Wideband absorbance tympanometry using pressure sweeps: system development and results on adults with normal hearing.
A system with potential for middle-ear screening and diagnostic testing was developed for the measurement of wideband energy absorbance (EA) in the ear canal as a function of air pressure, and tested on adults with normal hearing. Using a click stimulus, the EA was measured at 60 frequencies between 0.226 and 8 kHz. Ambient-pressure results were similar to past studies. To perform tympanometry, air pressure in the ear canal was controlled automatically to sweep between -300 and 200 daPa (ascending/descending directions) using sweep speeds of approximately 75, 100, 200, and 400 daPas. Thus, the measurement time for wideband tympanometry ranged from 1.5 to 7 s and was suitable for clinical applications. A bandpass tympanogram, calculated for each ear by frequency averaging EA from 0.38 to 2 kHz, had a single-peak shape; however, its tympanometric peak pressure (TPP) shifted as a function of sweep speed and direction. EA estimated at the TPP was similar across different sweep speeds, but was higher below 2 kHz than EA measured at ambient pressure. Future studies of EA on normal ears of a different age group or on impaired ears may be compared with the adult normal baseline obtained in this study.
Liu
Yi-Wen
YW
Boys Town National Research Hospital, Omaha, Nebraska 68131, USA.
Sanford
Chris A
CA
Ellison
John C
JC
Fitzpatrick
Denis F
DF
Gorga
Michael P
MP
Keefe
Douglas H
DH
D000158:Acoustic Impedance Tests / Q000379:methods* / Q000592:standards; D000161:Acoustic Stimulation; D000328:Adult; D000399:Air Pressure; D016477:Artifacts; D002138:Calibration; D004424:Ear Canal / Q000502:physiology*; D004432:Ear, Middle / Q000502:physiology*; D005240:Feasibility Studies; D006309:Hearing; D006801:Humans; D012016:Reference Values; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors; D055815:Young Adult