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| 2. |
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| 3. |
- Fredén Jansson, Karl-Johan, 1988, et al.
(författare)
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Magnetic resonance imaging investigation of the bone conduction implant - a pilot study at 1.5 Tesla.
- 2015
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Ingår i: Medical devices (Auckland, N.Z.). - 1179-1470. ; 8, s. 413-23
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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.
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| 4. |
- Fredén Jansson, Karl-Johan, 1988, et al.
(författare)
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Robustness and lifetime of the bone conduction implant - a pilot study
- 2019
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Ingår i: Medical Devices: Evidence and Research. - 1179-1470. ; 12, s. 89-100
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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.
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| 5. |
- Haque, Mohammad Mazharul, 1984, et al.
(författare)
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Identification of self-discharge mechanisms of ionic liquid electrolyte based supercapacitor under high-temperature operation
- 2021
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753. ; 485
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Tidskriftsartikel (refereegranskat)abstract
- Ionic liquids (ILs) are promising electrolytes for supercapacitors (SCs) aimed for high-temperature applications, where increased ionic conductivity results in superior capacitive performance compared to room temperature (RT) performance. However, an increased temperature also accelerates the self-discharge rate that adversely affects energy retention and restricts the usage of SCs in standalone applications. In this study, a detailed electrochemical investigation on the self-discharge behaviour of carbon-based SCs containing an IL, 1-Ethyl-3-methylimidazolium acetate (EMIM Ac), has been carried out in the temperature range RT - 60 °C, and the underlying self-discharge mechanisms are identified. The results reveal that at a high voltage of 1.5 V, the self-discharge is characterized by a combination of charge redistribution and diffusion at both RT and 60 °C. At 60 °C, the diffusion-controlled mechanism dominates at lower voltages over the charge redistribution effect, while at RT both mechanisms contribute to a similar extent. The observed difference in the self-discharge mechanism between RT and 60 °C is explained in terms of a decreased RC time constant (τRC) at elevated temperature, and the same conclusions are potentially applicable to other IL-containing SCs as well.
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| 6. |
- Håkansson, Bo, 1953, et al.
(författare)
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The bone conduction implant - a review and 1-year follow-up
- 2019
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Ingår i: International Journal of Audiology. - : Informa UK Limited. - 1499-2027 .- 1708-8186. ; 58:12, s. 945-955
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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.
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| 7. |
- Håkansson, Bo, 1953, et al.
(författare)
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VEMP using a new low-frequency bone conduction transducer
- 2018
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Ingår i: Medical Devices: Evidence and Research. - 1179-1470. ; 11, s. 301-312
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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.
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| 8. |
- Persson, Ann-Charlotte, 1970, et al.
(författare)
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Three-Year Follow-Up with the Bone Conduction Implant
- 2020
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Ingår i: Audiology and Neuro-Otology. - : S. Karger AG. - 1421-9700 .- 1420-3030. ; 25:5, s. 263-275
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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.
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| 9. |
- Reinfeldt, Sabine, 1978, et al.
(författare)
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Nasal sound pressure as objective verification of implant in active transcutaneous bone conduction devices
- 2019
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Ingår i: Medical Devices: Evidence and Research. - 1179-1470. ; 12, s. 193-202
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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.
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| 10. |
- Rigato, Cristina, 1989, et al.
(författare)
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Audiometric comparison between Bone Anchored Hearing Aid and Bone Conduction Implant
- 2016
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Ingår i: AudiologyNOW!2016.
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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.
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| 11. |
- Rigato, Cristina, 1989, et al.
(författare)
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Audiometric Comparison Between the First Patients With the Transcutaneous Bone Conduction Implant and Matched Percutaneous Bone Anchored Hearing Device Users
- 2016
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Ingår i: Otology & Neurotology. - : Ovid Technologies (Wolters Kluwer Health). - 1531-7129 .- 1537-4505. ; 37:9, s. 1381-1387
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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.
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| 12. |
- Rigato, Cristina, 1989, et al.
(författare)
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Audiometric comparison in BCI and BAHA matched patients
- 2015
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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
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| 13. |
- Rigato, Cristina, 1989, et al.
(författare)
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Audiometric results of the Bone Conduction Implant: a comparative study with the Bone Anchored Hearing Aid
- 2015
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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.
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| 14. |
- Rigato, Cristina, 1989, et al.
(författare)
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Direct bone conduction stimulation: effect of different transducer attachments
- 2017
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Ingår i: Osseo 2017, Nijmegen, The Netherlands.
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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.
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| 15. |
- Rigato, Cristina, 1989, et al.
(författare)
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Direct bone conduction stimulation: Ipsilateral effect of different transducer attachments in active transcutaneous devices
- 2018
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Ingår i: Hearing Research. - : Elsevier BV. - 0378-5955 .- 1878-5891. ; 361, s. 103-112
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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.
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| 16. |
- Rigato, Cristina, 1989
(författare)
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Direct Drive Bone Conduction Stimulation: Experimental Studies on Functionality and Transmission with Focus on the Bone Conduction Implant
- 2017
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sound is conducted to the inner ear in two ways: by air and by bone. Air conduction (AC) hearing consists of sound waves entering the ear canal and reaching the cochlea, the main hearing organ, via the middle ear. In bone conduction (BC) hearing, instead, the transmission is through soft tissues and bone. These two pathways coexist and complement each other, although innormal hearing subjects the AC part is prevalent over the BC part in most of the ordinary hearing situations.BC hearing can represent an effective way to rehabilitate hearing impaired patients who would not benet from conventional AC hearing aids. This is the case when the hearing impairment is located in the outer or middle ear, or if the patients have chronic infections or malformations preventing them from wearing earmolds. The key idea in bone conduction devices (BCDs) isto generate vibrations with a transducer and transmit them via the skull bone to the inner ear.At present, the most common BCD is probably the bone anchored hearing aid (BAHA), consisting of a single-unit device attached to a skin penetrating screw in the parietal bone. To overcome the issues related to the skin penetration, the development of BCDs is recently focusing on so-called active transcutaneous devices, whose main feature is to have the bone transducer implanted under intact skin.In this thesis, the novel active transcutaneous bone conduction implant (BCI), currently in advanced clinical trial phase, was compared to BAHAs in terms of audiological tests and perceived rehabilitation effect. The outcomes showed that the BCI can be a valid alternative to BAHAs for indicated patients. Preliminary investigations were also performed on how the transmission of vibrations is affected by different ways of attaching the transducer to the skull bone. It was found that the relation varies substantially with frequency, with a general trend of improved transmission when the contact area between transducer and bone is limited.Finally, a new verication method of the implant functionality was evaluated intra- and post- operatively. The method, consisting in the measurement of the sound pressure in the nostril, seems promising and the implant to bone transmission was found stable over time.
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| 17. |
- Rigato, Cristina, 1989, et al.
(författare)
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Effect of transducer attachment on vibration transmission and transcranial attenuation for direct drive bone conduction stimulation
- 2019
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Ingår i: Hearing Research. - : Elsevier BV. - 0378-5955 .- 1878-5891. ; 381
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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.
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| 18. |
- Rigato, Cristina, 1989
(författare)
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On Direct Drive Bone Conduction Devices - Hearing Rehabilitation and Objective Assessment of Stimulation Methods
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Bone conduction devices (BCDs) rely on the transmission of sound in form of vibrations generated by a transducer to the inner ear via the skull and surrounding soft tissues. Direct drive BCDs stimulate the skull bone directly, either via a skin-penetrating abutment (BAHAs, Bone Anchored Hearing Aids), or with a transducer implanted under intact skin (active transcutaneous devices). In this thesis, several aspects related to direct drive stimulation were addressed with objective and subjective measurements. Vibrational measurements were performed to assess how the transducer to bone attachment affects the vibrations transmission to the cochleae. Three different attachments for active transcutaneous stimulation were compared to each other and to the BAHA screw. A comparative study was done also between the BAHA system and the novel active transcutaneous Bone Conduction Implant (BCI), where the transducer is attached to the skull bone via a flat surface contact. The BCI is currently on a clinical trial, and a comprehensive assessment of the rehabilitation after three years of device usage is included in this thesis, reporting on a number of audiometric tests, self-reported questionnaires, and objective measurements. Among the objective measures, a new method for intra and post operative verification of the implant functionality was evaluated, consisting in the measurement of the induced sound pressure in the nostril under bone conduction stimulation. In addition to the test battery from the clinical trial protocol, an exploratory study was conducted to investigate the effect of the BCI in a complex multi-talker listening environment. The results from the vibrational measurements were highly frequency-dependent, with a general trend of improved transmission when the contact area between transducer and bone was limited, especially for frequencies above 5 kHz. Sound field tone and speech tests, and user reported questionnaires show that the BCI provides considerable improvement from the unaided condition and contributes to a general increase of patients' life quality, with consistent outcomes over time. The implant verification method seems promising and showed stable properties of the implant to bone transmission. When compared to BAHAs, the BCI was found to be a viable alternative for indicated patients. In noisy and complex listening environments, the BCI users showed a lower ability to make use of the spatial cues when aided with their device, but an overall greater tolerance to interfering talkers.
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| 19. |
- Rigato, Cristina, 1989, et al.
(författare)
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Rehabilitating Patients with Bone Conduction Hearing Devices: Two Effective Alternatives
- 2017
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Ingår i: Engineering Health.
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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.
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| 20. |
- Rigato, Cristina, 1989, et al.
(författare)
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The effect of an active transcutaneous bone conduction device on spatial release from masking
- 2020
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Ingår i: International Journal of Audiology. - : Informa UK Limited. - 1499-2027 .- 1708-8186. ; 59:5, s. 348-359
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The aim was to quantify the effect of the experimental active transcutaneous Bone Conduction Implant (BCI) on spatial release from masking (SRM) in subjects with bilateral or unilateral conductive and mixed hearing loss. Design: Measurements were performed in a sound booth with five loudspeakers at 0°, +/−30° and +/−150° azimuth. Target speech was presented frontally, and interfering speech from either the front (co-located) or surrounding (separated) loudspeakers. SRM was calculated as the difference between the separated and the co-located speech recognition threshold (SRT). Study Sample: Twelve patients (aged 22–76 years) unilaterally implanted with the BCI were included. Results: A positive SRM, reflecting a benefit of spatially separating interferers from target speech, existed for all subjects in unaided condition, and for nine subjects (75%) in aided condition. Aided SRM was lower compared to unaided in nine of the subjects. There was no difference in SRM between patients with bilateral and unilateral hearing loss. In aided situation, SRT improved only for patients with bilateral hearing loss. Conclusions: The BCI fitted unilaterally in patients with bilateral or unilateral conductive/mixed hearing loss seems to reduce SRM. However, data indicates that SRT is improved or maintained for patients with bilateral and unilateral hearing loss, respectively.
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