Usability Evaluation of a Virtual Reality Multisensory Sham-Feeding Device for Patients Undergoing Fasting Periods for Colorectal Cancer Surgery: Mixed Methods Study.

Background: Colorectal cancer surgery requires perioperative fasting to ensure safety, but this can cause physiological and psychological discomfort, such as impaired intestinal motility, bloating, immune suppression, anxiety, and appetite loss. To address this challenge, we developed the virtual reality (VR) multisensory sham-feeding device (VRMS-SFD), based on Pavlov conditioned reflex mechanism, where vagal stimulation triggered by seeing, smelling, or thinking about food activates cephalic-phase responses, promoting digestive secretion and intestinal motility. The device integrates multisensory stimulation-visual (food presentation), auditory (eating sounds and relaxing music), and olfactory (food-specific scents)-to create a VR dining experience. It features three VR scenes (Chinese restaurant, fruit shop, and dessert shop) with 23 food options, offering immersive interaction through a head-mounted display and synchronized scent release.

Objective: This study aimed to evaluate the usability, acceptability, and safety of the VRMS-SFD in patients with colorectal cancer during postoperative fasting, assessing its potential to alleviate discomfort, stimulate appetite, and enhance emotional well-being.

Methods: A mixed methods design was used. Participants used VRMS-SFD for 20 minutes during each meal time over 3 postoperative days. Quantitative data included the System Usability Scale (SUS) and demographic or clinical variables. Qualitative data were obtained from 15- to 30-minute semistructured interviews, transcribed verbatim, and thematically analyzed using NVivo (version 15.0; QSR International). When no new themes emerged, the sample size was considered sufficient, and data saturation was achieved. Two researchers independently coded transcripts, with discrepancies resolved by a third reviewer. The study was ethically approved (1087) and clinically registered.

Results: A total of 37 patients were included. The mean SUS score was 77.78 (SD 7.90; range 62.5-97.5), indicating high usability. Participants rated ease of use (mean 4.46, SD 0.56), learnability (mean 4.27, SD 0.69), and confidence (mean 4.27, SD 0.61) positively. There was no correlation between SUS score and age (r=0.05). Thematic analysis revealed four themes: (1) immersive and enjoyable experience, with patients describing the device as "novel" and "engaging"; (2) reduced fasting-related discomfort, including less bloating, improved mood, and reported peristalsis; (3) appetite stimulation, with many noting increased hunger; and (4) improvement suggestions, such as enhancing scent authenticity, simplifying controls, and diversifying music. One participant experienced transient dizziness, resolving within 5 minutes post-device removal, with no other adverse events. Quantitative and qualitative findings converged, confirming robust usability and clinical benefits.

Conclusions: The VRMS-SFD may be a feasible, well-accepted tool that mitigates fasting-related discomfort, enhances appetite, and improves emotional well-being in patients undergoing colorectal cancer surgery. Future iterations should refine scent calibration and the user interface. Larger trials with objective measures (eg, gastrointestinal motility and hormone levels) are needed to validate efficacy and explore applications in other conditions.

Trial registration: Chinese Clinical Trial Registry (ChiCTR), ChiCTR2100051419; https://www.chictr.org.cn/showprojEN.html?proj=134263.