Three dimensional vocal fold dynamics during a variety of phonatory conditions

Michael Doellinger

Digital high-speed imaging of the entire surface of one vocal fold was performed using an excised human hemi-larynx setup. To cover the three-dimensional dynamics of the entire vocal fold surface, 30 different tracking markers were placed within a bidirectional homogenous grid. Surface dynamics were characterized and differentiated across 24 different phonatory conditions.
During sustained, flow-induced oscillation, the local maxima of vocal fold mucosal displacements, velocities and acceleration values were analyzed for the markers. Also, their particular phase delays in the glottal cycle were investigated. Statistical analysis was performed, examining the influence on the dynamics of induced air flow, adductory stimulation, and length of the vocal fold.
Increasing the applied airflow, yielded higher values for lateral displacements as well as higher velocity and acceleration values. Elongating the vocal fold resulted in decreased lateral displacements. The mucosal wave propagation apparently increased for higher flow, elongated folds, and higher adduction forces.
To give an overview of occurring dynamical quantities, grand average values were computed and discussed for the complete series of 24 recordings.A significant increase in the dynamics between inferior and superior regions was detected. The data showed a nearly 180 degree phase delay between inferior and superior regions of the vocal fold with respect to lateral displacements, velocities, and accelerations. Phase delays for the vertical displacements were also present, but less pronounced.

Michael Doellinger¹, David A. Berry², Ulrich Eysholdt¹, Joerg Lohscheller¹

¹ UniversityHospital Erlangen, Medical School, Department of Phoniatrics and Pediatric Audiology, Bohlenplatz 21, 91054 Erlangen, Germany
Email: Michael.doellinger@phoni.ime.uni-erlangen.de
Fax: (+49)-9131-85-39272 Phone: (+49)-9131-85-33 815
² The Laryngeal Dynamics Laboratory, Division of Head and Neck Surgery, David Geffen School of Medicine at UCLA, 1000 Veteran Ave., Suite 31-24 Rehab Center, Los Angeles, CA, 90095-1794, Email: daberry@ucla.edu