Time-domain “wave” model of the human tympanic membrane

Forward and reverse transfer functions of the middle ear based on pressure and velocity DPOAEs with implications for differential hearing diagnosis

“…The estimate of T TM returned by the fitting procedure was 15.9 ms, which is significantly less than the values estimated from a middle-ear model for cat [36 ms, Puria and Allen (1998)], human subjects [24 ms, Parent and Allen (2010)] and human temporal bone [30 ms, O'Connor and Puria (2008)]. 7 However, the value is consistent with: 1) the smaller dimensions of the guinea-pig TM and 2) the overall forward delays of the middle ear found for guinea pig (Magnan et al, 1999) and another small laboratory animal, the gerbil (Olson, 1998;Dong and Olson, 2006;de La Rochefoucauld et al, 2008).…”

“…In differences between the expected and observed values in guinea pig can be accounted for by interspecies differences in propagation speed, which in turn depends on TM curvature, inclination to the ear canal and material anisotropy (Fay et al, 2006;Parent and Allen, 2007). With respect to the second assertion, it is clearly incorrect to equate one-way propagation delay in the forward direction to overall propagation delay in the forward direction (Parent and Allen, 2010). Nevertheless, it is instructive to compare the value of T TM measured here with the group delay of fluid pressure in scala vestibuli in response to sound pressure at the TM measured in guinea pig and gerbil.…”

“…With respect to the first assertion, using the comparative TMarea data in Nummela (1995) to estimate mean TM radius and assuming that the propagation speed on the TM is the same for all species, the ratio of T TM in guinea pig to T TM in cat would be 0.77 and to T TM in human would be 0.59; the ratio for gerbil would be 1.28. That is, based on the human-subject (Parent and Allen, 2010) and cat (Puria and Allen, 1998) data, respectively, the guinea-pig value might be expected to lie between 14 ms and 29 ms. The 14-ms value derived from human subjects is very close to the value that we obtained from the guinea-pig model.…”

Human middle-ear model with compound eardrum and airway branching in mastoid air cells

“…One goal was to evaluate the need for such delay in predicting a diverse set of transfer functions. The present model of TM delay differs from previous models (O 'Connor and Puria, 2008;Parent and Allen, 2010) in that the TM is assumed to have multiple compartments coupled by a timedelayed compliance. The multiple modal resonances in the umbo-free component of the TM approximate the types of eardrum motions with modal standing waves that have been observed in gerbil (de La Rouchefoucauld et al, 2010) and human temporal bone with widely open tympanic cleft (Cheng et al, 2010;Cheng et al, 2013).…”

“…The findings that these multiple modes of oscillation on the TM combined with the presence of TM delay were important in predicting the middle-ear impedance and reflectance in the ear canal, as well as transfer functions through the middle ear, differed from Parent and Allen (2010). They concluded that "complex, multi-modal propagation observed on the TM may not be critical to proper sound transmission along the ear.…”