| Abstract | Objective: Various causes, including muscle tension dysphonia, structural and neurogenic voice disorders, may affect the triggering of vocal fold vibration and voicing. Voice Onset Time (VOT) objectively measures the trigging timespan of voicing in stop consonant production. Therefore, we aimed to investigate the relation between perceptual voice quality (PVQ) and VOT and to compare VOT between secondary muscle dysphonia (SMD) and unilateral vocal fold motion impairment (UVMI).
Methods/Design: 24 cases of women with SMD (n=12) and UVFMI (n=12) were retrieved from the database of the Outpatient Clinic in Bahia’s Federal University Hospital. PVQ was assessed with the Brazilian CAPE-V protocol. Samples of [pe, paj, and pɔ] were extracted from the CAPE-V sentences for acoustic analysis with Praat. Mean fundamental frequency (fo), intensity (SPL (A)), Harmonics-to-Noise Ratio (HNR), and VOT were analyzed. A three-way multivariate analysis of variance (MANOVA) with post hoc tests was applied to determine the relation between voice disorder classification (SMD vs. UVFMI), PVQ, and type of vowel with VOT, fo, and HNR. A Kruskal-Wallis test was used to describe the effect of voice disorder classification, PVQ, and type of vowel with SPL.
Results: PVQ was significantly related to HNR, VOT, and SPL (p< .05), with higher HNR and VOT in higher dysphonia scores. Further, HNR was significantly different between almost all categories except for mild versus no voice deviation and mild versus moderate voice deviation; VOT was only significantly different between mild and no voice deviation. Voice disorder classification significantly affected VOT, fo (p< .05), HNR, and speaking SPL (p< .001). A higher mean fo and lower HNR was observed in patients with UVFMI. Women with SMD had a higher VOT than those with UVFMI. The type of vowel did not affect VOT, HNR, and fo.
Conclusions: The present study in voice-disordered women shows a relation between vocal hyperfunction and voice onset time, with a higher objective VOT than UVFMI. Moreover, VOT discriminated between no and mild voice deviation. Future studies should explore the diagnostic potential of these results in a larger group of voice-disordered compared to vocally healthy individuals.
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