Wideband reflectance tympanometry in normal adults

Robert H. Margolis, George L. Saly, Douglas H. Keefe

Research output: Contribution to journalArticle

80 Scopus citations

Abstract

Acoustic impedance/reflectance measurements were made at various ear- canal pressures in 20 subjects with a clinical acoustic immittance instrument and an experimental impedance/reflectance system. Measurements were made over a frequency range of 226-2000 Hz with the clinical system and 125-11310 Hz with the experimental system. For frequencies ≤2.0 kHz, tympanograms obtained with the two systems are similar, with patterns that progress through the same orderly sequence with increasing frequency. Eardrum impedance measurements were also similar. There are small gender differences in middle-ear impedance. Reflectance patterns (reflectance versus frequency) at ambient ear-canal air pressure are characterized by high reflectance at low frequencies, two distict minima at 1.2 and 3.5 kHz, increasing reflectance to 8.0 kHz, and decreasing reflectance above that frequency. Ear- canal pressure increases reflectance at low frequencies, decreases reflectance in the region of the minimum, and increases reflectance slightly at high frequencies. Reflectance tympanograms (reflectance versus ear-canal pressure) progress through a sequence of three patterns. At low frequencies, reflectance tympanograms are 'V' shaped, indicating that pressure increases reflectance. At frequencies near the minimum reflectance, the pattern inverts, indicating that pressure decreases reflectance. At high frequencies, the patterns are flat, indicating that ear-canal pressure has little effect. Results presented for one patient suggest that reflectance tympanometry may be useful for detecting middle-ear pathology.

Original languageEnglish (US)
Pages (from-to)265-280
Number of pages16
JournalJournal of the Acoustical Society of America
Volume106
Issue number1
DOIs
StatePublished - Jul 21 1999

ASJC Scopus subject areas

  • Arts and Humanities (miscellaneous)
  • Acoustics and Ultrasonics

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