Morphophysiological Adjustments of the Larynx and Vocal Tract of Young Women during the Dynamic Vocal Analysis by Dynamic Magnetic Resonance
OBJECTIVE: To investigate, using dynamic real-time MRI (dMRI), the morphophysiological adjustments of the larynx and vocal tract (VT) of vocally healthy young women during dynamic vocal analysis (DVA) tasks. METHOD: Ten vocally healthy women, speech-language pathologists, aged 21 to 42, performed DVA tasks during the dMRI exam. DVA tasks: sustained emission of the vowel /ae/ at habitual frequency and intensity, at high and low frequencies; and at soft and loud intensities. Image acquisition was programmed for the mid-sagittal plane using 3.0T device. The acquisition time for each task in the dMRI was 14s, with simultaneous audio recording. Vertical, length, area, and angle measurements were taken. For comparison purposes, the morphometry of the frequency and intensity variation tasks was compared with the habitual emission. RESULTS: Mean(standard deviation) values of the morphometry obtained from the habitual emission – vertical measurements: lip distance 1.38cm(0,21), palate-mandible 6.94cm(0,49), palate-hyoid 6.73cm(0,66), and palate-vocal fold (VF) 8.25cm(0,67); length of VT 15.26cm(0,58); area measurements: total area of VT 19.28cm2(2,59), pharynx 10.04cm2(1,52), laryngeal vestibule 3.23cm2(0,54), oral cavity 9.23cm2(1,46), and tongue 23.39cm2(1,71); angle measurements: palate-posterior nasal spine-soft palate 163.39°(5,14), posterior pharyngeal wall (PPW) and VF 90.83°(6,24). High frequency emissions showed shorter TV length, greater elevation of the soft palate and a smaller angle between PPW and VF. Low-frequency emissions were characterized by smaller lip opening, lower position of the hyoid bone and VF, greater VT length, larger total area of the VT, pharynx, and laryngeal vestibule, and greater elevation of the soft palate. Soft intensity emissions showed less lip opening, less jaw lowering, a smaller total area of the VT, and oral cavity. Loud intensity was characterized by greater lip opening, a lower vertical position of the hyoid, larger total area of the VT, pharynx, and oral cavity, greater elevation of the soft palate, and a smaller angle between the PPW and VF. CONCLUSION: The morphophysiological adjustments of the larynx and VT of vocally healthy women, measured on dMRI, differed significantly between the DVA tasks. The data from this study can be used as reference values in the investigation of the morphophysiology of the larynx and VT of dysphonic women.