Sound Localization Research Articles

Sound event localization and detection using a spatial omni-dimensional dynamic interactions network

Sound event localization and detection using a spatial omni-dimensional dynamic interactions network

A Developmental Switch in Cholinergic Mechanisms of Modulation in the Medial Nucleus of the Trapezoid Body.

The medial nucleus of the trapezoid body (MNTB) has been intensively investigated as a primary source of inhibition in brainstem auditory circuitry. MNTB-derived inhibition plays a critical role in the computation of sound location, as temporal features of sounds are precisely conveyed through the calyx of Held/MNTB synapse. In adult gerbils, cholinergic signaling influences sound-evoked responses of MNTB neurons via nicotinic acetylcholine receptors (nAChRs; Zhang et al., 2021) establishing a modulatory role for cholinergic input to this nucleus. However, the cellular mechanisms through which acetylcholine (ACh) mediates this modulation in the MNTB remain obscure. To investigate these mechanisms, we used whole-cell current and voltage-clamp recordings to examine cholinergic physiology in MNTB neurons from Mongolian gerbils (Meriones unguiculatus) of both sexes. Membrane excitability was assessed in brain slices, in pre-hearing (postnatal days 9-13) and post-hearing onset (P18-20) MNTB neurons during bath application of agonists and antagonists of nicotinic (nAChRs) and muscarinic receptors (mAChRs). Muscarinic activation induced a potent increase in excitability most prominently prior to hearing onset with nAChR modulation emerging at later time points. Pharmacological manipulations further demonstrated that the voltage-gated K+ channel KCNQ (Kv7) is the downstream effector of mAChR activation that impacts excitability early in development. Cholinergic modulation of Kv7 reduces outward K+ conductance and depolarizes resting membrane potential. Immunolabeling revealed expression of Kv7 channels as well as mAChRs containing M1 and M3 subunits. Together, our results suggest that mAChR modulation is prominent but transient in the developing MNTB and that cholinergic modulation functions to shape auditory circuit development.

Binaural advantages in sound temporal information processing by neurons in the rat inferior colliculus.

Previous studies on the advantages of binaural hearing have long been focused on sound localization and spatial stream segregation. The binaural advantages have also been observed in speech perception in reverberation. Both human speech and animal vocalizations contain temporal features that are critical for speech perception and animal communication. However, whether there are binaural advantages for sound temporal information processing in the central auditory system has not been elucidated. Gap detection threshold (GDT), the ability to detect the shortest silent interval in a sound, has been widely used to measure the auditory temporal resolution. In the present study, we determined GDTs of rat inferior collicular neurons under both monaural and binaural hearing conditions. We found that the majority of the inferior collicular neurons in adult rats exhibited binaural advantages in gap detection, i.e., better neural gap detection ability in binaural hearing conditions compared to monaural hearing condition. However, this binaural advantage in sound temporal information processing was not significant in the inferior collicular neurons of P14-21 and P22-30 rats. Additionally, we also observed age-related changes in neural temporal acuity in the rat inferior colliculus. These results demonstrate a new advantage of binaural hearing (i.e., binaural advantage in temporal processing) in the central auditory system in addition to sound localization and spatial stream segregation.

Development of a Smart Game Application for Auditory Training of Children with Spatial Processing Disorder in Iran: A Pilot Study

Background and Aim: Identifying sound localization defects in children and using appropriate rehabilitation methods lead to improve their problem to use binaural processing skills to successfully suppress background noise and selectively attend to a particular auditory source. This pilot study aims to design a game for auditory training of children with Spatial Processing Disorder (SPD) in Iran and compare their performance in engagement time and speech recognition in noise with those of normal peers. Methods: The game application was designed based on the spatial separation of target and competing stimuli by applying head-related transfer functions. The child’s task was to identify the picture of the target word from among the displayed options. Participants were 24 children with SPD and 27 normal peers aged 7–9 years, who performed the speech recognition tasks using the designed game. Results: The game was fascinating and easy to use for most participants. There was no significant difference in mean engagement time between the two groups. The mean engagement time of participants was significantly different between the two groups in terms of age. The children with SPD obtained lower scores in speech recognition in noise tasks. There was no significant difference in speech recognition scores between girls and boys. Conclusion: The designed game application has the potential for speech recognition in- noise training of children with SPD in Iran. It is a fascinating and user-friendly tool for simulating the real-life auditory situations for these children. Keywords: Smart game; speech recognition; application; auditory training; design; spatial auditory processing disorder.

Acoustic higher-order topological states in kagome lattice with split-ring resonators

The next-nearest-neighbour (NNN) hoppings can induce many unique topological phenomena but are rarely considered in acoustics. This work investigates the higher-order topological states induced by the NNN hoppings in acoustic kagome lattice with split-ring resonators (SRRs). We build an extended tight-binding model (TBM) considering NNN hoppings to predict the topological corner modes (CMs) of the acoustic system and obtain the coupling strengths between the SRRs in different rotational angles. During rotating the SRRs, two nontrivial and one trivial systems characterized by bulk polarization can be obtained. In these two nontrivial systems, four novel CMs induced by the NNN hoppings can be observed in the first bandgap. Furthermore, the interactions between resonant and Bragg scattering effect of the SRRs are researched and the defect modes (DMs) are realized in the second bandgap. Finally, the CMs predicted by the extended TBM and DMs match well with the numerical and experimental ones. These discoveries unveil the intricate physics driven by the NNN hoppings, paving the way for innovative approaches to the design of tunable sound energy localization and multi-band metamaterials.

Sustained Cognitive Improvement in Patients over 65 Two Years after Cochlear Implantation.

This study aimed to evaluate the long-term benefits of cochlear implantation (CI) on cognitive performance, speech perception, and psychological status in post-lingually deafened patients older than 65 (n = 33). Patients were consecutively enrolled in this prospective study and assessed before, one year after, and two years after CI for speech perception, depressive symptoms, perceived stress, and working memory and processing speed. The Wechsler Adult Intelligence Scale (WAIS) was used for the latter. Thirty-three patients (fourteen men and nineteen women) were included. The scores indicating "hearing in quiet" and "hearing with background noise" improved significantly one year after CI and remained so two years after CI. The sound localization scores improved two years after CI. The depressive symptoms and perceived stress scores were low at the study's onset and remained unchanged. Working memory improved significantly two years after CI, while processing speed improved significantly one year after CI and was maintained after that. The improvement in working memory and processing speed two years after CI suggests there is a sustained positive effect of auditory rehabilitation with CI on cognitive abilities.

A novel visual representation method for multi-dimensional sound scene analysis in source localization problem

A visual representation method, DoAgram, for multi-dimensional sound scene analysis is suggested. The visual representation of the sound source localization result gives intuitive information about the estimated one to the end user. Also, image-based deep learning is popularly used in the acoustic field nowadays, so such a visualized one can be used for data augmentation. To analyze the spatial sound scene for the moving source, the method displays the estimated azimuth angle and elevation angle of the source, and its corresponding time stamp and frequencies as RGB color channels and metadata by mapping the spatial coordinate to color space. Even though the suggested method is human-interpretable, decoding is needed for the quantitative analysis. Therefore, the time and frequency scanning method, and a histogram to estimate the DoA of the source are proposed. An experiment is conducted in an anechoic chamber to localize two quadcopter drones that have a mean angular velocity of 8°/s ± 9°/s (95 % CI) and 25°/s ± 31°/s (95 % CI), respectively, and the spatial sound scene analysis is implemented using the proposed methods. The test result shows that the trajectories with respect to the time of each source are well separated. Also, an additional test is conducted using an open-access audio dataset for machine learning. The cumulative source mapping method is adopted for the spatial sound scene analysis, and the decoded result shows that the DoAgram is feasible to adopt for machine learning applications.

The auditory phenotype of behavioural variant frontotemporal dementia

AbstractBackgroundPatients with behavioural variant frontotemporal dementia commonly exhibit abnormal hedonic and other behavioural responses to sounds, however hearing dysfunction in this disorder is poorly characterised. Here we addressed this issue using the Queen Square Tests of Auditory Cognition (QSTAC) – a neuropsychological battery for the systematic assessment of central auditory functions (including pitch pattern perception, environmental sound recognition, sound localisation and emotion processing) in cognitively impaired people.MethodThe QSTAC was administered to 15 patients with behavioural variant frontotempoal dementia, 24 patients with comparator dementia syndromes (primary progressive aphasia and typical Alzheimer’s disease) and 15 healthy age‐matched individuals. Participants also had pure tone audiometry to assess peripheral hearing function and a comprehensive general neuropsychological assessment.ResultAfter accounting for nonverbal executive and peripheral hearing performance, patients with behavioural variant frontotemporal dementia showed deficits of environmental sound and auditory emotion recognition and sound localisation, compared both with healthy controls and patients with Alzheimer’s disease. Patients with behavioural variant frontotemporal dementia were further differentiated from primary progressive aphasia patients on their performance across QSTAC (sound recognition and localisation) subtests.ConclusionBehavioural variant frontotemporal dementia has a distinct phenotype of auditory cognitive dysfunction which likely contributes to the hearing alterations that many patients with this diagnosis experience in daily life. Our findings call attention to an under‐recognised issue in frontotemporal dementia that warrants further clinical interpretation and the development of management strategies tailored to real‐world acoustic environments.

Enhanced approach to fusing automatic characteristic frequency extraction and adaptive array signals weighting for abnormal machine sound localization

In this paper, an enhanced approach for sound localization is proposed, which fuses automatic extraction of array signal characteristic frequencies and adaptive weighting. The method refines the autoregressive power spectral estimation algorithm and improves density-based spatial clustering of applications with noise algorithm for characteristic frequency extraction. Adaptive weighting technique is introduced to alleviate the problem of frequency mismatch in the localization process. The initial weight of narrowband signals is calculated and normalized using the frequency domain amplitude integration of narrowband signals, followed by adaptive threshold correction to eliminate invalid narrowband signal weights. The adaptive weight vector improves the localization method’s accuracy and interference suppression. The effectiveness and universality of the proposed method are demonstrated with test data from dry transformers and pumps, and its applicability is shown to extend to various spatial spectrum estimation algorithms and deep learning-based sound source localization techniques.

Dementia is an auditory brain disorder

AbstractBackgroundWhile impaired hearing has emerged as a major potentiating factor for dementia, the basis for this relationship has not been defined. Most studies have emphasised the role of peripheral hearing loss. However, we hear with our brains: natural listening places immense computational demands on neural circuitry, and the neural networks pre‐eminently targeted by major dementias are essential for decoding and responding appropriately to the auditory environment. Auditory brain dysfunction is therefore predicted both to contribute importantly to hearing impairment in Alzheimer’s and other dementias and to be integral to the expression of neurodegenerative pathologies. Here I present an overview of evidence that speaks to this hypothesis.MethodsIn a series of linked experiments, we have assessed aspects of auditory cognition – the processes whereby the brain perceives, interprets and acts upon sounds ‐ in patient cohorts with Alzheimer’s disease and major syndromes of frontotemporal dementia, relative to healthy older individuals. We designed novel psychoacoustic tests to assess aspects of auditory scene analysis (the ‘cocktail party effect’ and localisation of sounds in space), comprehension of acoustically degraded speech and the processing of semantic and emotional information in sound in cognitively impaired people. Neuroanatomical mechanisms were assessed using voxel‐based morphometry and functional MRI.ResultsAcross experiments, after taking peripheral hearing function and general cognitive performance into account, patients with Alzheimer’s disease and frontotemporal dementias showed characteristic ‘auditory phenotypes’ or profiles of auditory cognitive impairment. Alzheimer’s disease is associated with impaired auditory scene analysis, linked to atrophy and dysfunction of temporo‐parietal cortical regions in the core ‘default mode network’ targeted by Alzheimer pathology. Frontotemporal dementia syndromes produce distinct impairments of auditory feature analysis, sound recognition and emotional valuation.ConclusionsAuditory brain dysfunction plays a key role in everyday hearing impairment and reflects core pathophysiology in major dementias. These findings raise the exciting prospect that auditory cognitive measures might be used in the early diagnosis of dementia, in guiding novel hearing interventions and as dynamic markers of therapeutic response in the dawning era of disease modification.

Practical utility of a head-mounted gaze-directed beamforming system.

Assistive auditory devices that enhance signal-to-noise ratio must follow the user's changing attention; errors could lead to the desired source being suppressed as noise. A method for measuring the practical benefit of attention-following speech enhancement is described and used to show a benefit for gaze-directed beamforming over natural binaural hearing. First, participants watched a recorded video conference call between two people with six additional interfering voices in different directions. The directions of the target voices corresponded to the spatial layout of their video streams. A simulated beamformer was yoked to the participant's gaze direction using an eye tracker. For the control condition, all eight voices were spatially distributed in a simulation of unaided binaural hearing. Participants completed questionnaires on the content of the conversation, scoring twice as high in the questionnaires for the beamforming condition. Sentence-by-sentence intelligibility was then measured using new participants who viewed the same audiovisual stimulus for each isolated sentence. Participants recognized twice as many words in the beamforming condition. The results demonstrate the potential practical benefit of gaze-directed beamforming for hearing aids and illustrate how detailed intelligibility data can be retrieved from an experiment that involves behavioral engagement in an ongoing listening task.

Auditory Spatial Discrimination and Sound Localization in Single-Sided Deaf Participants Provided with a Cochlear Implant

Introduction: Spatial hearing is most accurate using both ears, but accuracy decreases in persons with asymmetrical hearing between ears. In participants with deafness in one ear but normal hearing in the other ear (single-sided deafness [SSD]), this difference can be compensated by a unilateral cochlear implant (CI). It has been shown that a CI can restore sound localization performance, but it is still unclear to what extent auditory spatial discrimination can be improved. Methods: The present study investigated auditory spatial discrimination using minimum audible angles (MAAs) in 18 CI-SSD participants. Results were compared to 120 age-matched normal-hearing (NH) listeners. Low-frequency (LF) and high-frequency (HF) noise bursts were presented from 4°, 30°, and 60° azimuth on the CI side and on the NH side. MAA thresholds were tested for correlation with localization performance in the same participants. Results: There were eight good performers and ten poor performers. There were more poor performers for LF signals than for HF signals. Performance on the CI side was comparable to performance on the NH side. Most difficulties occurred at 4° and at 30°. Eight of the good performers in the localization task were also good performers in the MAA task. Only the localization ability at 4° on the CI side was positively correlated with the MAA at that location. Conclusion: Our data suggest that a CI can restore localization ability but not necessarily auditory spatial discrimination at the same time. The ability to discriminate between adjacent locations may be trainable during rehabilitation to enhance important auditory skills.

A new complex mapping method of neural networks used in sound source localization

Sound source localization has a wide range of application prospects in many fields, such as smart home and audio monitoring. Traditional methods are difficult to achieve accurate location in the face of multi-path reflection, reverberation, and ambient noise. In this paper, a complex mapping conversion method for sound source location is proposed. By using complex-valued convolutional neural networks to fuse the amplitude and phase information of the data, a more accurate and comprehensive analysis can be carried out to improve its robustness and realize the accurate location of the sound source. The sound source location method based on complex-valued convolutional neural networks is studied, and the complex mapping principle is analyzed. Simulation and experimental studies were carried out, and the results of simulation and experiment are basically consistent. In the experiment, the positioning accuracy of the complex mapping method is 9.49% higher than that of the absolute value method and 15.81% higher than that of the phase angle method. In addition, its localization success rate, respectively, increased by 4.9% and 8.6% compared to two other methods. This paper opens up a new way for the application of complex-valued convolutional neural networks in sound source localization.

An inhibitory glycinergic projection from the cochlear nucleus to the lateral superior olive.

Auditory brainstem neurons in the lateral superior olive (LSO) receive excitatory input from the ipsilateral cochlear nucleus (CN) and inhibitory transmission from the contralateral CN via the medial nucleus of the trapezoid body (MNTB). This circuit enables sound localization using interaural level differences. Early studies have observed an additional inhibitory input originating from the ipsilateral side. However, many of its details, such as its origin, remained elusive. Employing electrical and optical stimulation of afferents in acute mouse brainstem slices and anatomical tracing, we here describe a glycinergic projection to LSO principal neurons that originates from the ipsilateral CN. This inhibitory synaptic input likely mediates inhibitory sidebands of LSO neurons in response to acoustic stimulation.

Error analysis of the compact microphone array for sound source localization

Smart sensing is used to provide specific information by using physical quantities measured by multiple sensors or multi-modal sensor modules. Nowadays, the smart sensor is configured as a compact system using very small transducers implemented by MEMS technology. Accordingly, the multi-modal sensing device is getting miniaturized. A microphone array can be classified as a smart sensing device that estimates the sound field information. However, it is difficult to implement a compact system because the measurable frequency range is limited by the spacing between adjacent microphones. Also, the calibration is difficult due to the irregularly shaped sensor element; therefore, the traceability is not yet established. In this study, sound source localization algorithms are applied for implementing the compact microphone array. The inherent error due to the sensor position tolerance, magnitude difference, and phase mismatch is analyzed. Because the coherent noise increases uncertainty in the actual test environment, the estimation error depending on the critical distance is analyzed. Finally, a compact webcam-based multi-modal sensor is implemented and the localization test result is reviewed.

A study on the influence of reflective surfaces on sound source localization using distributed acoustic measurement equipment

This research aims to develop a system that will detect sound source localization in a broad area using cross-correlation functions for signals from distributed microphone arrays, which is difficult with conventional methods that use microphone arrays. For the localization of sound sources, four microphones were distributed in an anechoic room. Based on the result, the system was able to estimate the sound source position within a plus or minus 20 mm of accuracy. To verify the accuracy of the system, a reflective surface was set up in an anechoic room to confirm the effect of reflected and diffracted sound. No significant increase in error was observed when the reflective surface was behind the microphone as viewed from the sound source. However, the estimation error increased when diffracted sound was present.

Numerical Simulation Results of Double Nearfield Acoustic Holography method with extrapolation

In my laboratory, the new sound localization method, Double Nearfield Acoustic Holography (DNAH) method is being developed. This method has high resolution in low frequency sound localization. It is presented at former inter-noise. On the other hand, the extrapolation of measurement points is effective for Nearfield Acoustic Holography method in low frequency. Therefore, the extrapolation technique is also applied for DNAH method. In this presentation, the numerical simulation results of DNAH method with extrapolation of measurement points is reported. With extrapolation, the DNAH shows higher resolution in low frequency sound localization than DNAH method without extrapolation, and higher resolution in low frequency sound localization than NAH method with extrapolation.

Further investigation of horizontal sound localization in noise

The accuracy of sound localization suffers significantly in a noisy environment. Noise can have an impact on the binaural localization cues such as interaural time difference (ITD) and interaural level difference (ILD). This impact is not only related to the signal-to-noise ratio (SNR), but also to the noise level. Therefore, it's crucial to understand how to describe binaural localization cues in noise. This study investigates the effect of noise level (ranging from 80 dB to 95 dB) and SNR (ranging from -15 dB to -5 dB) on the localization of horizontal sound sources at different azimuths. By analyzing the interaction between different binaural cues and localization accuracy in noise, the results demonstrate that there is a strong association between localization accuracy and interaural partial loudness difference. A follow-up experiment with modified ILD confirmed that the interaural partial loudness difference might more accurately reflect the auditory localization properties of the horizontal sound source in noise.

Class-Aware Contrastive Learning for Improving Performance of Sound Source Localization Model in Videos

Class-Aware Contrastive Learning for Improving Performance of Sound Source Localization Model in Videos

Evaluation of noise emissions of a ducted fan on a test rig

This paper presents an experimental research study on the sound excitation of a ducted fan designed for low-noise emissions. In particular, the influence of test rig vibrations as a significant systematic error when evaluating the noise emissions of ducted fans is discussed. A propulsor test rig was used to measure the sound emitted by a ducted fan. Significantly increased sound levels are ascertained at specific frequencies. The corresponding sources are often unexpectedly identified at the casing and structure of the rig using a sound source localization. By comparing sound pressures against vibrations, these sources are found to be excited by simultaneous test rig vibrations. When the rig vibrates, the sound pressure levels increase by up to 15 dB compared to vibration-free operation. The sound excitation caused by the rig vibrations predominates over the aerodynamically induced sound since the ducted fan itself emits little noise. In summary, these rig-dependent vibrations can lead to a considerable systematic measurement error for low-noise ducted fans. This error significantly complicates an accurate sound evaluation of such a ducted fan on an acoustic rig. Therefore, these results emphasize the importance of a vibration-free operating range and the necessity to quantify the sound excitation by rig-specific vibrations.