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Summary Objective The shape of the vocal tract and associated structures (eg, tongue and velum) is complicated and varies according to development and function. This variability challenges interpretation of voice experiments. Quantifying differences between shapes and understanding how vocal structures move in relation to each other is difficult using traditional linear and angle measurements. With statistical shape models, shape can be characterized in terms of independent modes of variation. Here, we build an active shape model (ASM) to assess morphologic and pitch-related functional changes affecting vocal structures and the airway. Method Using a cross-sectional study design, we obtained six midsagittal magnetic resonance images from 10 healthy adults (five men and five women) at rest, while breathing out, and while listening to, and humming low and high notes. Eighty landmark points were chosen to define the shape of interest and an ASM was built using these (60) images. Principal component analysis was used to identify independent modes of variation, and statistical analysis was performed using one-way repeated-measures analysis of variance. Results Twenty modes of variation were identified with modes 1 and 2 accounting for half the total variance. Modes 1 and 9 were significantly associated with humming low and high notes ( P < 0.001) and showed coordinated changes affecting the cervical spine, vocal structures, and airway. Mode 2 highlighted wide structural variations between subjects. Conclusion This study highlights the potential of active shape modeling to advance understanding of factors underlying morphologic and pitch-related functional variations affecting vocal structures and the airway in health and disease. [ABSTRACT FROM AUTHOR]

Summary: Objectives/Hypothesis: Traditional voice research occurs within a phonetic context. Accordingly, pitch-related contributions are inseparable from those due to articulator input. In humming, articulator input is negligible. Using magnetic resonance imaging, we test the hypothesis that voice production is accompanied by pitch-related adjustments unrelated to articulatory or postural input. Study Design/Method: In this cross-sectional study, 10 healthy volunteers (five men, five women, aged 20–47 years, median 25 years), including singers (6 months to 10 years tuition, median 2 years) and non-singers, were assessed to establish the lowest and highest notes they could comfortably sustain while humming over 20 seconds. With head position stable, midsagittal images were acquired while volunteers hummed these predetermined low and high notes. Twenty-two craniocervical, angular, and linear dimensions defined on these images were compared using one-way repeated-measures analysis of variance. Correlations between variables were sought using Pearson correlation coefficient. Results: We found significant differences between low- and high-note conditions in six of 22 measures and widespread pitch-related correlations between variables (r ≥0.63, P <0.05). Compared with low-note humming, high-note humming was accompanied by increased craniocervical angles opt/nsl and cvt/nsl (P =0.008 and 0.002, respectively); widening of the C3-menton distance (P =0.003), a rise of the larynx and hyoid in relation to the cranial base (P =0.012 and <0.001, respectively), and an increased sternum-hyoid distance (P <0.001). Conclusion: Voice production is accompanied by pitch-related adjustments that are currently being masked by, or mistakenly attributed to, articulatory or postural input, identification of which could improve understanding of mechanisms underlying speech and song. [Copyright &y& Elsevier]

Summary: Objectives: Traditional voice research focuses on the vocal tract, articulators, and larynx. By ignoring their direct/indirect attachments (skull, cervical spine, and sternum) important information may be missed. We aim to investigate vocal structures within this wider context and assess the validity of this approach for subsequent voice production studies. Study Design/Method: Using a cross-sectional study design, we obtained midsagittal MR images from 10 healthy adults (five males and five females) while at rest and breathing quietly. With reference points based on cephalometry, 17 craniocervical, craniocaudal, and anteroposterior variables were chosen to describe craniofacial morphology, craniocervical posture, and airway dimensions. Relationships between variables were sought using Pearson’s correlation coefficient. Results: We found widespread correlations relating vocal structures to the craniofacial skeleton and cervical spine (r >0.6). Increasing airway size (hyocervical distance) was associated with greater distances from the cranial base of the hyoid, larynx, epiglottis tip and uvula tip, and of C3 from the menton. A wider velopharyngeal opening was associated with a shorter and higher soft palate, and a greater (lower) craniocervical angle was associated with a wider laryngeal tube opening, narrower airway at the uvula tip and shorter distances of the hyoid and uvula tip from the cranial base. Conclusion: Finding widespread correlations relating vocal structures to the craniofacial skeleton and cervical spine confirms the potential of this approach to uncover functional activity during voice production and demonstrates the importance of considering vocal structures and the airway within this wider context if important information is not to be missed. [Copyright &y& Elsevier]