Physiology of Voice, Breathing, and Swallow

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Physiology of Voice, Breathing, and Swallow

Laryngology, Voice and Swallowing
Author Credentials 

Brianna K. Crawley, MD
Assistant Professor
Otolaryngology- Head and Neck Surgery
Loma Linda University Health
Loma Linda, California

Module Summary

The physiology of the voice, breathing, and swallowing are inextricably intertwined with each other and dependent upon the complex anatomy of the upper aerodigestive tract. The larynx has evolved to manage the critical tasks of breathing, phonation, and protection of the lower airways during swallowing. Evaluation of structure and function are achieved through direct or indirect examination, imaging, and other specific tests. Test results are combined to determine overall function of the larynx and associated structures.

Module Learning Objectives 
  1. Describe the normal function of the unified upper aerodigestive tract.
  2. Relate how normal anatomy produces normal function.
  3. Explain how breathing occurs.
  4. Indicate how voice production is achieved.
  5. Recount the phases of normal swallowing.
  6. Describe the protective mechanisms and reflexes that prevent aspiration.
  7. Determine appropriate steps in the evaluation of these processes.

Embryology

Learning Objectives 

Review the development of the:

  1. Upper and lower airways
  2. Esophagus
  3. Specialized tissues of the larynx and the interplay of structure with function during development
References 
  1. Pohunek P. Development, structure and function of the upper airways. Paediatr Respir Rev. 2004;5(1):2-8.
  2. Harding R. Function of the larynx in the fetus and newborn. Annu Rev Physiol. 1984;46:645-659.
  3. Fausett SR, Klingensmith J. Compartmentalization of the foregut tube: developmental origins of the trachea and esophagus. Wiley Interdiscip Rev Dev Biol. 2012;1(2):184-202.

Anatomy

Learning Objectives 
  1. Visualize the laryngeal skeleton
  2. Visualize the fibroelastic tissues of the larynx
  3. Review the origin and insertion of intrinsic and extrinsic muscles of the larynx
  4. Relate the actions of laryngeal muscles
  5. Describe the microanatomy/histology of the vocal fold
  6. Identify the blood supply to the larynx and pharynx
  7. Review sensory and motor innervation of
    1. Intrinsic and extrinsic muscles of the larynx
    2. Major and accessory muscles of breathing
    3. Mouth, tongue, palate, oropharynx, pharynx
    4. Upper and lower esophageal sphincters
    5. Esophagus
    6. Innervation that coordinates oral, pharyngeal, and esophageal phases of swallowing
  8. Describe reflex relays
    1. Laryngospasm
    2. Bradycardia
    3. Cough
    4. Swallow
  9. Review muscles of the lips, palate, tongue, pharynx, upper esophageal sphincter
  10. Review muscular anatomy of the esophagus
References 
  1. Janfaza P, et al. Surgical Anatomy of the Head and Neck. 2nd ed. Cambridge: Harvard University Press; 2011.
  2. Koike Y, Hirano M, Von Leden H. Vocal initiation: acoustic and aerodynamic investigation of normal subjects. Folia Phoniatr (Basel). 1967;19(3):173-82.
  3. Ludlow CL. Central Nervous System Control of Voice and Swallowing. J Clin Neurophysiol. 2015;32(4):294-303.
  4. Ertekin C, Aydogdu I. Neurophysiology of swallowing. Clin Neurophysiol. 2003;114(12):2226-2244.
  5. Sataloff RT, Heman-Ackah YD, Hawkshaw MJ. Clinical anatomy and physiology of the voice. Otolaryngol Clin North Am. 2007;40(5):909-929, v.

Basic Science

Learning Objectives 
  1. Phonation/breathing
    1. Air column/breath support
    2. Subglottic pressure
    3. Adduction of vocal folds
    4. Tension/length of vocal folds
    5. Body/cover structure supports vibration
  2. Swallowing
    1. Pharyngeal and pharyngoesophageal coordination
    2. Esophageal structure
      1. Muscular organization and bolus propagation
    3. Swallowing-ventilation central control
    4. Neurologic control of voluntary and involuntary phases of swallow
References 
  1. Mittal RK. Regulation and dysregulation of esophageal peristalsis by the integrated function of circular and longitudinal muscle layers in health and disease. Am J Physiol Gastrointest Liver Physiol. 2016;311(3):G431-443.
  2. Titze IR. Principles of voice production. Iowa City, IA: National Center for Voice and Speech, 2000.
  3. Berry DA, Montequin DW, Tayama N. High-speed digital imaging of the medial surface of the vocal folds. J Acoust Soc Am. 2001;110(5 Pt 1):2539-2547.
  4. Jiang J, Lin E, Hanson DG. Vocal fold physiology. Otolaryngol Clin North Am. 2000;33(4):699-718.
  5. Chhetri DK, Neubauer J, Sofer E, Berry DA. Influence and interactions of laryngeal adductors and cricothyroid muscles on fundamental frequency and glottal posture control. J Acoust Soc Am. 2014;135(4):2052-2064.

Patient Evaluation

Learning Objectives 

Recite tools and their appropriate applications in the:

  1. Evaluation of voice
    1. Subjective evaluation using validated patient questionnaires
    2. Perceptual evaluation
      1. GRBS, quality, resonance, phonation, rate
    3. Objective evaluation with acoustic measures, voice range profile, voice signal quality
    4. Flexible laryngoscopy
    5. Videostroboscopy
  2. Evaluation of breathing
    1. Physical exam
    2. Pulmonary function testing
    3. Identify computed tomography findings consistent with abnormalities in oropharynx, nasopharynx, larynx and trachea
    4. Detect normal structure and function on flexible endoscopic examination of the nasopharynx, oropharynx, hypopharynx, larynx, and subglottis
    5. Exercise endoscopy
    6. Dynamic abnormalities of the larynx and trachea/mainstem bronchi on awake tracheoscopy/bronchoscopy or sleep endoscopy
    7. Surgical approaches to evaluate the airway
  3. Evaluation of swallowing
    1. Compare advantages and disadvantages of FEEST and MBS studies
    2. Describe abnormalities on manometry
    3. Understand benefits and limitations of transnasal esophagoscopy
References 
  1. Kendall KA and Leonard RJ. Laryngeal Evaluation. New York: Thieme Medical Publishers, 2010.
  2. Brady S, Donzelli J. The modified barium swallow and the functional endoscopic evaluation of swallowing. Otolaryngol Clin North Am. 2013;46(6):1009-1022.

Measurement of Functional Status

Learning Objectives 

Apply the following assessments to evaluate function:

  1. Voice
    1. Acoustic measures
      1. Frequency, intensity and perturbation of these characteristics
    2. Maximum phonation time
    3. Voice range profile
    4. Laryngeal electromyography
  2. Breathing
    1. Aerodynamic measures
      1. Subglottic and supraglottic pressures
      2. Glottal impedance
      3. Airflow rate
    2. Pulmonary function testing
  3. Swallowing
    1. Functional endoscopic evaluation of swallowing (FEES), with sensory testing (FEEST)
    2. Modified barium swallow (MBS)
    3. Manometry of the pharynx and esophagus
References 
  1. Kimaid PA, Crespo AN, Moreira AL, Wolf AE, França-Jr MC. Laryngeal Electromyography Techniques and Clinical Use. J Clin Neurophysiol. 2015;32(4):274-283.
  2. Richter JE and Castell DO. The Esophagus. 5th ed. Chichester, West Sussex: Balckwell, 2012.

Imaging

Learning Objectives 

Determine appropriate imaging for evaluation of each task:

  1. Voicing
    1. MRI of soft tissues of the larynx and vocal tract; course of the vagus, brainstem
    2. CT of laryngeal cartilages and upper airway; course of the vagus
    3. Ultrasound of the larynx
    4. High-speed digital videoendoscopy
    5. Videokymography
  2. Breathing
    1. CT, ultrasound
    2. CXR
  3. Swallowing
    1. Modified barium swallow
    2. Esophagram
    3. Diagnostic swallow study
References 
  1. Tsui PH, Wan YL, Chen CK. Ultrasound imaging of the larynx and vocal folds: recent applications and developments. Curr Opin Otolaryngol Head Neck Surg. 2012;20(6):437-442.
  2. Belafsky PC and Kuhn MA. The Clinician’s Guide to Swallowing Fluoroscopy. 1st ed. New York: Springer, 2014.
  3. Yumoto E. Aerodynamics, voice quality, and laryngeal image analysis of normal and pathologic voices. Curr Opin Otolaryngol Head Neck Surg. 2004;12(3):166-173.

Review

Review Questions 
  1. How does the structure of the larynx allow for its function in voice production and breathing while protecting the lower airways during swallowing?
  2. Which nerves coordinate voice, breathing, and swallowing?
  3. What are the tools used in the evaluation of voice and why is each test important?
  4. What are the phases of swallowing and how are they evaluated?
References 
  1. Sulica L. Voice: Anatomy, physiology and clinical evaluation. In: Johnson JT, Rosen CA, editors. Bailey’s Head and Neck Surgery, Otolaryngology.5th ed. Baltimore, MD: Lippincott Williams & Wilkins; 2014:945-957.
  2. Smith LJ, Gross RD: Upper Digestive tract anatomy and physiology.  In: Johnson JT, Rosen CA, editors. Bailey’s Head and Neck Surgery, Otolaryngology.5th ed. Baltimore, MD: Lippincott Williams & Wilkins; 2014:817-824.
Resources 

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