Estimation of Alveolar Pressure During Speech Using Direct Measures of Tracheal Pressure The pressure in the alveoli of the lungs, created by the elastic recoil of the lungs and respiratory muscle activity, is referred to as alveolar pressure (Pa). The extent to which tracheal pressure (Pt) approximates Pa depends on the resistance to airflow offered by structures above and below the point ... Research Article
Research Article  |   October 01, 1999
Estimation of Alveolar Pressure During Speech Using Direct Measures of Tracheal Pressure
 
Author Affiliations & Notes
  • Eileen M. Finnegan
    Department of Speech Pathology and Audiology Wendell Johnson Speech and Hearing Center University of Iowa and Department of Otolaryngology University of Iowa Hospitals and Clinics Iowa City
  • Erich S. Luschei
    Department of Speech Pathology and Audiology Wendell Johnson Speech and Hearing Center University of Iowa and Department of Otolaryngology University of Iowa Hospitals and Clinics Iowa City
  • Henry T. Hoffman
    Department of Otolaryngology University of Iowa Hospitals and Clinics Iowa City
  • Corresponding author: e-mail: eileenfinnegan@uiowa.edu
Article Information
Regulatory, Legislative & Advocacy / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   October 01, 1999
Estimation of Alveolar Pressure During Speech Using Direct Measures of Tracheal Pressure
Journal of Speech, Language, and Hearing Research, October 1999, Vol. 42, 1136-1147. doi:10.1044/jslhr.4205.1136
History: Received May 11, 1998 , Accepted April 5, 1999
 
Journal of Speech, Language, and Hearing Research, October 1999, Vol. 42, 1136-1147. doi:10.1044/jslhr.4205.1136
History: Received May 11, 1998; Accepted April 5, 1999

The pressure in the alveoli of the lungs, created by the elastic recoil of the lungs and respiratory muscle activity, is referred to as alveolar pressure (Pa). The extent to which tracheal pressure (Pt) approximates Pa depends on the resistance to airflow offered by structures above and below the point at which tracheal pressure is measured. An understanding of the relationship among Pa, Pt, and upper and lower airway resistance, and how these values fluctuate during speech, could aid in interpretation and modeling of speech aerodynamics. The purpose of this study was to (a) obtain values for lower airway resistance (Rlaw), (b) use these Rlaw values to estimate Pa during speech, and (c) quantify the degree to which Pt approximates Pa during production of voiced and voiceless sounds, in comparison to inhalation. In addition, the results were discussed in terms of the degree to which the respiratory system functions as a pressure source. Tracheal pressure (obtained with tracheal puncture) and airflow were measured during sentence production in 6 subjects. Using a technique introduced in this paper, Rlaw was determined from measures of tracheal pressure and flow obtained during a sudden change in upper airway resistance because of release of a voiceless plosive. Mean Rlaw values ranged from 0.14 to 0.32 kPa/(l/s). Each subject's mean Rlaw was used to derive a time-varying measure of Pa during speech from continuous measures of tracheal pressure and airflow. Pt was approximately 95% of Pa during phonation (i.e., when the vocal folds were adducted), 75% of Pa during release of the voiceless stop consonant /p/, and 55% of Pa during inhalation (i.e., when the vocal folds were abducted). Therefore, the degree to which the respiratory system functioned as an ideal pressure source varied during speech. The ability to estimate Pa provides a measure of the pressure produced by the respiratory system that is not influenced by laryngeal activity.

Acknowledgments
This research was supported by Grant # P60 DC00976 from the National Institute on Deafness and Other Communication Disorders. Special thanks to Ingo Titze, Michael Karnell, Kelly Cole, and Charles A. Miller for their comments on an earlier version of this paper.
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