Document Detail

Phonation threshold pressure measurements during phonation by airflow interruption.
MedLine Citation:
PMID:  10089970     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE/HYPOTHESIS: Most methods to measure phonation threshold pressure (PTP) are clinically impractical because they are invasive. This report concerns an airflow interruption system developed to allow noninvasive estimation of (PTP) at different levels of vocal intensity. An estimation of PTP was made for normal subjects with normal larynges and no voice complaints and for individuals who had dysphonia associated with vocal polyps to compare the estimated minimal pressure across the glottis that was required to sustain phonation in the two conditions. STUDY DESIGN: This was a methodological study designed to measure an unanticipated PTP from a subject. METHODS: Subjects sustained a constant tone and the airflow was directed into a section of pipe with an airtight mask over the mouth and nose. The airflow, intramask pressure, and intensity of the acoustic output were recorded. A PTP was predicted from a difference between an estimate of the subglottal pressure and the vocal tract pressure at the point that phonation ceased after interruption of airflow. Eleven control subjects and 13 patients with vocal fold polyps were studied. In each population there were eight men and five women. The individuals in the group with vocal fold polyps averaged 39 years of age, and the control subject group averaged 49 years of age. Normal subjects produced a steady vowel /a/ at 75, 80, and 85 dB. Patients with polyps were unable to sustain phonation at these levels but were able to produce phonation at 65, 70, and 75 dB. The validity of the system was tested using a laryngeal model and in a patient with a normal larynx and voice who had a tracheotomy (placed for sleep apnea syndrome) which allowed direct measurement of subglottal pressure. RESULTS: The measured mean PTP levels (with standard deviation [SD]) for the control subjects were 2.38 (1.273), 2.67 (1.879), and 2.98 (2.23) cm H2O at 75, 80, and 85 dB, respectively. The measured mean PTP levels (with SD) for the patients with polyps were 4.79 (2.67), 5.85 (2.34), and 7.37 (3.26) cm H2O at 75, 80, and 85 dB, respectively. The differences in mean PTP between groups at 75, 80, and 85 dB were significant at P = .013, P = .017, and P = .010, respectively. CONCLUSIONS: The estimations of PTP for patients with vocal fold polyps were significantly higher than for the control subjects at three phonation levels.
J Jiang; T O'Mara; D Conley; D Hanson
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Laryngoscope     Volume:  109     ISSN:  0023-852X     ISO Abbreviation:  Laryngoscope     Publication Date:  1999 Mar 
Date Detail:
Created Date:  1999-04-05     Completed Date:  1999-04-05     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  8607378     Medline TA:  Laryngoscope     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  425-32     Citation Subset:  IM    
Department of Otolaryngology-Head and Neck Surgery, Northwestern University Medical School, Chicago, IL 60611, USA.
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MeSH Terms
Electrodiagnosis / instrumentation
Equipment Design
Laryngeal Neoplasms / diagnosis,  physiopathology
Middle Aged
Phonation / physiology*
Polyps / diagnosis,  physiopathology
Pulmonary Ventilation / physiology*
Reference Values
Signal Processing, Computer-Assisted / instrumentation
Vocal Cords / physiopathology
Voice Disorders / diagnosis,  physiopathology
Grant Support
P60 DC 94-002-02/DC/NIDCD NIH HHS; R01 DC 00254-11/DC/NIDCD NIH HHS; T32 DC 0015-15/DC/NIDCD NIH HHS

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