Single Session Virtual Reality Therapy in Acrophobia - and the Role of Respiration

Study Overview
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Brief Summary
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In recent years, in the treatment of phobias, exposure therapy in virtual reality is becoming more and more popular as an alternative for in-vivo exposure. Effectiveness of virtual reality exposure therapy (VRET) is comparable to in-vivo exposure therapy, though several characteristics of the VRET have an impact on the outcome of the therapy (e.g., immersion into the virtual environment (VE), familiarity with the VE). Additionally, the use of VRET varies from multiple exposure sessions to single-session VRET. Single-session therapy has an economic advantage and in in-vivo, post therapy outcomes show good results. In virtual reality, the assessment of outcome post therapy and in follow-up of single-session therapies is still needed for an evaluation of this approach. As an outcome measure, behavioral assessments are especially relevant for effectiveness studies as in fear of heights it is closer to the individual's life to know how high they voluntarily go up a building than to have hypothetical self-report questionnaire results. Much research has been conducted on physiological correlates of the subjective experience of fear in exposure therapy as they are assumed to be a prerequisite for effective exposure treatment. Skin conductance level (SCL) and heart rate can be used for objective manipulation checks of exposure therapy. SCL is found to increase during fearful situations independent of setting while heart rate only increases during in-vivo exposure. Contrary to heart rate, heart rate variability (HRV) is not thoroughly studied in VRET yet. HRV is associated with the adaptability of an organism to new environments and cognitive functioning. High Frequency HRV is found to be reduced in individuals with mental disorders, and positive and negative mood inductions lead to differential HRV responses overall. Respiration is a well-studied correlate of emotional experience and especially of the experience of fear and anxiety. In a series of experiments, it was found that sighing is tightly associated with relief in or after fearful or stressful situations and might become maladaptive when used disproportionally often. This study shows that respiration parameters have an impact on the handling of fearful situations in a reciprocal way. On the one hand, fear leads to an increased respiration rate and sigh rate while on the other hand, an altered sigh rate or respiration rate might have an impact on the experience of fear and be used as a defensive reaction to a fearful situation. As such, specific respiration patterns might act as emotion-driven behaviors (EDB). EDBs are responses to emotions that result in a short-term reduction of a negative state while in long-term support the maintenance of the phobia. The aim of this study is to examine the effectiveness of a single-session VRET for acrophobia with a multimethod outcome design. Familiarity of the setting will be high with the use of a well-known tower in this area. Immersion into the VE will be assessed with a presence questionnaire. For a manipulation check, physiological data will be assessed, i.e., SCL, heart rate and HRV. Primary outcome measure will be a behavioral approach test (BAT) as behavioral assessment. Additionally, after four weeks, a follow-up assessment will investigate the stability of the effectiveness of the VRET in comparison to a waitlist control group. A second aim of this study is to investigate the impact of respiration as an EDB on the effectiveness of an exposure therapy. Therefore, the association between respiration and outcome of the VRET will be analyzed. Hypothesis 1: Participants in the VRET condition show less height avoidance in the BAT after the intervention than participants in the control condition. Hypothesis 2: Participants in the VRET condition show less height avoidance in the BAT in a four-week follow-up assessment than participants in the control condition. Hypothesis 3: Participants in the VRET condition score significantly lower on the Acrophobia Questionnaire at follow-up than participants in the control condition. Hypothesis 4: During the VRET, breath holding is used as EDB. Participants that hold their breath, profit less from the VRET than participants that do not hold their breath. Hypothesis 5: During the VRET, sighing is used as EDB. Participants that sigh, profit less from the VRET than participants that do not sigh.

Official Title
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Virtual Reality Exposure Therapy for Acrophobia in a Single Session Design and the Role of Respiration for Fear Extinction

Conditions
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Acrophobia

Intervention / Treatment
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* Behavioral: virtual reality exposure for acrophobia
* Behavioral: movie


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: diagnosed acrophobia read, speak and write in German language Exclusion Criteria: current panic disorder lifetime psychotic disorder current suicidality neurological disorder current substance use disorder

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Participants are assigned to one of two conditions (virtual reality vs. waitlist control) for the initial phase. In the second phase the waitlist control group receives the virtual reality exposure while the other group does not receive a second intervention.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: intervention group<br>Virtual reality exposure for acrophobia - this arm receives the virtual reality exposure intervention in the initial phase and has a four-week follow-up assessment. | Behavioral: virtual reality exposure for acrophobia<br>* The setting of the virtual reality is the Gasometer Oberhausen, Europe's largest disc-type gas container which is one of the most famous high buildings in the area. After a baseline phase, participants will undergo a gradual exposure. Participants will first look up to the building and then be guided upstairs to have an exposure phase on 11 floors. On the highest floor they will walk around a gallery. In the end, there will be a recovery phase.<br>|
| Placebo Comparator: waitlist control group<br>This arm watches a movie in the initial phase in order to control for effects of behavioral approach test that is done before and after the intervention and for time effects. In the second phase after four weeks, this arm receives the virtual reality exposure after collection of outcome measures. | Behavioral: virtual reality exposure for acrophobia<br>* The setting of the virtual reality is the Gasometer Oberhausen, Europe's largest disc-type gas container which is one of the most famous high buildings in the area. After a baseline phase, participants will undergo a gradual exposure. Participants will first look up to the building and then be guided upstairs to have an exposure phase on 11 floors. On the highest floor they will walk around a gallery. In the end, there will be a recovery phase.<br>Behavioral: movie<br>* Participants will watch a movie without height content for the same amount of time as the virtual reality exposure will need.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Behavioral Approach Test Post | Participants are asked to walk up fire exit stairs of the university building where the treatment is applied. The number of steps upstairs is counted as dependent measure. | Within 1 hour after treatment /placebo intervention | 
| Behavioral Approach Test Follow-up | Participants are asked to walk up fire exit stairs of the university building where the treatment is applied. The number of steps upstairs is counted as dependent measure. | Four weeks +/- 3 day after the treatment / placebo intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Acrophobia Questionnaire Follow-up | Questionnaire by Cohen (1977); The scale ranges from 0 - not at all frightening to 6 - very frightening with a higher score indicating more anxiety. A total maximum score is 120 and minimum score 0. | Four weeks +/- 3 day after the treatment / placebo intervention | 
| Sigh Rate | Measured with inductive plethysmography and analyzed via ANSLAB | During virtual reality exposure session, at baseline (1; 5 minutes), on each floor of the tower (2-14; 3 minutes, in total 39 minutes) and in recovery phase (15; 5 minutes) | 
| Number of Apnoeas | Pauses after inspiration and expiration longer than 5 seconds, measured with inductive plethysmography and analyzed via ANSLAB | During virtual reality exposure session, at baseline (1; 5 minutes), on each floor of the tower (2-14; 3 minutes, in total 39 minutes) and in recovery phase (15; 5 minutes) | 
| Respiration Rate | Measured with inductive plethysmography and analyzed via ANSLAB | During virtual reality exposure session, at baseline (1; 5 minutes), on each floor of the tower (2-14; 3 minutes, in total 39 minutes) and in recovery phase (15; 5 minutes) | 
| Respiratory Instability | Measured with inductive plethysmography and analyzed via ANSLAB | During virtual reality exposure session, at baseline (1; 5 minutes), on each floor of the tower (2-14; 3 minutes, in total 39 minutes) and in recovery phase (15; 5 minutes) | 
| Subjective Units of Discomfort Change | Participants are asked how fearful they are on a scale from 0 to 10. Original scale by Wolpe & Lazarus (1966) | During virtual reality exposure session, at baseline (1; minute 1), on each floor of the tower (2-14; between minute 6 and 44) and in recovery phase (15; minute 50) | 
| Heart Rate | Measured with Electrocardiogram and analyzed via ANSLAB | During virtual reality exposure session, at baseline (1; 5 minutes), on each floor of the tower (2-14; 3 minutes, in total 39 minutes) and in recovery phase (15; 5 minutes) | 
| Heart Rate Variability | Measured with Electrocardiogram and analyzed via ANSLAB | During virtual reality exposure session, at baseline (1; 5 minutes), on each floor of the tower (2-14; 3 minutes, in total 39 minutes) and in recovery phase (15; 5 minutes) | 
| Skin conductance level | Skin conductance is recorded continuously with two electrodes placed on the medial phalanxes of the index and middle fingers of the nondominant hand. | During virtual reality exposure session, at baseline (1; 5 minutes), on each floor of the tower (2-14; 3 minutes, in total 39 minutes) and in recovery phase (15; 5 minutes) | 
| Video recording | A rating system for signs of muscular tension during virtual reality exposure will be designed. Therefore, in a first step it will be assessed whether signs of muscular tension are visible overall. In a second step, all signs from up to 10 randomly picked participants will be noted from two different raters in order to design a rating scale. This scale will then be applied to the rest of the participants by 2 independent raters and finally correlated with the post outcome measures and follow-up outcome measures. | During virtual reality exposure session, at baseline (1; 5 minutes), on each floor of the tower (2-14; 3 minutes, in total 39 minutes) and in recovery phase (15; 5 minutes) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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virtual reality exposure therapy, waitlist control design, single session exposure, emotion-driven behavior, respiration