Feasibility of Combining Transcranial Direct Current Stimulation and Active Fully Embodied Virtual Reality for Visual Height Intolerance: A Double-Blind Randomized Controlled Study

Virtual stressors with real impact: what virtual reality-based biobehavioral research can teach us about typical and atypical stress responsivity

Stress contributes to transdiagnostic morbidity and mortality across a wide range of physical and mental health problems. VR tasks have been validated as stressors with robust effect sizes for VR-based stressors to evoke stress across the most common autonomic and adrenocortical stress biomarkers. However, meta-analytic validation of VR stressors have resulted in inconsistent logic: why should something that isn't real evoke a very real suite of stress responses? This review posits that conceptually addressing this question requires differentiating a cause, "stressor", from effects, "stress". Stress comprises a series of well-delineated perturbations in biological systems, such as autonomic and adrenocortical biomarkers in response to stressors. Despite their ubiquity, decades of literature have back-calculated stressor intensity based on the magnitude of a stress response. This causal directionality is not logical, yet remains pervasive because seemingly objective stress indices have generated a wealth of findings showing how stress gets under the skin and skull. This has created challenges for providing clear guidance and strategies to measure acute stressor intensity. Binary thinking about whether something is (not) real has stifled advances in understanding how to measure the dosage of a stressful environment. As a function of being programmed, individualizable, and titrated, virtual reality (VR) based stressors offer the field a platform for quantifying the dose of a stressor and generating reliable dose-response curves. This also raises the possibility to safely and ethically integrate psychosocial stressor administration into clinical and therapeutic settings. For example, Social Evaluative Threat experiments effectively trigger a stress response both in a laboratory setting and in built environments, while also upholding hard-fought trust and rapport with care providers. By focusing attention on the measurement of the stressor, VR paradigms can advance tangible understanding of stressors themselves and the pathways to the stress response.

The efficacy of transcranial direct current stimulation in the treatment of anorexia nervosa: a randomized double-blind clinical trial

Background

Anorexia nervosa (AN) is a life-threatening disease with a low effectiveness of treatment. The high relapse and mortality rate indicate new treatment approaches are needed. Here, we represent the protocol for randomized clinical trial (RCT) of transcranial direct current stimulation (tDCS) efficiency in the AN treatment. The main purpose of the 3-week RCT is to determine the effect of tDCS on the mental state and advances in nutritional rehabilitation in patients with AN.

Methods

50 female inpatients (13-25 years old, body mass index (BMI) 17.5 kg/m2 or less) will be randomly allocated into groups: active (n=25) and sham (n=25) tDCS. Thirty 25-minute tDCS sessions (applied current at 2mA) will be given to DLPFC (F3 anode/F4 cathode) twice a day for 3 weeks on working days parallel to treatment as usual. The primary outcome measures include changes in symptoms related to eating disorders, as assessed by the Eating Attitudes Test (EAT-26), following tDCS sessions over a 3-week trial period. The secondary outcome measures include changes in: brain bioelectric activity, anthropometric measurements, mood, nutritional status, neurocognition, psychological symptoms, selected biological markers related to stress, food intake, inflammation and neurotrophins.

Discussion

This paper describes the evaluation of a 3-week tDCS-based intervention for AN patients. The study design was developed by a multidisciplinary research team to assess the treatment effect, taking into account various types of variables. This approach could help in better understanding the potential therapeutic tDCS strategy in AN.

Clinical trial registration

www.ClinicalTrials.gov, identifier NCT05814458.

Efficacy of virtual reality for pain relief in medical procedures: a systematic review and meta-analysis

BACKGROUND

Effective pain control is crucial to optimise the success of medical procedures. Immersive virtual reality (VR) technology could offer an effective non-invasive, non-pharmacological option to distract patients and reduce their experience of pain. We aimed to evaluate the efficacy of Immersive virtual reality (VR) technology in reducing patient's pain perception during various medical procedures by conducting a systematic review and meta-analysis.

METHODS

We searched MEDLINE, EMBASE, CENTRAL, CINAHL, and SIGLE until December 2022 for all randomised clinical trials (RCT) evaluating any type of VR in patients undergoing any medical procedure. We conducted a random effect meta-analysis summarising standardised mean differences (SMD) with 95% confidence intervals (CI). We evaluated heterogeneity using I 2 and explored it using subgroup and meta-regression analyses.

RESULTS

In total, we included 92 RCTs (n = 7133 participants). There was a significant reduction in pain scores with VR across all medical procedures (n = 83, SMD - 0.78, 95% CI - 1.00 to - 0.57, I 2 = 93%, p = < 0.01). Subgroup analysis showed varied reduction in pain scores across trial designs [crossover (n = 13, SMD - 0.86, 95% CI - 1.23 to - 0.49, I 2 = 72%, p = < 0.01) vs parallel RCTs (n = 70, SMD - 0.77, 95% CI - 1.01 to - 0.52, I 2 = 90%, p = < 0.01)]; participant age groups [paediatric (n = 43, SMD - 0.91, 95% CI - 1.26 to - 0.56, I 2 = 87%, p = < 0.01) vs adults (n = 40, SMD - 0.66, 95% CI - 0.94 to - 0.39, I 2 = 89%, p = < 0.01)] or procedures [venepuncture (n = 32, SMD - 0.99, 95% CI - 1.52 to - 0.46, I 2 = 90%, p = < 0.01) vs childbirth (n = 7, SMD - 0.99, 95% CI - 1.59 to - 0.38, I 2 = 88%, p = < 0.01) vs minimally invasive medical procedures (n = 25, SMD - 0.51, 95% CI - 0.79 to - 0.23, I 2 = 85%, p = < 0.01) vs dressing changes in burn patients (n = 19, SMD - 0.8, 95% CI - 1.16 to - 0.45, I 2 = 87%, p = < 0.01)]. We explored heterogeneity using meta-regression which showed no significant impact of different covariates including crossover trials (p = 0.53), minimally invasive procedures (p = 0.37), and among paediatric participants (p = 0.27). Cumulative meta-analysis showed no change in overall effect estimates with the additional RCTs since 2018.

CONCLUSIONS

Immersive VR technology offers effective pain control across various medical procedures, albeit statistical heterogeneity. Further research is needed to inform the safe adoption of this technology across different medical disciplines.

Frontopolar multifocal transcranial direct current stimulation reduces conditioned fear reactivity during extinction training: A pilot randomized controlled trial

Exposure-based therapies for anxiety and related disorders are believed to depend on fear extinction learning and corresponding changes in extinction circuitry. Frontopolar multifocal transcranial direct current stimulation (tDCS) has been shown to improve therapeutic safety learning during in vivo exposure and may modulate functional connectivity of networks implicated in fear processing and inhibition. A pilot randomized controlled trial was completed to determine the effects of frontopolar tDCS on extinction learning and memory. Community volunteers (n = 35) completed a 3-day fear extinction paradigm with measurement of electrodermal activity. Participants were randomized (single-blind) to 20-min of sham (n = 17, 30 s. ramp in/out) or active (n = 18) frontopolar (anode over Fpz, 10-10 EEG) multifocal tDCS (20-min, 1.5 mA) prior to extinction training. Mixed ANOVAs revealed a significant group*trial effect on skin conductance response (SCR) to the conditioned stimulus (CS + ) during extinction training (p = 0.007, Cohen's d = 0.55). The effects of frontopolar tDCS were greatest during the first two extinction trials, suggesting that tDCS may have promoted fear inhibition prior to safety learning. Return of fear to the CS + during tests were comparable across conditions (ps > 0.50). These findings suggest that frontopolar tDCS may modulate the processing of threat cues and associated circuitry or promote the inhibition of fear. This has clear implications for the treatment of anxiety and related disorders with therapeutic exposure.

Anxiety as a disorder of uncertainty: implications for understanding maladaptive anxiety, anxious avoidance, and exposure therapy

In cognitive-behavioral conceptualizations of anxiety, exaggerated threat expectancies underlie maladaptive anxiety. This view has led to successful treatments, notably exposure therapy, but is not consistent with the empirical literature on learning and choice alterations in anxiety. Empirically, anxiety is better described as a disorder of uncertainty learning. How disruptions in uncertainty lead to impairing avoidance and are treated with exposure-based methods, however, is unclear. Here, we integrate concepts from neurocomputational learning models with clinical literature on exposure therapy to propose a new framework for understanding maladaptive uncertainty functioning in anxiety. Specifically, we propose that anxiety disorders are fundamentally disorders of uncertainty learning and that successful treatments, particularly exposure therapy, work by remediating maladaptive avoidance from dysfunctional explore/exploit decisions in uncertain, potentially aversive situations. This framework reconciles several inconsistencies in the literature and provides a path forward to better understand and treat anxiety.