Comparison of Vocal Amplitude and Contact Speed according to SOVTE Type

Objectives: Observation of vocal fold vibration during semi-occluded vocal tract exercises (SOVTE) can help in understanding voice production due to semi-occlusion. This study aimed to investigate the differences in vocal fold vibration characteristics among various types of SOVTE. This study may provide valuable evidence to support more specific and effective methods in applying SOVTE to voice therapy. Methods: A total of 10 healthy young adults (5 males, 5 females) with a mean age of 24.28±4.54 years participated in the study. None of the participants had any voice-related diseases or were smokers. The participants performed various types of SOVTE including humming, voiced bilabial fricative, straw phonation, and water-resistance straw phonation. The authors measured the amplitude and contact speed of vocal fold using a vibration simulator and digital kymography (DKG). Results: The results showed that vocal fold amplitude was not significantly different among types of SOVTE, but there were significant differences in vocal fold contact speed (p=.046). In multiple comparisons, vocal fold contact speed was significantly faster in humming (p=.031) and water-resistance straw phonation (p=.018) compared to straw phonation. Conclusion: The difference in vocal fold contact speed indicates that the vocal fold vibration during SOVTE is affected by the shape of the vocal tract. The use of humming and water-resistance straw phonation can be an effective approach to improve voice quality by increasing vocal fold contact speed, which is a key factor in determining overall voice quality. These two methods can be useful in voice therapy after laryngeal microsurgery. In the field, conducting trial therapy rather than applying voice therapy according to the hierarchy of SOVTE may lead to successful results.