| 1. |
- Aazh, H, et al.
(författare)
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Influence of ear canal occlusion and static pressure difference on bone conduction thresholds: Implications for mechanisms of bone conduction
- 2005
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Ingår i: International Journal of Audiology. - : Informa Healthcare. - 1499-2027 .- 1708-8186. ; 44:5, s. 302-306
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 2. |
- Brandt, Anders, et al.
(författare)
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Properties of bone conduction hearing
- 2006
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Ingår i: XXIV International Modal Analysis Conference, St. Louis, Missouri.
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Konferensbidrag (refereegranskat)
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| 3. |
- Brandt, Anders, et al.
(författare)
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Properties of Bone Conduction Hearing
- 2006
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Konferensbidrag (refereegranskat)abstract
- Bone conduction sound, the transmission of sound as vibrations in the skull bone, is used in several areas, forexample for hearing aids, in audiometry, and in communication systems. The bone-anchored hearing aid (BAHA)has been commercially available for many years. This device utilizes titanium screws attached to the skull bonepenetrating the soft tissues thus providing a rigid attachment to the skull bone. Subjects equipped with suchtitanium screws have proven important for investigation of bone conducted sound and in the present paper anoverview of some results from different studies on such patients is given. Included are results from investigationsof resonance frequencies, propagation delays, and transcranial (cross-skull) attenuation.
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| 4. |
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| 5. |
- Eeg-Olofsson, Måns, 1967, et al.
(författare)
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Transmission of bone-conducted sound in the human skull measured by cochlear vibrations.
- 2008
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Ingår i: International journal of audiology. - : Informa UK Limited. - 1708-8186 .- 1499-2027. ; 47:12, s. 761-9
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Tidskriftsartikel (refereegranskat)abstract
- One limitation with the Bone Anchored Hearing Aid (Baha) is too poor amplification for patients with moderate to severe sensorineural hearing losses. Therefore, we investigated if bone conducted (BC) sound transmission improves when the stimulation approaches the cochlea. Also the influence from the squamosal suture on BC sound transmission was investigated. Both sides of the heads on seven human cadavers were used and vibrational stimulation was applied at eight positions on each side with a frequency range of 0.1-10 kHz. A laser Doppler vibrometer was used to measure the resulting velocity of the cochlear promontory. It was found that the velocity of the promontory increases as the stimulation position approaches the cochlea; this was especially apparent at distances within 2.5 cm from the ear canal opening and when the stimulation position was in the opened mastoid. At frequencies above 500 Hz there was on average 10 to 20 dB greater vibrational response at the cochlea when the stimulation was close to the cochlea compared with the normal Baha position. Moreover, even if there were general indications of attenuation of BC sound when passing the squamosal suture, an effect from the suture could not be conclusively determined.
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| 6. |
- Håkansson, Bo, et al.
(författare)
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A novel bone conduction implant (BCI)
- 2009
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Ingår i: 2<sup>nd</sup> Int Symposium on Bone Conduction Hearing – Craniofacial Osseointegration, Göteborg, Sweden.
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Konferensbidrag (refereegranskat)
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| 7. |
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| 8. |
- Håkansson, Bo, 1953, et al.
(författare)
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Percutaneous Versus Transcutaneous Bone Conduction Implant System : A Feasibility Study on a Cadaver Head
- 2008
-
Ingår i: Otology and Neurotology. - 1531-7129 .- 1537-4505. ; 29:8, s. 1132-1139
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Percutaneous bone-anchored hearing aid (BAHA) is an important rehabilitation alternative for patients who have conductive or mixed hearing loss. However, these devices use a percutaneous and bone-anchored implant that has some drawbacks reported. A transcutaneous bone conduction implant system (BCI) is proposed as an alternative to the percutaneous system because it leaves the skin intact. The BCI transmits the signal to a permanently implanted transducer with an induction loop system through the intact skin. The aim of this study was to compare the electroacoustic performance of the BAHA Classic-300 with a full-scale BCI on a cadaver head in a sound field. The BCI comprised the audio processor of the vibrant sound bridge connected to a balanced vibration transducer (balanced electromagnetic separation transducer).Methods: Implants with snap abutments were placed in the parietal bone (Classic-300) and 15-mm deep in the temporal bone (BCI). The vibration responses at the ipsilateral and contralateral cochlear promontories were measured with a laser Doppler vibrometer, with the beam aimed through the ear canal.Results: Results show that the BCI produces approximately 5 dB higher maximum output level and has a slightly lower distortion than the Classic-300 at the ipsilateral promontorium at speech frequencies. At the contralateral promontorium, the maximum output level was considerably lower for the BCI than for the Classic-300 except in the 1-2 kHz range, where it was similar.Conclusion: Present results support the proposal that a BCI system can be a realistic alternative to a BAHA.
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| 9. |
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| 10. |
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| 11. |
- Mishra, Sushmit, et al.
(författare)
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Speech understanding and cognitive spare capacity
- 2009
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Ingår i: Binaural Processing and Spatial Hearing, ISBN 87-990013-2-2. - Ballerup : The Danavox Jubilee Foundation. - 8799001322 ; , s. 305-313
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Konferensbidrag (refereegranskat)
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| 12. |
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| 13. |
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| 14. |
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| 15. |
- Reinfeldt, Sabine, 1978, et al.
(författare)
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Examination of bone-conducted transmission from sound field excitation measured by thresholds, ear-canal sound pressure, and skull vibrations
- 2007
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Ingår i: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 1520-8524 .- 0001-4966. ; 121:3, s. 1576-1587
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Tidskriftsartikel (refereegranskat)abstract
- Bone conduction (BC) relative to air conduction (AC) sound field sensitivity is here defined as the perceived difference between a sound field transmitted to the ear by BC and by AC. Previous investigations of BC-AC sound field sensitivity have used different estimation methods and report estimates that vary by up to 20 dB at some frequencies. In this study, the BC-AC sound field sensitivity was investigated by hearing threshold shifts, ear canal sound pressure measurements, and skull bone vibrations measured with an accelerometer. The vibration measurement produced valid estimates at 400 Hz and below, the threshold shifts produced valid estimates at 500 Hz and above, while the ear canal sound pressure measurements were found erroneous for estimating the BC-AC sound field sensitivity. The BC-AC sound field sensitivity is proposed, by combining the present result with others, as frequency independent at 50 to 60 dB at frequencies up to 900 Hz. At higher frequencies, it is frequency dependent with minima of 40 to 50 dB; at 2 and 8 kHz, and a maximum of 50 to 60 dB at 4 kHz. The BC-AC sound field sensitivity is the theoretical limit of maximum attenuation achievable with ordinary hearing protection devices. (c) 2007 Acoustical Society of America.
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| 16. |
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| 17. |
- Reinfeldt, Sabine, et al.
(författare)
-
Transcranial transmission of bone conducted sound measured acoustically and psychoacoustically
- 2007
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Ingår i: Middle Ear Mechanics in Research and Otology: Proceedings of the 4<sup>th</sup> International Symposium. - Singapore : World Scientific Publishing Co.. - 9789812707376 - 9789814475280 ; , s. 276-281
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This book includes representative, peer-reviewed articles of the lectures and papers presented during the symposium, and thereby gives an overview of the ongoing research and current knowledge in the function and mechanics of the normal, diseased and reconstructed middle ear. It covers basic research, engineering and clinical aspects of evaluation, diagnosis and surgery of the middle ear as well as implantable hearing devices in a very broad and interdisciplinary way. Following the tradition of the organizers of the previous conferences to collect the contributions of the symposium, this volume further initialized and promotes many fruitful discussions on middle ear mechanics with different points of view.
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| 18. |
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| 19. |
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| 20. |
- Stadler, Svante, 1979-
(författare)
-
Probabilistic Modelling of Hearing : Speech Recognition and Optimal Audiometry
- 2009
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hearing loss afflicts as many as 10\% of our population.Fortunately, technologies designed to alleviate the effects ofhearing loss are improving rapidly, including cochlear implantsand the increasing computing power of digital hearing aids. Thisthesis focuses on theoretically sound methods for improvinghearing aid technology. The main contributions are documented inthree research articles, which treat two separate topics:modelling of human speech recognition (Papers A and B) andoptimization of diagnostic methods for hearing loss (Paper C).Papers A and B present a hidden Markov model-based framework forsimulating speech recognition in noisy conditions using auditorymodels and signal detection theory. In Paper A, a model of normaland impaired hearing is employed, in which a subject's pure-tonehearing thresholds are used to adapt the model to the individual.In Paper B, the framework is modified to simulate hearing with acochlear implant (CI). Two models of hearing with CI arepresented: a simple, functional model and a biologically inspiredmodel. The models are adapted to the individual CI user bysimulating a spectral discrimination test. The framework canestimate speech recognition ability for a given hearing impairmentor cochlear implant user. This estimate could potentially be usedto optimize hearing aid settings.Paper C presents a novel method for sequentially choosing thesound level and frequency for pure-tone audiometry. A Gaussianmixture model (GMM) is used to represent the probabilitydistribution of hearing thresholds at 8 frequencies. The GMM isfitted to over 100,000 hearing thresholds from a clinicaldatabase. After each response, the GMM is updated using Bayesianinference. The sound level and frequency are chosen so as tomaximize a predefined objective function, such as the entropy ofthe probability distribution. It is found through simulation thatan average of 48 tone presentations are needed to achieve the sameaccuracy as the standard method, which requires an average of 135presentations.
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| 21. |
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| 22. |
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| 23. |
- Stenfelt, Stefan, 1969, et al.
(författare)
-
A model of the occlusion effect with bone-conducted stimulation
- 2007
-
Ingår i: International Journal of Audiology. - : Informa UK Limited. - 1499-2027 .- 1708-8186. ; 46:10, s. 595-608
-
Tidskriftsartikel (refereegranskat)abstract
- An acoustical model using simplified ear anatomy was designed to predict the ear-canal sound pressure occlusion effect in humans. These predictions were compared perceptually as well as with ear-canal sound pressure occlusion effect measurements using a foam earplug with shallow insertion, a foam earplug with deep insertion into the bony part of the ear canal, and a circumaural earmuff. There was good resemblance between model predictions and ear-canal sound pressure measurements. It was also found that all occlusion positions, even deep ear-canal occlusion, produced noticeable occlusion effects. With the bone-conduction transducer at the forehead, the perceived occlusion effect was close to that obtained from ear-canal sound pressure data in the 0.3 to 2 kHz frequency range; when the stimulation was at the mastoid the difference between the perceived and measured ear-canal sound pressure occlusion effect was around 10 dB at frequencies below 1 kHz. Further, the occlusion effect was obtained in two clinical settings: with supra-aural earphones (TDH39), and insert earphones (CIR22). Although both transducers produced occlusion effects, insert earphones produced a greater effect than surpaaural earphones at the low frequencies.
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| 24. |
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| 25. |
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| 26. |
- Stenfelt, Stefan
(författare)
-
Bilateral fitting of BAHAs and BAHA (R) fitted in unilateral deaf persons: Acoustical aspects
- 2005
-
Ingår i: International Journal of Audiology. - : Informa Healthcare. - 1499-2027 .- 1708-8186. ; 44:3, s. 178-189
-
Tidskriftsartikel (refereegranskat)abstract
- The benefit of a bone-anchored hearing aid (BAHA) to a patient fitted bilaterally; and the benefit of a BAHA(andREG;) to a unilaterally deaf person was estimated by four acoustical measurements: directional sensitivity of a BAHA(andREG;) placed at the skull, vibration transmission in the skull, gain, and estimated transcranial attenuation of bone conducted sound. Provided a patient has a similar bone conduction hearing ability at both cochlea, it was found that a patient should, theoretically, benefit from bilateral fitting of BAHAs in terms of better hearing thresholds from the front, and better overall hearing ability from the surround. The data indicates further, that bilateral fitting facilitates extraction of interaural cues, which should lead to greater ability to determine the direction of a sound source, as well as better hearing in noise. However, due to the cross-hearing of bone conducted sound, the binaural processing for the patient fitted bilaterally with BAHAs is less than for normal binaural air conduction hearing. Finally, the data showed that the benefit of fitting a BAHA(andREG;) in a unilaterally deaf person, depends on that persons transcranial attenuation.
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| 27. |
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| 28. |
- Stenfelt, Stefan, et al.
(författare)
-
Bone-conducted sound: Physiological and clinical aspects
- 2005
-
Ingår i: Otology and Neurotology. - : Lippincott Williams and Wilkins. - 1531-7129 .- 1537-4505. ; 26:6, s. 1245-1261
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Forskningsöversikt (refereegranskat)abstract
- Objective: The fact that vibration of the skull causes a hearing sensation has been known since the 19th century. This mode of hearing was termed hearing by bone conduction. Although there has been more than a century of research on hearing by bone conduction, its physiology is not completely understood. Lately, new insights into the physiology of hearing by bone conduction have been reported. Knowledge of the physiology, clinical aspects, and limitations of bone conduction sound is important for clinicians dealing with hearing loss and is the purpose of this review. Data Sources: The data were compiled from the published literature in the areas of clinical bone conduction hearing, bone conduction hearing aids, basic research on bone conduction physiology, and recent research on bone conduction hearing from our laboratory. Conclusion: Five factors contributing to bone conduction hearing have been identified: 1) sound radiated into the external ear canal, 2) middle ear ossicle inertia, 3) inertia of the cochlear fluids, 4) compression of the cochlear walls, and 5) pressure transmission from the cerebrospinal fluid. Of these five, inertia of the cochlear fluid seems most important. E-one conduction sound is believed to reflect the true cochlear function; however, certain conditions such as middle ear diseases can affect bone conduction sensitivity, but less than for air conduction. The bone conduction route can also be used for hearing aids; since the bone conduction route is less efficient than the air conduction route, bone conduction hearing aids are primarily used for hearing losses where, air conduction hearing aids are contraindicated.
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| 29. |
- Stenfelt, Stefan
(författare)
-
Bone conduction mechanisms and applications
- 2007
-
Ingår i: 32<sup>ND</sup> Annual National Hearing Conservation Conference – A Passion to Preserve, Savannah, Georgia.
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Konferensbidrag (refereegranskat)
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| 30. |
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| 31. |
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| 32. |
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| 33. |
- Stenfelt, Stefan
(författare)
-
Hörselscreening bland äldre
- 2009
-
Ingår i: Ålder och Hörsel – Audiologisk Dag, Linköping.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 34. |
- Stenfelt, Stefan
(författare)
-
Hörseltekniken – så ser den ut om 20 år
- 2009
-
Ingår i: Audio-Nytt. - Upplands Väsby : Hörsam. - 0347-6308. ; 36:1, s. 16-19
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 35. |
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| 36. |
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| 37. |
- Stenfelt, Stefan, 1969-
(författare)
-
Middle ear ossicles motion at hearing thresholds with air conduction and bone conduction stimulation
- 2006
-
Ingår i: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 119:5, s. 2848-2858
-
Tidskriftsartikel (refereegranskat)abstract
- 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. © 2006 Acoustical Society of America.
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| 38. |
- Stenfelt, Stefan
(författare)
-
Overview and recent advances in bone conduction physiology
- 2007
-
Ingår i: Middle Ear Mechanics in Research and Otology: Proceedings of the 4<sup>th</sup> International Symposium. - Singapore : World Scientific Publishing Co.. - 9789812707376 ; , s. 1-9
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- In the summer of 2006, the 5th International Symposium on Middle Ear Mechanics in Research and Otology was held at the University of Zurich, Switzerland. More than 250 participants from 33 countries in all five continents came together to present their most current research results, exchange their knowledge in practical applications, to discuss open questions and discover new unsolved problems. This book includes representative, peer-reviewed articles of the lectures and papers presented during the symposium, and thereby gives an overview of the ongoing research and current knowledge in the function and mechanics of the normal, diseased and reconstructed middle ear. It covers basic research, engineering and clinical aspects of evaluation, diagnosis and surgery of the middle ear as well as implantable hearing devices in a very broad and interdisciplinary way. Following the tradition of the organizers of the previous conferences to collect the contributions of the symposium, this volume further initialized and promotes many fruitful discussions on middle ear mechanics with different points of view.
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| 39. |
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| 40. |
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| 41. |
- Stenfelt, Stefan
(författare)
-
Physiology of Bone Conduction III
- 2007
-
Ingår i: 1<sup>st</sup> International Symposium – Bone Conduction Hearing and Osseointegration, Halifax, Canada.
-
Konferensbidrag (refereegranskat)
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| 42. |
- Stenfelt, Stefan
(författare)
-
Recent advances on direct bone conduction
- 2009
-
Ingår i: 2<sup>nd</sup> Int Symposium on Bone Conduction Hearing – Craniofacial Osseointegration, Göteborg, Sweden.
-
Konferensbidrag (refereegranskat)
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| 43. |
- Stenfelt, Stefan
(författare)
-
Screening strategies
- 2009
-
Ingår i: Deutsches Ärzteforum 2009, Berlin, Germany.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 44. |
- Stenfelt, Stefan, 1969-
(författare)
-
Simultaneous cancellation of air and bone conduction tones at two frequencies : Extension of the famous experiment by von Békésy
- 2007
-
Ingår i: Hearing Research. - : Elsevier BV. - 0378-5955 .- 1878-5891. ; 225:1-2, s. 105-116
-
Tidskriftsartikel (refereegranskat)abstract
- Cancellation experiments between air conduction (AC) and bone conduction (BC) tones were conducted at two frequencies (0.7 and 1.1 kHz) and three levels (40, 50, and 60 dB HL) in three subjects. The tests were divided into three categories: (1) single tone cancellation, (2) simultaneous cancellation of two tones, and (3) cancellation of one tone while a disturbing tone was present. In total, each subject performed twelve cancellation tasks. The hypothesis is that the AC and BC sound transmission behaves as linear systems and they both excite the basilar membrane in the cochlea similarly. The cancellation results are presented as the deviations from this hypothesis, except for a few larger deviations, the intrasubject deviations were generally less than 0.5 dB and 5°. The results from all three test categories indicate that the hypothesis of linear transmission systems and similarity of cochlear stimulation by AC and BC holds. However, due to the subjects' limited ability to conduct optimal cancellation and to imperfect methodology and equipment, the small deviations from perfectly linear cancellation that were observed do neither conclusively prove nor refute the possibility of small differences in the cochlear processing of AC and BC sound. Nonetheless, it is clear that if such differences in the processing of the two stimuli exist, they are small in magnitude. © 2006 Elsevier B.V. All rights reserved.
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| 45. |
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| 46. |
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| 47. |
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| 48. |
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| 49. |
- Stenfelt, Stefan, et al.
(författare)
-
The Signal-Cognition interface : interactions between degraded auditory signals and cognitive processes.
- 2009
-
Ingår i: Scandinavian journal of psychology. - : Wiley. - 1467-9450 .- 0036-5564. ; 50:5, s. 385-393
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Tidskriftsartikel (refereegranskat)abstract
- A hearing loss leads to problems with speech perception; this is exacerbated when competing noise is present. The speech signal is recognized by the cognitive system of the listener; noise and distortion tax the cognitive system when interpreting it. The auditory system must interact with the cognitive system for optimal signal decoding. This article discusses this interaction between the signal and cognitive system based on two models: an auditory model describing signal transmission and degeneration due to a hearing loss and a cognitive model for Ease of Language Understanding. The signal distortion depends on the specifics of the hearing impairment and thus differently distorted signals can affect the cognitive system in different ways. Consequently, the severity of a hearing loss may not only depend on the lesion itself but also on the cognitive recourses required to interpret the signal.
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| 50. |
- Stenfelt, Stefan, 1969-
(författare)
-
Towards understanding the specifics of cochlear hearing loss : a modelling approach
- 2008
-
Ingår i: International Journal of Audiology. - : Informa UK Limited. - 1499-2027 .- 1708-8186. ; 47:suppl 2, s. 10-15
-
Tidskriftsartikel (refereegranskat)abstract
- It is well known that two patients suffering from a sensorineural hearing loss with similar audiograms can benefit significantly differently from amplified hearing even if the same settings of the hearing aids are used. The origin of this problem is complex but one part can be caused by the diagnosis itself; all inner-ear hearing losses are assumed similar. Such hypothesis is a simplification that probably leads to suboptimal hearing-aid fitting. For a better understanding of the signal degeneration caused by a cochlear lesion a model layout of the signal transmission in the peripheral hearing organ is presented. This model differentiates between processes in the inner ear caused by the outer hair cells, the inner hair cells, and the endocochlear potential driving the system. The model is intended to predict alteration of the signal caused by different types of cochlear lesions. Ultimately, the model may lead to improved hearing aids and fittings.
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