The Fundamental Frequency of Voice as a Potential Stress Biomarker: A Systematic Review and Meta-Analysis.
Level 2 - randomized trial
Systematic review and meta-analysis of non-randomized experimental and naturalistic pre-post studies.
PubMed 41102940 · doi:10.1002/smi.70112
What was done
A systematic review and random-effects meta-analysis following PRISMA guidelines examined the effect of acute stress on vocal fundamental frequency (F0). Searches across PubMed and Scopus covered January 2010 to September 2024. Eligible studies evaluated adult participants exposed to experimental or naturalistic stressors with objective pre- and post-stress acoustic voice recordings. Subgroup analyses evaluated differences across gender, speech type (spontaneous vs. standardized), and stress induction methodology.
What was found
Across 10 studies encompassing 1,148 observations, acute stress significantly increased vocal F0 (SMD = 0.5504, 95% CI [0.3014, 0.7995], p < 0.001) with substantial heterogeneity (I² = 69.2%). However, after adjusting for observed publication bias via trim-and-fill, the effect became nonsignificant (SMD = 0.1710, 95% CI [-0.1472, 0.4891], p = 0.2923). Subgroup analyses found significant F0 increases in women (SMD = 0.7128, 95% CI [0.3763, 1.0492], p < 0.001) and during spontaneous speech (SMD = 0.7911, 95% CI [0.4492, 1.1331], p < 0.001), but nonsignificant effects in men and during standardized speech. Differences between naturalistic and laboratory stressors were not statistically significant.
Why it matters
Vocal fundamental frequency is frequently proposed as a noninvasive biomarker of physiological and psychological stress, but these findings show the overall effect is heavily undermined by publication bias and context-dependent factors such as gender and speech task.
Limits
The meta-analysis included only 10 studies. There was high between-study heterogeneity (I² = 69.2%) and clear evidence of publication bias that eliminated statistical significance under trim-and-fill modeling. Stress effects were inconsistent across subgroups, failing to achieve significance in men or during standardized speech protocols.
Cited by
- supports Experiencing nervousness or acute anxiety causes a person's vocal pitch to elevate above their natural speaking tone.