Acoustic Analysis of Upper Airway Obstruction in the Excised Human Larynx

Abstract

Upper airway obstruction is an emergency that requires quick and decisive intervention. Stridor is the sound created by airflow through a partially obstructed airway, and has been described to vary with the site and degree of obstruction. This study sought to determine the sound characteristics of stridor in the excised human larynx. Five fresh cadaver human larynges were harvested and subjected to obstructions at supraglottic, glottic, and subglottic subsites. Subglottic pressure, airflow, and audio signal were recorded. Data were analyzed on the basis of laryngeal obstruction subsite and the degree of laryngeal resistance. Visual inspection demonstrated certain trends in peak spectral energy depending on the site and, more significantly, the amount of obstruction. Statistical analysis of spectral waveforms showed better correlation with the amount of obstruction than with the site of obstruction. In summary, the frequency distribution of stridor produced in an excised human larynx was influenced by the amount of laryngeal resistance, but not by the site of airway obstruction.

Keywords

acoustics airway obstruction Fourier analysis stridor

Get full access to this article

View all access options for this article.

References

Yoganathan

Gupta

Corcoran

. Fast Fourier transform in the analysis of biomedical data. Med Biol Eng 1976; 14: 239–45.

Gray

Denneny

III Carvajal

Jahrsdoerfer

. Fourier analysis of infantile stridor: Preliminary data. Int J Pediatr Otorhinolaryngol 1985; 10: 191–9.

Leiberman

Cohen

Tal

. Digital signal processing of stridor and snoring in children. Int J Pediatr Otorhinolaryngol 1986; 12: 173–85.

Malone

Black

Lydon

Cinnamond

. Acoustic analysis of infantile stridor: A review. Med Biol Eng Comput 1993; 31: 85–96.

Rao

Niwa

Watanabe

Fukuta

Yanagita

. Spectral analysis of airflow sounds in patent versus occluded tracheostomy tubes: A pilot study in tracheostomized adult patients. Laryngoscope 1990; 100: 536–40.

Yonemaru

Kikuchi

Mori

. Detection of tracheal stenosis by frequency analysis of tracheal sounds. J Appl Physiol 1993; 75: 605–12.

Coleman

Schechter

. A basic model to study acoustic evaluation of airway obstruction. Arch Otolaryngol Head Neck Surg 1991; 117: 1144–9.

Cooper

. Research in laryngeal physiology with excised larynges. In: Cummings

, ed. Otolaryngology-head and neck surgery, 1st ed. St Louis, Mo: CV Mosby, 1986: 1766–76.

Yanagi

Slavit

McCaffrey

. Study of phonation in the excised canine larynx. Otolaryngol Head Neck Surg 1991; 105: 586–95.

10.

Cotton

Reilly

. Stridor and airway obstruction. In: Bluestone

Stool

, eds. Pediatric otolaryngology. Philadelphia, Pa: Saunders, 1983: 1190–204.

11.

Fredberg

Wohl

Glass

Dorkin

. Airway area by acoustic reflections measured at the mouth. J Appl Physiol 1980; 48: 749–58.

12.

Hoffstein

Zamel

. Tracheal stenosis measured by the acoustic reflection technique. Am Rev Respir Dis 1984; 130: 472–5.

13.

Hirschberg

. Acoustic analysis of pathological cries, stridors and coughing sounds in infancy. Int J Pediatr Otorhinolaryngol 1980; 2: 287–300.

14.

Acres

Kryger

. Clinical significance of pulmonary function tests: Upper airway obstruction. Chest 1981; 80: 207–11.

15.

Childers

Wong

. Measuring and modeling vocal tract source-tract interaction. IEEE Trans Biomed Eng 1994; 41: 663–71.

16.

Parsons

. Voice and speech processing. New York, NY: McGraw-Hill, 1987: 59–83, 136–69.