| 1. |
|
|
| 2. |
- Eeg-Olofsson, Måns, 1967, et al.
(author)
-
Transmission of bone-conducted sound in the human skull measured by cochlear vibrations.
- 2008
-
In: International journal of audiology. - : Informa UK Limited. - 1708-8186 .- 1499-2027. ; 47:12, s. 761-9
-
Journal article (peer-reviewed)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.
|
|
| 3. |
- Granström, Gösta, 1950, et al.
(author)
-
Sleeping implant in the temporal bone: report of a case with 20-year follow-up.
- 2012
-
In: Clinical implant dentistry and related research. - : Wiley. - 1708-8208 .- 1523-0899. ; 14:2, s. 236-40
-
Journal article (peer-reviewed)abstract
- Background: There is limited knowledge of the long-term fate of “sleeping” or nonloaded implants in the temporal bone. Purpose: This article describes the fate of a fixture installed in the temporal bone that remained unloaded for 20 years. Patient and Methods: A 25-year-old male with hemifacial microsomia had three osseointegrated implants installed for an auricular episthesis and bone-anchored hearing aid (BAHA) in the left temporal bone in 1988. Two of the implants for the ear episthesis were activated the same year, but the fixture for the hearing aid was not uncovered until 2008. When the patient experienced hearing problems at his office, he wanted to reactivate the sleeping implant. An audiogram showed a maximum conductive hearing loss with good preserved cochlear function. Before reactivation, an Accuitomo three-dimensional, cone beam computed tomography was performed. Resonance frequency analysis (RFA) using the Ostell technique was done when the implant was uncovered. Results: Preoperative x-ray investigation showed the sleeping implant to be well integrated in the temporal bone, covered with 1 mm bone, and with no signs of resorption. Geometric measurements correlating to the two loaded implants showed the sleeping implant to be positioned too close to these to be able to anchor a BAHA without interference with the episthesis. Surgical exploration was done to analyze the implant. The clinical status correlated well to that diagnosed from the x-ray investigation. RFA revealed the implant to be well integrated. A new fixture and abutment for BAHA was installed in the temporal line and activated 2 months after surgery. The patient is today supplied with a BAHA. Conclusion: It seems possible to use sleeping implants in the temporal bone even 20 years after installation.
|
|
| 4. |
- Heo, S J, et al.
(author)
-
Stability measurements of craniofacial implants by means of resonance frequency analysis. A clinical pilot study.
- 1998
-
In: The Journal of laryngology and otology. - : Cambridge University Press (CUP). - 0022-2151 .- 1748-5460. ; 112:6, s. 537-42
-
Journal article (peer-reviewed)abstract
- Nineteen patients previously treated with 52 implants for anchorage of craniofacial prostheses were subjected to implant stability measurements by means of resonance frequency analysis (RFA), six months to 15 years after implant placement. The resonance frequency (RF) of a transducer attached to the implant abutment was measured by using a frequency response analyser, a personal computer (PC) and dedicated software. Statistically significant higher RF values were seen for implants in the temporal bone as compared to implants in the nose and periorbital regions. There was a positive correlation with time since implant placement for the period from six months up to seven years. It was concluded that the preliminary results suggest that implant stability increases with time and that implants in temporal bone are more stable than implants in the bone in the nose and periorbital regions, probably reflecting differences in bone density.
|
|
| 5. |
- Håkansson, Bo, 1953, et al.
(author)
-
The mechanical impedance of the human skull via direct bone conduction implants
- 2020
-
In: Medical Devices: Evidence and Research. - 1179-1470. ; 13, s. 293-313
-
Journal article (peer-reviewed)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.
|
|
| 6. |
- Larsson, Anna, 1973, et al.
(author)
-
Implant Losses for the Bone-Anchored Hearing Devices Are More Frequent in Some Patients.
- 2015
-
In: Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. - 1537-4505. ; 36:2, s. 336-340
-
Journal article (peer-reviewed)abstract
- Our knowledge of implant losses for bone-anchored hearing devices (BAHD) is still limited. This study examined the long-term survival rate, the reasons for implant loss, and the need for implant replacement in a large cohort with a long follow-up.
|
|
| 7. |
|
|
| 8. |
- Mudry, Albert, et al.
(author)
-
Historical background of bone conduction hearing devices and bone conduction hearing aids.
- 2011
-
In: Advances in oto-rhino-laryngology. - : S. Karger AG. - 0065-3071. ; 71, s. 1-9
-
Journal article (peer-reviewed)abstract
- During the last 20 years, bone-anchored hearing aids (Baha(®)) became a familiar solution in the treatment of some types of hearing loss. The aim of this chapter is to present the different historical steps which have permitted the production of this new bone conduction hearing device. The recognition of bone conduction hearing is old and was known at least in Antiquity. During the Renaissance, Girolamo Cardano demonstrated a method by which sound may be transmitted to the ear by means of a rod or the shaft of a spear held between one's teeth: this was the beginning of teeth stimulators to improve hearing, firstly in connection with a musical instrument and then, in the second part of the 19th century, with the speaker. The development of the carbon microphone at the beginning of the 20th century allowed the construction of the bone conduction vibrator placed on the mastoid area, notably supported by eyeglasses since the 1950s. Confronted by various problems, and notably the loss of part of sound in the soft tissue of the external mastoid, the idea to implant the vibrator into the mastoid bone was developed in Göteborg, and the first Baha was implanted in 1977 by Anders Tjellström. From that date, various improvements allowed the development of the actual Baha. These different steps are presented in this study, supported by original documentation.
|
|
| 9. |
- Priwin, Claudia, 1971, et al.
(author)
-
Bilateral bone-anchored hearing aids (BAHAs): an audiometric evaluation
- 2004
-
In: Laryngoscope. - : Laryngoscope. - 0023-852X .- 1531-4995. ; 114:1, s. 77-84
-
Journal article (peer-reviewed)abstract
- OBJECTIVES: Since the technique to implant bone-anchored hearing aids (BAHAs) with the use of osseointegrated implants was developed in 1977, more than 15,000 patients have been fitted with BAHAs worldwide. Although the majority have bilateral hearing loss, they are primarily fitted unilaterally. The main objective of this study was to reveal benefits and drawbacks of bilateral fitting of BAHAs in patients with symmetric or slight asymmetric bone-conduction thresholds. The possible effects were divided into three categories: hearing thresholds, directional hearing, and binaural hearing. STUDY DESIGN: Prospective study of 12 patients with bilateral BAHAs. METHODS: Baseline audiometry, directional hearing, speech reception thresholds in quiet and in noise, and binaural masking level difference were tested when BAHAs were fitted unilaterally and bilaterally. RESULTS: Eleven of the 12 patients used bilateral BAHAs on a daily basis. Tests performed in the study show a significant improvement in sound localization with bilateral BAHAs; the results with unilateral fitting were close to the chance level. Furthermore, with bilateral application, the improvement of the speech reception threshold in quiet was 5.4 dB. An improvement with bilateral fitting was also found for speech reception in noise. CONCLUSIONS: Overall, the results with bilateral fitted BAHAs were better than with unilaterally fitted BAHA; the benefit is not only caused simply by bilateral stimulation but also, to some extent, by binaural hearing. Bilateral BAHAs should be considered for patients with bilateral hearing loss otherwise suitable for BAHAs.
|
|
| 10. |
|
|
