A Dynamic Magnetic Resonance Imaging-Based Method to Examine in Vivo Levator Veli Palatini Muscle Function during Speech

• Published in: Journal of speech, language, and hearing research Vol. 62; no. 8; pp. 2713 - 2722
• Main Authors: Pelland, Catherine M, Feng, Xue, Borowitz, Kathleen C, Meyer, Craig H, Blemker, Silvia S
• Format: Journal Article
• Language: English
• Published: United States American Speech-Language-Hearing Association 01.08.2019
• Subjects: Adult; Adults; Anatomy; Anatomy & physiology; Biomechanics; Body Composition; Brain Hemisphere Functions; Congenital Impairments; Diagnostic imaging; Diagnostic Tests; Female; Force; Fricatives; Future predictions; Healthy Volunteers; Human Body; Humans; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Methods; Muscles; Musculoskeletal system; NMR; Nuclear magnetic resonance; Palatal Muscles - diagnostic imaging; Pharyngeal Muscles - diagnostic imaging; Phonation; Phonemes; Phonology; Physiology; Psychomotor Skills; Sampling; Speech; Speech - physiology; Speech Communication; Speech Production Measurement - methods; Syllables; Velocity; Velopharyngeal insufficiency; Vowels; Young Adult
• ISSN: 1092-4388; 1558-9102; 1558-9102
• DOI: 10.1044/2019_JSLHR-S-18-0459

Purpose: The aim of this study was to develop a method able to quantify levator veli palatini (LVP) muscle shortening and contraction velocities using dynamic magnetic resonance imaging (MRI) throughout speech samples and relate these measurements to velopharyngeal portal dimensions. Method: Six healthy adults (3 men and 3 women, M = 24.5 years) produced syllables representing 4 different manners of production during real-time dynamic MRI scans. We acquired an oblique-coronal slice of the velopharyngeal mechanism, which captured the length of the LVP, and manually segmented each frame. LVP shortening and muscle velocities were calculated from the acquired images. Results: Using our method, we found that subjects demonstrated greater LVP shortening and higher maximum contraction velocities during fricative and plosive syllable production than during nasal or vowel syllable production. LVP shortening and maximum contraction velocity positively correlated with velopharyngeal port depth. Conclusions: In vivo LVP function differs between manners of production, as expected, and an individual's velopharyngeal portal dimensions influence LVP function. These measures, contextualized with the force-length and force-velocity muscle relationships, provide new insight into LVP function. Future studies could use this method to investigate LVP function in healthy speakers and individuals with velopharyngeal dysfunction and how function relates to velopharyngeal anatomy.