Effects of intense auditory stimulation: hearing losses and inner ear changes in the squirrel monkey. II

1973 ◽  
Vol 54 (5) ◽  
pp. 1179-1183 ◽  
Author(s):  
Ivan M. Hunter‐Duvar ◽  
Donald N. Elliott
Author(s):  
K. Nishizaki ◽  
S.-I. Usami ◽  
M. Anniko ◽  
W. Arnold
Keyword(s):  

1987 ◽  
Vol 103 (5) ◽  
pp. 161-169 ◽  
Author(s):  
Toshio Yoshihara ◽  
Shinichi Usami ◽  
Makoto Igarashi ◽  
Cesar Fermin
Keyword(s):  

ORL ◽  
1995 ◽  
Vol 57 (2) ◽  
pp. 87-93 ◽  
Author(s):  
K. Nishizaki ◽  
S.-I. Usami ◽  
M. Anniko ◽  
W. Arnold
Keyword(s):  

1969 ◽  
Vol 45 (1) ◽  
pp. 342-342 ◽  
Author(s):  
C. Wilpizeski ◽  
J. Sataloff ◽  
R. Innis ◽  
W. Shiner

2021 ◽  
Vol 11 (3) ◽  
pp. 335-341
Author(s):  
Miriam Geal-Dor ◽  
Haim Sohmer

Soft tissue conduction is an additional mode of auditory stimulation which can be initiated either by applying an external vibrator to skin sites not overlying skull bone such as the neck (so it is not bone conduction) or by intrinsic body vibrations resulting, for example, from the heartbeat and vocalization. The soft tissue vibrations thereby induced are conducted by the soft tissues to all parts of the body, including the walls of the external auditory canal. In order for soft tissue conduction to elicit hearing, the soft tissue vibrations which are induced must penetrate into the cochlea in order to excite the inner ear hair cells and auditory nerve fibers. This final stage can be achieved either by an osseous bone conduction mechanism, or, more likely, by the occlusion effect: the vibrations of the walls of the occluded canal induce air pressures in the canal which drive the tympanic membrane and middle ear ossicles and activate the inner ear, acting by means of a more air conduction-like mechanism. In fact, when the clinician applies his stethoscope to the body surface of his patient in order to detect heart sounds or pulmonary air flow, he is detecting soft tissue vibrations.


2017 ◽  
Vol 28 (02) ◽  
pp. 152-160 ◽  
Author(s):  
Ofri Ronen ◽  
Miriam Geal-Dor ◽  
Michal Kaufmann-Yehezkely ◽  
Ronen Perez ◽  
Shai Chordekar ◽  
...  

Background: Hearing can be induced not only by airborne sounds (air conduction [AC]) and by the induction of skull vibrations by a bone vibrator (osseous bone conduction [BC]), but also by inducing vibrations of the soft tissues of the head, neck, and thorax. This hearing mode is called soft tissue conduction (STC) or nonosseous BC. Purpose: This study was designed to gain insight into the mechanism of STC auditory stimulation. Research Design: Fluid was applied to the external auditory canal in normal participants and to the mastoidectomy common cavity in post–radical mastoidectomy patients. A rod coupled to a clinical bone vibrator, immersed in the fluid, delivered auditory frequency vibratory stimuli to the fluid. The stimulating rod was in contact with the fluid only. Thresholds were assessed in response to the fluid stimulation. Study Sample: Eight ears in eight normal participants and eight ears in seven post–radical mastoidectomy patients were studied. Data Collection and Analysis: Thresholds to AC, BC, and fluid stimulation were assessed. The postmastoidectomy patients were older than the normal participants, with underlying sensorineural hearing loss (SNHL). Therefore, the thresholds to the fluid stimulation in each participant were corrected by subtracting his BC threshold, which expresses any underlying SNHL. Results: Hearing thresholds were obtained in each participant, in both groups in response to the fluid stimulation at 1.0 and 2.0 kHz. The fluid thresholds, corrected by subtracting the BC thresholds, did not differ between the groups at 1.0 kHz. However, at 2.0 kHz the corrected fluid thresholds in the mastoidectomy patients were 10 dB lower (better) than in the normal participants. Conclusions: Since the corrected fluid thresholds at 1.0 kHz did not differ between the groups, the response to fluid stimulation in the normal participants at least at 1.0 kHz was probably not due to vibrations of the tympanic membrane and of the ossicular chain induced by the fluid stimulation, since these structures were absent in the mastoidectomy patients. In addition, the fluid in the external canal (normal participants) and the absence of the tympanic membrane and the ossicular chain (mastoidectomy patients) induced a conductive hearing loss (threshold elevation to air-conducted sounds coming from the bone vibrator), so that AC mechanisms were probably not involved in the thresholds to the fluid stimulation. In addition, as a result of the acoustic impedance mismatch between the fluid and skull bone, the audio-frequency vibrations induced in the fluid at threshold would probably not lead to vibrations of the bony wall of the meatus, so that hearing by osseous BC is not likely. Therefore, it seems that the thresholds to the fluid stimulation, in the absence of AC and of osseous BC, represent an example of STC, which is an additional mode of auditory stimulation in which the cochlea is activated by fluid pressures transmitted along a series of soft tissues, reaching and exciting the inner ear directly. STC can explain the mechanism of several auditory phenomena.


1982 ◽  
Vol 234 (2) ◽  
pp. 213-225 ◽  
Author(s):  
Allen F. Ryan ◽  
Paul Goodwin ◽  
Nigel K. Woolf ◽  
Frank Sharp

1980 ◽  
Vol 49 (6) ◽  
pp. 1070-1082 ◽  
Author(s):  
J. P. Landolt ◽  
K. E. Money ◽  
E. D. Topliff ◽  
A. D. Nicholas ◽  
J. Laufer ◽  
...  

More than 90 squirrel monkeys with bilateral myringotomies (a small hole in each ear drum) were rapidly decompressed in a hyperbaric chamber according to a special diving profile in which 35% of attempts produced disorders ("hits") confined to the inner ear. Monkeys receiving inner ear hits (as determined by the sudden onset of vigorous head or eye nystagmus during decompression) were tested and killed at times ranging from 1 h to more than 12 mo following the dive. Histologically, in monkeys killed 1 mo or less after the hit, hemorrhage and/or a deep purple-staining precipitated material were frequently found in the otic fluid spaces. In those monkeys killed more than 1 mo after a hit, ectopic new bone growth in the arms of the semicircular canals was a common sequela. New bone growth never appeared in the cochlea. In unaffected ears, and in both ears of control animals, the precipitated material was somewhat less than in ears damaged by decompression; and, furthermore, new bone growth did not occur. Behaviorally, the hit monkeys showed vestibular deficits that were consistent with the structural damage revealed by histology.


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