Virtual reality exposure therapy with graded interviewer reactions for public speaking anxiety in university students: a randomized controlled trial protocol

Abstract Background Public speaking anxiety (PSA) significantly impairs academic and professional outcomes among university students. While virtual reality exposure therapy (VRET) shows promise for PSA treatment, the specific contribution of social and emotional interviewer reactions remains unclear. This study examines whether VRET with graded interviewer reactions leads to greater reduction in public speaking anxiety than standard automated VR exposure. Methods This two-arm, parallel-group, superiority randomized controlled trial will recruit 92 Korean university students aged ≥18 years with elevated PRPSA (Personal Report of Public Speaking Anxiety-18 ≥ 58). Participants will be randomized 1:1 to receive either VR interview training with graded interviewer reactions or control VR training with automated voice prompts only. The intervention consists of three VR sessions, with assessments conducted at baseline, immediately after each session, and at 6- and 12-week follow-ups. The primary outcome is change from baseline in Public Speaking Anxiety Scale (PSAS) total scores at each post-baseline assessment occasion, analyzed using a linear mixed-effects model including fixed effects for group, assessment occasion, and their interaction. Secondary outcomes include Liebowitz Social Anxiety Scale–Self Report and Fear of Negative Evaluation–Brief scores, as well as physiological indicators reflecting anxiety responses during VR exposure, including heart rate variability and electrodermal activity. Exploratory analyses will examine behavioral synchrony using motion energy analysis of video recordings and acoustic features of speech to capture anxiety-related movement and vocal patterns. Discussion This trial addresses the limited evidence regarding the added value of graded interviewer reactions in VRET for public speaking anxiety by examining whether they improve outcomes beyond those achieved with standard automated VR exposure. The findings may clarify the role of socially responsive feedback in virtual exposure and inform the development of VR-based anxiety interventions. Trial registration Clinical Research Information Service (CRiS) KCT0011111. Registered on 06 November 2025.