Desensitizing Anxiety Through Imperceptible Change: Feasibility Study on a Paradigm for Single-Session Exposure Therapy for Fear of Public Speaking

Abstract

Background: Exposure therapy (ET) for anxiety disorders involves introducing the participant to an anxiety-provoking situation over several treatment sessions. Each time, the participant is exposed to a higher anxiety-provoking stimulus; for example, in the case of fear of heights, the participant would successively experience being at a greater height. ET is effective, and its counterpart, virtual reality (VR) exposure therapy (VRET), where VR substitutes real-world exposure, is equally so. However, ET is time-consuming, requiring several sessions.

Objective: This study aimed to compare the results of single-session exposure with those of traditional VRET with regard to reducing public speaking anxiety.

Methods: We introduced a paradigm concerned with public speaking anxiety where the VR exposure occurred in a single session while the participant interacted with a virtual therapist. Over time, the therapist transformed into an entire audience with almost imperceptible changes. We carried out a feasibility study with 45 participants, comparing 3 conditions: single-session exposure (n=16, 36%); conventional multiple-session exposure (n=14, 31%), where the same content was delivered in successive segments over 5 sessions; and a control group (n=15, 33%), who interacted with a single virtual character to talk about everyday matters. A week later, the participants were required to speak on a stage in front of a large audience in VR.

Results: Across most of the series of conventional public speaking anxiety measures, the single-session exposure was at least as effective in reducing anxiety as the multiple-session exposure, and both these conditions were better than the control condition. The 12-item Personal Report of Confidence as a Speaker was used to measure public speaking anxiety levels, where higher values indicated more anxiety. Using a Bayesian model, the posterior probabilities of improvement compared to a high baseline were at least 1.7 times greater for single- and multiple-session exposures compared to the control group. The State Perceived Index of Competence was used as a measure of anticipatory anxiety for speaking on a stage in front of a large audience, where lower values indicated higher anxiety. The probabilities of improvement were just over 4 times greater for single- and multiple-session exposures compared to the control group for a low baseline and 489 (single) and 53 (multiple) times greater for a middle baseline.

Conclusions: Overall, the results of this feasibility study show that for moderate public speaking anxiety, the paradigm of gradual change in a single session is worth following up with further studies with more severe levels of anxiety and a larger sample size, first with a randomized controlled trial with nonpatients and subsequently, if the outcomes follow those that we have found, with a full clinical trial with patients.

Keywords: anxiety; anxiety disorder; change blindness; desensitization; exposure therapy; fear of public speaking; feasibility study; gradual exposure; public speaking; virtual reality.

Figure 1

The scenario. (A) A male participant embodied in a male virtual body with a virtual mirror to his left. The inset shows the person with the HMD and controllers. (B) Single-session exposure: the virtual counselor talks to the participant, while new copies of him divide and gradually transform into different virtual human characters. (C) Multiple-session exposure (session 2): the participant is exposed to 3 virtual characters forming the audience. (D) The full audience in both single- and multiple-session conditions. HMD: head-mounted display.

Figure 2

Control condition and concert scenario. (A and B) Virtual humans for the control condition. (C) Virtual audience seen from the stage from the viewpoint of the participant in front of the microphone prior to introducing the band Dire Straits. (D) View from the audience once the concert started.

Figure 3

Posterior distributions for each response variable using equation 2. The red curves are for the single-session condition, green for the multiple-session condition, and blue for the control condition. For all except postSTAI, these are conditional distributions with the prevariable: lowest (L), middle (M), or highest (H) values. For postSTAI, it is the unconditional distribution. The familiarity variable is set at its median of 3. IAT: Implicit Association Test; PRCA: Personal Report of Communication Apprehension; SPIC: State Perceived Index of Competence; STAI: State-Trait Anxiety Inventory.