Acoustics of the human middle-ear air space.
The impedance of the middle-ear air space was measured on three human cadaver ears with complete mastoid air-cell systems. Below 500 Hz, the impedance is approximately compliance-like, and at higher frequencies (500-6000 Hz) the impedance magnitude has several (five to nine) extrema. Mechanisms for these extrema are identified and described through circuit models of the middle-ear air space. The measurements demonstrate that the middle-ear air space impedance can affect the middle-ear impedance at the tympanic membrane by as much as 10 dB at frequencies greater than 1000 Hz. Thus, variations in the middle-ear air space impedance that result from variations in anatomy of the middle-ear air space can contribute to inter-ear variations in both impedance measurements and otoacoustic emissions, when measured at the tympanic membrane.
Stepp
Cara E
CE
Picker Engineering Program, Smith College, 51 College Lane, Northampton, Massachusetts 01063, USA.
Voss
Susan E
SE
D000161:Acoustic Stimulation; D002102:Cadaver; D004432:Ear, Middle / Q000502:physiology*; D017097:Electric Impedance; D006801:Humans; D011312:Pressure; D014432:Tympanic Membrane / Q000502:physiology*