| 1. |
- den Besten, C. A., et al.
(författare)
-
Stability, Survival, and Tolerability of an Auditory Osseointegrated Implant for Bone Conduction Hearing: Long-Term Follow-Up of a Randomized Controlled Trial
- 2016
-
Ingår i: Otology & Neurotology. - : Ovid Technologies (Wolters Kluwer Health). - 1531-7129. ; 37:8, s. 1077-1083
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: To compare implant stability, survival, and soft tissue reactions for a novel (test) and previous generation (control) percutaneous auditory osseointegrated implant for bone conduction hearing at long-term follow-up of 5 years. Study Design: Single follow-up visit of a previously completed multicenter, randomized, controlled trial. Patients: Fifty-seven of the 77 participants of a completed randomized controlled trial on a new auditory osseointegrated implant underwent a single follow-up visit 5 years after implantation, which comprised implant stability measurements and collection of Holgers scores. Additionally, implant survival was recorded for all 77 patients from the original trial. Results: The test implant showed significantly higher implant stability quotient (ISQ) values compared with the control implant throughout the 5-year follow-up. Mean area under the curve of ISQ high from baseline to 5 years was 71.6 (standard deviation [SD] +/-2.0) and 66.7 (SD +/-3.4) for the test and control implant, respectively (p < 0.0001). For both implants, the mean ISQ value recorded at 5 years was higher compared with implantation (test group +2.03 [SD +/-2.55, within group p < 0.0001] and control group +2.25 [SD +/-4.95, within group p = 0.12]). No difference was noticed in increase from baseline between groups (p = 0.64). Furthermore, evaluation of soft tissue reactions continued to show superiority of the test implant. At the 5-year follow-up visit, one patient (2.5%) presented with a Holgers grade 2 in the test group, compared with four patients (23.5%) in the control group (p = 0.048); no patient presented with more severe soft tissue reactions. Excluding explantations, the survival rate was 95.8% for the test group and 95.0% for the control group. The corresponding rates including explantations were 93.9 and 90.0%. Conclusion: The test implant showed superiority in terms of higher mean ISQ values and less adverse soft tissue reactions, both at the single 5-year follow-up visit and during the complete follow-up. In addition, both implants showed an equally high implant survival.
|
|
| 2. |
- Eeg-Olofsson, Måns, 1967, et al.
(författare)
-
BCI-bone conduction implant.
- 2013
-
Ingår i: The Fourth International Symposium on Bone Conduction Hearing – Craniofacial Osseointegration. Newcastle, UK.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Eeg-Olofsson, Måns, 1967, et al.
(författare)
-
Evaluation of bone tissue formation in a flat surface attachment of a Bone Conduction Implant - A pilot study in a sheep model
- 2014
-
Ingår i: Audiology & Neurotology Extra. - : S. Karger AG. - 1664-5537. ; 4:3, s. 62-76
-
Tidskriftsartikel (refereegranskat)abstract
- The Bone Conduction Implant (BCI) is a new bone conduction hearing device implanted under intact skin. The transducer has a flat direct contact to the mastoid part of the temporal bone and no screws are used. The sound signal is transmitted from the external audio processor to the implant by means of magnetic induction. In this study, osseointegration of a flat passive BCI transducer dummy in sheep skulls was assessed using quantitative and qualitative histology as well as Cone Beam Computed Tomography (CBCT) and Computed Tomography (CT). The histology results were also related to the mechanical properties of the bone to implant interface. Eight months after the surgical implantation, histology sections of the bone close to the implant showed bone remodelling, compact bone and some degree of osseointegration. The histological findings corresponded well to the mechanical measurements indicating stiffer bone close to the implant, and unaffected skull vibration transmission. Neither CBCT nor CT had enough resolution to visualize the bone to implant interface in detail. In this study, using an animal model, it is shown that a flat implant in contact with bone, can be a feasible method for efficient vibration transmission to the skull bone.
|
|
| 8. |
- Eeg-Olofsson, Måns, 1967, et al.
(författare)
-
Implications for contralateral bone-conducted transmission as measured by cochlear vibrations.
- 2011
-
Ingår i: Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. - : LWW. - 1537-4505 .- 1531-7129. ; 32:2, s. 192-8
-
Tidskriftsartikel (refereegranskat)abstract
- The velocity response at the contralateral cochlea from bone-conducted (BC) stimulation depends on the stimulation position.
|
|
| 9. |
|
|
| 10. |
|
|
| 11. |
|
|
| 12. |
|
|
| 13. |
|
|
| 14. |
- Eeg-Olofsson, Måns, 1967, et al.
(författare)
-
Transmission of bone conducted sound – Correlation between hearing perception and cochlear vibration
- 2013
-
Ingår i: Hearing Research. - : Elsevier. - 0378-5955 .- 1878-5891. ; 306, s. 11-20
-
Tidskriftsartikel (refereegranskat)abstract
- The vibration velocity of the lateral semicircular canal and the cochlear promontory was measured on 16 subjects with a unilateral middle ear common cavity, using a laser Doppler vibrometer, when the stimulation was by bone conduction (BC). Four stimulation positions were used: three ipsilateral positions and one contralateral position. Masked BC pure tone thresholds were measured with the stimulation at the same four positions. Valid vibration data were obtained at frequencies between 0.3 and 5.0 kHz. Large intersubject variation of the results was found with both methods. The difference in cochlear velocity with BC stimulation at the four positions varied as a function of frequency while the tone thresholds showed a tendency of lower thresholds with stimulation at positions close to the cochlea. The correlation between the vibration velocities of the two measuring sites of the otic capsule was high. Also, relative median data showed similar trends for both vibration and threshold measurements. However, due to the high variability for both vibration and perceptual data, low correlation between the two methods was found at the individual level. The results from this study indicated that human hearing perception from BC sound can be estimated from the measure of cochlear vibrations of the otic capsule. It also showed that vibration measurements of the cochlea in cadaver heads are similar to that measured in live humans.
|
|
| 15. |
|
|
| 16. |
- Eeg-Olofsson, Måns, 1967
(författare)
-
Transmission of bone conducted sound in the human skull based on vibration and perceptual measures
- 2012
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- For patients who are rehabilitated with bone conduction (BC) hearing aids, the position on the skull of the hearing aid is critical for the perception of the sound. The aim of this work was to describe the vibration of the cochlea from BC sound stimulation at different positions on the skull. The relevance of the vibration velocity of the cochlea as a perceptual measure was also investigated. In human cadavers vibration stimulation was applied at eight positions on each side of the skull with a frequency range of 0.1-10 kHz. The resulting velocity of the cochlear vibration was measured by a laser Doppler vibrometer from both ipsilateral and contralateral stimulation. A prototype of a novel bone conduction implant (BCI), positioned approximately 5 mm behind the ear canal, was tested with the same methodology. In live human subjects vibration stimulation was applied at four positions on the head. The resulting vibration velocity of the otic capsule was measured with a laser Doppler vibrometer. Bone conducted hearing thresholds in the same subjects were compared to the otic capsule vibration results. With vibration stimulation on the ipsilateral side there was an increased magnitude response of the cochlear vibration with shorter distance between the stimulation position and the cochlea. When the bone conducted stimulation was on the contralateral side the change in magnitude of the cochlear vibration between positions was limited. BC stimulation at a position close to the ipsilateral cochlea increased the response magnitude difference between the cochleae. The results of stimulating with a BCI and a transducer were similar. The influence of the squamosal suture on BC sound transmission was not clear but indications of a small damping effect were found. With simultaneous bilateral stimulation at the low frequencies correlated signals were added constructively or destructively while non-correlated signals gave a 3 dB sound energy increase. Time separation between ipsilateral and contralateral stimulation was found to be largest at positions close to the cochlea. The velocity response at the otic capsule from BC stimulation was similar between human cadavers and live humans. In live humans the correlation between vibration of the otic capsule and hearing perception was low at the individual level, while median data showed similar trends between the two methods. When BC sound stimulation is applied at a smaller distance between the stimulation position and the cochlea, sound transmission improves to the ipsilateral cochlea and is decreased to the contralateral cochlea. Measures of the vibration of the otic capsule from BC sound stimulation as an estimation of BC hearing perception was investigated and the results indicate that the method is valid. A patient with a hearing loss where there is an indication for BC hearing aids can likely benefit from increased ipsilateral stimulation, and also an improved binaural hearing from bilateral stimulation, when the hearing aid is applied close to the cochlea. The BCI is a realistic alternative to other BC hearing aids.
|
|
| 17. |
- Eeg-Olofsson, Måns, 1967, et al.
(författare)
-
Transmission of bone-conducted sound in the human skull measured by cochlear vibrations.
- 2008
-
Ingår i: International journal of audiology. - : Informa UK Limited. - 1708-8186 .- 1499-2027. ; 47:12, s. 761-9
-
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.
|
|
| 18. |
- Eeg-Olofsson, Måns, 1967, et al.
(författare)
-
TTCOV19: timing of tracheotomy in SARS-CoV-2-infected patients: a multicentre, single-blinded, randomized, controlled trial
- 2022
-
Ingår i: Critical Care. - : Springer Science and Business Media LLC. - 1364-8535. ; 26:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Critically ill COVID-19 patients may develop acute respiratory distress syndrome and the need for respiratory support, including mechanical ventilation in the intensive care unit. Previous observational studies have suggested early tracheotomy to be advantageous. The aim of this parallel, multicentre, single-blinded, randomized controlled trial was to evaluate the optimal timing of tracheotomy. Methods: SARS-CoV-2-infected patients within the Region Vastra Gotaland of Sweden who needed intubation and mechanical respiratory support were included and randomly assigned to early tracheotomy (<= 7 days after intubation) or late tracheotomy (>= 10 days after intubation). The primary objective was to compare the total number of mechanical ventilation days between the groups. Results: One hundred fifty patients (mean age 65 years, 79% males) were included. Seventy-two patients were assigned to early tracheotomy, and 78 were assigned to late tracheotomy. One hundred two patients (68%) underwent tracheotomy of whom sixty-one underwent tracheotomy according to the protocol. The overall median number of days in mechanical ventilation was 18 (IQR 9; 28), but no significant difference was found between the two treatment regimens in the intention-to-treat analysis (between-group difference:- 1.5 days (95% CI -5.7 to 2.8); p= 0.5). A significantly reduced number of mechanical ventilation days was found in the early tracheotomy group during the per-protocol analysis (between-group difference: - 8.0 days (95% CI - 13.8 to - 2.27); p= 0.0064). The overall correlation between the timing of tracheotomy and days of mechanical ventilation was significant (Spearman's correlation: 0.39, p < 0.0001). The total death rate during intensive care was 32.7%, but no significant differences were found between the groups regarding survival, complications or adverse events. Conclusions: The potential superiority of early tracheotomy when compared to late tracheotomy in critically ill patients with COVID-19 was not confirmed by the present randomized controlled trial but is a strategy that should be considered in selected cases where the need for MV for more than 14 days cannot be ruled out.
|
|
| 19. |
|
|
| 20. |
- Fredén Jansson, Karl-Johan, 1988, et al.
(författare)
-
Magnetic resonance imaging investigation of the bone conduction implant - a pilot study at 1.5 Tesla.
- 2015
-
Ingår i: Medical devices (Auckland, N.Z.). - 1179-1470. ; 8, s. 413-23
-
Tidskriftsartikel (refereegranskat)abstract
- The objective of this pilot study was to investigate if an active bone conduction implant (BCI) used in an ongoing clinical study withstands magnetic resonance imaging (MRI) of 1.5 Tesla. In particular, the MRI effects on maximum power output (MPO), total harmonic distortion (THD), and demagnetization were investigated. Implant activation and image artifacts were also evaluated.
|
|
| 21. |
- Fredén Jansson, Karl-Johan, 1988, et al.
(författare)
-
MRI Induced Torque and Demagnetization in Retention Magnets for a Bone Conduction Implant
- 2014
-
Ingår i: IEEE Transactions on Biomedical Engineering. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9294 .- 1558-2531. ; 61:6, s. 1887-1893
-
Tidskriftsartikel (refereegranskat)abstract
- Performing magnetic resonance imaging (MRI) examinations in patients who use implantable medical devices involve safety risks both for the patient and the implant. Hearing implants often use two permanent magnets, one implanted and one external, for the retention of the external transmitter coil to the implanted receiver coil to achieve an optimal signal transmission. The implanted magnet is subjected to both demagnetization and torque, magnetically induced by the MRI scanner. In this paper, demagnetization and a comparison between measured and simulated induced torque is studied for the retention magnet used in a bone conduction implant (BCI) system. The torque was measured and simulated in a uniform static magnetic field of 1.5 T. The magnetic field was generated by a dipole electromagnet and permanent magnets with two different types of coercive fields were tested. Demagnetization and maximum torque for the high coercive field magnets was 7.7% +/- 2.5% and 0.20 +/- 0.01 Nm, respectively and 71.4% +/- 19.1% and 0.18 +/- 0.01 Nm for the low coercive field magnets, respectively. The simulated maximum torque was 0.34 Nm, deviating from the measured torque in terms of amplitude, mainly related to an insufficient magnet model. The BCI implant with high coercive field magnets is believed to be magnetic resonance (MR) conditional up to 1.5 T if a compression band is used around the skull to fix the implant. This is not approved and requires further investigations, and if removal of the implant is needed, the surgical operation is expected to be simple.
|
|
| 22. |
- Fredén Jansson, Karl-Johan, 1988, et al.
(författare)
-
Robustness and lifetime of the bone conduction implant - a pilot study
- 2019
-
Ingår i: Medical Devices: Evidence and Research. - 1179-1470. ; 12, s. 89-100
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: The objective of this study was to develop methods for evaluating the mechanical robustness and estimating the lifetime of the novel bone conduction implant (BCI) that is used in a clinical study. The methods are intended to be applicable to any similar device. Materials and methods: The robustness was evaluated using tests originally developed for cochlear implants comprising a random vibration test, a shock test, a pendulum test, and an impact test. Furthermore, magnetically induced torque and demagnetization during magnetic resonance imaging at 1.5 T were investigated using a dipole electromagnet. To estimate the lifetime of the implant, a long-term age-accelerated test was performed. Results: Out of all the tests, the pendulum and the impact tests had the largest effect on the electro-acoustic performance of the BCI implant, even if the change in performance was within acceptable limits (< 20%). In comparison with baseline data, the lower and higher resonance peaks shifted down in frequency by 13% and 18%, respectively, and with a loss in magnitude of 1.1 and 2.0 dB, respectively, in these tests. Conclusion: A complete series of tests were developed, and the BCI passed all the tests; its lifetime was estimated to be at least 26 years for patients who are using the implant for 12 hours on a daily basis.
|
|
| 23. |
- Hakansson, B., et al.
(författare)
-
VEMP using a new low-frequency bone conduction transducer
- 2018
-
Ingår i: Medical Devices-Evidence and Research. - : Informa UK Limited. - 1179-1470. ; 11, s. 301-312
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: A new prototype bone conduction (BC) transducer B250, with an emphasized low-frequency response, is evaluated in vestibular evoked myogenic potential (VEMP) investigations. The aim was to compare cervical (cVEMP) and ocular (oVEMP) responses using tone bursts at 250 and 500 Hz with BC stimulation using the B250 and the conventional B81 transducer and by using air conduction (AC) stimulation. Methods: Three normal subjects were investigated in a pilot study. BC stimulation was applied to the mastoids in cVEMP, and both mastoid and forehead in oVEMP investigations. Results: BC stimulation was found to reach VEMP thresholds at considerably lower hearing levels than in AC stimulation (30-40 dB lower oVEMP threshold at 250 Hz). Three or more cVEMP and oVEMP responses at consecutive 5 dB increasing mastoid stimulation levels were only obtained in all subjects using the B250 transducer at 250 Hz. Similar BC thresholds were obtained for both ipsilateral and contralateral mastoid stimulation. Forehead stimulation, if needed, may require a more powerful vibration output. Conclusion: Viable VEMP responses can be obtained at a considerably lower hearing level with BC stimulation than by AC stimulation. The cVEMP and oVEMP responses were similar when measured on one side and with the B250 attached to both ipsilateral and contralateral mastoids.
|
|
| 24. |
- Håkansson, Bo, et al.
(författare)
-
A novel bone conduction implant (BCI)
- 2009
-
Ingår i: 2<sup>nd</sup> Int Symposium on Bone Conduction Hearing – Craniofacial Osseointegration, Göteborg, Sweden.
-
Konferensbidrag (refereegranskat)
|
|
| 25. |
- Håkansson, Bo, 1953, et al.
(författare)
-
A novel bone conduction implant (BCI): engineering aspects and pre-clinical studies.
- 2010
-
Ingår i: International journal of audiology. - : Informa UK Limited. - 1499-2027 .- 1708-8186. ; 49:3, s. 203-15
-
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.
|
|
| 26. |
|
|
| 27. |
- Håkansson, Bo, 1953, et al.
(författare)
-
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
-
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.
|
|
| 28. |
- Håkansson, Bo, 1953, et al.
(författare)
-
The bone conduction implant - a review and 1-year follow-up
- 2019
-
Ingår i: International Journal of Audiology. - : Informa UK Limited. - 1499-2027 .- 1708-8186. ; 58:12, s. 945-955
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: The objective of this study is to evaluate its safety and effectiveness of the bone conduction implant (BCI) having an implanted transducer and to review similar bone conduction devices. Design: This is a consecutive prospective case series study where the patients were evaluated after 1, 3, 6 and 12 months. Outcome measures were focussed on intraoperative and postoperative safety, the effectiveness of the device in terms of audiological performance and patient's experience. Study sample: Sixteen patients with average age of 40.2 (range 18-74) years have been included. Thirteen patients were operated in Gothenburg and three in Stockholm. Results: It was found that the procedure for installing the BCI is safe and the transmission condition was stable over the follow-up time. No serious adverse events or severe adverse device effects occurred. The hearing sensitivity, speech in noise and the self-assessment as compared with the unaided condition improved significantly with the BCI. These patients also performed similar or better than with a conventional bone conduction reference device on a softband. Conclusions: In summary, it was found that the BCI can provide a safe and effective hearing rehabilitation alternative for patients with mild-to-moderate conductive or mixed hearing impairments.
|
|
| 29. |
- Jansson, K. J. F., et al.
(författare)
-
Bone Conduction Stimulated VEMP Using the B250 Transducer
- 2021
-
Ingår i: Medical Devices-Evidence and Research. - 1179-1470. ; 14, s. 225-237
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Bone conduction (BC) stimulation is rarely used for clinical testing of vestibular evoked myogenic potentials (VEMPs) due to the limitations of conventional stimulation alternatives. The aim of this study is to compare VEMP using the new B250 transducer with the Minishaker and air conduction (AC) stimulation. Methods: Thirty normal subjects between 20 and 37 years old and equal gender distribution were recruited, 15 for ocular VEMP and 15 for cervical VEMP. Four stimulation conditions were compared: B250 on the mastoid (FM); Minishaker and B250 on the forehead (FZ); and AC stimulation using an insert earphone. Results: It was found that B250 at FM required a statistically significant lower hearing level than with AC stimulation, in average 41 dB and 35 dB lower for ocular VEMP and cervical VEMP, respectively, but gave longer n10 (1.1 ms) and n23 (1.6 ms). No statistical difference was found between B250 at FM and Minishaker at FZ. Conclusion: VEMP stimulated with B250 at FM gave similar response as the Minishaker at FZ and for a much lower hearing level than AC stimulation using insert earphones.
|
|
| 30. |
- Johansson, Martin L, et al.
(författare)
-
Long-term osseointegration of laser-ablated hearing implants in sheep cranial bone
- 2022
-
Ingår i: Frontiers in Surgery. - : Frontiers Media SA. - 2296-875X. ; 9
-
Tidskriftsartikel (refereegranskat)abstract
- Osseointegration, the ability for an implant to be anchored in bone tissue with direct bone-implant contact and allowing for continuous adaptive remodelling, is clinically used in different reconstructive fields, such as dentistry, orthopedics and otology. The latter uses a bone conducting sound processor connected to a skin-penetrating abutment that is mounted on a titanium implant placed in the temporal bone, thereby acting as a path for transmission of the vibrations generated by the sound processor. The success of the treatment relies on bone healing and osseointegration, which could be improved by surface modifications. The aim of this study was to evaluate the long-term osseointegration in a sheep skull model and compare a laser-ablated implant surface with a machined implant. Commercially available 4mm titanium implants, either with a machined (Wide Ponto) or a laser-ablated surface (Ponto BHX, Oticon Medical, Sweden), were used in the current study. The surfaces were evaluated by scanning electron microscopy. The implantation was performed with a full soft tissue flap and the osteotomy was prepared using the MIPS drill kit (Oticon Medical, Sweden) prior to installation of the implants in the frontal bone of eight female sheep. After five months, biopsies including the implant and surrounding bone tissue obtained, processed and analysed using histology, histomorphometry, scanning electron microscopy and Raman spectroscopy. The animals healed well, without signs of adverse events. Histomorphometry showed a large amount of bone tissue around both implant types, with 75% of the threaded area occupied by bone for both implant types. A large amount of bone-implant contact was observed for both implant types, with 67%–71% of the surface covered by bone. Both implant types were surrounded by mature remodelled lamellar bone with high mineral content, corroborating the histological observations. The current results show that the laser-ablated surface induces healing similar to the well-known clinically used machined surface in ovine cranial bone. In conclusion, the present long-term experimental results indicate that a laser-ablated implant performs equally well as a clinically used implant with a machined surface. This, together with previously reported, improved early biomechanical anchorage, suggests future, safe and efficient clinical potential.
|
|
| 31. |
- Pauli, Nina, et al.
(författare)
-
Tracheotomy in COVID-19 patients: A retrospective study on complications and timing
- 2021
-
Ingår i: Laryngoscope Investigative Otolaryngology. - : Wiley. - 2378-8038. ; 6:3, s. 446-452
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives The aim of this study was to analyze the timing of tracheotomy and the duration of mechanical ventilation and stay in the intensive care unit (ICU) in patients with COVID‐19 infection. Furthermore, we aimed to investigate tracheotomy complications and mortality. Methods Consecutive patients with COVID‐19 infection admitted to the Department of Infectious Diseases in Gothenburg, Sweden were identified. Medical records were retrieved and retrospectively assessed. Results One hundred eighty‐eight patients with COVID‐19 infection requiring hospital care were identified. Of these, 116 patients were critically ill and intubated, and 55 patients underwent tracheotomy. The mean time from endotracheal intubation to tracheotomy was 12days (range 5‐28days). There was a correlation between the timing of tracheotomy and the duration of mechanical ventilation, where a shorter time between intubation and tracheotomy was correlated with a shorter duration of mechanical ventilation (r .58, P<.001), and a correlation was identified between the timing of tracheotomy and the duration of ICU stay (r .52, P<.001). Perioperative hypoxemia was registered in 9% of tracheotomies performed, whereas postoperative bleeding was observed in 27% of cases, the majority of which were minor. Conclusions This retrospective cohort study indicates that early tracheotomy is related to a reduced need for mechanical ventilation and a shorter duration of stay in the ICU in severe cases of COVID‐19 disease. Complications during and after tracheotomy in this specific cohort included risk perioperative hypoxia and postoperative bleeding. Prospective randomized controlled trials would be of value to confirm these findings.
|
|
| 32. |
- Persson, Ann-Charlotte, 1970, et al.
(författare)
-
A novel method for objective in-situ measurement of audibility in bone conduction hearing devices - a pilot study using a skin drive BCD
- 2023
-
Ingår i: International Journal of Audiology. - : Informa UK Limited. - 1499-2027 .- 1708-8186. ; 62:4, s. 357-361
-
Tidskriftsartikel (refereegranskat)abstract
- Objective Objective measurement of audibility (verification) using bone conduction devices (BCDs) has long remained an elusive problem for BCDs. For air conduction hearing aids there are well-defined and often used objective methods, and the aim of this study is to develop an objective method for BCDs. Design In a novel setup for audibility measurements of bone-anchored hearing aid (BAHA) attached via a soft band, we used a skin microphone (SM) on the forehead measuring in-situ sound field thresholds, maximum power output (MPO) and international speech test signal (ISTS) responses. Study sample Five normal-hearing persons. Result Using the electrical output of SM it was possible to objectively measure the audibility of a skin drive BCD, presented as an eSPL-o-gram showing thresholds, MPO and ISTS response. Normalised eSPL-o-gram was verified against corresponding FL-o-grams (corresponding force levels from skull simulator and artificial mastoid (AM)). Conclusion The proposed method with the SM can be used for objective measurements of the audibility of any BCDs based on thresholds, MPO and speech response allowing for direct comparisons of hearing and BCD output on the same graph using an eSPL-o-gram. After normalisation to hearing thresholds, the audibility can be assessed without the need for complicated calibration procedures.
|
|
| 33. |
- Persson, Ann-Charlotte, 1970, et al.
(författare)
-
Objective verification of audibility in bone conduction devices
- 2024
-
Ingår i: International Journal of Audiology. - 1499-2027 .- 1708-8186.
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: To objectively measure audibility in patients wearing bone conduction devices (BCDs) with a new approach using a skin microphone at the patient’s forehead. Design: The skin microphone was attached by a softband and shielded by an earmuff. This set-up was confirmed not to be influenced by neither noise floor nor sound bypassing the BCD. Sound field warble tones were used for measuring aided hearing thresholds and maximum power output (MPO) whereas an international speech test signal (ISTS) was presented at different speech levels. Study sample: 29 patients were tested (two were bilateral), 19 used percutaneous, eight used active transcutaneous and two used passive transcutaneous devices. Results: The skin microphone responses at ISTS levels, hearing threshold and MPO, could be obtained in all patients. Two patients with poor audibility are highlighted in this article as examples. After adjusting the gain of the BCD, they were retested with the skin microphone (for verification) and with speech-in-noise tests (for validation). Both tests confirmed an improved audibility after the adjustments. Conclusion: In summary, the proposed measurement of audibility of speech using a skin microphone is a promising method that can be used in a clinical setting for all types of BCDs.
|
|
| 34. |
- Persson, Ann-Charlotte, 1970, et al.
(författare)
-
Three-Year Follow-Up with the Bone Conduction Implant
- 2020
-
Ingår i: Audiology and Neuro-Otology. - : S. Karger AG. - 1421-9700 .- 1420-3030. ; 25:5, s. 263-275
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The bone conduction implant (BCI) is an active transcutaneous bone conduction device where the transducer has direct contact to the bone, and the skin is intact. Sixteen patients have been implanted with the BCI with a planned follow-up of 5 years. This study reports on hearing, quality of life, and objective measures up to 36 months of follow-up in 10 patients. Method: Repeated measures were performed at fitting and after 1, 3, 6, 12, and 36 months including sound field warble tone thresholds, speech recognition thresholds in quiet, speech recognition score in noise, and speech-to-noise thresholds for 50% correct words with adaptive noise. Three quality of life questionnaires were used to capture the benefit from the intervention, appreciation from different listening situations, and the ability to interact with other people when using the BCI. The results were compared to the unaided situation and a Ponto Pro Power on a soft band. The implant functionality was measured by nasal sound pressure, and the retention force from the audio processor against the skin was measured using a specially designed audio processor and a force gauge. Results: Audiometry and quality of life questionnaires using the BCI or the Ponto Pro Power on a soft band were significantly improved compared to the unaided situation and the results were statistically supported. There was generally no significant difference between the two devices. The nasal sound pressure remained stable over the study period and the force on the skin from the audio processor was 0.71 ± 0.22 N (mean ± 1 SD). Conclusion: The BCI improves the hearing ability for tones and speech perception in quiet and in noise for the indicated patients. The results are stable over a 3-year period, and the patients subjectively report a beneficial experience from using the BCI. The transducer performance and contact to the bone is unchanged over time, and the skin area under the audio processor remains without complications during the 3-year follow-up.
|
|
| 35. |
- Reinfeldt, Sabine, 1978, et al.
(författare)
-
Bone conduction hearing sensitivity in normal-hearing subjects: Transcutaneous stimulation at BAHA vs BCI position
- 2014
-
Ingår i: International journal of audiology. - : Informa UK Limited. - 1708-8186 .- 1499-2027. ; 53:6, s. 360-369
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Bone conduction (BC) stimulation closer to the cochlea has previously been shown to give higher cochlear promontory acceleration measured by laser Doppler vibrometry (LDV). This study is investigating whether stimulation closer to the cochlea also gives improved hearing sensitivity. Furthermore, the study compares shifts in hearing sensitivity (BC thresholds) and ear-canal sound pressure (ECSP). Design: BC hearing thresholds and ECSP have been measured for stimulation at two positions: the existing bone-anchored hearing aid (BAHA) position, and a new bone conduction implant (BCI) position that is located closer to the cochlea. Study sample: The measurements were made on 20 normal-hearing subjects. Results: Depending on frequency, the ipsilateral hearing threshold was 3-14 dB better, and the ipsilateral ECSP was 2-12 dB higher for the BCI than for the BAHA position, with no significant differences between threshold and ECSP shifts at group level for most frequencies, and individually only for some subjects. Conclusions: It was found that both the objective ECSP and the subjective hearing threshold measurements gave similar improvement as previous LDV measurements for stimulation closer to the cochlea. One exception was that the LDV measurements did not show the improved sensitivity for frequencies below 500 Hz found here.
|
|
| 36. |
- Reinfeldt, Sabine, 1978, et al.
(författare)
-
Long-term follow-up and review of the Bone Conduction Implant
- 2022
-
Ingår i: Hearing Research. - : Elsevier BV. - 0378-5955 .- 1878-5891. ; 421
-
Tidskriftsartikel (refereegranskat)abstract
- Active transcutaneous bone conduction devices are a type of bone conduction device developed to keep the skin intact and provide direct bone conduction stimulation. The Bone Conduction Implant (BCI) is such a device and has been implanted in 16 patients. The objective of this paper is to give a broad overview of the BCI development to the final results of 13 patients at 5-year follow-up. Follow-up of these patients included audiological performance investigations, questionnaires, as well as safety evaluation and objective functionality testing of the device. Among those audiological measure-ments were sound field warble tone thresholds, speech recognition threshold (SRT), speech recognition score (SRS) and signal to noise ratio threshold (SNR-threshold).The accumulated implant time for all 16 patients was 113 years in February 2022. During this time, no serious adverse events have occurred. The functional improvement for the 13 patients reported in this paper was on average 29.5 dB (average over 0.5, 1, 2 and 4 kHz), while the corresponding effective gain was-12.4 dB. The SRT improvement was 24.5 dB and the SRS improvement was 38.1%, while the aided SNR-threshold was on average -6.4 dB.It was found that the BCI can give effective and safe hearing rehabilitation for patients with conduc-tive and mild-to-moderate mixed hearing loss. (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )
|
|
| 37. |
- Reinfeldt, Sabine, 1978, et al.
(författare)
-
Nasal sound pressure as objective verification of implant in active transcutaneous bone conduction devices
- 2019
-
Ingår i: Medical Devices: Evidence and Research. - 1179-1470. ; 12, s. 193-202
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Active transcutaneous bone conduction devices consist of an external audio processor and an internal implant under intact skin. During the surgical procedure, it is important to verify the functionality of the implant before the surgical wound is closed. In a clinical study with the new bone conduction implant (BCI), the functionality of the implant was tested with an electric transmission test, where the output was the nasal sound pressure (NSP) recorded in the ipsilateral nostril. The same measurement was performed in all follow-up visits to monitor the implant's functionality and transmission to bone over time. The objective of this study was to investigate the validity of the NSP method as a tool to objectively verify the implant's performance intraoperatively, as well as to follow-up the implant's performance over time. Design: Thirteen patients with the BCI were included, and the NSP measurement was part of the clinical study protocol. The implant was electrically stimulated with an amplitude-modulated signal generator using a swept sine 0.1-10 kHz. The NSP was measured with a probe tube microphone in the ipsilateral nostril. Results: The NSP during surgery was above the noise floor for most patients within the frequency interval 0.4-5 kHz, showing NSP values for expected normal transmission of a functioning implant. Inter-subject comparison showed large variability, but follow-up results showed only minor variability within each subject. Further investigation showed that the NSP was stable over time. Conclusion: The NSP method is considered applicable to verify the implant's functionality during and after surgery. Such a method is important for implantable devices, but should be simplified and clinically adapted. Large variations between subjects were found, as well as smaller variability in intra-subject comparisons. As the NSP was found to not change significantly over time, stable transmission to bone, and implant functionality, were indicated.
|
|
| 38. |
- Reinfeldt, Sabine, 1978, et al.
(författare)
-
New developments in bone-conduction hearing implants: a review
- 2015
-
Ingår i: Medical Devices: Evidence and Research. - 1179-1470. ; 8, s. 79-93
-
Tidskriftsartikel (refereegranskat)abstract
- The different kinds of bone-conduction devices (BCDs) available for hearing rehabilitation are growing. In this paper, all BCDs currently available or in clinical trials will be described in categories according to their principles. BCDs that vibrate the bone via the skin are referred to as skin-drive devices, and are divided into conventional devices, which are attached with softbands, for example, and passive transcutaneous devices, which have implanted magnets. BCDs that directly stimulate the bone are referred to as direct-drive devices, and are further divided into percutaneous and active transcutaneous devices; the latter have implanted transducers directly stimulating the bone under intact skin. The percutaneous direct-drive device is known as a bone-anchored hearing aid, which is the BCD that has the largest part of the market today. Because of some issues associated with the percutaneous implant, and to some extent because of esthetics, more transcutaneous solutions with intact skin are being developed today, both in the skin-drive and in the direct-drive category. Challenges in developing transcutaneous BCDs are mostly to do with power, attachment, invasiveness, and magnetic resonance imaging compatibility. In the future, the authors assume that the existing percutaneous direct-drive BCD will be retained as an important rehabilitation alternative, while the transcutaneous solutions will increase their part of the market, especially for patients with bone-conduction thresholds better than 35 dB HL (hearing level). Furthermore, the active transcutaneous direct-drive BCDs appear to be the most promising systems, but to establish more detailed inclusion criteria, and potential benefits and drawbacks, more extensive clinical studies are needed.
|
|
| 39. |
- Reinfeldt, Sabine, 1978, et al.
(författare)
-
Study of the Feasible Size of a Bone Conduction Implant Transducer in the Temporal Bone
- 2015
-
Ingår i: Otology and Neurotology. - 1531-7129 .- 1537-4505. ; 36:4, s. 631-637
-
Tidskriftsartikel (refereegranskat)abstract
- Hypothesis: The aim was to assess the temporal bone volume to determine the suitable size and position of a bone conduction implant (BCI) transducer. Background: A BCI transducer needs to be sufficiently small to fit in the mastoid portion of the temporal bone for a majority of patients. The anatomical geometry limits both the dimension of an implanted transducer and its positions in the temporal bone to provide a safe and simple surgery. Methods: Computed tomography (CT) scans of temporal bones from 22 subjects were virtually reconstructed. With an algorithm in MATLAB, the maximum transducer diameter as function of the maximum transducer depth in the temporal bone, and the most suitable position were calculated in all subjects. Results: An implanted transducer diameter of 16 mm inserted at a depth of 4 mm statistically fitted 95% of the subjects. If changing the transducer diameter to 12 mm, a depth of 6 mm would fit in 95% of the subjects. The most suitable position was found to be around 20 mm behind the ear canal. Conclusion: The present BCI transducer casing, used in ongoing clinical trials, was designed from the results in this study, demonstrating that the present BCI transducer casing (largest diameter [diagonal]: 15.5 mm, height: 6.4 mm) will statistically fit more than 95% of the subjects. Hence, the present BCI transducer is concluded to be sufficiently small to fit most normal-sized temporal bones and should be placed approximately 20 mm behind the ear canal.
|
|
| 40. |
- Reinfeldt, Sabine, 1978, et al.
(författare)
-
The bone conduction implant: Clinical results of the first six patients.
- 2015
-
Ingår i: International journal of audiology. - : Informa UK Limited. - 1708-8186 .- 1499-2027. ; 54:6, s. 408-416
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: To investigate audiological and quality of life outcomes for a new active transcutaneous device, called the bone conduction implant (BCI), where the transducer is implanted under intact skin. Design: A clinical study with sound field audiometry and questionnaires at six-month follow-up was conducted with a bone-anchored hearing aid on a softband as reference device. Study sample: Six patients (age 18-67 years) with mild-to-moderate conductive or mixed hearing loss. Results: The surgical procedure was found uneventful with no adverse events. The first hypothesis that BCI had a statistically significant improvement over the unaided condition was proven by a pure-tone-average improvement of 31.0 dB, a speech recognition threshold improvement in quiet (27.0 dB), and a speech recognition score improvement in noise (51.2 %). At speech levels, the signal-to-noise ratio threshold for BCI was - 5.5 dB. All BCI results were better than, or similar to the reference device results, and the APHAB and GBI questionnaires scores showed statistically significant improvements versus the unaided situation, supporting the second and third hypotheses. Conclusions: The BCI provides significant hearing rehabilitation for patients with mild-to-moderate conductive or mixed hearing impairments, and can be easily and safely implanted under intact skin.
|
|
| 41. |
- Rigato, Cristina, 1989, et al.
(författare)
-
Audiometric comparison between Bone Anchored Hearing Aid and Bone Conduction Implant
- 2016
-
Ingår i: AudiologyNOW!2016.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Patients suffering from conductive or mixed hearing losses can often be successfully rehabilitated using bone conduction devices (BCDs). Percutaneous BCDs are widely used today, but the trend is to develop transcutaneous solutions able to providing equally good rehabilitation and less complications. Here, the transcutaneous Bone Conduction Implant was compared with percutaneous BCDs under the hypothesis that they are equally effective. Tone and speech audiometry and questionnaires were utilized to assess the overall performance. The outcome confirmed the initial hypothesis.
|
|
| 42. |
- Rigato, Cristina, 1989, et al.
(författare)
-
Audiometric Comparison Between the First Patients With the Transcutaneous Bone Conduction Implant and Matched Percutaneous Bone Anchored Hearing Device Users
- 2016
-
Ingår i: Otology & Neurotology. - : Ovid Technologies (Wolters Kluwer Health). - 1531-7129 .- 1537-4505. ; 37:9, s. 1381-1387
-
Tidskriftsartikel (refereegranskat)abstract
- Hypothesis:The transcutaneous bone conduction implant (BCI) is compared with bone-anchored hearing aids (BAHAs) under the hypothesis that the BCI can give similar rehabilitation from an audiological as well as patient-related point of view.Background:Patients suffering from conductive and mixed hearing losses can often benefit more from rehabilitation using bone conduction devices (BCDs) rather than conventional air conduction devices. The most widely used BCD is the percutaneous BAHA, with a permanent skin-penetrating abutment. To overcome issues related to percutaneous BCDs, the trend today is to develop transcutaneous devices, with intact skin. The BCI is an active transcutaneous device currently in a clinical trial phase. A potential limitation of active transcutaneous devices is the loss of power in the induction link over the skin. To address this issue, countermeasures are taken in the design of the BCI, which is therefore expected to be as effective as percutaneous BCDs.Methods:An early observational study with a matched-pair design was performed to compare BCI and BAHA groups of patients over several audiometric measurements, including speech audiometry and warble tones thresholds with and without the device. Additionally, questionnaires were used to assess the general health condition, benefit, and satisfaction level of patients.Results:No statistically significant difference was detected in any of the audiological measurements. The outcome of patient-related measurements was slightly superior for BCI in all subscales.Conclusion:Results confirm the initial hypothesis of the study: the BCI seems to be capable of providing as good rehabilitation as percutaneous devices for indicated patients.
|
|
| 43. |
- Rigato, Cristina, 1989, et al.
(författare)
-
Audiometric comparison in BCI and BAHA matched patients
- 2015
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Purpose: Patients that are suffering from outer or middle ear hearing impairment can often benefit more from rehabilitation using bone conduction devices (BCDs) rather than conventional air conduction devices. The most widely used BCD is the percutaneous Bone Anchored Hearing Aid (BAHA), which gives excellent sound, but can cause side effects from the skin penetration abutment. There is a growing interest in the development of transcutaneous BCDs such as the Bone Conduction Implant (BCI), comprising an externally worn audio processor wirelessly driving a transducer implanted in the temporal bone. In an ongoing clinical study, the device is used in six patients and the objective with this study is to compare their audiometric results with patients using the BAHA.Methods & Materials: Audiometric measurements are currently carried out on patients using a BAHA (Ponto Pro Power, Oticon Medical) that are matched one by one according to age- and hearing loss-based criteria with the six first patients treated with the BCI. In particular, warble tone thresholds, speech recognition score (SRS) in noise, speech recognition threshold (SRT) and signal-to-noise ratio (SNR) threshold are compared in a sound field. The patients’ general health status and personal satisfaction is also evaluated using Glasgow Benefit Inventory and Abbreviated Profile of Hearing Aid Benefit questionnaires. Furthermore, maximum power output and total harmonic distortion are measured for each device on a skullsimulator.Results: The study is on-going and detailed results will be presented. Preliminary results from two patients tested with the BAHA indicate that they generally perform the same or slightly worse than matched patients with BCI regarding warble tone thresholds, SRS, SRT and SNR threshold. The self-reported questionnaires show in general similar outcome for both devices, but slightly better results for BCI compared with the BAHA concerning physical benefit and avoidance of negative reactions to unpleasant sounds.Conclusion: Preliminary results from audiometric measurements show a clear improvement over the unaided condition for both devices, and indicate that the BCI is equal or slightly better
|
|
| 44. |
- Rigato, Cristina, 1989, et al.
(författare)
-
Audiometric results of the Bone Conduction Implant: a comparative study with the Bone Anchored Hearing Aid
- 2015
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Background:Patients suffering from conductive-, sensorineural- or mixed hearing loss that are unable to use conventional air conduction hearing aids, can often be rehabilitated with bone conduction devices (BCDs) . The most widely used BCD is the percutaneous Bone Anchored Hearing Aid (BAHA), which gives excellent sound but has some known complications related to the side effects from the skin penetration. In order to overcome such issues, the development of transcutaneous BCDs has increased. Among them, the Bone Conduction Implant (BCI) is an active BCD developed in Gothenburg, Sweden. It comprises an externally worn audio processor unit which is magnetically attached to an implanted unit to wirelessly drive a transducer in the temporal bone. The device is currently implanted in six patients in the clinical trial phase and the objective with this study is to compare the BCI and BAHA devices.Methods:Audiometric measurements are currently carried out on BCI and BAHA patients matched one by one according to age- and hearing loss-based criteria. In particular, pure tones hearing thresholds, speech recognition threshold (SRT) in quiet and speech recognition score (SRS) in noise are compared as well as signal to noise ratio (SNR). In addition, maximum power output (MPO) and total harmonic distortion (THD) are measured for each device on a skullsimulator in an anechoic chamber. The patients’ satisfaction and general health condition are also evaluated by means of questionnaires. Results:Results from three patients tested with the BAHA indicate that they generally perform as or slightly worse than matched patients with BCI in all tested audiometric measurements. The self-reported questionnaires show in general similar outcome for both devices, with slightly better results for BCI compared with the BAHA concerning physical benefit and avoidance of negative reactions to unpleasant sounds.Conclusions:Results from audiometric measurements show a clear improvement over the unaided condition for both devices, and indicate that the BCI is equal or slightly better than the BAHA. As this is a pilot study currently ongoing, the results may change when all six BCI patients have been matched with a BAHA patient.
|
|
| 45. |
- Rigato, Cristina, 1989, et al.
(författare)
-
Direct bone conduction stimulation: effect of different transducer attachments
- 2017
-
Ingår i: Osseo 2017, Nijmegen, The Netherlands.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Objective(s): When choosing a method to implant a transducer for direct bone conduction stimulation, several options are available with the trade-off being, among other aspects, between achieving a robust contact to the bone and keeping an open possibility for potential future explantation. The aim of this study is to compare how different attachment methods for direct bone conduction stimulation can affect the vibrations transmission to the cochleae. The ultimate goal is to gain more insights on the dynamical properties of the skull to apply them to the design and optimization of bone conduction devices for hearing rehabilitation.Study design:Experimental.Patients:Measurements were performed on four human heads. The tympanic membrane, the malleus and the incus were removed to expose the cochlear promontory on both sides of each subject. The subjects have not undergone any previous surgery as verified by visual inspection.Methods:Three different attachments are tested on eight sides: (A) flat small-sized surface, (B) flat wide surface and (C) two separated screws. The different typologies of contact to bone are established by three dummy implants and an adapter to attach the transducer giving a swept sine stimulus from 0.1 to 10 kHz. The response is evaluated in terms of cochlear promontory acceleration and ear canal sound pressure level (ECSP). The measurement setup consists of the following parts: human head, transducer with adaptor (to apply the stimulus), signal generator and analyzer (to drive the transducer and receive the recorded data), Laser Doppler Vibrometer (LDV, measuring the cochlear promontory acceleration), video to USB converter (to couple the built-in camera of LDV with the computer), microphones (to measure ECSP) and laptop (to save data).Results:Average results show slightly higher ECSP level and cochlear promontory acceleration for attachment A compared to attachment B especially at frequencies above 1 kHz. An improvement in transmission is achieved with attachment C compared to B in the frequency range 5–7 kHz, where the levels differ by nearly 10 dB both ipsi- and contralaterally. In the same frequency range, the transmission from attachment C appears to be slightly higher relative to attachment A as well, however no statistical significance is found. The comparison between attachment A and C is not straightforward due to high variability over frequencies and sometimes contradictory results between LDV and ECSP measurements.Conclusion:On an average level, the screw stimulation technique seems to improve the transmission at frequencies above 5 kHz. However,, when considering the whole frequency range, average results from the different attachment techniques are comparable. Still, conclusions for single subjects should be drawn with care as measurements show a very high inter-subject variability.
|
|
| 46. |
- Rigato, Cristina, 1989, et al.
(författare)
-
Direct bone conduction stimulation: Ipsilateral effect of different transducer attachments in active transcutaneous devices
- 2018
-
Ingår i: Hearing Research. - : Elsevier BV. - 0378-5955 .- 1878-5891. ; 361, s. 103-112
-
Tidskriftsartikel (refereegranskat)abstract
- Active transcutaneous bone conduction devices, where the transducer is implanted, are used for rehabilitation of hearing impaired patients by directly stimulating the skull bone. The transducer and the way it is attached to the bone play a central role in the design of such devices. The actual effect of varying the contact to bone has not been addressed yet. The aim of this study is therefore to compare how different attachment methods of the transducer to the bone for direct stimulation affect the ear canal sound pressure and vibration transmission to the ipsilateral cochlea. Three different attachments to the bone were tested: (A) via a flat small-sized surface, (B) via a flat wide surface and (C) via two separated screws. Measurements were done on four human heads on both sides. The attachments were compared in terms of induced cochlear promontory velocity, measured by a laser Doppler vibrometer, and ear canal sound pressure, measured by a low noise microphone. A swept sine stimulus was used in the frequency range 0.1-10 kHz. On an average level, the attachment method seems to affect the transmission mainly at frequencies above 5 kHz. Furthermore, the results suggest that a smaller contact surface might perform better in terms of transmission of vibrations at mid and high frequencies. However, when considering the whole frequency range, average results from the different attachment techniques are comparable. (C) 2018 The Authors. Published by Elsevier B.V.
|
|
| 47. |
- Rigato, Cristina, 1989, et al.
(författare)
-
Effect of transducer attachment on vibration transmission and transcranial attenuation for direct drive bone conduction stimulation
- 2019
-
Ingår i: Hearing Research. - : Elsevier BV. - 0378-5955 .- 1878-5891. ; 381
-
Tidskriftsartikel (refereegranskat)abstract
- Direct drive bone conduction devices (BCDs) are used to rehabilitate patients with conductive or mixed hearing loss by stimulating the skull bone directly, either with an implanted transducer (active trans cutaneous BCDs), or through a skin penetrating abutment rigidly coupled to an external vibrating transducer (percutaneous BCDs). Active transcutaneous BCDs have been under development to overcome limitations of the percutaneous bone anchored hearing aid (BAHA), mainly related to the skin penetration. The attachment of a direct drive BCD to the skull bone can differ significantly between devices, and possibly influence the vibrations' transmission to the cochleae. In this study, four different attachments are considered: (A) small-sized flat surface, (B) extended flat surface, (C) bar with a screw at both ends, and (D) standard bone anchored hearing aid screw. A, B, and C represent three active transcutaneous options, while D is for percutaneous applications. The primary aim of this study was to investigate how the different transcutaneous attachments (A, B, and C) affect the transmission of vibrations to the cochleae to the ipsilateral and the contralateral side. A secondary aim was to evaluate and compare transcranial attenuation (TA, ipsilateral minus contralateral signal level) between transcutaneous (A, B, and C) and percutaneous attachments (D). Measurements were performed on four human heads, measuring cochlear promontory velocity with a LDV (laser Doppler vibrometer) and sound pressure in the ear canal (ECSP) with an inserted microphone. The stimulation signal was a swept sine between 0.1 and 10 kHz. The comparison of ipsilateral transmission between transcutaneous adaptors A, B, and C was in agreement with previous findings, confirming that: (1) Adaptor C seems to give the most effective transmission for frequencies around 6 kHz but somewhat lower in the mid frequency range, and (2) keeping a smaller contact area seems to provide advantages compared to a more extended one. The same trends were seen ipsilaterally and contralaterally. The observed TA was similar for adaptors A, B, and C at the mastoid position, ranging-10-0 dB below 500 Hz, and 10-20 dB above. A lower TA was seen above 500 Hz when using adaptor D at the parietal position. (C) 2019 The Authors. Published by Elsevier B.V.
|
|
| 48. |
- Rigato, Cristina, 1989, et al.
(författare)
-
Rehabilitating Patients with Bone Conduction Hearing Devices: Two Effective Alternatives
- 2017
-
Ingår i: Engineering Health.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Background: Bone conduction devices (BCDs) are today widely used to rehabilitate patients suffering from specific types of hearing impairment, when the main hearing loss originates in the middle or outer ear. BCDs act by stimulating the skull bone with vibrations that are directly transmitted to the cochlea in the inner ear and result in a hearing sensation, referred to as bone conduction hearing.BCDs are on the market since several decades in various alternative designs, externally worn or partially implanted. In 1977 the first bone anchored hearing aid (BAHA) was implanted in a patient in Gothenburg, and now this technology is one of the most used all over the world. A novel device, the BCI (Bone Conduction Implant), was developed in collaboration between Chalmers and Sahlgrenska in the past few years. The BCI is an alternative to the well-established BAHA that aims at overcoming some of its limitations mainly related to the skin-penetrating abutment. Objectives: In this study, the well-established BAHA and the novel BCI are compared in terms of rehabilitation effect on hearing impaired patients. The purpose of comparing the BCI with an established device available on the market is to find out if the BCI can be a valuable rehabilitation alternative for indicated patients.Methods: Audiometric measurements and user self-reported questionnaires were performed on two groups of patients, one fitted with the BCI and one fitted with BAHAs.Six BCI users were included in the study as part of the clinical trial for the device, and six BAHA users were selected in order to match them one by one in terms of hearing ability, gender and age.Results: The overall results from the performed measurements show a clear improvement over the unaided condition for both devices. Outcomes from the audiometric tests as well as from the patient-related measurements were comparable in the two groups. Conclusions: The two devices seem to give an equally satisfactory rehabilitation for indicated patients. The novel BCI is shown to be a successful example of translational science, where the collaboration between Chalmers and Sahlgrenska provided solid bases to integrate technical and medical requirements.
|
|
| 49. |
- Rönnblom, Anton, 1981-
(författare)
-
Middle ear mechanics : using temporal bone experiments to improve clinical methods
- 2022
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- BackgroundThe middle ear transmits and amplifies sound vibrations from the tympanic membrane via three ossicles to the inner ear. Moreover, it contains two muscles, the stapedius muscle (SM) which protects the inner ear from loud noise, and the tensor tympani (TT) whose function is still debated. The majority of hearing loss caused by disruption of the ossicular chain is a result of chronic otitis media and cholesteatoma. Variations in pathology, surgical skill and individual healing conditions make objective evaluation of ossicular replacement prosthesis in vivo difficult. Prosthesis development and the investigation of trauma mechanisms are affected by the same challenges. With few changes postmortem, the temporal bone (TB) is suitable for studies of middle ear mechanics and allows a controlled environment. Equally important, it allows theories to be tested without patient risk. In this thesis we used human TBs to find factors associated with optimal sound transfer in the two types of ossicular replacement prostheses. Furthermore, we investigated the mechanism and forces involved in rare cases of isolated malleus fractures. We also investigated the morphology, fibre phenotype composition and vascularization of the human middle ear muscles in order to better understand their roles.Materials and MethodsLaser Doppler vibrometry (LDV) is an established method of measuring sound transfer in human TBs. We have further developed a surgical model that allows testing of a wide range of prostheses and their placements. In Paper I beneficial factors in partial ossicular replacement prostheses (PORPs) were tested. In Paper II we evaluated different types of total ossicular replacement prostheses (TORPs) including an experimental prosthesis inspired by the single ossicle system of birds. In Paper III the negative pressure trauma typically associated with isolated malleus fractures, produced by a finger being withdrawn from a wet ear canal after a shower or bath, was simulated in TBs. Based on measurement from control persons the forces involved were calculated and measured in models developed for this purpose. The force of the TT was estimated by comparing its cross-sectional area and fibre composition with those reported in published references. In Paper IV we used immunohistochemical, enzyme histochemical, biochemical and morphometric techniques on TT, SM and human orofacial and limb muscle control samples.ResultsOf the prostheses, PORPs and TORPs with lateral contact with both the tympanic membrane and the malleus handle performed best, and TORPs with distal malleus contact proved superior. Our experimental bird-type prosthesis was the most stable in such placement and performed equally to or better than other prostheses. In Paper III the application of negative pressure via the ear canal did not fracture the malleus shaft, with only a passive counterforce from support structures, although the force exceeded that required for a malleus shaft fracture. We estimate that when adding calculated counteracting forces from the TT muscle, sufficient force is generated to cause a malleus fracture. Both human middle ear muscles are predominated by fast type 2 fibres, and have rich capillarization and nerve innervation compared with limb muscles. Muscle spindles were found in the TT but not the SM.ConclusionsWhere possible, an ossicular replacement prosthesis should be placed to allow distal contact with both the TM and the malleus handle. The sound transfer capabilities combined with the stable placement of our experimental prostheses suggest room for improvement. The combination of a negative pressure created by a finger being withdrawn from a wet ear canal and a simultaneous counteracting reflexive force by the TT muscle was found to be sufficient to cause an isolated malleus fracture. The finding of muscle spindles in TT, but not in SM, suggests a difference in regulatory control; furthermore, it indicates that the TT can be activated by a sudden stretch reflex as described in the malleus fracture trauma. The human middle ear muscles have a highly specialized muscle morphology, which is more similar to orofacial than to limb muscles. The fibre phenotype composition suggests capability for fine-tuned, fast, strong and relatively sustainable contractions. Based on fibre type patterns the TT is among the fastest muscles in the human body.
|
|
| 50. |
- Taghavi, Hamidreza, 1981, et al.
(författare)
-
A vibration investigation of a flat surface contact to skull bone for direct bone conduction transmission in sheep skulls in vivo.
- 2013
-
Ingår i: Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. - 1537-4505 .- 1531-7129. ; 34:4, s. 690-8
-
Tidskriftsartikel (refereegranskat)abstract
- Hypothesis: Bone conduction implant (BCI) attached with a flat surface contact will offer efficient and linear vibration transmission over time. Background: Despite that percutaneous bone conduction devices (PBCD) are successful in treating patients with conductive hearing loss, there are some drawbacks related to the need of a permanent skin penetration. The BCI system is designed as an alternative to the PBCD because it leaves the skin intact. Methods: BCI dummy implants were installed in 3 sheep skulls in vivo to study the vibration transmission characteristics over time. Mechanical point impedances and vibration transfer response functions of the BCI implants were measured at the time of surgery and after a healing period of 8 months. Results: In 1 sheep both implants healed without complications. In the other 2 sheep, the implants were either partially loose or lost to follow up. In the sheep with stable implants, it was found by the resonance frequency shift of the mechanical point impedance that a firmer integration between the implant and bone tissue as seen in osseointegrated surfaces developed over time. It was also shown that the transcranial vibration transmission remains stable and linear. Providing bone chips in the contact between the implant and the bone did not enhance vibration transmission. The surgical procedure for installing the BCI dummy implants was uneventful. Conclusion: The mechanical point impedances and vibration transfer response functions indicate that the BCI implants integrate and that transmission conditions remain stable over time.
|
|
