Development and Usability of a Virtual Reality Human–Human Interface to Deliver Psychotherapy to People Experiencing Auditory Verbal Hallucinations, a feasibility study.

Technical Summary: Development and Usability of a Virtual Reality Human–Human Interface for Auditory Verbal Hallucinations

Problem Statement
While digital technologies hold promise for transforming psychiatric treatment, particularly for schizophrenia, few genuinely innovative approaches have emerged beyond translating manualized therapies (e.g., exposure therapy) into digital formats. A specific challenge lies in the treatment of auditory verbal hallucinations (AVH), where the patient's internal experience is often inaccessible to the therapist. AVATAR therapy addresses this by rendering the hallucination tangible through a visual and auditory representation. However, despite evidence of efficacy, many VR-based therapeutic programs fail to achieve sustained integration into routine clinical practice. A primary determinant of this failure is system usability and patient engagement. There is a critical gap in understanding the applicability and acceptability of these digital approaches specifically among the target population—patients actively experiencing voices—versus non-clinical users.

Methodology
The authors conducted a three-armed, non-randomized feasibility study using a convenience sample of 86 participants from the University Hospital of Zurich. The study was designed to evaluate the feasibility and patient involvement of a novel VR human–human interface before a larger clinical trial. The three arms were:

1. Voice-Hearing Patients: Inpatients with self-reported verbal auditory hallucinations.
2. Control Patients: Inpatients without verbal auditory hallucinations.
3. Administrative Staff: Healthy controls without direct patient contact or therapeutic backgrounds.

Procedure:
Participants underwent a "hands-on" session where they were introduced to the theoretical background and the VR interface. They then created and customized an avatar (representing the voice) and its voice before experiencing the interaction via a head-mounted display. The system utilized the Unity Game Engine, connecting two devices for bidirectional audio. A therapist's voice was modulated via a Roland VT-4 voice transformer to match the patient's hallucinations, with lip-sync synchronization to the avatar.

Measurement:
Following the session, all participants completed the System Usability Scale (SUS), a 10-item questionnaire yielding a global score (0–100) and a raw sum score. Statistical analysis included ANOVA for continuous variables (SUS scores) and chi-square tests for proportions (demographics). Exploratory factor analysis (MLFA) was conducted to examine the latent dimensions of usability across groups.

Key Results

• Demographics: The sample (mean age 37.53 ± 11.24) was evenly distributed across the three arms with no significant differences in age, sex, or education.
• Overall Usability: The mean global SUS score was 79.91 ± 14.25, indicating "good to excellent" usability across all groups.
• Group Differences: Voice-hearing patients scored significantly lower on the global SUS (73.61 ± 18.75) compared to control patients (82.74 ± 11.39) and administrative staff (82.86 ± 9.95) ($F(2, 83) = 4.13, p = 0.019$).
• Item-Level Analysis: Voice-hearing patients found specific aspects significantly more challenging:
  • "I thought the system was easy to use" (Item 3).
  • "I found the system very cumbersome to use" (Item 8).
  • "I need to learn a lot of things before I could get going with this system" (Item 10).
• Factor Structure: Multilevel factor analysis revealed that usability is constituted by different determinants across groups. For voice-hearing patients, items related to ease of use, perceived complexity, and the need for support had high loadings (>0.7), suggesting these factors drive their overall perception. In contrast, non-voice-hearing groups showed a more uniform distribution of item contributions.
• Safety: No participants reported side effects or distress from using the interface.

Key Contributions

1. Differentiated Usability: The study demonstrates that usability is not a uniform construct; it varies significantly based on the user's clinical status. While the system is generally usable, the target population (voice-hearers) perceives the creation and interaction process as more demanding and support-intensive than non-affected users.
2. Clinical Implications for Onboarding: The findings suggest that for patients with AVH, the avatar creation phase is not merely a technical prerequisite but a distinct, challenging preparatory phase of treatment. This phase requires specific guidance, psychoeducation, and continuous scaffolding to manage the distress associated with externalizing internal experiences.
3. Feasibility Validation: The study confirms that VR human–human interfaces are feasible for acutely hospitalized patients with severe psychiatric disorders, provided that adequate therapist support and structured onboarding are in place.

Significance and Claims
The paper claims that while AVATAR therapy and similar VR interventions show efficacy, their successful implementation in routine care depends heavily on patient-centered usability. The study highlights that even with high overall usability ratings, patients with target symptoms may find the technology effortful. Therefore, the authors argue that:

• Therapists must be trained to guide patients through the preparation and creation of the embodied hallucination.
• Implementation protocols must include structured onboarding and explicit psychoeducation regarding the emotional impact of confronting voices in VR.
• Digital therapies for this population require active therapist support rather than standalone deployment.

The authors maintain a modest tone, noting that the study was a feasibility pilot without standardized psychometric testing (to avoid overburdening participants) and that the design did not account for all sociodemographic or clinical variables (e.g., illness duration, digital affinity). They position this work as a necessary complement to growing efficacy evidence, emphasizing that understanding the experience of using the technology is critical for designing scalable treatment pathways.