title: Dynamic vocal fold parameters with changing adduction in ex-vivo hemilarynx experiments.
abstract: Ex-vivo hemilarynx experiments allow the visualization and quantification of three-dimensional dynamics of the medial vocal fold surface. For three excised human male larynges, the vibrational output, the glottal flow resistance, and the sound pressure during sustained phonation were analyzed as a function of vocal fold adduction for varying subglottal pressure. Empirical eigenfunctions, displacements, and velocities were investigated along the vocal fold surface. For two larynges, an increase of adduction level resulted in an increase of the glottal flow resistance at equal subglottal pressures. This caused an increase of lateral and vertical oscillation amplitudes and velocity indicating an improved energy transfer from the airflow to the vocal folds. In contrast, the third larynx exhibited an amplitude decrease for rising adduction accompanying reduction of the flow resistance. By evaluating the empirical eigenfunctions, this reduced flow resistance was assigned to an unbalanced oscillation pattern with predominantly lateral amplitudes. The results suggest that adduction facilitates the phonatory process by increasing the glottal flow resistance and enhancing the vibrational amplitudes. However, this interrelation only holds for a maintained balanced ratio between vertical and lateral displacements. Indeed, a balanced vertical-lateral oscillation pattern may be more beneficial to phonation than strong periodicity with predominantly lateral vibrations.
authors.affiliation: Division of Phoniatrics and Pediatric Audiology-Computational Medicine, Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Erlangen, Medical School at Friedrich-Alexander-Universität Erlangen-Nürnberg, Bohlenplatz 21, 91054 Erlangen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Döllinger
authors.affiliation: The Laryngeal Dynamics Laboratory, Division of Head and Neck Surgery, David Geffen School of Medicine at UCLA, 31-24 Rehab Center, 1000 Veteran Avenue, Los Angeles, California 90095-1794, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Berry
authors.affiliation: Division of Phoniatrics and Pediatric Audiology-Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Erlangen, Medical School at Friedrich-Alexander-Universität Erlangen-Nürnberg, Bohlenplatz 21, 91054 Erlangen, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Kniesburges
mesh_terms: D000328:Adult; D000368:Aged; D000403:Airway Resistance; D002102:Cadaver; D006801:Humans; D007830:Larynx / Q000033:anatomy & histology / Q000502:physiology*; D008297:Male; D009038:Motion; D010699:Phonation; D011312:Pressure; D013016:Sound; D013499:Surface Properties; D013997:Time Factors; D014732:Vibration; D014827:Vocal Cords / Q000033:anatomy & histology / Q000502:physiology*