How Age and Frequency Impact the Thyroid Cartilages of Professional Singers.

OBJECTIVES/HYPOTHESIS: Young professional singers can easily reach very high pitches. In contrast, older singers often complain that they have to exert substantially more laryngopharyngeal force to reach the same high pitch compared with their earlier years. Various factors such as the property changes of the mucosa and ossification that impact the singing apparatus were suggested as explanations in the literature. The aim of this study was to analyze thyroid deformation-and thereby stiffness indirectly-during singing as a potential reason for this phenomenon. STUDY DESIGN: Prospective study. METHODS/DESIGN: We examined 44 female professional singers. High-resolution computed tomography scans were performed during singing at the fundamental mean speaking frequency and the first and second octaves above it. Digital Imaging and Communications in Medicine scan data were rendered and visualized 3-dimensionally using MIMICS software. By superimposition of the different 3-dimensional images, different positions of the thyroid were visualized. The distance from the posterior border of the thyroid was measured in all the examinations. RESULTS: All laryngeal cartilages could be three-dimensionally visualized. The magnitude of the thyroidal deformation significantly depends on pitch and significantly correlates with age (r2 = 0.7, P < 0.001). CONCLUSIONS: The thyroid cartilage is flexible and its formability is especially important during singing. At higher pitches, the cartilage was more deformed. The larynx in older singers showed less thyroid cartilage deformation.

3D analysis of the movements of the laryngeal cartilages during singing.

OBJECTIVE: The vocal range of untrained singers rarely exceeds one and a half octaves, but professional singers have a range of at least two and a half octaves. The aim of this study was to better understand the muscle and cartilage movements responsible for the control of vocal pitch in singing. STUDY DESIGN: Prospective study. METHODS: We recruited 49 female professional singers (25 sopranos and 24 altos) and analyzed laryngeal three-dimensional images derived from high-resolution computed tomography scans obtained at the mean speaking fundamental frequency (F0) and at one (F1) and two octaves (F2) above this pitch. RESULTS: From F0 to F1, the only observable movement was a backward cricoid tilting caused by the cricothyroid muscles (CTMs), leading to vocal fold stretching. Above F1, a medial rotation and inward rocking of the arytenoid cartilages was observed, caused by the lateral cricothyroid muscles (LCAMs) and leading to inferior displacement of the vocal process of the arytenoid cartilage, and thus to further vocal fold stretching. CONCLUSION: Trained singers achieve the first octave of pitch elevation by simple cricothyroid approximation. Further pitch elevation necessitates a complex movement of the arytenoids, first by CTM contraction and second by LCAM contraction. LEVEL OF EVIDENCE: 4. Laryngoscope, 127:1639-1643, 2017.

Three-dimensional Imaging of High-resolution Computer Tomography of Singers' Larynges-A Pilot Study.

OBJECTIVES/HYPOTHESIS: Biplanar imaging technique is not sufficient for an exact visualization and evaluation of the laryngeal biomechanics during speaking or singing. The aim of this pilot study was to test a 3D-visualization software MIMICS (Materialize Interactive Medical Image Control System, Materialize, Leuven, Belgium) for visualizing laryngeal cartilages and resonance space of living humans during singing based on high-resolution computed tomography (HRCT) and analyzing the biomechanics thereof. STUDY DESIGN: This is a prospective pilot study. METHODS: A total of 10 professional female singers (five sopranos and five altos) was scanned with HRCT in three singing positions fundamental frequency (ƒo), first octave (ƒo+1 8va) and second octave (ƒo+2 8va). RESULTS: All relevant laryngeal structures and resonance space could be 3D visualized. Superimposing the different HRCT scans showed an inward rotation and rocking of the arytenoid cartilages from ƒo+1 8va to ƒo+2 8va and a backward tilting of the cricoid cartilage from ƒo+1 8va to ƒo+2 8va. Moreover, we could demonstrate a vocal fold elongation of 13% from ƒo to ƒo+1 8va and an additional elongation from ƒo+1 8va to ƒo+2 8va of 10% in type A cricothyroid joints (CTJ) A and 4% in CTJ's type B/C. There were no significant differences between sopranos and altos in all parameters (length of the glottis, subglottic diameter, distance between anterior commissure and cervical spine, and CTJ distribution). CONCLUSIONS: This noninvasive 3D-visualization technique with MIMICS allows the anatomical structures and landmarks of the larynx to be analyzed. We believe that this pilot study will serve as a basis for further biomechanical studies on speakers' and singers' larynges.