A Critical Assessment of the Use of SSQ as a Measure of General Discomfort in VR Head-Mounted Displays

Title of the Paper

A Critical Assessment of the Use of SSQ as a Measure of General Discomfort in VR Head-Mounted Displays

Paper Information

• Research Domain: Virtual Reality (VR), Human-Computer Interaction, Simulator Sickness, Digital Eye Strain, Ergonomics-related Discomfort Assessment
• Keywords: SSQ, Simulator Sickness, Digital Eye Strain (DES), Discomfort, Head-Mounted Display (HMD), Virtual Reality

Research Background and Problem

• Problem and Challenges:
  The authors point out that the Simulator Sickness Questionnaire (SSQ) is widely used to assess general discomfort in VR head-mounted displays. However, SSQ focuses solely on one category of symptoms (simulator sickness) while neglecting other critical categories (e.g., digital eye strain (DES) and ergonomic issues (ERG)). This leads to limitations in research on VR-related discomfort.

• Significance:
  As VR technology becomes increasingly widespread, user experience quality is gaining importance. Discomfort may impact VR usage satisfaction and adoption rates. A more comprehensive understanding of discomfort symptoms in VR usage can help improve device design and user experience.

• Motivation and Related Work:

  • Existing studies indicate that using SSQ as a general discomfort assessment tool has limitations, such as its inability to cover digital eye strain and ergonomic issues.
  • The authors aim to conduct a systematic literature review and user study to critically evaluate current practices of using SSQ and propose a more comprehensive factor-based model to measure VR discomfort symptoms.

Solution

• Methods and Approach:
  The authors investigate discomfort issues in VR through the following methods:

  1. Systematic Literature Review: Reviewing over 300 relevant papers from the past decade to analyze the application of SSQ in VR research.
  2. Online User Study (N=352): Comparing the severity and correlation of three major symptom categories—simulator sickness, digital eye strain, and ergonomic issues—and proposing a factor-based comprehensive scale model.

• Innovations:

  • Critically assessing the applicability of SSQ and proposing an extended model that incorporates digital eye strain (DES) and ergonomic issues (ERG) into discomfort assessment.
  • The study reveals that discomfort symptoms during VR usage are more inclined toward DES and ERG rather than simulator sickness, providing a theoretical foundation for developing more comprehensive and sensitive scales in the future.

• Implementation Steps and Techniques:

  • Using the PRISMA method to screen and analyze literature in the systematic review.
  • Designing an online user experiment with a 7-point Likert scale to evaluate the three symptom categories.
  • Applying factor analysis and other statistical methods to integrate and validate the measurement model.

Research Findings

• Specific Findings:

  1. The literature review shows that approximately 61% of studies use SSQ to assess discomfort symptoms but fail to fully consider its original limitation to simulator sickness. Only 4% of studies simultaneously consider DES and ERG.
  2. The user study reveals that among DES, ERG, and simulator sickness, ERG has the most significant impact on user discomfort, followed by DES, while simulator sickness has the least impact.

• Advantages and Comparison:

  • The study proposes an extended discomfort assessment model that includes DES and ERG. Unlike traditional methods relying solely on SSQ, this model is more comprehensive and better aligned with the actual needs of current VR users.

• Experimental or Evaluation Results:

  • Factor analysis results indicate that discomfort distribution can be divided into six independent factors: ERG (“physical discomfort caused by wearing the device”), DES (“digital eye strain”), and simulator sickness (“motion sickness”).
  • Experimental data show that the physical changes users experience while wearing the device (e.g., restricted movement) and related ergonomic issues are the most significant sources of discomfort.

• Limitations and Future Directions:

  • Limitations:
    • The study only examines three major categories—DES, ERG, and simulator sickness—without addressing potential issues such as psychological factors.
    • The sample primarily consists of frequent VR device users, potentially overlooking the experiences of novice users.
  • Future Directions:
    • Developing more comprehensive questionnaire tools to cover all relevant discomfort categories, including psychological and social factors.
    • Conducting studies targeting different user groups (e.g., novice users) to analyze whether higher symptom values or significant differences exist.