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Results for “Bone Conduction”

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At least 19 recordsLinked to original sources
PubMed2006

Middle ear ossicles motion at hearing thresholds with air conduction and bone conduction stimulation.

Hearing threshold data with bone conduction and air conduction stimulation are combined with physiological and mechanical measurements of the middle ear ossicles vibration to compute the vibration level of the ossicles at threshold stimulation. By comparing the displacements of the stapes footplate with the two stimulation modalities and assuming the vibration of the stapes footplate to be the input to the cochlea when stimulation is by air conduction, the importance of middle ear ossicles inertia with bone conduction stimulation is evaluated. Given the limitations of the analysis, the results indicate that the inertia of the middle ear is not an important contribution to the perception of BC sound for frequencies below 1.5 kHz; it seems to contribute to perception of bone conducted sound between the frequencies 1.5 and 3.5 kHz. At frequencies above 4 kHz, the analysis failed since the input to the cochlea is probably not through the oval window with bone conduction stimulation. Comparison of basilar membrane vibration data verified the calculations for frequencies between 0.8 and 3.5 kHz. It was also found that the fluid flow at the round window, rather than at the oval window, reflects the stimulation of the basilar membrane with bone conduction stimulation.

Acoustic Stimulation↗
PubMed1981

[Air conduction or bone conduction hearing aids? Comments on hearing aids for sound conduction deafness (author's transl)].

Measuring curves and psycho-acoustical measurements are used for an investigation of the extent to which the bone-conduction hearing aid is equivalent to the air-conduction hearing aid. It can be shown that basically there is no objection against the use of a bone-conduction hearing aid (ear-level aid) for patients suffering only from sound-conduction hearing defects. The air-conduction hearing aid significantly superior in those cases where the requirements to be met by the hearing aid with respect to the frequency range (music) are higher. If the sound conduction disorder is accompanied by a sound paralgia, this means that the essentially reduced dynamic range of the bone-conduction hearing aid significantly restricts the possible applications of the bone-conduction hearing aid.

Bone Conduction↗
PubMedDate not supplied

Acceleration levels at hearing threshold with direct bone conduction versus conventional bone conduction.

Some patients with hearing disorders cannot use a conventional air conduction hearing aid, but have to use a bone conduction hearing aid. The technique of introducing a permanent, skin-penetrating titanium implant has made it possible to develop a bone-anchored hearing aid with all parts in a single housing. Ten patients have been using such an aid for almost 2 years. This investigation deals with absolute acceleration threshold measurements in 7 of these patients. The measuring apparatus consisted mainly of a Békésy audiometer and an accelerometer, Brüel & Kjaer 4344. In the frequency range from 250 to 6 000 Hz, the acceleration levels at hearing threshold decreased by between 16 and 28 dB when measured directly on the titanium screw, as compared with when measured on the intact skin surface. This lowering in acceleration thresholds can be explained by the fact that skin and subcutaneous soft tissues act as a shunt for acceleration.

Adolescent↗
PubMed1984

Hearing thresholds with direct bone conduction versus conventional bone conduction.

Some patients who need hearing aids are unable to use an aid which transmits the sound via the external ear canal but have to use a bone-conduction hearing aid. The pressure needed to apply the transducer often gives the patient discomfort, and the attenuating effect of the skin gives poor electroacoustical function of the aid. A permanent skin penetration has made it possible to develop a bone-anchored hearing aid with all components in one housing. Ten patients have been equipped with such an aid. This paper deals with a comparative hearing threshold measurement on 10 patients. Békésy audiometry was performed and a conventional Oticon (A-type) transducer was used. In the frequency range 600 to 6 000 Hz, there was a lowering of 10-20 dB in thresholds when skin penetration was performed. This lowering in thresholds means lower transducer distortion, lower electrical gain, and lower power consumption to produce a given sensation level.

Acoustic Impedance Tests↗
PubMed2004

Round window membrane motion with air conduction and bone conduction stimulation.

The vibration patterns of the round window (RW) membrane in human cadaver temporal bone specimens were assessed by measurements of the velocity of reflective targets placed on the RW membrane with an approximate spacing of 0.2 mm. The velocity was measured in the frequency range 0.1-10 kHz by a laser Doppler vibrometer in four specimens with air conduction (AC) stimulation and in four specimens with bone conduction (BC) stimulation. The response pattern was investigated by analyzing the velocity response of all targets on the RW membrane, by making iso-amplitude and iso-phase contour plots of the membrane surface, and by creating animations of the surface vibration at several frequencies. Similar response pattern was found with AC and BC stimulations. At frequencies below 1.5 kHz, the RW membrane vibrates nearly as a whole in an in-and-out motion and above 1.5 kHz, the membrane moves primarily in two sections that vibrate with approximately 180 degrees difference. Indication of some traveling wave motion of the RW membrane at those frequencies was also found. At higher frequencies, above 3 kHz, the membrane motion is complex with a mixture of modal and traveling wave motion. An increase of the stimulation level did not alter the vibration pattern; it only gave an increase of the RW membrane vibration amplitude corresponding to the increase in stimulation. When the mode of stimulation at the oval window was altered, by the insertion of a 0.6 mm piston, the vibration pattern of the RW membrane changed.

Acoustic Stimulation↗
PubMed2005

Influence of ear canal occlusion and static pressure difference on bone conduction thresholds: implications for mechanisms of bone conduction.

The effect of air pressure change on bone conduction (BC) hearing thresholds in the occluded ear was investigated. The pump manometer system of an impedance bridge was used to change the air pressure in the ear canal of twenty-two normally hearing subjects. BC thresholds were measured with: (1) open ear; (2) the ear canal occluded with a probe tube and application of 0 daPa air pressure; and (3) the ear canal occluded with a probe tube and application of 350 daPa air pressure. Thresholds were lower in condition 2 than in condition 1, the difference decreasing from 27 dB at 2500 Hz to 4.5 dB at 2000 Hz. Thresholds were higher in condition 3 than in condition 2. The results are interpreted in terms of changes in the relative contribution of the three routes of transmission for BC sound produced by occlusion and by a static pressure difference.

Acoustic Impedance Tests↗
PubMed1999

Comparison of air-conduction and bone-conduction hearing thresholds for pure tones and octave-band filtered sound effects.

The purpose of this study was to measure air-conduction (AC) and bone-conduction (BC) hearing thresholds with pure-tone and filtered sound effect stimuli using standard audiometric equipment. A group of 20 young, normal-hearing listeners participated in the study. Pure-tone stimuli were 250, 500, 1000, 2000, and 4000 Hz. Sound effect stimuli were 12 natural sounds that were spectrally limited to an octave bandwidth centered at either 250, 500, 1000, 2000, or 4000 Hz. The AC and BC detection thresholds were measured using a clinical audiometer (Madsen Orbiter 922) with a B-71 bone oscillator and TDH-50 earphones. Results indicated that detection thresholds for the pure-tone and corresponding octave-band sound effect stimuli were within 3 to 4 dB of each other for both AC and BC testing. The findings support the notion that octave-filtered sound effects are a viable alternative to pure-tone stimuli for use in audiology clinics.

Adolescent↗
PubMed2006

Properties of binaural vestibular evoked myogenic potentials elicited with air-conducted and bone-conducted tone bursts.

The purpose of this investigation was to compare the effects of monaural and binaural stimulation on unilaterally-measured vestibular evoked myogenic potential (VEMP) magnitude and latency. The subjects were eighteen normal-hearing adults with no history of vestibular disease. Monaural VEMPs were acquired with air-conducted (AC) and bone-conducted (BC) 500 Hz tone bursts presented at 95 dB nHL and 70 dB nHL, respectively. These stimuli were simultaneously paired with 95 dB nHL contralateral tone bursts at 250, 500, 750, or 1000 Hz during acquisition of binaural VEMPs. Results indicated that AC-VEMP relative magnitudes decreased in each of the binaural conditions compared to the monaural condition. However, no changes in relative magnitude between conditions occurred for BC-VEMPs. Similar latencies were observed for monaural and binaural VEMPs. Differences in bilateral interaction seen between the AC-VEMP and BC-VEMP conditions are consistent with modification of sound transmission through the ear during presentations of binaural sound.

Acoustic Stimulation↗
PubMed1977

Calibration force levels for bone conduction vibrators.

Two bone conduction vibrators (Radioear B71 and B72) and a headband (Radioear P-3333) have been developed to meet specifications of both the International Electrotechnical Commission and the American National Standard Institute. Pure-tone thresholds for air conduction and bone conduction were obtained from 24 normal-hearing young adults at audiometric frequencies between 250 and 4000 Hz. Results of this study are in good agreement with the standard air conduction threshold sound pressure levels (ANSI) and with bone conduction threshold force levels reported in the literature.

Adult↗
PubMed1989

[Evaluation of hearing in patients with otospongiosis based on direct measurement of bone conduction].

The conventional bone conduction audiometry does not allow an objective assessment of hearing in patients with otospongiosis. We evaluated a new method of direct bone conduction audiometry with the stimulator applied to the promontory intraoperatively. A comparison of conventional and direct bone conduction audiometry thresholds was made in 100 patients in various stages of otospongiosis before stapedectomy. A significant correlation between hearing thresholds obtained by both methods was observed for all frequencies tested (500, 1000, 2000 and 4000 Hz). The direct bone conduction method was at least 30 dB more sensitive for all frequencies. Interestingly, the average direct bone conduction threshold curve did not exhibit a Carhart notch at 2000 Hz compared to the conventional method. We concluded that our bone conduction technique enabled a better assessment of cochlear reserve in patients with otospongiosis.

Adult↗
PubMed1978

Audiometric bone conduction.

Audiometric bone conduction test data are obtained with a unit that permits comparison with a recognized standard because the unit can be calibrated to operate within specified limits. Proper calibration of the unit is necessary if the equipment is to be accurate. Two procedures can be helpful in determining the need for calibration: the average loss method and the input voltage measurement method. Neither should supplant calibration, but each offers a means of checking the output of the unit. Confidence in auditory test data is increased when there is a high degree of consistency among the various tests; the availability of several different tests in the audiometric series can be used to an advantage then in a determination of consistency. An additional opportunity to ascertain the existence of consistency is present when tuning fork tests are employed as part of the total evaluation. The use of a masking stimulus in the nontest ear simultaneously with the presentation of the test tone to the test ear can be extremely useful in defining the type as well as the extent of the hearing loss. Presentation of the test tone and the masking stimulus in controlled discrete steps is the key to the interpretation of masking results.

Acoustic Stimulation↗