Understanding the basic mechanisms of normal and abnormal voice production is centrally important to the treatment of voice disorders. Glottal insufficiency from vocal fold paresis and paralysis is one of the most common voice disorders encountered in clinical medicine. Neuromuscular dysfunction leads to laryngeal left/right asymmetry and abnormalities of the two main independent variables related to glottal vibratory characteristics and acoustic output: (1) vocal fold stiffness and (2) glottal channel pre- phonatory shape (length, vertical height, and contour). A significant knowledge gap exits in our understanding of the cause-effect relationship between these aspects of glottal asymmetry and their acoustic, vibratory, and perceptual consequences. In this proposal we will systematically study laryngeal asymmetry by (1) quantifying the effects of asymmetric laryngeal activation on acoustics, aerodynamics, glottal vibration and vocal quality, (2) investigate glottal channel shape changes and their effects on vibration in paresis/paralysis conditions and in normal phonation, and (3) systematically evaluate the role of vocal fold implant stiffness and medial surface shape in the treatment of vocal insufficiency. These investigations will provide an improved knowledge base on which to build an evidence-based approach to treatment of neurogenic voice disorders.

Public Health Relevance

Vocal fold paresis (weakness) and paralysis are neuromuscular diseases of the larynx and the most common etiology of laryngeal insufficiency and abnormal voice. Current surgical treatments for these conditions have not yielded consistent results, because a significant knowledge gap exists in our understanding of the cause-effect relationship between phonatory variables missing due to laryngeal paresis and paralysis, and the acoustic, vibratory, and perceptual consequences on voice, thus limiting optimal rehabilitation. The proposed investigations will examine such cause-effect relationships, and enable surgeons to select optimal vocal fold implants for rehabilitation of laryngeal insufficiency.

National Institute of Health (NIH)
National Institute on Deafness and Other Communication Disorders (NIDCD)
Research Project (R01)
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Motor Function, Speech and Rehabilitation Study Section (MFSR)
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Shekim, Lana O
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University of California Los Angeles
Schools of Medicine
Los Angeles
United States
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Vahabzadeh-Hagh, Andrew M; Zhang, Zhaoyan; Chhetri, Dinesh K (2018) Hirano's cover-body model and its unique laryngeal postures revisited. Laryngoscope 128:1412-1418
Dewan, Karuna; Vahabzadeh-Hagh, Andrew; Soofer, Donna et al. (2017) Neuromuscular compensation mechanisms in vocal fold paralysis and paresis. Laryngoscope 127:1633-1638
Vahabzadeh-Hagh, Andrew M; Zhang, Zhaoyan; Chhetri, Dinesh K (2017) Three-dimensional posture changes of the vocal fold from paired intrinsic laryngeal muscles. Laryngoscope 127:656-664
Shiba, Travis L; Chhetri, Dinesh K (2016) Dynamics of phonatory posturing at phonation onset. Laryngoscope 126:1837-43
Chhetri, Dinesh K; Park, Soo Jin (2016) Interactions of subglottal pressure and neuromuscular activation on fundamental frequency and intensity. Laryngoscope 126:1123-30
Chhetri, Dinesh K; Neubauer, Juergen (2015) Differential roles for the thyroarytenoid and lateral cricoarytenoid muscles in phonation. Laryngoscope 125:2772-7
Zhang, Zhaoyan; Chhetri, Dinesh K; Bergeron, Jennifer L (2015) Effects of implant stiffness, shape, and medialization depth on the acoustic outcomes of medialization laryngoplasty. J Voice 29:230-5
Jamal, Nausheen; Erman, Andrew; Chhetri, Dinesh K (2015) Partial Epiglottoplasty for Pharyngeal Dysphagia due to Cervical Spine Pathology. Otolaryngol Head Neck Surg 153:586-92
Long, Jennifer L; Chhetri, Dinesh K (2015) Tissue engineering. Restoring voice. Science 350:908-9
Chhetri, Dinesh K; Neubauer, Juergen; Sofer, Elazar (2014) Influence of asymmetric recurrent laryngeal nerve stimulation on vibration, acoustics, and aerodynamics. Laryngoscope 124:2544-50

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