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Cartilage conduction is characterized by vibrations of the cartilaginous portion of the ear canal.

Nishimura T, Hosoi H, Saito O, Miyamae R, Shimokura R, Yamanaka T, Kitahara T, Levitt H - PLoS ONE (2015)

Bottom Line: When the water was additionally injected to reach the cartilaginous portion, the thresholds at 0.5 and 1 kHz dramatically decreased by 27.4 and 27.5 dB, respectively.CC generates airborne sound in the canal more efficiently than BC.The current findings suggest that CC is not a hybrid of AC and BC.

View Article: PubMed Central - PubMed

Affiliation: Department of Otolaryngology-Head and Neck surgery, Nara Medical University, Kashihara, Japan.

ABSTRACT
Cartilage conduction (CC) is a new form of sound transmission which is induced by a transducer being placed on the aural cartilage. Although the conventional forms of sound transmission to the cochlea are classified into air or bone conduction (AC or BC), previous study demonstrates that CC is not classified into AC or BC (Laryngoscope 124: 1214-1219). Next interesting issue is whether CC is a hybrid of AC and BC. Seven volunteers with normal hearing participated in this experiment. The threshold-shifts by water injection in the ear canal were measured. AC, BC, and CC thresholds at 0.5-4 kHz were measured in the 0%-, 40%-, and 80%-water injection conditions. In addition, CC thresholds were also measured for the 20%-, 60%-, 100%-, and overflowing-water injection conditions. The contributions of the vibrations of the cartilaginous portion were evaluated by the threshold-shifts. For AC and BC, the threshold-shifts by the water injection were 22.6-53.3 dB and within 14.9 dB at the frequency of 0.5-4 kHz, respectively. For CC, when the water was filled within the bony portion, the thresholds were elevated to the same degree as AC. When the water was additionally injected to reach the cartilaginous portion, the thresholds at 0.5 and 1 kHz dramatically decreased by 27.4 and 27.5 dB, respectively. In addition, despite blocking AC by the injected water, the CC thresholds in force level were remarkably lower than those for BC. The vibration of the cartilaginous portion contributes to the sound transmission, particularly in the low frequency range. Although the airborne sound is radiated into the ear canal in both BC and CC, the mechanism underlying its generation is different between them. CC generates airborne sound in the canal more efficiently than BC. The current findings suggest that CC is not a hybrid of AC and BC.

No MeSH data available.


Related in: MedlinePlus

Subject’s head condition during the measurements.The subject’s head was fixed in the condition of the entrance of the ear canal facing up to the ceiling. The pillow had the space which enabled a masker earphone to be worn without the interference with the pillow.
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pone.0120135.g002: Subject’s head condition during the measurements.The subject’s head was fixed in the condition of the entrance of the ear canal facing up to the ceiling. The pillow had the space which enabled a masker earphone to be worn without the interference with the pillow.

Mentions: The subject lay on a bed in a lateral recumbent position. The entrance of the ear canal faced up to the ceiling, and the head was fixed to avoid the water fluctuating in the canal (Fig. 2). The temperature of the injected water was set at 37 degrees Celsius to prevent vertigo. Prior to obtaining measurements, the volume of the ear canal for each subject was measured by injecting water into the ear canal, as described above. The volume of water to be injected was then determined for each experimental condition. The volume of water filling the ear canal but not overflowing into the cavity of the concha was defined as 100% full.


Cartilage conduction is characterized by vibrations of the cartilaginous portion of the ear canal.

Nishimura T, Hosoi H, Saito O, Miyamae R, Shimokura R, Yamanaka T, Kitahara T, Levitt H - PLoS ONE (2015)

Subject’s head condition during the measurements.The subject’s head was fixed in the condition of the entrance of the ear canal facing up to the ceiling. The pillow had the space which enabled a masker earphone to be worn without the interference with the pillow.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4359134&req=5

pone.0120135.g002: Subject’s head condition during the measurements.The subject’s head was fixed in the condition of the entrance of the ear canal facing up to the ceiling. The pillow had the space which enabled a masker earphone to be worn without the interference with the pillow.
Mentions: The subject lay on a bed in a lateral recumbent position. The entrance of the ear canal faced up to the ceiling, and the head was fixed to avoid the water fluctuating in the canal (Fig. 2). The temperature of the injected water was set at 37 degrees Celsius to prevent vertigo. Prior to obtaining measurements, the volume of the ear canal for each subject was measured by injecting water into the ear canal, as described above. The volume of water to be injected was then determined for each experimental condition. The volume of water filling the ear canal but not overflowing into the cavity of the concha was defined as 100% full.

Bottom Line: When the water was additionally injected to reach the cartilaginous portion, the thresholds at 0.5 and 1 kHz dramatically decreased by 27.4 and 27.5 dB, respectively.CC generates airborne sound in the canal more efficiently than BC.The current findings suggest that CC is not a hybrid of AC and BC.

View Article: PubMed Central - PubMed

Affiliation: Department of Otolaryngology-Head and Neck surgery, Nara Medical University, Kashihara, Japan.

ABSTRACT
Cartilage conduction (CC) is a new form of sound transmission which is induced by a transducer being placed on the aural cartilage. Although the conventional forms of sound transmission to the cochlea are classified into air or bone conduction (AC or BC), previous study demonstrates that CC is not classified into AC or BC (Laryngoscope 124: 1214-1219). Next interesting issue is whether CC is a hybrid of AC and BC. Seven volunteers with normal hearing participated in this experiment. The threshold-shifts by water injection in the ear canal were measured. AC, BC, and CC thresholds at 0.5-4 kHz were measured in the 0%-, 40%-, and 80%-water injection conditions. In addition, CC thresholds were also measured for the 20%-, 60%-, 100%-, and overflowing-water injection conditions. The contributions of the vibrations of the cartilaginous portion were evaluated by the threshold-shifts. For AC and BC, the threshold-shifts by the water injection were 22.6-53.3 dB and within 14.9 dB at the frequency of 0.5-4 kHz, respectively. For CC, when the water was filled within the bony portion, the thresholds were elevated to the same degree as AC. When the water was additionally injected to reach the cartilaginous portion, the thresholds at 0.5 and 1 kHz dramatically decreased by 27.4 and 27.5 dB, respectively. In addition, despite blocking AC by the injected water, the CC thresholds in force level were remarkably lower than those for BC. The vibration of the cartilaginous portion contributes to the sound transmission, particularly in the low frequency range. Although the airborne sound is radiated into the ear canal in both BC and CC, the mechanism underlying its generation is different between them. CC generates airborne sound in the canal more efficiently than BC. The current findings suggest that CC is not a hybrid of AC and BC.

No MeSH data available.


Related in: MedlinePlus