What middle ear parameters tell about impedance matching and high frequency hearing

Hemilä, Simo; Nummela, Sirpa; Reuter, Tom

doi:10.1016/0378-5955(95)00031-x

Cited by 128 publications

(228 citation statements)

References 19 publications

Supporting

Mentioning

196

Contrasting

Unclassified

Order By: Relevance

“…For the stapes, the relationship between pressure applied to the TM and the force present on the stapes is less straightforward. On our specimens, we measured the projected PT surface area and found 25.7 mm 2 , which is comparable with the value of 28.2 given in literature Hemilä et al (1995). In the approximation that the PT moves as a uniform plate, multiplication with umbo movement gives a value of 1.3 mJ of dissipated energy per movement cycle at a pressure change rate of 1.5 kPa/s and 3.8 mJ at 200 Pa/s.…”

Section: Figsupporting

confidence: 87%

Quasi-static Transfer Function of the Rabbit Middle Ear‚ Measured with a Heterodyne Interferometer with High-Resolution Position Decoder

Dirckx

Buytaert

Decraemer

2006

JARO

View full text Add to dashboard Cite

Due to changes in ambient pressure and to the gasexchange processes in the middle ear (ME) cavity, the ear is subject to ultra-low-frequency pressure variations, which are many orders of magnitude larger than the loudest acoustic pressures. Little quantitative data exist on how ME mechanics deals with these large quasi-static pressure changes and because of this lack of data, only few efforts could be made to incorporate quasi-static behavior into computer models. When designing and modeling ossicle prostheses and implantable ME hearing aids, the effects of large ossicle movements caused by quasistatic pressures should be taken into account. We investigated the response of the ME to slowly varying pressures by measuring the displacement of the umbo and the stapes in rabbit with a heterodyne interferometer with position decoder. Displacement versus pressure curves were obtained at linear pressure change rates between 200 Pa/s and 1.5 kPa/s, with amplitude T2.5 kPa. The change in stapes position associated with a pressure change is independent of pressure change rate (34 mm peak-to-peak at T2.5 kPa). The stapes displacement versus pressure curves are highly nonlinear and level off for pressures beyond T1 kPa. Stapes motion shows no measurable hysteresis at 1.5 kPa/s, which demonstrates that the annular ligament has little viscoelasticity. Hysteresis increases strongly at the lowest pressure change rates. The stapes moves in phase with the umbo and with pressure, but the sense of rotation of the hysteresis loop of stapes is phase inversed. Stapes motion is not a simple lever ratio mimic of umbo motion, but is the consequence of complex changes in ossicle joints and ossicle position. The change in umbo position produced by a T2.5 kPa pressure change decreases with increasing rate from 165 mm at 200 Pa/s to 118 mm at 1.5 kPa/s. Umbo motion already shows significant hysteresis at 1.5 kPa/s, but hysteresis increases further as pressure change rate decreases. We conclude that in the quasi-static regime, ossicle movement is not only governed by viscoelasticity, but that other effects become dominant as pressure change rate decreases below 1 kPa/s. The increasing hysteresis can be caused by increasing friction as speed of movement decreases, and incorporating speed-dependent friction coefficients will be essential to generate realistic models of ossicle movements at slow pressure change rates.

show abstract

Section: Figsupporting

confidence: 87%

Quasi-static Transfer Function of the Rabbit Middle Ear‚ Measured with a Heterodyne Interferometer with High-Resolution Position Decoder

Dirckx

Buytaert

Decraemer

2006

JARO

View full text Add to dashboard Cite

show abstract

“…Middle ear response characteristics are influenced by the ability of the inner ear to process the frequencies being transmitted by the middle ear (Hemilä et al 1995;Manley 1972Manley , 1973Ruggero and Temchin 2002;Lavender et al 2011). Thus, any conclusions regarding frequency responses need to take the inner ear into account.…”

Section: Early Middle Ears and The Hearing Of Mammalian Ancestorsmentioning

confidence: 99%

“…Two types of eutherian middle ear, with many intermediates, have been recognized (Fleischer 1978;Lavender et al 2011), a "microtype" in small mammals and a "freely mobile" type in medium to large mammals. Ossicular rotational axes differ between species (Puria and Steele 2010) and scaling with animal size is a general, but not universal, principle (Hemilä et al 1995).…”

Section: A Decisive and Unique Step In Evolution: The Integration Of mentioning

confidence: 99%

“…Far from being uniform structures with a single origin, bullae obviously arose quite a number of times independently and are constructed out of different parts of bony, cartilaginous, and even membranous tissue components (Novacek 1977). Although it is generally true that larger mammals have a lower upper frequency limit than smaller mammals, remarkable specializations are seen, as in the low upper frequency limit (~13 kHz) of the very small mole rats (Hemilä et al 1995;Müller et al 1992). …”

Section: When Did Mammals Develop High-frequency and Ultrasonic Hearing?mentioning

confidence: 99%

See 1 more Smart Citation

Evolutionary Paths to Mammalian Cochleae

Manley

2012

JARO

View full text Add to dashboard Cite

Evolution of the cochlea and high-frequency hearing (920 kHz; ultrasonic to humans) in mammals has been a subject of research for many years. Recent advances in paleontological techniques, especially the use of micro-CT scans, now provide important new insights that are here reviewed. True mammals arose more than 200 million years (Ma) ago. Of these, three lineages survived into recent geological times. These animals uniquely developed three middle ear ossicles, but these ossicles were not initially freely suspended as in modern mammals. The earliest mammalian cochleae were only about 2 mm long and contained a lagena macula. In the multituberculate and monotreme mammalian lineages, the cochlea remained relatively short and did not coil, even in modern representatives. In the lineage leading to modern therians (placental and marsupial mammals), cochlear coiling did develop, but only after a period of at least 60 Ma. Even Late Jurassic mammals show only a 270°cochlear coil and a cochlear canal length of merely 3 mm. Comparisons of modern organisms, mammalian ancestors, and the state of the middle ear strongly suggest that high-frequency hearing (920 kHz) was not realized until the early Cretaceous (~125 Ma). At that time, therian mammals arose and possessed a fully coiled cochlea. The evolution of modern features of the middle ear and cochlea in the many later lineages of therians was, however, a mosaic and different features arose at different times. In parallel with cochlear structural evolution, prestins in therian mammals evolved into effective components of a new motor system. Ultrasonic hearing developed quite late-the earliest bat cochleae (~60 Ma) did not show features characteristic of those of modern bats that are sensitive to high ultrasonic frequencies.

show abstract

“…The goals of this study are to test for taxonomic differences in primate middle and outer ear morphology and estimate their functional characteristics using models based on acoustical theory to investigate how well these model predictions relate to actual hearing performance. Similar lines of investigation have been applied to other vertebrate groups (e.g., rodents and felids), but primates have received only limited attention in this regard, with the few relevant studies narrowly focused on only a few taxa (Packer and Sarmiento, 1984;Masali et al, 1992;Hemilä et al, 1995;Moggi-Cecchi and Collard, 2002).…”

mentioning

confidence: 99%

Primate auditory diversity and its influence on hearing performance

2004

View full text Add to dashboard Cite

The auditory region contains numerous structures that have proven useful for phylogenetic classification at various taxonomic levels. However, little work has been done in primates relating differences in morphology to variations in hearing performance. This study documents anatomical and physiological distinctions within primates and begins to address the functional and evolutionary consequences of these and other auditory features. The dimensions of the outer ear (pinna) were measured in cadaveric specimens representing nearly every primate family and used to calculate a shape ratio (height/width). It was found that nonanthropoids have a significantly higher ratio than anthropoids, although the actual height was not found to differ. This indicates that most nonanthropoids have ears that are tall and narrow, whereas monkeys and apes are characterized by ears with more equal height and width dimensions. Eardrum area, stapedial footplate area, and ossicular lever arm lengths were measured in dried specimens to calculate an impedance transformer ratio. A distinction was found between anthropoids and strepsirrhines, with the latter group having a transformer ratio indicative of a higher percentage of acoustic energy transmission through the middle ear. Audiogram data were gathered from the literature to analyze hearing sensitivity and it was found that platyrrhines illustrate more low-frequency sensitivity than like-sized lorisoids. The effects of intraspecific variation on the audiogram results were also examined and were found to produce similar results as the analysis using species mean threshold values. Lastly, correlations between morphological and audiogram variables were examined. Several measures of hearing sensitivity were found to be correlated with pinna shape but correlations with middle ear transmission properties were weaker. In addition to using traditional statistical techniques, phylogenetic corrective methods were applied to address the problem of statistical nonindependence of the data and the results of both analyses are compared. These findings are discussed with respect to how sensory adaptations and phylogenetic history may be related to the current radiation of primates. Key words: primate hearing; outer ears; middle ears; audiogram; phylogenyPrimates express numerous modifications on the fundamental mammalian middle ear morphology and these differences have proven useful for phylogenetic classification at various taxonomic levels (MacPhee and Cartmill, 1986). Among extant strepsirrhines, most Malagasy primates are characterized by a free-floating tympanic ring surrounded by a single relatively large tympanic cavity while lorisoids have a tympanic ring that is fused to the lateral wall of a smaller tympanic cavity. Lorises appear to maintain a substantial effective cavity volume by having additional pneumatic spaces off of the epitympanic recess. Extant haplorhines are similar to lorises in possessing epitympanic sinuses (except tarsiers) (MacPhee and Cartmill, 1986) and a fused tym...

show abstract

What middle ear parameters tell about impedance matching and high frequency hearing

Cited by 128 publications

References 19 publications

Quasi-static Transfer Function of the Rabbit Middle Ear‚ Measured with a Heterodyne Interferometer with High-Resolution Position Decoder

Quasi-static Transfer Function of the Rabbit Middle Ear‚ Measured with a Heterodyne Interferometer with High-Resolution Position Decoder

Evolutionary Paths to Mammalian Cochleae

Primate auditory diversity and its influence on hearing performance

Contact Info

Product

Resources

About