TY  - JOUR
U1  - Zeitschriftenartikel, wissenschaftlich - begutachtet (reviewed)
A1  - Warnholtz, Birthe
A1  - Schär, Merlin
A1  - Sackmann, Benjamin
A1  - Lauxmann, Michael
A1  - Chatzimichalis, Michail
A1  - Prochazka, Lukas
A1  - Dobrev, Ivo
A1  - Huber, Alexander
A1  - Sim, Jae Hoon
T1  - Contribution of the flexible incudo-malleal joint to middle-ear sound transmission under static pressure loads
JF  - Hearing research
N2  - The incudo-malleal joint (IMJ) in the human middle ear is a true diarthrodial joint and it has been known that the flexibility of this joint does not contribute to better middle-ear sound transmission. Previous studies have proposed that a gliding motion between the malleus and the incus at this joint prevents the transmission of large displacements of the malleus to the incus and stapes and thus contributes to the protection of the inner ear as an immediate response against large static pressure changes. However, dynamic behavior of this joint under static pressure changes has not been fully revealed. In this study, effects of the flexibility of the IMJ on middle-ear sound transmission under static pressure difference between the middle-ear cavity and the environment were investigated. Experiments were performed in human cadaveric temporal bones with static pressures in the range of +/- 2 kPa being applied to the ear canal (relative to middle-ear cavity). Vibrational motions of the umbo and the stapes footplate center in response to acoustic stimulation (0.2-8 kHz) were measured using a 3D-Laser Doppler vibrometer for (1) the natural IMJ and (2) the IMJ with experimentally-reduced flexibility. With the natural condition of the IMJ, vibrations of the umbo and the stapes footplate center under static pressure loads were attenuated at low frequencies below the middle-ear resonance frequency as observed in previous studies. After the flexibility of the IMJ was reduced, additional attenuations of vibrational motion were observed for the umbo under positive static pressures in the ear canal (EC) and the stapes footplate center under both positive and negative static EC pressures. The additional attenuation of vibration reached 4~7 dB for the umbo under positive static EC pressures and the stapes footplate center under negative EC pressures, and 7~11 dB for the stapes footplate center under positive EC pressures. The results of this study indicate an adaptive mechanism of the flexible IMJ in the human middle ear to changes of static EC pressure by reducing the attenuation of the middle-ear sound transmission. Such results are expected to be used for diagnosis of the IMJ stiffening and to be applied to design of middle-ear prostheses.
KW  - adaptation to static pressure changes
KW  - attenuation of the middle-ear transfer function
KW  - incudo-malleal joint
KW  - flexibility of the incudo-malleal joint
KW  - static pressure
KW  - transfer function of the middle ear
KW  - middle-ear ossicular joints
Y1  - 2021
UN  - https://nbn-resolving.org/urn:nbn:de:bsz:rt2-opus4-31425
SN  - 0378-5955
SS  - 0378-5955
U6  - https://doi.org/10.1016/j.heares.2021.108272
DO  - https://doi.org/10.1016/j.heares.2021.108272
VL  - 406
SP  - 1
EP  - 10
S1  - 10
PB  - Elsevier
CY  - Amsterdam
ER  -