Effects of ear-canal pressurization on middle-ear bone- and air-conduction responses

摘要: Abstract In extremely loud noise environments, it is important to not only protect one’s hearing against transmitted through the air-conduction (AC) pathway, but also bone-conduction (BC) pathways. Much of energy BC pathways concentrated in mid-frequency range around 1.5–2 kHz, which likely due structural resonance middle ear. One potential approach for mitigating this transmission introduce a positive or negative static pressure ear canal, known reduce as well AC sensitivity. present study, middle-ear ossicular velocities at umbo and stapes were measured using human cadaver temporal bones response both excitations, while air pressures ±400 mm H2O applied canal. For maximum −400 mm H2O, mean stapes-velocity reductions about 5–8 dB observed frequency from 0.8 2.5 kHz, with peak reduction 8.6(±4.7) dB 1.6 kHz. Finite-element analysis indicates that BC-response tends be because resonance, typically suppressed by pressure-induced stiffening structure. The data show responses are reduced more than pressures. This may attributable difference distribution among components depending on polarity pressure. characteristics found largely consistent available psychoacoustic data, therefore indicative relative importance mechanism hearing.