Sexual Dimorphism and Development of the Human Cochlea: Computer 3-D Measurement

Sato, H.; Sando, Isamu; Takahashi, Hiroki

doi:10.3109/00016489109138447

Cited by 53 publications

(80 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This finding is consistent with numerous prior reports indicating a large extent of variation in human cochlear length (Bredberg 1968;Ulehlova et al 1987;Wright et al 1987;Hardy 1968;Kawano et al 1996;Ketten et al 1998: Skinner et al 2002. We did not observe a significant difference between female and male OC length as reported by Sato et al (1991), who found OC lengths of 32.3 T 1.8 mm for females and 37.1 T 1.6 mm for males (total n = 18). However, our findings are consistent with those of Ketten et al (1998) and Skinner et al (2002), who also reported no significant male-vs-female difference in OC length, based upon high-resolution CT studies and data from a large group of temporal bones (n = 33).…”

Section: Measurements Of Oc Sg and Mw And Implications For CIsupporting

confidence: 93%

Frequency Map for the Human Cochlear Spiral Ganglion: Implications for Cochlear Implants

Stakhovskaya

Sridhar

Bonham

et al. 2007

JARO

354

357

View full text Add to dashboard Cite

The goals of this study were to derive a frequencyposition function for the human cochlear spiral ganglion (SG) to correlate represented frequency along the organ of Corti (OC) to location along the SG, to determine the range of individual variability, and to calculate an Baverage^frequency map (based on the trajectories of the dendrites of the SG cells). For both OC and SG frequency maps, a potentially important limitation is that accurate estimates of cochlear place frequency based upon the Greenwood function require knowledge of the total OC or SG length, which cannot be determined in most temporal bone and imaging studies. Therefore, an additional goal of this study was to evaluate a simple metric, basal coil diameter that might be utilized to estimate OC and SG length. Cadaver cochleae (n = 9) were fixed G24 h postmortem, stained with osmium tetroxide, microdissected, decalcified briefly, embedded in epoxy resin, and examined in surface preparations. In digital images, the OC and SG were measured, and the radial nerve fiber trajectories were traced to define a series of frequency-matched coordinates along the two structures. Images of the cochlear turns were reconstructed and measurements of basal turn diameter were made and correlated with OC and SG measurements. The data obtained provide a mathematical function for relating represented frequency along the OC to that of the SG.Results showed that whereas the distance along the OC that corresponds to a critical bandwidth is assumed to be constant throughout the cochlea, estimated critical band distance in the SG varies significantly along the spiral. Additional findings suggest that measurements of basal coil diameter in preoperative images may allow prediction of OC/SG length and estimation of the insertion depth required to reach specific angles of rotation and frequencies. Results also indicate that OC and SG percentage length expressed as a function of rotation angle from the round window is fairly constant across subjects. The implications of these findings for the design and surgical insertion of cochlear implants are discussed.

show abstract

Section: Measurements Of Oc Sg and Mw And Implications For CIsupporting

confidence: 93%

Frequency Map for the Human Cochlear Spiral Ganglion: Implications for Cochlear Implants

Stakhovskaya

Sridhar

Bonham

et al. 2007

JARO

354

357

View full text Add to dashboard Cite

show abstract

“…Their 3D reconstruction of these measurements includes the elevation of the cochlear spiral and has a larger radius than the surface method, as halfway between the inner and outer edges of the BM may fall nearer to the second or third row of outer hair cells than to the junction of the outer pillar with the first outer hair cell. It will be shown that Sato et al 8 found the male average to be about 3 mm longer and the female average to be about 1 mm shorter than the same averages found by other methods. The reasons for these differences are unknown.…”

Section: Methods Used To Measure the Anatomical Length Of The Cochleamentioning

confidence: 69%

“…In a study of a single cochlea, they found good agreement with the Guild/ Schuknecht method when the serial sections were corrected by computer to be parallel to the mid-modiolar axis. This 3D method was applied by Sato et al 8 to study sex differences. However, unlike previous investigators, they measured along the inner and outer borders of the basilar membrane ͑BM͒ and took the average of the two lengths to represent cochlear length.…”

Section: Methods Used To Measure the Anatomical Length Of The Cochleamentioning

confidence: 99%

“…For these reasons, a possible sex difference in the length of the cochlea is important as it might imply important sex differences in the numbers of sensory cells, numbers of primary afferent fibers, and in auditory function. One study of the human cochlea ͑Sato et al 8 ͒ reported a large sex difference in length of the organ of Corti. Electrophysiological measurement of response delay times combined with assumptions about cochlear mechanics led Don et al 9 to a similar conclusion.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Sex differences in the length of the organ of Corti in humans

Miller

2007

The Journal of the Acoustical Society of America

View full text Add to dashboard Cite

Sato et al. [Acta. Otolaryngol. 111 (6), 1037–1040 (1991)] reported that the human cochlea is, on average, 15% longer for males than females. This corresponds to 4.7mm in length and to 2.78 standard deviations (SD). Anatomical measurements of the lengths of cochleas from 148 heads (194 cochleas) from eleven sources are reviewed and summarized. A sex difference of 3.36% is observed. This corresponds to 1.11mm in length and to 0.49SD. The mean lengths of the male and female cochleas are approximately 34 and 33mm, respectively, and the population SD is 2.28mm. The statistical significance of the observed difference is questionable.

show abstract

“…Human cochleae lengths are highly variable among populations, 62 and the length is significantly longer in males than females. 63 This leads to significantly longer delays in male cochleae for lower frequencies to reach their characteristic place, in comparison to female cochleae, 16 and a subsequent decrease in neural synchrony. 39 Therefore, consistent with the present study, wave V latencies are later for males and have greater variability than for females.…”

Section: B Chirp 'Goodness-of-fit'mentioning

confidence: 99%

Spectral and synchrony differences in auditory brainstem responses evoked by chirps of varying durations

Petoe

Bradley

Wilson

2010

The Journal of the Acoustical Society of America

View full text Add to dashboard Cite

The chirp-evoked ABR has been termed a more synchronous response, referring to the fact that rising-frequency chirp stimuli theoretically compensate for temporal dispersions down the basilar membrane. This compensation is made possible by delaying the higher frequency content of the stimulus until the lower frequency traveling waves are closer to the cochlea apex. However, it is not yet clear how sensitive this temporal compensation is to variation in the delay interval. This study analyzed chirp-and click-evoked ABRs at low intensity, using a variety of tools in the time, frequency, and phase domains, to measure synchrony in the response. Additionally, this study also examined the relationship between chirp sweep rate and response synchrony by varying the delay between high-and low-frequency portions of chirp stimuli. The results suggest that the chirp-evoked ABRs in this study exhibited more synchrony than the click-evoked ABRs and that slight gender-based differences exist in the synchrony of chirp-evoked ABRs. The study concludes that a tailoring of chirp parameters to gender may be beneficial in pathologies that severely affect neural synchrony, but that such a customization may not be necessary in routine clinical applications.

show abstract

Sexual Dimorphism and Development of the Human Cochlea: Computer 3-D Measurement

Cited by 53 publications

References 0 publications

Frequency Map for the Human Cochlear Spiral Ganglion: Implications for Cochlear Implants

Frequency Map for the Human Cochlear Spiral Ganglion: Implications for Cochlear Implants

Sex differences in the length of the organ of Corti in humans

Spectral and synchrony differences in auditory brainstem responses evoked by chirps of varying durations

Contact Info

Product

Resources

About