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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

Threshold-shifts by the seven water-injection conditions in cartilage conduction.Threshold-shifts from the 0%-water injection condition were described. The water injection first elevated the thresholds at all frequencies. Beyond 60% of the ear canal, the thresholds at 0.5 and 1 kHz were improved. In addition, when the injected water overflowed to touch the transducer, the thresholds at 2 and 4 kHz were improved. Vertical bars indicate standard deviations.
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pone.0120135.g005: Threshold-shifts by the seven water-injection conditions in cartilage conduction.Threshold-shifts from the 0%-water injection condition were described. The water injection first elevated the thresholds at all frequencies. Beyond 60% of the ear canal, the thresholds at 0.5 and 1 kHz were improved. In addition, when the injected water overflowed to touch the transducer, the thresholds at 2 and 4 kHz were improved. Vertical bars indicate standard deviations.

Mentions: Fig. 5 shows the threshold-shifts for the second set of data in which CC thresholds were obtained for water injected in steps of 20%. A two–way repeated-measures ANOVA revealed statistically effects for water volume (F [6, 36] = 155.47, p < 0.001) and frequency (F [3, 18] = 56.45, p < 0.001). The interaction between the main factors was significant (F [18, 108] = 47.15, p < 0.001). The CC thresholds were significantly elevated at all four frequencies by the initial 20% water injection. Increasing water injection from 40% to 60% significantly improved thresholds at 0.5 and 1 kHz. Thresholds at 2 and 4 kHz also significantly improved in the overflowing-water condition while the threshold-shift at 1 kHz significantly increased in the overflowing-water condition.


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)

Threshold-shifts by the seven water-injection conditions in cartilage conduction.Threshold-shifts from the 0%-water injection condition were described. The water injection first elevated the thresholds at all frequencies. Beyond 60% of the ear canal, the thresholds at 0.5 and 1 kHz were improved. In addition, when the injected water overflowed to touch the transducer, the thresholds at 2 and 4 kHz were improved. Vertical bars indicate standard deviations.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0120135.g005: Threshold-shifts by the seven water-injection conditions in cartilage conduction.Threshold-shifts from the 0%-water injection condition were described. The water injection first elevated the thresholds at all frequencies. Beyond 60% of the ear canal, the thresholds at 0.5 and 1 kHz were improved. In addition, when the injected water overflowed to touch the transducer, the thresholds at 2 and 4 kHz were improved. Vertical bars indicate standard deviations.
Mentions: Fig. 5 shows the threshold-shifts for the second set of data in which CC thresholds were obtained for water injected in steps of 20%. A two–way repeated-measures ANOVA revealed statistically effects for water volume (F [6, 36] = 155.47, p < 0.001) and frequency (F [3, 18] = 56.45, p < 0.001). The interaction between the main factors was significant (F [18, 108] = 47.15, p < 0.001). The CC thresholds were significantly elevated at all four frequencies by the initial 20% water injection. Increasing water injection from 40% to 60% significantly improved thresholds at 0.5 and 1 kHz. Thresholds at 2 and 4 kHz also significantly improved in the overflowing-water condition while the threshold-shift at 1 kHz significantly increased in the overflowing-water condition.

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