Acoustic Stimuli Research Articles

Quantitative analysis of 3D-printed custom ossicular prostheses motion using laser Doppler vibrometry.

<b><br>Introduction:</b> In chronic otitis media, the reconstruction of the middle ear's sound conducting system involves repairing the tympanic membrane and filling the space between ossicular chain remnants. The final shape of the prosthesis is usually determined intraoperatively. However, the ossicular chain may be preoperatively measured using computed tomography (CT) scans, and an individualized prosthesis can be designed. Custom 3D printing seems to be an attractive solution for optimal adjustment.</br> <b><br>Aim:</b> Our study aimed to assess the 3D-printed custom prosthesis movability and compare it to the original ossicular chain.</br> <b><br>Material and methods:</b> Five fresh-frozen temporal bone specimens were used. Using Cone-Beam CT scans, the incus model was designed individually and 3D-printed. The ossicular chain was reconstructed inside the cadaveric temporal bone. Acoustic stimuli were applied to the external ear canal one frequency at a time. The laser Doppler vibrometer (LDV) measured the intact and 3D-printed prosthesis reconstructed ossicular chain vibrations.</br> <b><br>Results:</b> At all stimulation frequencies, there was no significant difference in velocity values between the intact and reconstructed ossicular chain at the intensity of 80 dB SPL. The obtained values of the velocity gain were: -7.9 (SD-19) dB, -6.8 (SD8.12) dB, -10,9 (SD-5.3) dB, -7.4 (SD-8.16) dB for 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz, respectively. The vibration threshold shift values ranged between -0.57 dB at 500 Hz and 3.81 dB at 2000 Hz.</br> <b><br>Conclusions:</b> This study analyzed the movability of individualized 3D-printed custom ossicular prostheses using LDV. Compared to the intact ossicular chain, the reconstructed ossicular chain movability was characterized by statistically insignificant reduced movability at all tested frequencies. Because the prosthesis's new design conception as custom 3D individualized printing allows for patient-specific ossiculoplasty, it represents a promising new direction for ossicular chain reconstruction. It seems to be an attractive solution for prosthesis optimal adjustment and, hopefully, better hearing results.</br&gt.

Investigation of the Effect of Tinnitus and Hearing Loss on Hippocampus Volume

Objective: This study aims to compare hippocampal changes with a correlation of audiological testing results in patients suffering from tinnitus. Methods: Patients diagnosed with tinnitus in the university hospital between February 2021 and March 2022 were prospectively included in the study by performing magnetic resonance imaging. The volume was determined by manually tracing the hippocampus' margins on the images using the Vitrea2® workstation (Canon Medical Systems Vital Images, Minnesota, USA). Statistics were used to assess the correlation between the parameters of the hearing test. Results: The distribution of the patient group (21 males, 19 females) and control group (15 males, 15 females) was uniform, and the mean ages of the two groups were 50.23±12.09 and 32.30±7.97, respectively. Significant statistical differences existed in the mean ages of the groups (p<0.05). Bilateral hippocampal volumes, right bone, and air conduction all differed significantly (p<0.05). The median values in the patient group were as follows: right HC 2620 mm3 (range 1600-3610), left HC 2450 mm3 (range 1610-3990), right air conduction 20 dB (range 10-61), left air 21 dB (range 11-65), and right bone 13.5 dB (range 8-49). Age was positively correlated with bilateral measurements of air and bone hearing levels (p 0.05; right air r=0.513, right bone r=0.438, left air r=0.589, left bone r=0.487). Between the 30-39 and 60-69 age groups, there was a significant difference in bone and air conduction levels (p<0.05). Conclusion: In this study, it was found that the hippocampus volumes of healthy hearing people with tinnitus complaints were significantly higher in MRI examinations compared to the control group. In addition, in cases of tinnitus accompanied by bone conduction hearing loss, hippocampus volumes were found to be less than those of tinnitus alone, but not less than in the control group. It is suggested that chronic acoustic stimulation caused by tinnitus causes an increase in hippocampus volume and that problems in sensorineural integrity prevent this increase.

Auditory stimulation during REM sleep modulates REM electrophysiology and cognitive performance

REM sleep is critical for memory, emotion, and cognition. Manipulating brain activity during REM could improve our understanding of its function and benefits. Earlier studies have suggested that auditory stimulation in REM might modulate REM time and reduce rapid eye movement density. Building on this, we studied the cognitive effects and electroencephalographic responses related to such stimulation. We used acoustic stimulation locked to eye movements during REM and compared two overnight conditions (stimulation and no-stimulation). We evaluated the impact of this stimulation on REM sleep duration and electrophysiology, as well as two REM-sensitive memory tasks: visual discrimination and mirror tracing. Our results show that this auditory stimulation in REM decreases the rapid eye movements that characterize REM sleep and improves performance on the visual task but is detrimental to the mirror tracing task. We also observed increased beta-band activity and decreased theta-band activity following stimulation. Interestingly, these spectral changes were associated with changes in behavioural performance. These results show that acoustic stimulation can modulate REM sleep and suggest that different memory processes underpin its divergent impacts on cognitive performance.

Experimental research on enhanced heat and mass transfer in transport membrane condenser under an acoustic stimulus

The transport membrane condenser (TMC) is a novel membrane contactor that efficiently recovers moisture and waste heat from flue gas. However, the presence of non-condensing gas boundary layers and cooling water boundary layers significantly diminishes the heat and mass transfer performance of ceramic membranes. Additional fields (electric and vibrational) become one of the effective ways to solve the problem. However, the mechanism by which acoustic fields affect water vapor recovery through ceramic membranes remains unclear. Therefore, this study employs an acoustic field-coupled TMC to investigate the influence of acoustic fields on the heat and mass transfer performance. Two engineering schemes coupling TMC with acoustic fields are proposed, and the feasibility of their application is analyzed. The results demonstrate that arranging the acoustic field on the water side yields superior heat and mass transfer performance. A significant vortex effect is discovered when the acoustic field frequency is between 300 and 400 Hz, resulting in a 44% increase in mass transfer rate and a 52% increase in condensation rate. Taking a 330 MW coal-fired power plant as an example, the incorporation of acoustic fields in the two proposed schemes reduces the payback period by 1.56 years and 1.58 years, respectively, and increases the net present value by 143% and 90%.

The human middle ear in motion: 3D visualization and quantification using dynamic synchrotron-based X-ray imaging

The characterization of the vibrations of the middle ear ossicles during sound transmission is a focal point in clinical research. However, the small size of the structures, their micrometer-scale movement, and the deep-seated position of the middle ear within the temporal bone make these types of measurements extremely challenging. In this work, dynamic synchrotron-based X-ray phase-contrast microtomography is used on acoustically stimulated intact human ears, allowing for the three-dimensional visualization of entire human eardrums and ossicular chains in motion. A post-gating algorithm is used to temporally resolve the fast micromotions at 128 Hz, coupled with a high-throughput pipeline to process the large tomographic datasets. Seven ex-vivo fresh-frozen human temporal bones in healthy conditions are studied, and the rigid body motions of the ossicles are quantitatively delineated. Clinically relevant regions of the ossicular chain are tracked in 3D, and the amplitudes of their displacement are computed for two acoustic stimuli.

Evidence for individual vocal recognition in a pair-bonding poison frog, Ranitomeya imitator.

Individually distinctive vocalizations are widespread in nature, although the ability of receivers to discriminate these signals has only been explored through limited taxonomic and social lenses. Here, we asked whether anuran advertisement calls, typically studied for their role in territory defense and mate attraction, facilitate recognition and preferential association with partners in a pair-bonding poison frog (Ranitomeya imitator). Combining no- and two-stimulus choice playback experiments, we evaluated behavioral responses of females to male acoustic stimuli. Virgin females oriented to and approached speakers broadcasting male calls independent of caller identity, implying that females are generally attracted to male acoustic stimuli outside the context of a pair bond. When pair-bonded females were presented with calls of a mate and a stranger, they showed significant preference for calls of their mate. Moreover, behavioral responses varied with breeding status: females with eggs were faster to approach stimuli than females that were pair bonded but did not currently have eggs. Our study suggests a potential role for individual vocal recognition in the formation and maintenance of pair bonds in a poison frog and raises new questions about how acoustic signals are perceived in the context of monogamy and biparental care.

Neural Decoding of the Speech Envelope: Effects of Intelligibility and Spectral Degradation.

During continuous speech perception, endogenous neural activity becomes time-locked to acoustic stimulus features, such as the speech amplitude envelope. This speech-brain coupling can be decoded using non-invasive brain imaging techniques, including electroencephalography (EEG). Neural decoding may provide clinical use as an objective measure of stimulus encoding by the brain-for example during cochlear implant listening, wherein the speech signal is severely spectrally degraded. Yet, interplay between acoustic and linguistic factors may lead to top-down modulation of perception, thereby complicating audiological applications. To address this ambiguity, we assess neural decoding of the speech envelope under spectral degradation with EEG in acoustically hearing listeners (n = 38; 18-35 years old) using vocoded speech. We dissociate sensory encoding from higher-order processing by employing intelligible (English) and non-intelligible (Dutch) stimuli, with auditory attention sustained using a repeated-phrase detection task. Subject-specific and group decoders were trained to reconstruct the speech envelope from held-out EEG data, with decoder significance determined via random permutation testing. Whereas speech envelope reconstruction did not vary by spectral resolution, intelligible speech was associated with better decoding accuracy in general. Results were similar across subject-specific and group analyses, with less consistent effects of spectral degradation in group decoding. Permutation tests revealed possible differences in decoder statistical significance by experimental condition. In general, while robust neural decoding was observed at the individual and group level, variability within participants would most likely prevent the clinical use of such a measure to differentiate levels of spectral degradation and intelligibility on an individual basis.

Functional neurogenomic responses to acoustic threats, including a heterospecific referential alarm call and its referent, in the auditory forebrain of red-winged blackbirds

In animal communication, functionally referential alarm calls elicit the same behavioral responses as their referents, despite their typically distinct bioacoustic traits. Yet the auditory forebrain in at least one songbird species, the black-capped chickadee Poecile atricapillus, responds similarly to threat calls and their referent predatory owl calls, as assessed by immediate early gene responses in the secondary auditory forebrain nuclei. Whether and where in the brain such perceptual and cognitive equivalence is processed remains to be understood in most other avian systems. Here, we studied the functional neurogenomic (non-) equivalence of acoustic threat stimuli perception by the red-winged blackbird Agelaius phoeniceus in response to the actual calls of the obligate brood parasitic brown-headed cowbird Molothrus ater and the referential anti-parasitic alarm calls of the yellow warbler Setophaga petechia, upon which the blackbird is known to eavesdrop. Using RNA-sequencing from neural tissue in the auditory lobule (primary and secondary auditory nuclei combined), in contrast to previous findings, we found significant differences in the gene expression profiles of both an immediate early gene, ZENK (egr-1), and other song-system relevant gene-products in blackbirds responding to cowbird vs. warbler calls. In turn, direct cues of threats (including conspecific intruder calls and nest-predator calls) elicited higher ZENK and other differential gene expression patterns compared to harmless heterospecific calls. These patterns are consistent with a perceptual non-equivalence in the auditory forebrain of adult male red-winged blackbirds in response to referential calls and the calls of their referents.

Dissociable Roles of the Auditory Midbrain and Cortex in Processing the Statistical Features of Natural Sound Textures.

Sound texture perception takes advantage of a hierarchy of time-averaged statistical features of acoustic stimuli, but much remains unclear about how these statistical features are processed along the auditory pathway. Here, we compared the neural representation of sound textures in the inferior colliculus (IC) and auditory cortex (AC) of anesthetized female rats. We recorded responses to texture morph stimuli that gradually add statistical features of increasingly higher complexity. For each texture, several different exemplars were synthesized using different random seeds. An analysis of transient and ongoing multiunit responses showed that the IC units were sensitive to every type of statistical feature, albeit to a varying extent. In contrast, only a small proportion of AC units were overtly sensitive to any statistical features. Differences in texture types explained more of the variance of IC neural responses than did differences in exemplars, indicating a degree of "texture type tuning" in the IC, but the same was, perhaps surprisingly, not the case for AC responses. We also evaluated the accuracy of texture type classification from single-trial population activity and found that IC responses became more informative as more summary statistics were included in the texture morphs, while for AC population responses, classification performance remained consistently very low. These results argue against the idea that AC neurons encode sound type via an overt sensitivity in neural firing rate to fine-grain spectral and temporal statistical features.

Optimum stimulus for eliciting masseter vestibular-evoked myogenic potential: a comparative exploration with three different acoustic stimuli

ObjectiveTo compare the EMG rectified amplitude, absolute latencies, interpeak interval, and Interaural asymmetry parameters of masseter vestibular-evoked myogenic potential (mVEMP) elicited using clicks, 500 Hz tone bursts, and 500 Hz NB CE-chirps.MethodTwenty-five young healthy adults in the age range of 18–27 years participated for the study. mVEMP was recorded using three different acoustic stimuli i.e., clicks, 500 Hz tone bursts, and 500 Hz NB CE-chirps. mVEMP was recorded at an intensity of 125 dB peSPL with 5.1/s repetition rate. The potentials were recorded ipsilaterally using zygomatic electrode montage and were filtered between 0.1 and 3000 Hz. EMG rectification of the responses was made prior to analysis.ResultsThe latencies of P1 and N1 were significantly earlier for chirps then followed by click and tone bursts. The EMG rectified amplitude was significantly larger for the potentials obtained using chirps followed by tone bursts and then the clicks. Masseter VEMP obtained using chirps had significantly larger interpeak interval than tone bursts and clicks. The mean amplitude asymmetry ratio was greater in the potentials obtained using chirps than the other two stimuli.ConclusionThe present study reveals that 500 Hz NB CE-chirps tend to produce mVEMP with larger response amplitude and earlier latencies and thus are considered better and constructive stimuli compared to clicks and tone bursts.

Validation of the acoustic change complex (ACC) prediction model to predict speech perception in noise in adult patients with hearing loss: a study protocol

BackgroundSpeech perception tests are essential to measure the functional use of hearing and to determine the effectiveness of hearing aids and implantable auditory devices. However, these language-based tests require active participation and are influenced by linguistic and neurocognitive skills limiting their use in patients with insufficient language proficiency, cognitive impairment, or in children. We recently developed a non-attentive and objective speech perception prediction model: the Acoustic Change Complex (ACC) prediction model. The ACC prediction model uses electroencephalography to measure alterations in cortical auditory activity caused by frequency changes. The aim is to validate this model in a large-scale external validation study in adult patients with varying degrees of sensorineural hearing loss (SNHL) to confirm the high predictive value of the ACC model and to assess its test–retest reliability.MethodsA total of 80 participants, aged 18–65 years, will be enrolled in the study. The categories of severity of hearing loss will be used as a blocking factor to establish an equal distribution of patients with various degrees of sensorineural hearing loss. During the first visit, pure tone audiometry, speech in noise tests, a phoneme discrimination test, and the first ACC measurement will be performed. During the second visit (after 1–4 weeks), the same ACC measurement will be performed to assess the test–retest reliability. The acoustic change stimuli for ACC measurements consist of a reference tone with a base frequency of 1000, 2000, or 4000 Hz with a duration of 3000 ms, gliding to a 300-ms target tone with a frequency that is 12% higher than the base frequency. The primary outcome measures are (1) the level of agreement between the predicted speech reception threshold (SRT) and the behavioral SRT, and (2) the level of agreement between the SRT calculated by the first ACC measurement and the SRT of the second ACC measurement. Level of agreement will be assessed with Bland–Altman plots.DiscussionPrevious studies by our group have shown the high predictive value of the ACC model. The successful validation of this model as an effective and reliable biomarker of speech perception will directly benefit the general population, as it will increase the accuracy of hearing evaluations and improve access to adequate hearing rehabilitation.

Psychophysical and Electrophysiological Parameters of the Auditory Analyzer as Indicators of the Effectiveness of Cochlear Implantation in Children with Bilateral Deafness

Background. The results of rehabilitation of patients with deafness after cochlear implantation (CI) depends on many factors related on both the individual characteristics of the patient and the technical parameters of auditory nerve stimulation — fitting of the CI system processor. Article presents the results of a study of the relationship between psychophysical (subjective) auditory sensations and electrophysiological (objective) responses of the structures of the auditory analyzer to electrical stimulation. Aims — to evaluate the relationship between the electrophysiological responses of the auditory analyzer and the psychophysical parameters of the thresholds of sound perception and speech intelligibility in patients with deafness after CI. Methods. The study involved 88 patients with IV bilateral sensorineural hearing loss, borderline with deafness, aged 6 to 17 years 11 months, among whom 54.5% (n = 48) of girls and 45.5% (n = 40) of boys. Of the patients included in the follow-up, 40% (n = 35) underwent unilateral CI; 60% (n = 53) of children underwent bilateral sequential CI. In our study, slightly more than half of the patients (51.1%) had experience using the CI system for more than 5 years. At the first stage of the study, we studied the relationship between sound perception thresholds (tonal audiometry in a free field) and registered ASSR (auditory steady state response) thresholds in patients with deafness receiving rehabilitation after CI surgery. The relationship between behavioral and electrophysiological (objective) thresholds was assessed by comparing the results of tonal threshold audiometry and the responses received during ASSR registration to acoustic stimulation in a free field. At the second stage, patients with indications for processor fitting (decreased speech intelligibility, uncomfortable sensations) underwent speech audiometry, evoked compound action potentials (ECAP) registration, according to the results of which the parameters of the CI processor were changed. Results. Research data showed the effectiveness of the approach of including the ECAP registration test, followed by the creation of a fitting card and correction of the level of auditory nerve stimulation under the control of speech audiometry in the protocol of fitting the CI processor. Conclusions. The results of the conducted studies allow us to recommend the use of the developed method of objective recording of sound perception thresholds in patients with CI as one of the indicators of the effectiveness of CI in the early period of auditory-speech rehabilitation in patients with undeveloped speech skills and when it is impossible to conduct objective tests accompanied by supra-threshold stimulation of the auditory nerve.

Tripolar configuration and pulse shape in cochlear implants reduce channel interactions in the temporal domain

The present study investigates effects of current focusing and pulse shape on threshold, dynamic range, spread of excitation and channel interaction in the time domain using cochlear implant stimulation. The study was performed on 20 adult guinea pigs using a 6-channel animal cochlear implant, recording was performed in the auditory midbrain using a multielectrode array. After determining the best frequencies for individual recording contacts with acoustic stimulation, the ear was deafened and a cochlear implant was inserted into the cochlea. The position of the implant was controlled by x-ray. Stimulation with biphasic, pseudomonophasic and monophasic stimuli was performed with monopolar, monopolar with common ground, bipolar and tripolar configuration in two sets of experiments, allowing comparison of the effects of the different stimulation strategies on threshold, dynamic range, spread of excitation and channel interaction. Channel interaction was studied in the temporal domain, where two electrodes were activated with pulse trains and phase locking to these pulse trains in the midbrain was quantified. The results documented multifactorial influences on the response properties, with significant interaction between factors. Thresholds increased with increasing current focusing, but decreased with pseudomonophasic and monophasic pulse shapes. The results documented that current focusing, particularly tripolar configuration, effectively reduces channel interaction, but that also pseudomonophasic and monophasic stimulation and phase duration intensity coding reduce channel interactions.

Effectiveness of transcutaneous vagus nerve stimulation (tVNS) on salicylate-induced tinnitus

IntroductionTinnitus is the most common symptom of auditory system disorders. It affects the quality of life of millions of people, but it is still incurable in most cases. Vagus nerve stimulation (VNS) therapy is a potential new treatment for subjective tinnitus. In this study, transcutaneous vagus nerve stimulation (tVNS) combined with tones was utilized to treat salicylate-induced tinnitus since salicylate is a reliable and convenient approach for rapidly inducing tinnitus. MethodsWistar rats were divided into acoustic stimulation alone (AS, n = 6), tVNS alone (n = 6), and tVNS with AS (n = 6) groups for behavioral and electrophysiological tests. They were assessed by auditory brainstem response (ABR), prepulse inhibition (PPI), gap prepulse inhibition of the acoustic startle (GPIAS), social interactions, and aggressive behavior tests at baseline and seven days’ post-salicylate (175 mg/kg, twice a day) injection. ResultsThe inhibition percentage of the GPIAS test was significantly reduced post-salicylate injection in the tVNS and AS alone groups, while it was not significant in the tVNS with AS group. There was no significant difference in the mean percentage of the GPIAS test between the tVNS groups (with or without AS) after salicylate injections. Social interactions were significantly different in the AS alone group pre- and post-salicylate injections, but they were not significant in other groups. Moreover, the results of aggressive behavior tests showed significantly increased post-salicylate injections in the AS alone group, while they were not significant in the tVNS groups (with or without AS). ConclusionsThe current study revealed that the application of tVNS alone produced improved social interaction and mood and alleviated salicylate-induced tinnitus severity. Moreover, combining tVNS with acoustic stimulation can prevent salicylate-induced tinnitus.

Reliability of some tinnitus psychoacoustic measures

IntroductionPsychoacoustic measures are used to quantify tinnitus perception in clinical and research settings. Residual inhibition (RI), for instance, is defined as a temporary reduction in tinnitus loudness after the presentation of an acoustic stimulus. A novel approach was developed recently to assess the minimum sound level producing RI, the minimum residual inhibition level (MRIL), after the repeated presentation of short sounds separated by short periods of silence. Two studies were performed: the objective of the study 1 was to assess the reliability and the reproducibility of this measures as well as others, including the minimum masking level (MML). The objective of study 2 was to assess whether a smoother envelope of the sound would produce similar levels of MML and MRIL and improve listening comfort.MethodsThirty participants with chronic tinnitus completed each study. For study 1, MML and MRIL were obtained at the seven standard audiometric frequencies at around 1-month interval. For study 2, MML and MRIL were obtained using triangular and trapezoidal-shaped NBN signals centered at three different frequencies.ResultsThe mean absolute test-retest difference was 3 dB for both MML and MRIL [Intraclass correlation, ICC (2,1) of 0.70 and 0.84, respectively] for the measures obtained in test and retest (86% of cases for MML and 21% of cases for complete MRIL). While the two types of envelopes provided comparable MRIL, the “triangular” envelope provided more listening comfort.DiscussionIn sum, the novel approach provides quick and reliable MML and MRIL measurement, with the potential benefit of subtyping participants.

Gamma music: a new acoustic stimulus for gamma-frequency auditory steady-state response.

A frequency range exceeding approximately 30 Hz, denoted as the gamma frequency range, is associated with various cognitive functions, consciousness, sensory integration, short-term memory, working memory, encoding and maintenance of episodic memory, and retrieval processes. In this study, we proposed a new form of gamma stimulation, called gamma music, combining 40 Hz auditory stimuli and music. This gamma music consists of drums, bass, and keyboard sounds, each containing a 40 Hz frequency oscillation. Since 40 Hz stimuli are known to induce an auditory steady-state response (ASSR), we used the 40 Hz power and phase locking index (PLI) as indices of neural activity during sound stimulation. We also recorded subjective ratings of each sound through a questionnaire using a visual analog scale. The gamma music, gamma drums, gamma bass, and gamma keyboard sounds showed significantly higher values in 40 Hz power and PLI compared to the control music without a 40 Hz oscillation. Particularly, the gamma keyboard sound showed a potential to induce strong ASSR, showing high values in these indices. In the subjective ratings, the gamma music, especially the gamma keyboard sound, received more relaxed, comfortable, preferred, pleasant, and natural impressions compared to the control music with conventional gamma stimulation. These results indicate that our proposed gamma music has potential as a new method for inducing ASSR. Particularly, the gamma keyboard sound proved to be an effective acoustic source for inducing a strong ASSR while preserving the comfortable and pleasant sensation of listening to music. Our developed gamma music, characterized by its pleasantness to the human ear, offers a significant advantage for the long-term use of gamma stimulation. The utilization of this music could potentially reduce the physical and psychological burden on participants compared to conventional 40 Hz stimuli. This music is not only expected to contribute to fundamental neuroscience research utilizing ASSR but also to facilitate the implementation of gamma music-based interventions aimed at enhancing human cognitive functions in everyday life.

Localization of Low- and High-Frequency Sounds in Cochlear Implant Recipients Using a Contralateral Hearing Aid.

The ability to localize sounds is partly recovered in patients using a cochlear implant (CI) in one ear and a hearing aid (HA) on the contralateral side. Binaural processing seems effective at least to some extent, despite the difference between electric and acoustic stimulation in each ear. To obtain further insights into the mechanisms of binaural hearing in these listeners, localization of low- and high-frequency sounds was tested. The study used a within-subject design, where participants were tasked with localizing sound sources in the horizontal plane. The experiment was conducted in an anechoic chamber, where an array of seven loudspeakers was mounted along the 24 azimuthal angle span from -90° to +90°. Stimuli were applied with different frequencies: broadband noise and high- and low-frequency noise. Ten CI recipients participated in the study. All had an asymmetric hearing loss with a CI in the poorer ear and an HA on the contralateral side. Accuracy of sound localization in terms of angular error and percentage of correct localization scores. The median angular error was 40° in bimodal conditions for both broadband noise and high-frequency noise stimuli. The angular error increased to 47° for low-frequency noise stimuli. In the unilaterally aided condition with an HA, only a median angular error of 78° was observed. Irrespective of the frequency composition of the stimuli, this group of bimodal listeners showed some ability to localize sounds. Angular errors were larger than those reported in the literature for bilateral CI users or single-sided deaf listeners with a CI. In the unilateral listening condition with HA, only localization of sounds was not possible for most subjects.

Acoustic‐Based Microbubble Grippers for Automatic On‐Chip Selection of Spherical Microrobot Models

AbstractSpherical micro/nanorobots are reported as attractive candidates in nano‐surgery, contamination degradation, analytical chemistry, medical engineering, etc. Unlike macroscopic robots, the standard fabrication and inspection strategy to control the high quality of microrobots are rarely explored before. Overcoming the geometrical discrepancy is now essential to keep an identical locomotion behavior for spherical microrobot individuals for complex usages. Herein, acoustic‐based microbubble grippers are proposed controlled by a machine vision system to realize agile recognition and sorting of unqualified spherical microrobot models. Theoretical analysis and numerical simulation reveal the basic grabbing mechanisms via acoustic stimuli. The acoustic resonation of microbubbles can generate a locally enhanced acoustic field, attracting microrobots toward the bubble surface by the acoustic forces. The viscosity of microfluid makes it possible to instantaneously grab or release just by controlling the microbubble activation. Further, a machine vision‐based monitor and control system is proposed to enable automatic control for the entire process. Based on extracted characteristic parameters, target microrobot models are quickly selected and grabbed out. It is expected that such a combination of microgrippers with an advanced control system will pave the way for high‐qualified inspection for microrobots and improve their unique versatility in myriad micromanipulation scenarios.

Drug repurposing for neurodegenerative diseases using Zebrafish behavioral profiles

Drug repurposing can accelerate drug development while reducing the cost and risk of toxicity typically associated with de novo drug design. Several disorders lacking pharmacological solutions and exhibiting poor results in clinical trials - such as Alzheimer’s disease (AD) - could benefit from a cost-effective approach to finding new therapeutics. We previously developed a neural network model, Z-LaP Tracker, capable of quantifying behaviors in zebrafish larvae relevant to cognitive function, including activity, reactivity, swimming patterns, and optomotor response in the presence of visual and acoustic stimuli. Using this model, we performed a high-throughput screening of FDA-approved drugs to identify compounds that affect zebrafish larval behavior in a manner consistent with the distinct behavior induced by calcineurin inhibitors. Cyclosporine (CsA) and other calcineurin inhibitors have garnered interest for their potential role in the prevention of AD. We generated behavioral profiles suitable for cluster analysis, through which we identified 64 candidate therapeutics for neurodegenerative disorders.

Treatments and regulatory mechanisms of acoustic stimuli on mood disorders and neurological diseases.

Acoustic stimuli such as music or ambient noise can significantly affect physiological and psychological health in humans. We here summarize positive effects of music therapy in premature infant distress regulation, performance enhancement, sleep quality control, and treatment of mental disorders. Specifically, music therapy exhibits promising effects on treatment of neurological disorders such as Alzheimer's disease (AD) and Parkinson's disease (PD). We also highlight regulatory mechanisms by which auditory intervention affects an organism, encompassing modulation of immune responses, gene expression, neurotransmitter regulation and neural circuitry. As a safe, cost-effective and non-invasive intervention, music therapy offers substantial potential in treating a variety of neurological conditions.