulate complex, real situations and contexts, offers researchers unprecedented opportunities to investigate human behavior in well controlled designs in the laboratory. One important application of VR is the investigation of pathological processes in mental disorders, especially anxiety disorders. Research on the processes underlying threat perception, fear, and exposure therapy has shed light on more general aspects of the relation between perception and emotion. Being by its nature virtual, i.e., simulation of reality, VR strongly relies on the adequate selection of specific perceptual cues to activate emotions. Emotional experiences in turn are related to presence, another important concept in VR, which describes the user’s sense of being in a VR environment. This paper summarizes current research into perception of fear cues, emotion, and presence, aiming at the identification of the most relevant aspects of emotional experience in VR and their mutual relations. A special focus lies on a series of recent experiments designed to test the relative contribution of perception and conceptual information on fear in VR. This strand of research capitalizes on the dissociation between perception (bottom–up input) and conceptual information (top-down input) that is possible in VR. Further, we review the factors that have so far been recognized to influence presence, with emotions (e.g., fear) being the most relevant in the context of clinical psychology. Recent research has highlighted the mutual influence of presence and fear in VR, but has also traced the limits of our current understanding of this relationship. In this paper, the crucial role of perception on eliciting emotional reactions is highlighted, and the role of arousal as a basic dimension of emotional experience is discussed. An interoceptive attribution model of presence is suggested as a first step toward an integrative framework for emotion research in VR. Gaps in the current literature and future directions are outlined.

Virtual reality exposure in anxiety disorders: Impact on psychophysiological reactivity

Abstract Objectives. Anxiety disorders are among the most frequently encountered psychiatric disorders. Recommended treatments include cognitive behavioural therapy (CBT) and/or medication. In recent years, beneficial effects of virtual reality (VR) exposure therapy have been shown, making this technique a promising addition to CBT. However, the ability of VR to mimic threatening stimuli in a way comparable to in vivo cues has been discussed. In particular, it has been questioned whether VR is capable of provoking psychophysiological symptoms of anxiety. Since psychophysiological arousal is considered a prerequisite for effective exposure treatment, this systematic review aims to evaluate the evidence for the potential of VR exposure to evoke and modulate psychophysiological fear reactions. Methods. PubMed and PsycINFO/Academic Search Premier databases were searched. Thirty-eight studies investigating challenge or habituation effects were included. Results. VR exposure does provoke psychophysiological arousal, especially in terms of electrodermal activity. Results on psychophysiological habituation in VR are inconclusive. Study design and methodological rigour vary widely. Conclusions. Despite several limitations, this review provides evidence that VR exposure elicits psychophysiological fear reactions in patients and healthy subjects, rendering VR a promising treatment for anxiety disorders, and a potent research tool for future investigations of psychophysiological processes and their significance during exposure treatment.

Dopamine D3 receptor gene variation: impact on electroconvulsive therapy response and ventral striatum responsiveness in depression

Dysfunction of dopamine D₃ receptors, particularly in the mesocorticolimbic system, has been linked to the pathogenesis of major depression. Preclinical data show enhanced D₃ receptor binding in the striatum upon antidepressant medication and electroconvulsive therapy (ECT). Thus, the potential impact of dopamine D₃ receptor gene (DRD3) variation on ECT outcome in treatment-resistant major depression was evaluated by applying a combined molecular and imaging genetic approach. Altogether, 10 representative variants covering 95.4% of DRD3 gene variation were investigated for association with response to ECT in a sample of 104 (71 female, 33 male) Caucasian patients with pharmacorefractory major depression. Additionally, ventral striatum responsiveness to happy faces was assessed in two independent samples of depressed patients (total N=54) by means of functional magnetic resonance imaging at 3 T. Significant association of DRD3 rs3732790, rs3773679 and rs9817063 variants with response (uncorrected p=0.02-0.03) and remission (uncorrected p=0.01) after ECT was discerned. Logistic regression analyses revealed association of rs3732790 (uncorrected p=0.009; corrected p=0.045) and rs3773679 (uncorrected p=0.009; corrected p=0.045) with remission when applying a recessive model of inheritance. The rs3732790T allele conferring a more favourable treatment response was furthermore found to be associated with stronger striatal responsiveness to happy facial expressions (sample 1: cluster-corrected p=0.002; sample 2: p=0.023). In summary, the present study suggests some impact of DRD3 gene variation on ECT response, potentially mediated by alteration of striatal engagement during the processing of emotionally rewarding stimuli.

Virtual Reality in Psychotherapy

Virtual reality (VR) provides a new medium for the presentation of emotionally relevant, complex stimuli in an ecologically valid and at the same time highly controlled manner. Therefore, VR applications have attracted the attention of psychotherapists and researchers. In the past years, viable VR systems for varied applications in psychotherapy have been developed, most notably for exposure therapy in anxiety disorders. This article resumes the major applications of VR in psychotherapy, gives an overview of the current literature on its efficacy, and provides an outlook on future perspectives for psychotherapy and clinical research.

Acute Shift in Glutamate Concentrations Following Experimentally Induced Panic with Cholecystokinin Tetrapeptide—A 3T-MRS Study in Healthy Subjects

According to preclinical studies, glutamate has been implicated in the pathogenesis of anxiety. In order to elucidate the role of glutamate in anxiety and panic in humans, brain glutamate+glutamine (Glx) levels were measured during cholecystokinin-tetrapeptide (CCK-4)-induced panic using magnetic resonance spectroscopy (MRS). Eighteen healthy subjects underwent a CCK-4 challenge. MR spectra were obtained from the anterior cingulate cortex (ACC) using a single voxel point-resolved spectroscopy method and analyzed using LCModel. A combined fitting of Glx was performed. Panic was assessed using the Acute Panic Inventory (API) and Panic Symptom Scale (PSS) scores. Moreover, hypothalamic–pituitary–adrenal axis stimulation was monitored throughout the challenge. There was a significant panic response following CCK-4 as revealed by a marked increase in both the panic scores (API: F(1,17)=149.41; p<0.0001; PSS: F(1,17)=88.03; p<0.0001) and heart rate (HR: F(1,17)=72.79; p<0.0001). MRS measures showed a significant increase of brain Glx/creatine (Glx/Cr) levels peaking at 2–10 min after challenge (F(1,17)=15.94; p=0.001). There was also a significant increase in CCK-4-related cortisol release (F(6,11)=8.68; p=0.002). Finally, significant positive correlations were found between baseline Glx/Cr and both APImax (r=0.598; p=0.009) and maximum heart rate (HRmax) during challenge (r=0.519; p=0.027). Our results suggest that CCK-4-induced panic is accompanied by a significant glutamate increase in the bilateral ACC. The results add to the hypothesis of a disturbance of the inhibitory–excitatory equilibrium and suggest that apart from static alterations rapid and dynamic neurochemical changes might also be relevant for the neural control of panic attacks.

COMT val158met influence on electroconvulsive therapy response in major depression

There is strong evidence for a genetic contribution to the pathogenesis of depression, with the functional catechol‐O‐methyltransferase (COMT) val158met polymorphism having been suggested as a potential susceptibility factor. In the present study, the effect of COMT val158met on response to electroconvulsive therapy (ECT) was analyzed in a sample of 104 Caucasian patients (f = 71, m = 33) with pharmacologically treatment‐resistant Major Depression. The higher active COMT 158val allele was found to be associated with (1) higher pre‐ECT severity of depression and (2) better treatment response to ECT particularly regarding the core symptoms of depression as well as sleep‐related symptoms. These findings were restricted to the female subgroup of patients. In summary, the present study supports a potentially gender‐specific significant impact of COMT gene variation on electroconvulsive therapy response, with COMT 158val risk allele carriers suffering from more severe, pharmacologically less efficiently treatable depression and thus possibly deriving greater benefit from ECT in the first place.

Temporal dynamics in the relation between presence and fear in virtual reality

Stereoscopy increases presence and fear in virtual reality exposure.Presence was found to predict fear during initial exposures.At later stages of exposure, presence and fear were mutually interdependent.The relationship between presence and fear thus appears dynamic. Virtual reality (VR) is increasingly investigated as a new medium for exposure therapy, but process variables are not well understood. In particular, presence and fear during VR exposure correlate strongly, but the causal relationship between them remains unclear. We assigned 22 female spider-fearful participants randomly to either a stereoscopic (high presence) or a monoscopic (low presence) condition and exposed them repeatedly to a large virtual spider presented on a Powerwall. Presence and fear were assessed on subjective, physiological, and behavioral levels. Fear reactions were stronger and presence ratings were higher in the stereoscopic than the monoscopic condition. Presence in the first exposure trial correlated significantly with fear in the second exposure trial, while fear in the first exposure trial did not correlate significantly with presence in the second exposure trial. For the following exposure trials, correlations between presence and fear were significant in both directions. Limitations of our study include the small sample and the fact that we did not check diagnostic criteria of specific phobia. This is the first study to show temporal dynamics of the relationship between presence and fear. Initially, presence in VR seems to directly influence fear, while over time, presence and fear appear mutually dependent.

Fear and physiological arousal during a virtual height challenge—effects in patients with acrophobia and healthy controls

Virtual reality (VR) exposure therapy is becoming increasingly established, but the mode of action is not well understood. One potential efficacy factor might be physiological arousal. To investigate arousal during VR exposure, we exposed 40 patients with acrophobia and 40 matched healthy controls to a VR height challenge and assessed subjective (fear ratings) and physiological (heart rate, skin conductance level, salivary cortisol) fear reactions. Patients experienced a significant increase of subjective fear, heart rate and skin conductance level. Unexpectedly, controls, who reported no subjective fear, also showed an increase in heart rate and skin conductance. There was no increase in salivary cortisol levels in either group. Physiological arousal in acrophobic patients, in contrast to subjective fear, might not be stronger than that of controls confronted with height cues in VR, indicating marked discordance across symptom domains. The lack of a cortisol response in a clearly stressful paradigm warrants further study.

Therapy-refractory panic: current research areas as possible perspectives in the treatment of anxiety

Panic disorder (PD) is characterized by recurrent panic attacks that are defined as distinct episodes of intense fear, accompanied by symptoms related to physical arousal. Because most patients interpret these symptoms as signs of serious somatic disease (e.g., a heart attack), utilization of healthcare services is high in PD sufferers. PD can become debilitating, interfering significantly with patients’ lives. Fortunately, effective treatments are available, but a considerable proportion of patients do not respond sufficiently. The aim of this paper is to outline some promising research strategies aimed at improving established treatments.

Comparison of combined psycho- and pharmacotherapy with monotherapy in anxiety disorders: controversial viewpoints and clinical perspectives

Anxiety disorders are among the most frequent psychiatric disorders. Experimental evidence supports both psychotherapy as well as pharmacotherapy as effective treatments. There is, however, a controversy concerning the efficacy of a combination of both approaches. While some studies suggest that combined treatment enhances efficacy, others report conflicting results. This article traces the positions in this debate. We present the results from two recent meta-analyses and discuss implications for clinical practice and further research. We suggest that a research strategy that strives to establish differential indications based on patient characteristics should be preferred over attempts to reach a global judgement of the question, which appears too simplistic given the complexity of the issue.