Search Results (16)

Laser Doppler vibrometry (LDV) is an essential tool in assessing by evaluating ossicle vibrations. It is used in fundamental research to understand hearing physiology better and develop new surgical techniques and implants. It is also helpful for the intraoperative hearing assessment and evaluation of postoperative treatment results. Traditional volumetric LDVs require access in a straight line to the test object, which is challenging due to the structure of the middle ear and the way the auditory ossicles are accessible. Here, we demonstrate the usage of a fiber-based laser Doppler vibrometer (FLDV) for middle ear diagnostics. Compared to classical vibrometers, the main advantages of this device are the ability to analyze several arbitrarily selected points simultaneously and the flexibility achieved by employing fiber optics to perform analysis in hard-to-reach locations, which are particularly important during endoscopic ear surgery. The device also allows for a simple change in measuring probes depending on the application. In this work, we demonstrate the properties of the designed probe and show that using it together with the FLDV enables recording vibrations of the auditory ossicles of the human ear. The obtained signals enable hearing analysis. Full article

This study delves into the intricate mechanics of human middle ear implants by examining a lumped parameter model with five degrees of freedom to estimate sound transfer. The ASTM standard, recognized globally as a benchmark, served as a reference for analysis, ensuring test accuracy and providing a comprehensive evaluation framework. To assess the implant’s usability, numerical simulations were conducted and compared against both the ASTM standard and the experimental results obtained from temporal bone studies. This investigation uncovered the bistability of periodic responses induced by the implant, prompting an analysis of the bistability in periodic solutions and the creation of basins of attraction for various initial conditions. The discovery of new solutions underscores this study’s significance in the operation and reliability of implants. Consequently, this research not only enhances the theoretical comprehension of the system, but also holds promise for practical applications in the design and optimization of middle ear implants that transfer energy to the stapes and the cochlea. Full article

Background: Middle ear active implants, such as the Vibrant Soundbridge (VSB), offer an alternative to reconstructive surgery and other implantable hearing aid systems for patients with conductive, mixed, or sensorineural hearing loss. The primary objective of this work is to describe the auditory results obtained with VSB in our patient cohort, measuring the auditory gain in terms of average tonal thresholds and spoken word discrimination at 65 dB. Secondly, auditory gain differences between different types of hearing loss, coupling to the ossicular chain compared to round and oval windows, and the impact of open versus more conservative surgical approaches, were analyzed. Methods: A cross-sectional observational study, with retrospective data collection, was conducted at a tertiary care center. Clinical and audiometric data pre- and post-implantation were included, from patients who underwent VSB device placement surgery between 2001 and 2024. Results: 55 patients with an average age of 62.58 ± 17.83 years and a slight preference in terms of the female gender (52.72%) were included in the study. The average gain in the PTA for all types of hearing loss was 41.56 ± 22.63 dB, while for sensorineural hearing loss (SNHL) the gain was 31.04 ± 8.80 dB. For mixed-conductive hearing loss (C-MHL) a gain of 42.96 ± 17.70 was achieved, notably, in terms of absolute values, at frequencies of 4000 and 6000 Hz, with gains reaching 49.25 ± 20.26 dB at 4 K and 51.16 ± 17.48 dB at 6 K. In terms of spoken word discrimination, for all types of hearing loss, an improvement of 75.20 ± 10.11% was achieved. However, patients with C-MHL exhibited an approximately 13% higher gain compared to those with SNHL (69.32 ± 24.58% vs. 57.79 ± 15.28%). No significant differences in auditory gain were found between open and closed surgical techniques, nor in the proportion of adverse effects, when comparing one technique with the other. Conclusions: The VSB is effective in improving hearing in patients with mixed, conductive, and sensorineural hearing loss, with significant gains at high frequencies, especially through the round window membrane approach. The choice of surgical technique should consider the patient’s anatomical characteristics and specific needs in order to optimize auditory outcomes and minimize postoperative complications. Full article

Active bone-conducting hearing devices (aBCHD; e.g., MEDEL Bonebridge^® (BB)) and active middle ear implants (aMEI; e.g., MEDEL Vibrant Soundbridge^® (VSB)) use radio frequency transmission to send information from an external microphone and sound processor to an internally implanted transducer. These devices potentially have an advantage over devices with percutaneous links because the skin is closed over the implantable components, which should reduce the risk of skin problems and infection. On the other hand, surgical procedures are more complex, with a greater risk of damage due to surgery. The objectives of this research were to quantify the reliability and long-term survival of MEDEL VSB and BB devices, determine the adverse and serious adverse device-related complications, and consider associated causes. A multi-center observational retrospective and prospective study was conducted at eleven auditory implant centers in the United Kingdom. Data was collected using a surgical questionnaire and audiological reports. Data were obtained from patient notes or from prospective cases that had a minimum follow-up of one year post-implant. Consecutive patient records were reviewed. Datasets from 109 BB and 163 VSB were reviewed. Of these, 205 were retrospective case note reviews, and 67 were prospective cases. The mean follow-up was 4 and 6 years, respectively, for BB and VSB. Kaplan–Meier Survival analyses indicated that the BB survival was 97% and 93.3% at 1 and 5 years, respectively, and the VSB was 92.1% and 87% at the same time points. This is a large cohort study for the field and has indicated that BB and VSB are safe interventions. Care should be taken to monitor magnet strength in the first few months. For the majority of device-related effects, there was no apparent association with etiology. However, an interesting pattern emerged for individuals who exhibited an inflammatory response, e.g., adhesions or device extrusion, and those with a history of chronic suppurative otitis media. This should be considered in future work and is not surprising given that many VSB recipients have a complicated hearing history, often associated with otitis media. Full article

Bone conduction implants (BCIs) and middle ear implants (MEIs) are promising options for individuals with persistent chronic inflammation of the middle or outer ear. However, the structure of the middle ear is often altered in patients who undergo mastoidectomy or posterior wall removal for refractory otitis media, leaving uncertainty regarding the efficacy of hearing devices. Only a few studies have examined auditory outcomes based on the etiology of hearing impairment. We investigated hearing outcomes, including speech audiometry, in patients who underwent implantation after surgery for refractory otitis media. Our findings indicated that patients who received BCIs or MEIs achieved favorable hearing outcomes. Furthermore, a correlation was observed between the preoperative bone-conduction threshold at 1 kHz in the better ear and the sound-field threshold at 1 kHz with BCIs, whereas no correlation was observed between the preoperative bone-conduction threshold and the sound-field threshold with MEIs. This study highlights the positive impact of BCIs and MEIs in patients who undergo implantation after surgery for refractory otitis media. Additionally, our study identified parameters that predict postoperative efficacy. Full article

A platform to help clinicians ensure that hearing device candidates are informed about the benefits and drawbacks of their recommended treatment option would be of clinical counselling benefit because it could help each candidate form realistic expectations about life with their treatment option. Following the World Café approach, 54 participants (surgeons, audiologist, and researchers) generated lists of the benefits and drawbacks of each treatment option for single-sided deafness (SSD) and bone conduction (BC) solutions. They then prioritized the benefits and drawbacks. After the World Café, literature research was performed on each topic to check if the statements (on benefits and drawbacks) are supported by quality peer-reviewed publications. Each participant was surveyed to ensure a collective agreement was reached. The HEARRING Counselling 1.0 Platform was developed. Thus far, sections for SSD and BC solutions have been completed. Initial feedback has been highly positive. The platform will be expanded to cover middle ear implant solutions and cochlear implants. A plan is in place to ensure the information continues to be timely. The HEARRING Counselling 1.0 helps clinicians provide comprehensive information to candidates about their treatment option and thereby helps establish that candidates have realistic expectations about the benefits and drawbacks of device use. Full article

Background: The Carina system (Cochlear Ltd., Sydney, Australia) is a totally implantable device providing acoustic amplification in adult patients with moderate-to-severe sensorineural or mixed hearing loss. One of the main concerns about such a totally implantable device has been represented by the subcutaneous battery lifespan. The aim of this article is to report the analysis of battery performances in a series of Carina-implanted patients after a long follow up. Methods: In this retrospective study, the technical data of a series of patients implanted with the Carina middle ear implant in our clinic have been analysed, extracting the data from the log of telemetric measures. Results: The mean lifespan cutback was 0.43 h/years (from 0 to 0.71 h/year), with a strong negative significant correlation between the follow-up period and the percentage of battery residual lifespan. Conclusion: The lifespan of the Carina’s battery seems consistent with the manufacturer statement of a pluri-decennial lifespan, avoiding the need of an early surgical substitution and providing a full day of use of the system even after up to 12 years from the implantation. Full article

The primary objectives of this study were to evaluate the effect of hearing implant (HI) use on quality of life (QoL) and to determine which QoL measure(s) quantify QoL with greater sensitivity in users of different types of HIs. Participants were adult cochlear implant (CI), active middle ear implant (VIBRANT SOUNDBRIDGE (VSB)), or active transcutaneous bone conduction implant (the BONEBRIDGE (BB)) recipients. Generic QoL and disease-specific QoL were assessed at three intervals: pre-activation, 6 months of device use, and 12 months of device use. 169 participants completed the study (110 CI, 18VSB, and 41BB). CI users’ QoL significantly increased from 0–6 m device use on both the generic- and the disease-specific measures. On some device-specific measures, their QoL also significantly increased between 6 and 12 m device use. VSB users’ QoL significantly increased between all tested intervals with the disease-specific measure but not the generic measure. BB users’ QoL significantly increased from 0–6 m device use on both the generic- and the disease-specific measures. In sum, HI users experienced significant postoperative increases in QoL within their first 12 m of device use, especially when disease-specific measures were used. Disease-specific QoL measures appeared to be more sensitive than their generic counterparts. Full article

Background: the Bonebridge hearing implant is an active transcutaneous bone conduction implant suitable for various types of hearing loss. It was first launched in 2012 as the BCI 601, with a newer internal part (BCI 602) released in 2019. With the new size and shape, the BCI 602 can be used in patients previously excluded due to insufficient anatomical conditions, especially in patients with congenital defects of the outer and middle ear. Objectives: the purpose of this study is to evaluate the objective and subjective benefits of the new Bonebridge BCI 602 in children who have hearing impairment due to conductive or mixed hearing loss. Safety and effectiveness of the device was assessed. Methods: the study group included 22 children aged 8–18 years (mean age 14.7 years) who had either conductive or mixed hearing loss. All patients were implanted unilaterally with the new Bonebridge BCI 602 implant. Pure tone audiometry, speech recognition tests (in quiet and noise), and free-field audiometry were performed before and after implantation. Word recognition scores were evaluated using the Demenko and Pruszewicz Polish Monosyllabic Word Test, and speech reception thresholds in noise were assessed using the Polish Sentence Matrix Test. The subjective assessment of benefits was carried outusing the APHAB (Abbreviated Profile of Hearing Aid Benefit) questionnaire. Results: after implantation of the Bonebridge BCI 602 all patients showed a statistically significant improvement in hearing and speech understanding. The mean word recognition score (WRS) changed from 12.1% before implantation to 87.3% after 6 months. Mean speech reception threshold (SRT) before implantation was +4.79 dB SNR and improved to −1.29 dB SNR after 6 months. All patients showed stable postoperative results. The APHAB questionnaire showed that difficulties in hearing decreased after implantation, with a statistically significant improvement in global score. Pre-operative scores (M = 35.7) were significantly worse than post-operative scores at 6 months (M = 25.7). Conclusions: the present study confirms that the Bonebridge BCI 602 is an innovative and effective solution, especially for patients with conductive and mixed hearing loss due to anatomical ear defects. The Bonebridge BCI 602 system provides valuable and stable audiological and surgical benefits. Subjective assessment also confirms the effectiveness of the BCI 602. The BCI 602 offers the same amplification as the BCI601, but with a smaller size. The smaller dimensions make it an effective treatment option for a wider group of patients, especially children with congenital defects of the outer and middle ear. Full article

Making use of magnetic resonance imaging (MRI) for diagnostics on patients with implanted medical devices requires caution due to mutual interactions between the device and the electromagnetic fields used by the scanner that can cause a number of adverse events. The presented study offers a novel test method to quantify the risk of unintended output of acoustically stimulating hearing implants. The design and operating principle of an all-optical, MRI safe vibrometer is outlined, followed by an experimental verification of a prototype. Results obtained in an MRI environment indicate that the system can detect peak displacements down to 8 pm for audible frequencies. Feasibility testing was performed with an active middle ear implant that was exposed to several pulse sequences in a 1.5 Tesla MRI environment. Magnetic field induced actuator vibrations, measured during scanning, turned out to be equivalent to estimated sound pressure levels between 25 and 85 dB SPL, depending on the signal frequency. These sound pressure levels are situated well below ambient sound pressure levels generated by the MRI scanning process. The presented case study therefore indicates a limited risk of audible unintended output for the examined hearing implant during MRI. Full article

Sound localization in daily life is one of the important functions of binaural hearing. Bilateral bone conduction devices (BCDs), middle ear implants, and cartilage conduction hearing aids have been often applied for patients with conductive hearing loss (CHL) or mixed hearing loss, for example, resulting from bilateral microtia and aural atresia. In this review, factors affecting the accuracy of sound localization with bilateral BCDs, middle ear implants, and cartilage conduction hearing aids were classified into four categories: (1) types of device, (2) experimental conditions, (3) participants, and (4) pathways from the stimulus sound to both cochleae. Recent studies within the past 10 years on sound localization and lateralization by BCDs, middle ear implants, and cartilage conduction hearing aids were discussed. Most studies showed benefits for sound localization or lateralization with bilateral devices. However, the judgment accuracy was generally lower than that for normal hearing, and the localization errors tended to be larger than for normal hearing. Moreover, it should be noted that the degree of accuracy in sound localization by bilateral BCDs varied considerably among patients. Further research on sound localization is necessary to analyze the complicated mechanism of bone conduction, including suprathreshold air conduction with bilateral devices. Full article

This report describes the design of a new piezoelectric transducer for round window (RW)-driven middle ear implants. The transducer consists of a piezoelectric element, gold-coated copper bellows, silicone elastomer (polydimethylsiloxane, PDMS), metal cylinder (tungsten), and titanium housing. The piezoelectric element is fixed to the titanium housing and mechanical resonance is generated by the interaction of the bellows, PDMS, and tungsten cylinder. The dimensions of PDMS and the tungsten cylinder with output characteristics suitable for compensation of sensorineural hearing loss were derived by mechanical vibrational analysis (equivalent mechanical model and finite element analysis (FEA)). Based on the results of FEA, the RW piezoelectric transducer was implemented, and bench tests were performed under no-load conditions to confirm the output characteristics. The transducer generates an average displacement of 219.6 nm in the flat band (0.1–1 kHz); the resonance frequency is 2.3 kHz. To evaluate the output characteristics, the response was compared to that of an earlier transducer. When driven by the same voltage (6 V_p), the flat band displacement averaged 30 nm larger than that of the other transducer, and no anti-resonance was noted. Therefore, we expect that the new transducer can serve as an output device for hearing aids, and that it will improve speech recognition and treat high-frequency sensorineural hearing loss more effectively. Full article

To overcome the inherent deficiencies of hearing aids, implantable middle ear hearing devices (IMEHDs) have emerged as a new treatment for hearing loss. However, clinical results show that the IMEHD performance varies with its transducer’s stimulating site. To numerically analyze the influence of the piezoelectric transducer’s stimulating sites on its hearing compensation performance, we constructed a human ear finite element model and confirmed its validity. Based on this finite element model, the displacement stimulation, which simulates the piezoelectric transducer’s stimulation, was applied to the umbo, the incus long process, the incus body, the stapes, and the round window membrane, respectively. Then, the stimulating site’s effect of the piezoelectric transducer was analyzed by comparing the corresponding displacements of the basilar membrane. Besides, the stimulating site’s sensitivity to the direction of excitation was also studied. The result of the finite element analysis shows that stimulating the incus body is least efficient for the piezoelectric transducer. Meanwhile, stimulating the round window membrane or the stapes generates a higher basilar membrane displacement than stimulating the eardrum or the incus long process. However, the performance of these two ideal sites’ stimulation is sensitive to the changes in the excitation’s direction. Thus, the round window membrane and the stapes is the ideal stimulating sites for the piezoelectric transducer regarding the driving efficiency. The direction of the excitation should be guaranteed for these ideal sites. Full article

Implantable middle ear hearing devices (IMEHDs) have been developed as a new technology to overcome the limitations of conventional hearing aids. The piezoelectric cantilever transducers currently used in the IMEHDs have the advantages of low power consumption and ease of fabrication, but generate less high-frequency output. To address this problem, we proposed and designed a new piezoelectric transducer based on a piezoelectric stack for the IMEHD. This new transducer, attached to the incus body with a coupling rod, stimulates the ossicular chain in response to the expansion-and-contraction of its piezoelectric stack. To test its feasibility for hearing loss compensation, a bench testing of the transducer prototype and a temporal bone experiment were conducted, respectively. Bench testing results showed that the new transducer did have a broad frequency bandwidth. Besides, the transducer was found to have a low total harmonic distortion (<0.75%) in all frequencies, and small release time (1 ms). The temporal bone experiment further proved that the transducer has the capability to produce sufficient vibrations to compensate for severe sensorineural hearing loss, especially at high frequencies. This property benefits the treatment of the most common sloping high-frequency sensorineural hearing loss. To produce a 100 dB SPL equivalent sound pressure at 1 kHz, its power consumption is 0.49 mW, which is low enough for the transducer to be utilized in the IMEHD. Full article

Fully implantable, self-powered hearing aids with no external unit could significantly increase the life quality of patients suffering severe hearing loss. This highly demanding concept, however, requires a strongly miniaturized device which is fully implantable in the middle/inner ear and includes the following components: frequency selective microphone or accelerometer, energy harvesting device, speech processor, and cochlear multielectrode. Here we demonstrate a low volume, piezoelectric micro-electromechanical system (MEMS) cantilever array which is sensitive, even in the lower part of the voice frequency range (300–700 Hz). The test array consisting of 16 cantilevers has been fabricated by standard bulk micromachining using a Si-on-Insulator (SOI) wafer and aluminum nitride (AlN) as a complementary metal-oxide-semiconductor (CMOS) and biocompatible piezoelectric material. The low frequency and low device footprint are ensured by Archimedean spiral geometry and Si seismic mass. Experimentally detected resonance frequencies were validated by an analytical model. The generated open circuit voltage (3–10 mV) is sufficient for the direct analog conversion of the signals for cochlear multielectrode implants. Full article