Abstract
Electroglottographic (EGG) jitter and shimmer have been described as more sensitive than acoustic perturbation. Recent studies documented significant voice intensity effects on acoustic parameters even in “normal” voice intensity. The aim of this cross-sectional single cohort study was to compare voice intensity effects in acoustic and electroglottographic measurements in several voice tasks. Forty healthy adults (1:1 f:m) aged 20–40 years phonated /a/ at subjective “soft,” “medium,” and “loud” voice and at 65, 75, 85, and 95 dB. Voice intensity and perturbation measurement method effects were assessed with ANOVA. Electroglottographic and acoustic perturbation were significantly different (p<0.001) at all intensity levels and lowest at highest voice intensities. Biggest differences were found between “soft” and “loud” voice in EGG measurements. Electroglottographic results were significantly higher in all tasks, for example mean shimmer in “soft” voice: acoustic 4.4% (SEM: 0.58%) and electroglottographic 7.35% (SEM: 1.02%). The measurement difference was smaller in prescribed intensities (mean shimmer at 65dB: acoustic 2.5% (SEM: 0.23) and electroglottographic 3.0% (SEM: 0.28%). Voice intensity changes strongly influence acoustic and electroglottographic perturbation and are minimized when patients control for voice intensity. Electroglottographic measurements are generally higher and stronger influenced by voice intensity changes. Future work should cover if this reflects a better sensitivity or more measurement error.
Brockmann, M