Middle‐ear development VI: Structural maturation of the rat conducting apparatus

Zimmer, Wayne M.; Rosin, Deborah; Saunders, James C.

doi:10.1002/ar.1092390413

Cited by 28 publications

(20 citation statements)

References 16 publications

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“…[Bulla volume also increases significantly beyond 20 DAB and therefore may partly account for some of the data of Cohen et al 1993, which were obtained with a closed bulla, but this change should not have influenced other measurements of stapes vibrations, such as our own, obtained with the bulla widely opened.] In neonatal rats the improvement of middle-ear sensitivity (Doan et al, 1996) is also positively correlated with the growth in ossicular mass (the malleus and incus reach mature values of mass at 34 and 26 days) (Zimmer et al, 1994).…”

Section: G Interpretation Of the Development Of Middle-ear Transmissionmentioning

confidence: 97%

Development of wide-band middle ear transmission in the Mongolian gerbil

Overstreet

Ruggero

2002

The Journal of the Acoustical Society of America

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Stapes vibrations were measured in deeply anesthetized adult and neonatal (ages: 14 to 20 days) Mongolian gerbils. In adult gerbils, the velocity magnitude of stapes responses to tones was approximately constant over the entire frequency range of measurements, 1 to 40 kHz. Response phases referred to pressure near the tympanic membrane varied approximately linearly as a function of increasing stimulus frequency, with a slope corresponding to a group delay of 30 μs. In neonatal gerbils, the sensitivity of stapes responses to tones was lower than in adults, especially at midfrequencies (e.g., by about 15 dB at 10-20 kHz in gerbils aged 14 days). The input impedance of the adult gerbil cochlea, calculated from stapes vibrations and published measurements of pressure in scala vestibuli near the oval window [E. Olson, J. Acoust. Soc. Am. 103, 3445-3463 (1998)], is principally dissipative at frequencies lower than 10 kHz. Conclusions-(a)middle-ear vibrations in adult gerbils do not limit the input to the cochlea up to at least 40 kHz, i.e., within 0.5 oct of the high-frequency cutoff of the behavioral audiogram; and (b) the results in both adult and neonatal gerbils are inconsistent with the hypothesis that mass reactance controls high-frequency ossicular vibrations and support the idea that the middle ear functions as a transmission line.

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Section: G Interpretation Of the Development Of Middle-ear Transmissionmentioning

confidence: 97%

Development of wide-band middle ear transmission in the Mongolian gerbil

Overstreet

Ruggero

2002

The Journal of the Acoustical Society of America

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“…The middle-ear anatomy of the rat is identical to that of the mouse, only larger [Fleischer, 1978;Saunders and Summers, 1982;Zimmer et al, 1994;Doan et al, 1996b]. Our experience with the malleus-incus joint in the rat indicated that it was tightly bound together (author's personal observation), like that seen in the mouse [Saunders and Garfinkle, 1983;Saunders and Crumling, 2001].…”

Section: Discussionmentioning

confidence: 61%

“…The line drawing in figure 1 B outlines the ossicles [Zimmer et al, 1994]. The rat is classified as a microtype middle ear [Fleischer, 1978] and has several unique attributes.…”

Section: Middle-ear Morphologymentioning

confidence: 99%

Outer- and Middle-Ear Contributions to Presbycusis in the Brown Norway Rat

et al. 2007

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This paper examines the contribution of the outer and middle ears to the hearing loss associated with presbycusis in Brown Norway rats. Animals were formed into two groups; young adults (2–3 months old) and aged animals (approximately 34 months old). Auditory brainstem response (ABR) thresholds were obtained with the outer ear intact or surgically removed. Tympanic membrane (TM) velocity transfer functions were measured from the umbo with the outer ear removed. The length of the auditory meatus, TM surface area, and TM thickness were quantified. The ABR thresholds were 17–26 dB less sensitive in the aged animals between 8.0 and 40.0 kHz when the outer ear was intact. A significant and reliable reduction in the aged rat velocity transfer function of 5–8 dB occurred between 10.0 and 32.0 kHz, while the low frequency velocity response was only a few decibels greater in the younger animals. The ABR threshold differences between young adult and aged ears were compensated by removing the outer/middle ear effects of aging to reveal a purely sensorineural component of presbycusis. The outer and middle ear effects were calculated directly when the ABR and TM velocity data were obtained with the outer ear removed. The outer ear intact condition was modeled in order to compare the ABR data obtained with the outer ear intact with the TM velocity data obtained with the outer removed. With either procedure, removal of the age-related contributions of the outer and middle ear to the ABR threshold resulted in similar age-related ABR threshold shifts between the two age groups. The pure sensorineural threshold shift component of the ABR response was restricted to frequencies between 5.0 and 20.0 kHz and reached a maximum of approximately 15 dB. These results support the conclusion that there is an outer- and middle-ear contribution to the threshold loss defining presbycusis.

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“…66 mm 2 [Donaldson et al, 1992], whereas in the rat it is only approx. 11 mm 2 [Zimmer et al, 1994]. The relative sizes of the pars tensa and pars flaccida are also quite different -while the human has a very small pars flaccida compared with the total size of the tympanic membrane, in rats the pars flaccida occupies between one quarter and one third of the tympanic membrane area.…”

mentioning

confidence: 94%

An Experimental Study of Tympanic Membrane and Manubrium Vibrations in Rats

Akache

Funnell²,

Daniel

2006

Audiol Neurotol

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Rats are potentially very useful for auditory research because the middle ear structures are easily approachable and because rats are relatively inexpensive. The goal of the present study was to better characterize the mechanics of the rat middle ear by measuring frequency responses at multiple points on the tympanic membrane and manubrium. A laser Doppler vibrometer was used to measure the vibrations. Measurements were made on 7 rats. Tympanic membrane vibrations are presented for 7 different points in the frequency range of 1–10 kHz. The repeatability of the measurements and the interanimal variability at the umbo are also presented. The vibration modes of the tympanic membrane and manubrium were investigated.

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Middle‐ear development VI: Structural maturation of the rat conducting apparatus

Cited by 28 publications

References 16 publications

Development of wide-band middle ear transmission in the Mongolian gerbil

Development of wide-band middle ear transmission in the Mongolian gerbil

Outer- and Middle-Ear Contributions to Presbycusis in the Brown Norway Rat

An Experimental Study of Tympanic Membrane and Manubrium Vibrations in Rats

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