An eight-channel database of head-related impulse responses (HRIRs) and binaural room impulse responses (BRIRs) is introduced. The impulse responses (IRs) were measured with three-channel ...behind-the-ear (BTEs) hearing aids and an in-ear microphone at both ears of a human head and torso simulator. The database aims at providing a tool for the evaluation of multichannel hearing aid algorithms in hearing aid research. In addition to the HRIRs derived from measurements in an anechoic chamber, sets of BRIRs for multiple, realistic head and sound-source positions in four natural environments reflecting daily-life communication situations with different reverberation times are provided. For comparison, analytically derived IRs for a rigid acoustic sphere were computed at the multichannel microphone positions of the BTEs and differences to real HRIRs were examined. The scenes' natural acoustic background was also recorded in each of the real-world environments for all eight channels. Overall, the present database allows for a realistic construction of simulated sound fields for hearing instrument research and, consequently, for a realistic evaluation of hearing instrument algorithms.
As a result of newborn hearing screening, hearing aids are usually prescribed and fitted by 2–3 months of age. However, the assessment data used for prescribing hearing aids in infants and toddlers ...are limited in quality and quantity. There is great interest in finding appropriate physiological measures that can be help to facilitate and improve the management process of hearing impaired children. It seems that cortical auditory evoked potentials (CAEPs) can provide information before it is possible to obtain reliable information from behavioral assessment procedures. This article will review the studies conducted in this area during the past15 years to determine the advantages, disadvantages and future research areas of CAEPs as an objective method in the management of hearing impaired children.
The focus of this article is on level set based topology optimization of vibroacoustic hearing instruments. The goal is to demonstrate the applicability of the proposed framework for optimization of ...3D industrial scale hearing instruments. The framework employs an immersed boundary cut element method to handle the modeling of complex design geometries on fixed unstructured meshes. Utilization of unstructured meshes allows for optimizing small parts of a complex hearing instrument without disturbing the overall geometry. The remaining parts of the model which are not included in the optimization process are modeled with segregated approach. The design parameterization is based on an explicit level set approach, for which the nodal level set values are linked to the mathematical design variables. The optimization problem is solved using mathematical programming and the sensitivities are obtained with a discrete adjoint approach. A validation study is carried out comparing the proposed cut element model to a body fitted mesh for a large range of frequencies. The optimization framework is then applied on the tube and the suspension structures of a hearing instrument system considering two sets of material properties for the design parts. The optimization considers the minimization of sound pressure on the microphone surface for discrete frequencies aiming to reduce the feedback paths and to increase the amplification that the device can deliver to the user. Both optimization cases improve the performance of the hearing instrument system by effectively reducing the sound pressure on the microphone surface for the considered frequency range.
•A 3D level set based topology optimization method for strongly coupled vibroacoustics.•An accurate 3D cut element method allowing for optimization with crisp interfaces.•Method validation by comparison to body fitted mesh analysis.•Demonstrated for the minimization of feedback paths in an industrial hearing system.
Recurrent neural networks (RNNs) are well-suited for sequential tasks such as speech enhancement (SE). However, their performance comes with high-computational complexity and latency. This impedes ...their deployment to battery-powered and resource-constrained hearing instruments (HIs) that need to operate for 16-18 h daily at only a few milliwatts (mW). In this article, we introduce PeakEngine, a configurable ASIC accelerator that decreases the amount of computation and memory accesses, and thus latency, in a gated recurrent unit (GRU) by means of adaptive inference. The reduction is achieved by on-the-fly pruning that selects the top <inline-formula> <tex-math notation="LaTeX">K </tex-math></inline-formula> elements based on magnitudes of delta changes across timesteps from both input and hidden state sequences. Since <inline-formula> <tex-math notation="LaTeX">K </tex-math></inline-formula> is constant, it results in a deterministic execution time. PeakEngine is synthesized in a 22-nm CMOS process, and the simulations show that it dissipates <inline-formula> <tex-math notation="LaTeX">11.83 ~\mu \text{J} </tex-math></inline-formula> per inference for the baseline (unpruned) network and only 4.14-<inline-formula> <tex-math notation="LaTeX">5.04 ~\mu \text{J} </tex-math></inline-formula> for the pruned networks, with maximum acceptable degradation to no degradation in the improvement in audio quality and intelligibility. Moreover, the inference is on average sped up 2.2-<inline-formula> <tex-math notation="LaTeX">2.97\times </tex-math></inline-formula>, hence meeting the real-time requirements imposed by a HI application. To the best of our knowledge, PeakEngine is the first ASIC accelerator for deterministic and dynamic pruning in RNNs targeting HIs and SE.
An ear-to-ear (E2E) propagation model based on geometrical theory of diffraction (GTD) is presented. The model uses the creeping wave loss along the geodesic paths that connect the ears. It is the ...first model to investigate which geodesic paths that link the ears. The model uses GTD expressions for a lossy dielectric material, which is a much better approximation of the human body than the perfect electric conductor approximation often used. The model is validated for the industrial, scientific, and medical band at 2.45 GHz. The model is valid at any frequency range as long as the propagation loss through the head is significantly higher than the propagation loss around the head. Similarly, the model could be used for other areas of the body. The comparison with simulations shows strong correlation. The antenna orientation and frequency sweeps were performed to further investigate the model. The sweeps change the radiation pattern of the antenna to utilize different paths around the head, but the model still correlates with the simulation. This validates the model's division of the E2E propagation into different geodesic paths around the head.
This paper presents the compact wideband loop antenna with a small size of 7.05mm's radius covering ultra-wideband above 6 GHz, Wi-Fi, and Bluetooth bands for earbuds. The wide bandwidth of the ...proposed compact loop antenna is obtained with the antenna structure consisting of the loop antenna and the capacitive loading pin inserted in the middle of the loop antenna. The loop antenna with the capacitive loading pin supports multi-resonant modes. A wider bandwidth can be obtained by adjusting the position of the capacitive loading pin. The half-wavelength resonant frequency of the basic loop can easily be tuned through the physical capacitance between the capacitive loading pin and loop antenna. Additionally, the impedance loop is considered for the impedance matching of the compact wideband loop antenna. The simulated and measured results are included to evaluate the performance of the proposed compact wideband loop antenna. Consequently, we obtained that the simulation and measurements results are consistent.
The benefit of using external acoustic sensor nodes for noise reduction in hearing aids is demonstrated in a simulated acoustic scenario with multiple sound sources. A distributed adaptive ...node-specific signal estimation (DANSE) algorithm, that has a reduced communication bandwidth and computational load, is evaluated. Batch-mode simulations compare the noise reduction performance of a centralized multi-channel Wiener filter (MWF) with DANSE. In the simulated scenario, DANSE is observed not to be able to achieve the same performance as its centralized MWF equivalent, although in theory both should generate the same set of filters. A modification to DANSE is proposed to increase its robustness, yielding smaller discrepancy between the performance of DANSE and the centralized MWF. Furthermore, the influence of several parameters such as the DFT size used for frequency domain processing and possible delays in the communication link between nodes is investigated.
A novel in-the-ear (ITE) antenna solution for hearing instruments that operates at 2.45 GHz is presented. The antenna consists of a quarter wave monopole and a ground plane that are placed in the ...ear. The simulated path gain |S21| is −86 dB and the measured path gain is −80 dB. Simulations and measurements show that the antenna covers the entire 2.40–2.48 GHz industrial, scientific and medical (ISM) band. It is the first ever ITE-antenna solution that demonstrates the possibility of establishing an ear-to-ear link by using a standard Bluetooth chip.
Osseointegrated bone conduction (BC) devices are an important rehabilitation option for patients with mixed or conductive hearing loss or single-sided deafness. The development of new devices is ...ongoing and requires evaluation of the performance of new hearing aids. Here, we compared the audiologic outcome and subjective benefit of two different designs of osseointegrated implant systems from different manufacturers.
Prospective, experimental, monocentric, crossover study performed at the Medical University Hannover, Germany.
Eleven patients, already implanted with an adequate abutment, tested each device in daily life situations sequentially for a period of 3 weeks.
Bone conduction, word recognition in quiet (Freiburg monosyllable test, L50%), and speech reception thresholds in noise (Oldenburg Sentence Test) were measured unaided and aided with the devices after each test period. The subjective benefit was assessed by the Abbreviated Profile of Hearing Aid Benefit; the Speech, Spatial and Qualities of Hearing Scale-Comparative questionnaire; and a self-developed handling questionnaire.
Audiologic results indicate a slightly better performance of the BCB. However, subjective benefit and patient satisfaction and preference evaluated with questionnaires were higher with the BCP than with the BCB.
Amplification-wise, both devices are suitable treatments for hearing-impaired patients. Nevertheless, audiometric tests do not reflect subjective benefit and patients' satisfaction, and both options should be tested to provide each patient with the best possible hearing solution. The study further elucidates the importance and necessity of questionnaires in the process of evaluating the hearing benefit of hearing devices.
A new system for single-channel speech enhancement is proposed which achieves a joint suppression of late reverberant speech and background noise with a low signal delay and low computational ...complexity. It is based on a generalized spectral subtraction rule which depends on the variances of the late reverberant speech and background noise. The calculation of the spectral variances of the late reverberant speech requires an estimate of the reverberation time (RT) which is accomplished by a maximum likelihood (ML) approach. The enhancement with this blind RT estimation achieves almost the same speech quality as by using the actual RT. In comparison to commonly used post-filters in hearing aids which only perform a noise reduction, a significantly better objective and subjective speech quality is achieved. The proposed system performs time-domain filtering with coefficients adapted in the non-uniform (Bark-scaled) frequency-domain. This allows to achieve a high speech quality with low signal delay which is important for speech enhancement in hearing aids or related applications such as hands-free communication systems.
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