Impact of Subharmonic and Aperiodic Laryngeal Dynamics on the Phonatory Process Analyzed in Ex Vivo Rabbit Models

Abstract

Normal voice is characterized by periodic oscillations of the vocal folds. On the other hand, disordered voice dynamics (e.g., subharmonic and aperiodic oscillations) are often associated with voice pathologies and dysphonia. Unfortunately, not all investigations may be conducted on human subjects; hence animal laryngeal studies have been performed for many years to better understand human phonation. The rabbit larynx has been shown to be a potential model of the human larynx. Despite this fact, only a few studies regarding the phonatory parameters of rabbit larynges have been performed. Further, to the best of our knowledge, no ex vivo study has systematically investigated phonatory parameters from high-speed, audio and subglottal pressure data with irregular oscillations. To remedy this, the present study analyzes experiments with sustained phonation in 11 ex vivo rabbit larynges for 51 conditions of disordered vocal fold dynamics. (1) The results of this study support previous findings on non-disordered data, that the stronger the glottal closure insufficiency is during phonation, the worse the phonatory characteristics are; (2) aperiodic oscillations showed worse phonatory results than subharmonic oscillations; (3) in the presence of both types of irregular vibrations, the voice quality (i.e., cepstral peak prominence) of the audio and subglottal signal greatly deteriorated compared to normal/periodic vibrations. In summary, our results suggest that the presence of both types of irregular vibration have a major impact on voice quality and should be considered along with glottal closure measures in medical diagnosis and treatment.

3D-FV-FE Aeroacoustic Larynx Model for Investigation of Functional Based Voice Disorders

“…Moreover, the results of SPL show good qualitative agreement with those reported by Thornton et al ( 2019 ) and Döllinger et al ( 2018 ), see Table 3 . They executed ex vivo experiments with rabbit larynxes and three different glottal insufficiency grades (complete glottal closure, partial glottal closure, no contact of vocal folds).…”

“…The high CPP values for GC2 and GC3 for symmetrically oscillating VFs shows, that the acoustic signal is still tonal and physiological for small posterior gaps as often observed in physiological phonation of women and childs (Södersten and Lindestad, 1990 ; Södersten et al, 1995 ; Inwald et al, 2010 ; Patel et al, 2012 ; Kniesburges et al, 2020 ). Quantitatively, our CPP values are in the range of values reported by Döllinger et al ( 2018 ) and Thornton et al ( 2019 ).…”

“…The same observations have been made in in vivo studies executed by Samlan et al ( 2014 ) and Chen et al ( 2011 ). Furthermore, the qualitative trend of CPP was also found in ex vivo studies with human (Birk et al, 2017b ) and rabbit larynges (Döllinger et al, 2018 ; Thornton et al, 2019 ), as shown in Table 4 . The high CPP values for GC2 and GC3 for symmetrically oscillating VFs shows, that the acoustic signal is still tonal and physiological for small posterior gaps as often observed in physiological phonation of women and childs (Södersten and Lindestad, 1990 ; Södersten et al, 1995 ; Inwald et al, 2010 ; Patel et al, 2012 ; Kniesburges et al, 2020 ).…”

“…Whereas in vivo studies are difficult to perform and are mainly restricted to pure observation of the vocal fold oscillations (Inwald et al, 2010;Döllinger et al, 2012), ex vivo experiments with excised cadaver larynges (e.g., canine, porcine, human) provide better access to the laryngeal area and enable to manipulate the larynx (Hoffman et al, 2012;Birk et al, 2017b). Ex vivo studies about different levels of glottal insufficiency were reported by Döllinger et al (2018) and Thornton et al (2019) using rabbit larynges and Birk et al (2017b) who used porcine larynges. Moreover, Oren et al (2016) investigated asymmetric vocal fold oscillations in excised canine larynges.…”

Intersegmenter Variability in High‐Speed Laryngoscopy‐Based Glottal Area Waveform Measures

“…4 Second, it can be applied to all types of vocal fold vibrations, even the least periodic ones. 5 Third, it can be utilized in case of very short and unstable (for example due to voice breaks and spasms) phonations with varying period properties. 6 Fourth, it allows for a detailed spatiotemporal analysis of vocal fold vibrations.…”