Supplementary Material for: Voice Signatures Of Momentary Psychological Stress In Real-Life Environments: Results From The Colive Voice Study

Introduction Voice is hypothesized to be modulated by stress, and thus could be used as a potential stress detection and monitoring solution. In the literature, vocal biomarkers for stress have mostly been developed on experimental data, with limited samples. Therefore, this study aims to present insights into the effect of momentary psychological stress on voice in real-life recordings, across different languages, genders, and vocal tasks. Methods Participants from the Colive Voice study reported their stress level on a 1 to 5 Likert scale. Two tasks were performed: a text-reading task and an A-vowel phonation. We analyzed the data cross-sectionally. We extracted vocal features with the DisVoice library and performed ordinary least squares regression models to evaluate the association of vocal features with stress. Models were stratified by gender and language (French/English) and controlled for age, smoking status, alcohol consumption, the presence of chronic disease, education level, mother tongue, well-being, fatigue, and depression. Benjamini-Hochberg correction was applied to control for multiple testing. Results We analyzed a sample of 4155 participants, 2011 in French (1621 women, 390 men) and 2144 in English (1105 women, 1039 men). In the text reading task, we found that stress was associated with two articulatory features for English-speaking women. Among French-speaking women, higher stress was linked with lower pitch and higher shimmer. The duration of pauses and one glottal feature were also associated with stress. In the A-vowel phonation task, pitch and the variability of the pitch perturbation quotient were lower with stress in English-speaking men. French-speaking women had increased voice intensity and loudness with stress. Conclusion We were able to confirm the association of momentary psychological stress with various vocal features in real-life settings, but not across languages, vocal tasks, or gender. Future research should include longitudinal studies to investigate the potential of using voice as an intra-individual monitoring biomarker for stress.