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| 2. |
- Taghavi, Hamidreza, 1981, et al.
(författare)
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Technical design of a new bone conduction implant (BCI) system
- 2015
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Ingår i: International Journal of Audiology. - : Informa UK Limited. - 1499-2027 .- 1708-8186. ; 54:10, s. 736-744
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The objective of this study is to describe the technical design and verify the technical performance of a new bone conduction implant (BCI) system. Design: The BCI consists of an external audio processor and an implanted unit called the bridging bone conductor. These two units use an inductive link to communicate with each other through the intact skin in order to drive an implanted transducer. Study sample: In this study, the design of the full BCI system has been described and verified on a skull simulator and on real patients. Results: It was found that the maximum output force (peak 107 dB re 1 N) of the BCI is robust for skin thickness range of 2-8 mm and that the total harmonic distortion is below 8% in the speech frequency range for 70 dB input sound pressure level. The current consumption is 7.5 mA, which corresponds to 5-7 days use with a single battery. Conclusions: This study shows that the BCI is a robust design that gives a sufficiently high output and an excellent sound quality for the hearing rehabilitation of indicated patients.
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| 3. |
- 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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| 6. |
- Håkansson, Bo, et al.
(författare)
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Linearity of sound transmission through the human skull in vivo
- 1996
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Ingår i: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 99:4, s. 2239-2243
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Tidskriftsartikel (refereegranskat)abstract
- The linearity of sound propagation through the human skull was investigated. One male subject, equipped with bilateral skin-penetrating titanium fixtures for attachment of bone-anchored hearing aids, was studied thoroughly. Three different methods were used: comparison of the frequency response functions estimated at different signal levels (using stepped sine as well as random noise), comparison of the coherence function at different signal levels (using random noise), and the Hilbert transform of the estimated frequency response function. Frequencies from 0.1 to 10 kHz and signal levels up to 77 dB HL at discrete frequencies were used. No indication of any significant nonlinear behavior was found with the three methods used.
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| 7. |
- Håkansson, Bo, et al.
(författare)
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Resonance frequencies of the human skull in vivo
- 1994
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Ingår i: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 95:3, s. 1474-1481
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Tidskriftsartikel (refereegranskat)abstract
- Patients with skin penetrating titanium implants in the temporal bone, for attachment of bone-anchored hearing aids, have made it possible to investigate the free-damped natural frequencies (resonance frequencies) of the human skull in vivo. The resonance frequencies of the skull of six subjects were investigated. Teh resonance frequencies were extracted from two frequency response functions (acceleration/force) measured on each subject: One point measurement where the force and acceleration were both measured at the same point, and one transcranial measurement where the acceleration was measured contralaterally. Between 14 and 19 resonance frequencies were identified for each subject in the frequency range 500 Hz to 7.5 kHz. The two lowest resonance frequencies were found to be on the average 972 (range 828-1164) and 1230 (range 981-1417) Hz. The relative damping coefficients of all resonances were found to be between 2.6 and 8.9%. Due to the relatively high damping coefficients, it is assumed that the resonance frequencies do not significantly affect bone conducted sound. In the transcranial measurements, however, a few large antiresonances were found which may affect bone-conducted sound. Intersubject variations were large, probably due to individual variations in skull geometry and in mechanical parameters. The results were shown to be consistent with previous results obtained on dry skulls. No obvious correlation between lowest resonance frequency and skull size was found.
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| 8. |
- Håkansson, Bo
(författare)
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Vardagens kyrka: Gustaf Wingrens kyrkosyn och folkkyrkans framtid. Summary: A Church for Every Day: The Ecclesiology of Gustaf Wingren and the Future of the National Church (the "Folk Church")
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis explores the ecclesiology of the Swedish theologian Gustaf Wingren and discusses the future of the "folk church". Three questions What, Who and Where is the Church? sustain the structure of this investigation. Wingren reflected on issues related to the openness and the identity of the church. His main concern was the interpretation the gospel as the liberating message to the guilt-ridden. For Wingren, the church is neither an institution, nor a communion of true believers. The gospel and the sacraments constitute the church. Wingren stressed the role of Christ's human nature. His main concern was to construct an ecclesiology appropriate to everyday life. Wingren asserts that the church must never be allowed to regard itself as a distinct community because the doctrine of creation recognises the presence of God everywhere and the gospel has a universal scope. There has been a broad agreement throughout the Church of Sweden that the church, even after disestablishment, ought to continue as a "folk church", but Swedish ecclesiology has also offered criticism of the "folk church" idea. The alternative advocated instead is the "communion-orientated" model. Recent criticism has found support in the trinitarian ecclesiology of communion. Developing models for the proper exercise of the priesthood of all believers, and for discovering ways to proclaim the gospel to everyone rather than forming tightly knit communities seem to be the most urgent task for an ecclesiology, based on the idea of the "folk church". Wingrens occupation with the Lutheran doctrine of vocation made it possible for him to concentrate on everyday life and to use the pattern of baptism to interpret the daily work. He applies the notion of justification by faith alone as a measuring rod for modern society. This enables him to offer a critical view of while avoiding the trap of moralism. A "folk church" can be regarded as nothing but the one, holy, catholic and apostolic church. Apart from in its social structure, the "folk church" does not differ in essence from other manifestations of the church. Provided the emphasis is not exclusively laid on the faith of its members, it would seem that there is some possibility for the "folk church" to survive. The church as an institution supporting its members may have a mission in the 21st century.
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| 9. |
- Håkansson, Bo, 1953, et al.
(författare)
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A novel bone conduction implant (BCI): engineering aspects and pre-clinical studies.
- 2010
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Ingår i: International journal of audiology. - : Informa UK Limited. - 1499-2027 .- 1708-8186. ; 49:3, s. 203-15
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Tidskriftsartikel (refereegranskat)abstract
- Percutaneous bone anchored hearing aids (BAHA) are today an important rehabilitation alternative for patients suffering from conductive or mixed hearing loss. Despite their success they are associated with drawbacks such as skin infections, accidental or spontaneous loss of the bone implant, and patient refusal for treatment due to stigma. A novel bone conduction implant (BCI) system has been proposed as an alternative to the BAHA system because it leaves the skin intact. Such a BCI system has now been developed and the encapsulated transducer uses a non-screw attachment to a hollow recess of the lateral portion of the temporal bone. The aim of this study is to describe the basic engineering principals and some preclinical results obtained with the new BCI system. Laser Doppler vibrometer measurements on three cadaver heads show that the new BCI system produces 0-10 dB higher maximum output acceleration level at the ipsilateral promontory relative to conventional ear-level BAHA at speech frequencies. At the contralateral promontory the maximum output acceleration level was considerably lower for the BCI than for the BAHA.
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| 10. |
- Håkansson, Bo, 1953, et al.
(författare)
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The mechanical impedance of the human skull via direct bone conduction implants
- 2020
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Ingår i: Medical Devices: Evidence and Research. - 1179-1470. ; 13, s. 293-313
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The mechanical skull impedance is used in the design of direct bone drive hearing systems. This impedance is also important for the design of skull simulators used in manufacturing, service, and fitting procedures of such devices. Patients and Methods: The skull impedance was measured in 45 patients (25 female and 20 male) who were using percutaneous bone conduction implants (Ponto system or Baha system). Patients were recruited as a consecutive prospective case series and having an average age of 55.4 years (range 18–80 years). Seven patients were treated in Gothenburg, Sweden, and 38 patients in Edmonton, Canada. An impedance head (B&K 8001), driven by an excitation transducer with emphasized low-frequency response, was used to measure the mechanical point impedance with a swept sine from 100 to 10k Hz. Results and Discussion: The skull impedance was found to have an anti-resonance of approximately 150 Hz, with a median maximum magnitude of 4500 mechanical ohms. Below this anti-resonance, the mechanical impedance was mainly mass-controlled corresponding to an effective skull mass of 2.5 kg at 100 Hz with substantial damping from neck and shoulder. Above the anti-resonance and up to 4 kHz, the impedance was stiffness-controlled, with a total compliance of approximately 450n m/N with a small amount of damping. At frequencies above 4 kHz, the skull impedance becomes gradually mass-controlled originating from the mass of the osseointegrated implant and adjacent bone. No significant differences related to gender or skull abnormalities were seen, just a slight dependence on age and major ear surgeries. The variability of the mechanical impedance among patients was not found to have any clinical importance. Conclusion: The mechanical skull impedance of percutaneous implants was found to confirm previous studies and can be used for optimizing the design and test procedures of direct bone drive hearing implants. © 2020 Håkansson et al.
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