Three Professional Singers' Vocal Tract Dimensions in Operatic Singing, Kulning, and Edge-A Multiple Case Study Examining Loud Singing.

OBJECTIVE: A comprehensive understanding of how vocal tract dimensions vary among different types of loud voice productions has not yet been fully formed. This study aims to expand the existing knowledge on the topic. METHODS: Three trained professional singers together practiced the vocal techniques underlying Opera and Kulning singing styles for one hour and, afterwards, phonated using these techniques on vowel [iː] at pitch C5 (523 Hz), while their vocal tracts were scanned via MRI. One of the participants also produced the samples in the Edge vocal mode using [ɛː]. Several dimensional vocal tract measurements were calculated from the MRIs. Spectral analysis was conducted on the filtered audio recorded during the MRI. RESULTS: The Operatic technique demonstrated a lower larynx, a larger tongue-palate distance, and larger epilaryngeal and pharyngeal tube diameters compared to Kulning. Edge showed the highest laryngeal position, narrowest pharynx and epilarynx tubes, and the least forward-tilted larynx out of the styles studied. The spectra of Opera and Kulning showed a dominant first harmonic, while in Edge, the second harmonic was the strongest. CONCLUSIONS: The results shed light on the magnitude of vocal tract changes necessary for genre-typical vocal projection. This information can be pedagogically helpful.

Acoustic Voice Quality Index as a Potential Tool for Voice Screening.

INTRODUCTION: To diminish the risk of voice disorders in people who are highly dependent on their voices, such as teachers, vocal screening is important already at the beginning of such individuals' professional studies. A reliable, specified screening tool is needed. The Acoustic Voice Quality Index (AVQI) has been found to differentiate normal voices from abnormal voices and to serve as a treatment outcome measure. This study investigated whether AVQI could be a screening tool in combination with auditory- and self-perception of the voice to discriminate normal from slightly poor voices. TYPE OF STUDY: Experimental. METHODS: Some 128 female teaching students (mean age 26.39 years, SD 9.80 years) with no diagnosed voice disorders participated in this study. They read aloud a text in Finnish, sustained the vowel /a:/, and filled the Voice Handicap Index (VHI) questionnaire. Voice samples were recorded with an AKG C544L headset microphone, iFocusrite soundcard, and Praat software using a 44100 sample rate and 16-bit amplitude quantization. Five expert voice therapists evaluated the samples to determine the grade of dysphonia (G) using a scale of 0-0.5 (=normal), 0.5-1 (=mild), 1-2 (=moderate), and 2-3 (=severe). Three medial seconds of [a:] and the first 31 syllables of the text were analyzed using AVQI script version 03.01 in Praat (5.3.55). The analysis gives one AVQI score per participant (scale 0-10). The AVQI threshold of normal and disordered voices for Finnish speakers is 1.83; a Gmean = 0.0-0.5 and VHI score <19 were considered normal. Statistical analysis was done using the receiver operating characteristic (ROC) curve, Spearman's correlation coefficient, and the independent samples t test. RESULTS: According to the AVQI results, the area under the curve (AROC) was 0.554, which is fair. The Youden index gave a cutoff value of 0.30 with a sensitivity of 85% and a specificity of 81.1%. There were weak but significant correlations between Gmean and AVQI and two AVQI parameters, smoothed cepstral peak prominence and harmonic-to-noise ratio (r = 0.27; --0.24; -0.20, respectively; |P < 0.05); and between total VHI and AVQI score and cepstral peak prominence (r = 0.21; 0.20, respectively; P < 0.05). Furthermore, the AVQI scores differed significantly between the groups with a VHI total score <19 and ≥19. CONCLUSIONS: AVQI did not differentiate between voices that had been perceptually judged as normal or slightly abnormal, but a combination of perceptual assessment in the form of AVQI and VHI could better screen slightly deviant voices.

How Much Loading Does Water Resistance Voice Therapy Impose on the Vocal Folds? An Experimental Human Study.

OBJECTIVES: Water resistance voice therapy applies phonation into water through a tube. This study investigates how strenuous this therapy can be for the vocal folds in terms of impact stress (IS). It further examines whether it is possible to estimate the IS using the contact quotient (CQ) and maximum derivative from an electroglottogram (EGG). STUDY DESIGN: Experimental study. METHODS: A male participant sustained a rounded back vowel [u:] or [o:] at a comfortable speaking pitch and loudness, and phonated into a silicone "Lax Vox" tube submerged 2 cm in water. High-speed videolaryngoscopy was performed with a rigid scope. Oral air pressure (Poral) was registered in a mouthpiece through which an endoscope was inserted into the larynx. An EGG was recorded. RESULTS: The CQEGG from the EGG and the closed quotient from the glottal width (CQarea) increased, while the maximum glottal amplitude and absolute value of derivative minimum (dmin) and also the derivative maximum from the EGG decreased for phonation into water. Normalized amplitude quotient from the glottal width variation also decreased but the change was not significant. CONCLUSIONS: Based on the glottal area findings, water resistance therapy does not seem to increase vocal fold loading (in terms of increased IS) even if the increase of CQarea, and CQEGG suggest so. CQEGG may qualitatively correspond to that of area, but the reliability of CQ (from the glottal area or the EGG) and the maximum derivative from the EGG as estimates of IS in semiocclusion exercises warrant further studies.