Measurement of the Middle Ear Transfer Function in Cat, Chinchilla and Guinea Pig

As part of a study aimed at determining the origines) of the interspecific differencies in susceptibility to noise (Décory, 1989), we have measured the transfer function of the middle ear (TFME) in the cat, the chinchilla and the guinea pig, For a given stimulus applied in front of the tympanic membrane (TM), the sound pressure at the base of the scala vestibuli (SV) has been recorded from 100 to 20000 Hz. Using these experimental data in relation to the measurements of the displacement of the umbo or the stapes performed by various authors we have calculated the acoustic power Wc) entering the cochlea and the acoustic imput impedance of the cochlea (Zc in these three species.