Background: While it is well established that audio-visual inputs significantly affect speech perception, and clinicians use both eyes and ears for assessing their patients, research and clinical training in voice quality assessment often rely solely on audio recordings. This discrepancy between clinical practice and training methodologies may limit the effectiveness of voice quality assessments. This study addresses this gap by examining the effect of visual information on the perception of vocal effort and dysphonia severity.

Method: Twelve individuals diagnosed with laryngeal dystonia were video-recorded while speaking six sentences from the Consensus of Auditory Perceptual Evaluation of Voice (CAPE-V). These recordings were evaluated for dysphonia severity and vocal effort using a visual analog scale by 24 speech-language pathology graduate students, who were randomly assigned to either an audio-only group or an audio-visual group. Post-evaluation, all students reported their confidence levels in their assessments. The audio-visual group additionally completed a survey to explore how visual cues influenced their ratings. A mixed model ANOVA was used to evaluate the effects of presentation modality on the ratings.

Results: There was a significant difference in dysphonia severity ratings, with the video group assigning higher severity ratings than the audio-only group. No significant difference was found in the ratings of vocal effort or in the confidence levels of the raters across both groups. The survey results indicate that visual information did have an effect on the perception of vocal effort and severity. Some raters felt that the video allowed them to discern more visual characteristics that denote effort levels. Others claimed that they expected to see more physical effort or strain in the videos but noticed no physical signs of strain, even when voices sounded severe.

Conclusion: The inclusion of visual information can significantly influence the assessment of dysphonia severity, potentially introducing bias into research and clinical training. This highlights the importance for clinicians to be aware of the possible impact of visual information on their judgments and to consider these effects in their diagnostic and treatment processes.