Stuttering adaptation is stronger in VR than in real-world settings
How this was rated
Quasi-experimental design (n=24) without randomization. Findings are suggestive and informative for hypothesis generation.
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This study examined whether people who stutter show the expected decline in stuttering across repeated readings in VR compared to real-world settings. Twenty-four adults completed tasks in both environments, and the adaptation effect was actually stronger in VR.
A quasi-experimental study suggesting that Arabic-language VR speaking practice may be feasible for adults who stutter, with effect estimates limited by the non-randomized design.
Key findings
- Stuttering severity decreased across successive trials in both real and virtual environments
- The reduction in stuttering was more pronounced in the VR environment for both reading and spontaneous speech
- In VR, there was no significant difference in stuttering severity between reading and spontaneous speech tasks
- Inter-rater reliability was excellent (Cronbach's alpha = 0.98 real, 0.99 virtual)
Background
When people who stutter read the same passage several times in a row, their stuttering typically decreases with each reading. This well-documented phenomenon, known as the adaptation effect, is a fundamental part of how speech fluency is understood and assessed. However, it was unclear whether this same pattern would hold in virtual reality, or whether the novelty and immersive qualities of VR might disrupt it.
What the researchers did
Twenty-four Arabic-speaking adults who stutter (15 male / 9 female, ages 19-33, mean 24.8, SD 4.07, all native Saudi Arabian speakers) completed repeated reading and spontaneous speech tasks in two settings: a standard real-world room and a VR environment. Stuttering severity spanned a wide range - from very mild to very severe per the Stuttering Severity Instrument-4 (SSI-4). A single investigator analyzed the recordings (the paper’s Limitations section explicitly states “data were examined by a single investigator”). A Cronbach’s alpha of 0.98-0.99 is reported in the paper, though this internal consistency figure appears in tension with single-rater data collection - a contradiction the paper itself does not resolve.
What they found
Stuttering severity decreased across successive trials in both settings, confirming that the adaptation effect occurs in VR just as it does in real life. Surprisingly, the reduction was even more pronounced in the VR environment. Another notable finding was that in VR, stuttering severity during spontaneous speech was not significantly different from stuttering during reading - a gap that typically exists in real-world assessments. Inter-rater reliability was excellent in both conditions.
Why this matters
The stronger adaptation effect in VR suggests that virtual environments may create conditions that help people who stutter settle into their speech more quickly. The narrowing of the gap between reading and spontaneous speech is particularly interesting, as it implies VR might ease the transition from structured to unstructured speaking tasks. Clinicians could leverage this property when helping people move from controlled practice to more naturalistic communication.
Limitations
The study used a single-session design, so it is unclear whether the stronger VR adaptation effect would persist over multiple visits. All participants were Arabic-speaking adults, limiting generalizability to other languages and age groups. The study also did not explore why VR produced a stronger effect, leaving the underlying mechanism open to future investigation.
Implications for practice
VR environments may produce a stronger adaptation effect, making them strategically useful during generalization phases. VR appeared to reduce the difficulty gap between reading and spontaneous speech.
Where this connects to Therapy withVR
The study above is independent research and does not endorse any product. The notes below are commentary from withVR on how the themes in this research relate to features of Therapy withVR. The research findings are not claims about Therapy withVR.
Repeatable VR Sessions
This study examined adaptation effects in VR - Therapy withVR's saved profiles enable identical session setups for tracking how speech patterns change across repeated exposures.
Classroom Environment
The virtual classroom used in this study is available in Therapy withVR, providing the same type of speaking context that produced genuine stuttering responses.
Cite this study
If you reference this study in your work, the canonical citation formats are:
@article{almudhi2021,
author = {Almudhi, A.},
title = {Evaluating adaptation effect in real versus virtual reality environments with people who stutter},
journal = {Expert Review of Medical Devices},
year = {2021},
doi = {10.1080/17434440.2021.1894124},
url = {https://withvr.app/evidence/studies/almudhi-2021}
}TY - JOUR
AU - Almudhi, A.
TI - Evaluating adaptation effect in real versus virtual reality environments with people who stutter
JO - Expert Review of Medical Devices
PY - 2021
DO - 10.1080/17434440.2021.1894124
UR - https://withvr.app/evidence/studies/almudhi-2021
ER - Know of research that should be in this hub? If a relevant peer-reviewed study is not listed here, send the reference to hello@withvr.app. The hub is kept up to date as the literature grows.
Funding & independence
King Khalid University Deanship of Scientific Research, Grant GRP 204-41. No withVR BV involvement in funding, study design, or authorship. Summary prepared independently by withVR using the published paper.