[Study on the clinical characteristics of auditory neuropathy patients with normal pure tone average or mild hearing loss].

Objective: The purpose of this study was to analyze the clinical characteristics of auditory neuropathy (AN) patients with normal hearing or mild hearing loss. Methods: Data from Multicenter Study on Clinical Diagnosis and Intervention of Acoustic Neuropathy (registration number: ChiCTR2100050125). According to the Chinese clinical practice guideline of auditory neuropathy (version 2022), these patients divided into two groups: the normal hearing group (PTA Normal, PTAN group, the average hearing threshold<20 dB HL) and the mild hearing loss group (PTA Mild hearing loss, PTAM group, the average hearing threshold between 20-35 dBHL). The audiology characteristics, clinical features, and follow-up were analyzed. Data analysis was conducted using GraphPad Prism 8 and SPSS 20.0 software. Results: A total of 75 AN with normal hearing or mild hearing loss were included in this study. The PTAN group consisted of 19 patients (38 ears), including 12 males and 7 females. The average onset age was (16.9±4.5) years old, while the test age was (22.1±5.8) years old for PTAN group. The PTAM group consisted of 56 patients (112 ears), including 29 males and 27 females. The average onset age was (16.2±7.9) years old, while the test age was (23.9±9.0) yeas old for PTAM group. The average hearing threshold of low frequency (0.125-0.5 kHz) was significantly decreased. ABR disappeared in 86.00% (126/150) of the patients. The speech recognition rate was 71.80±22.44% in the PTAN group and 58.08±29.28% in the PTAM group.-SP/AP was 0.98±0.47 in the PTAN and 1.07±0.63 in PTAM group; 40 (53.33%) patients had tinnitus. 29 patients (58 ears) were followed up, including 10 patients (20 ears) in the PTAN group and 19 patients (38 ears) in the PTAM group. There was no significant change in hearing threshold in short-term follow-up (<3 years). With the extension of the disease duration (>3 years), the PTAN group tended to decrease at low frequency, and the PTAM group decreased at high frequency first. The hearing threshold at 0.25 kHz in the PTAN group and 4 kHz in the PTAM group decreased significantly. Conclusions: AN patients with normal hearing or mild hearing loss exhibit abnormal results in audiological examination results, including ABR, electrocochleography and speech discrimination score. A combination of audiological tests should be used to make the diagnosis of AN. With the progression of the disease, AN with normal hearing or mild hearing loss tends to decrease.

[Recognition of unilateral auditory neuropathy in children].

Objective: This study aimed to compare the audiological characteristics between children with unilateral auditory neuropathy (UAN) and single-sided deafness (SSD) to establish a valid basis for the differential diagnosis of children with UAN. Methods: A retrospective analysis was conducted on audiological and imaging evaluations of children with UAN and SSD who were treated at Beijing Children's Hospital of Capital Medical University between May 2015 and June 2023. There were 17 children with UAN, comprising 10 males and 7 females, with an average age of 4.7 years. Additionally, there were 43 children with SSD, consisting of 27 males and 16 females, with an average age of 6.5 years. Audiological assessments included Auditory brainstem response (ABR), Steady-state auditory evoked potential (ASSR), Behavioural audiometry, Cochlear microphonic potential (CM), Distortino-product otoacoustic emission (DPOAE), and acoustic immittance test. The results of the audiological assessment and imaging phenotypic between the two groups of children were compared and analyzed by applying SPSS 27.0 statistical software. Results: (1) The UAN group (77.8%) had a significantly higher rate of ABR wave IIIL than the SSD group (20.9%) (P<0.01). The PA thresholds at 500 Hz and 1 000 Hz of children with SSD were higher than those of children with UAN, while the ASSR thresholds at 500 Hz, 1000 Hz, 2 000 Hz, and 4 000 Hz of children with SSD were significantly higher than those of children with UAN (P<0.05). (2) The degree of hearing loss in both UAN and SSD children was predominantly complete hearing loss. The percentage of complete hearing loss was significantly higher (χ²=4.353, P=0.037) in the SSD group (93.0%, 40/43) than in the UAN group (63.6%, 7/11). However, the percentage of profound hearing loss was significantly higher in the UAN group (27.3%, 3/11) than in the SSD group (2.3%, 1/43) (Fisher's exact test, P=0.023). In terms of hearing curve configuration, the percentage of flat type was significantly higher in the SSD group (76.7%, 33/43) than in the UAN group (36.4%, 4/11). The proportion of the UAN group (27.3%, 3/11) was significantly higher than that in the SSD group (2.3%, 1/43) in ascending type (P<0.05). There were no statistically significant differences in the hearing curves of the declining type and other types between the two groups (P>0.05). (3) The proportion of imaging assessment without abnormality was significantly more common in the UAN group (81.8%) than in the SSD group (37.1%) (χ²=6.695, P=0.015). Conclusions: Compared to children with SSD, the occurrence of wave IIIL on the ABR test was significantly more common in children with UAN. The percentage of ascending hearing curves was significantly higher in children with UAN than in children with SSD. ASSR thresholds were significantly lower in children with UAN. The normal imaging phenotype was significantly more common in children with UAN than in children with SSD.

Relationship Between Hypertension and Hearing Loss: Analysis of the Related Factors.

Purpose: The impact of hypertension extends to hearing loss, aging, and mental Health. The purpose of this study was to investigate the characteristics of hearing loss and hearing thresholds at different frequencies in individuals with hypertension. Through a comprehensive analysis, in the present study, it aimed to uncover the contributing factors that underlie hearing loss in this patient cohort, shedding light on the complex relationship between hypertension and auditory impairment. Patients and Methods: This was a single-center population-based observational study, and clinical, biological, and hospital data were collected from the inpatient ward. In the present study, 517 patients (1034 ears) with or without hypertension were included, and the proportion of patients with hearing loss, mean pure-tone average hearing threshold, low-frequency pure-tone average hearing threshold (LFPTA), medium-frequency pure-tone average hearing threshold (MFPTA) and high-frequency pure-tone average hearing threshold (HFPTA) were evaluated. Risk factors related to hearing loss and hearing threshold were also estimated at different frequencies. Results: The proportion of patients with hearing loss was higher in the hypertensive group than in the nonhypertensive group (P<0.05). After including risk factors for cardiovascular disease that can have an impact on the parameters of hearing and ambulatory blood pressure in the regression model, factors related to hearing loss included the albumin-to-creatinine ratio (ACR) and the standard deviation of the 24-hour systolic blood pressure (24h-SSD). ACR, 24h-SSD, and day systolic blood pressure (Day SBP) were associated with the mean pure-tone average hearing threshold, LFPTA, MFPTA, and HFPTA. The area under the receiver operating characteristic curve of ACR + 24h-SSD for hearing loss was 0.873, with a sensitivity of 86.73%, specificity of 90.52%, and a 95% confidence interval of 0.821-0.914. Conclusion: Hypertension is correlated with hearing loss, and the combination of ACR and 24h-SSD demonstrates an improved predictive capacity for hearing loss in hypertensive patients.

Frequency-dependent temporary threshold shifts in the Eastern painted turtle (Chrysemys picta picta).

Testudines are a highly threatened group facing an array of stressors, including alteration of their sensory environment. Underwater noise pollution has the potential to induce hearing loss and disrupt detection of biologically important acoustic cues and signals. To examine the conditions that induce temporary threshold shifts (TTS) in hearing in the freshwater Eastern painted turtle (Chrysemys picta picta), three individuals were exposed to band limited continuous white noise (50-1000 Hz) of varying durations and amplitudes (sound exposure levels ranged from 151 to 171 dB re 1 µPa2 s). Control and post-exposure auditory thresholds were measured and compared at 400 and 600 Hz using auditory evoked potential methods. TTS occurred in all individuals at both test frequencies, with shifts of 6.1-41.4 dB. While the numbers of TTS occurrences were equal between frequencies, greater shifts were observed at 600 Hz, a frequency of higher auditory sensitivity, compared to 400 Hz. The onset of TTS occurred at 154 dB re 1 µPa2 s for 600 Hz, compared to 158 dB re 1 µPa2 s at 400 Hz. The 400-Hz onset and patterns of TTS growth and recovery were similar to those observed in previously studied Trachemys scripta elegans, suggesting TTS may be comparable across Emydidae species.

Extending Subcortical EEG Responses to Continuous Speech to the Sound-Field.

The auditory brainstem response (ABR) is a valuable clinical tool for objective hearing assessment, which is conventionally detected by averaging neural responses to thousands of short stimuli. Progressing beyond these unnatural stimuli, brainstem responses to continuous speech presented via earphones have been recently detected using linear temporal response functions (TRFs). Here, we extend earlier studies by measuring subcortical responses to continuous speech presented in the sound-field, and assess the amount of data needed to estimate brainstem TRFs. Electroencephalography (EEG) was recorded from 24 normal hearing participants while they listened to clicks and stories presented via earphones and loudspeakers. Subcortical TRFs were computed after accounting for non-linear processing in the auditory periphery by either stimulus rectification or an auditory nerve model. Our results demonstrated that subcortical responses to continuous speech could be reliably measured in the sound-field. TRFs estimated using auditory nerve models outperformed simple rectification, and 16 minutes of data was sufficient for the TRFs of all participants to show clear wave V peaks for both earphones and sound-field stimuli. Subcortical TRFs to continuous speech were highly consistent in both earphone and sound-field conditions, and with click ABRs. However, sound-field TRFs required slightly more data (16 minutes) to achieve clear wave V peaks compared to earphone TRFs (12 minutes), possibly due to effects of room acoustics. By investigating subcortical responses to sound-field speech stimuli, this study lays the groundwork for bringing objective hearing assessment closer to real-life conditions, which may lead to improved hearing evaluations and smart hearing technologies.

Effects of spatial configuration and fundamental frequency on speech intelligibility in multiple-talker conditions in the ipsilateral horizontal plane and median planea).

Spatial separation and fundamental frequency (F0) separation are effective cues for improving the intelligibility of target speech in multi-talker scenarios. Previous studies predominantly focused on spatial configurations within the frontal hemifield, overlooking the ipsilateral side and the entire median plane, where localization confusion often occurs. This study investigated the impact of spatial and F0 separation on intelligibility under the above-mentioned underexplored spatial configurations. The speech reception thresholds were measured through three experiments for scenarios involving two to four talkers, either in the ipsilateral horizontal plane or in the entire median plane, utilizing monotonized speech with varying F0s as stimuli. The results revealed that spatial separation in symmetrical positions (front-back symmetry in the ipsilateral horizontal plane or front-back, up-down symmetry in the median plane) contributes positively to intelligibility. Both target direction and relative target-masker separation influence the masking release attributed to spatial separation. As the number of talkers exceeds two, the masking release from spatial separation diminishes. Nevertheless, F0 separation remains as a remarkably effective cue and could even facilitate spatial separation in improving intelligibility. Further analysis indicated that current intelligibility models encounter difficulties in accurately predicting intelligibility in scenarios explored in this study.

Neurometric amplitude modulation detection in the inferior colliculus of Young and Aged rats.

Amplitude modulation is an important acoustic cue for sound discrimination, and humans and animals are able to detect small modulation depths behaviorally. In the inferior colliculus (IC), both firing rate and phase-locking may be used to detect amplitude modulation. How neural representations that detect modulation change with age are poorly understood, including the extent to which age-related changes may be attributed to the inherited properties of ascending inputs to IC neurons. Here, simultaneous measures of local field potentials (LFPs) and single-unit responses were made from the inferior colliculus of Young and Aged rats using both noise and tone carriers in response to sinusoidally amplitude-modulated sounds of varying depths. We found that Young units had higher firing rates than Aged for noise carriers, whereas Aged units had higher phase-locking (vector strength), especially for tone carriers. Sustained LFPs were larger in Young animals for modulation frequencies 8-16 Hz and comparable at higher modulation frequencies. Onset LFP amplitudes were much larger in Young animals and were correlated with the evoked firing rates, while LFP onset latencies were shorter in Aged animals. Unit neurometric thresholds by synchrony or firing rate measures did not differ significantly across age and were comparable to behavioral thresholds in previous studies whereas LFP thresholds were lower than behavior.

Impact of Hearing Aids on Language Outcomes in Preschool Children With Mild Bilateral Hearing Loss.

This study aimed to investigate the role of hearing aid (HA) usage in language outcomes among preschool children aged 3-5 years with mild bilateral hearing loss (MBHL). The data were retrieved from a total of 52 children with MBHL and 30 children with normal hearing (NH). The association between demographical, audiological factors and language outcomes was examined. Analyses of variance were conducted to compare the language abilities of HA users, non-HA users, and their NH peers. Furthermore, regression analyses were performed to identify significant predictors of language outcomes. Aided better ear pure-tone average (BEPTA) was significantly correlated with language comprehension scores. Among children with MBHL, those who used HA outperformed the ones who did not use HA across all linguistic domains. The language skills of children with MBHL were comparable to those of their peers with NH. The degree of improvement in audibility in terms of aided BEPTA was a significant predictor of language comprehension. It is noteworthy that 50% of the parents expressed reluctance regarding HA use for their children with MBHL. The findings highlight the positive impact of HA usage on language development in this population. Professionals may therefore consider HAs as a viable treatment option for children with MBHL, especially when there is a potential risk of language delay due to hearing loss. It was observed that 25% of the children with MBHL had late-onset hearing loss. Consequently, the implementation of preschool screening or a listening performance checklist is recommended to facilitate early detection.

Neural processing in the primary auditory cortex following cholinergic lesions of the basal forebrain in ferrets.

Cortical acetylcholine (ACh) release has been linked to various cognitive functions, including perceptual learning. We have previously shown that cortical cholinergic innervation is necessary for accurate sound localization in ferrets, as well as for their ability to adapt with training to altered spatial cues. To explore whether these behavioral deficits are associated with changes in the response properties of cortical neurons, we recorded neural activity in the primary auditory cortex (A1) of anesthetized ferrets in which cholinergic inputs had been reduced by making bilateral injections of the immunotoxin ME20.4-SAP in the nucleus basalis (NB) prior to training the animals. The pattern of spontaneous activity of A1 units recorded in the ferrets with cholinergic lesions (NB ACh-) was similar to that in controls, although the proportion of burst-type units was significantly lower. Depletion of ACh also resulted in more synchronous activity in A1. No changes in thresholds, frequency tuning or in the distribution of characteristic frequencies were found in these animals. When tested with normal acoustic inputs, the spatial sensitivity of A1 neurons in the NB ACh- ferrets and the distribution of their preferred interaural level differences also closely resembled those found in control animals, indicating that these properties had not been altered by sound localization training with one ear occluded. Simulating the animals' previous experience with a virtual earplug in one ear reduced the contralateral preference of A1 units in both groups, but caused azimuth sensitivity to change in slightly different ways, which may reflect the modest adaptation observed in the NB ACh- group. These results show that while ACh is required for behavioral adaptation to altered spatial cues, it is not required for maintenance of the spectral and spatial response properties of A1 neurons.

An Exploration of the Memory Performance in Older Adult Hearing Aid Users on the Integrated Digit-in-Noise Test.

This study aimed to preliminarily investigate the associations between performance on the integrated Digit-in-Noise Test (iDIN) and performance on measures of general cognition and working memory (WM). The study recruited 81 older adult hearing aid users between 60 and 95 years of age with bilateral moderate to severe hearing loss. The Chinese version of the Montreal Cognitive Assessment Basic (MoCA-BC) was used to screen older adults for mild cognitive impairment. Speech reception thresholds (SRTs) were measured using 2- to 5-digit sequences of the Mandarin iDIN. The differences in SRT between five-digit and two-digit sequences (SRT5-2), and between five-digit and three-digit sequences (SRT5-3), were used as indicators of memory performance. The results were compared to those from the Digit Span Test and Corsi Blocks Tapping Test, which evaluate WM and attention capacity. SRT5-2 and SRT5-3 demonstrated significant correlations with the three cognitive function tests (rs ranging from -.705 to -.528). Furthermore, SRT5-2 and SRT5-3 were significantly higher in participants who failed the MoCA-BC screening compared to those who passed. The findings show associations between performance on the iDIN and performance on memory tests. However, further validation and exploration are needed to fully establish its effectiveness and efficacy.

Does Intraoperative Extracochlear Electrocochleography Correlate With Postoperative Audiometric Hearing Thresholds in Cochlear Implant Surgery? A Retrospective Analysis of Cochlear Monitoring.

In recent years, tools for early detection of irreversible trauma to the basilar membrane during hearing preservation cochlear implant (CI) surgery were established in several clinics. A link with the degree of postoperative hearing preservation in patients was investigated, but patient populations were usually small. Therefore, this study's aim was to analyze data from intraoperative extracochlear electrocochleography (ECochG) recordings for a larger group.During hearing preservation CI surgery, extracochlear recordings were made before, during, and after CI electrode insertion using a cotton wick electrode placed at the promontory. Before and after insertion, amplitudes and stimulus response thresholds were recorded at 250, 500, and 1000 Hz. During insertion, response amplitudes were recorded at one frequency and one stimulus level. Data from 121 patient ears were analyzed.The key benefit of extracochlear recordings is that they can be performed before, during, and after CI electrode insertion. However, extracochlear ECochG threshold changes before and after CI insertion were relatively small and did not independently correlate well with hearing preservation, although at 250 Hz they added some significant information. Some tendencies-although no significant relationships-were detected between amplitude behavior and hearing preservation. Rising amplitudes seem favorable and falling amplitudes disadvantageous, but constant amplitudes do not appear to allow stringent predictions.Extracochlear ECochG measurements seem to only partially realize expected benefits. The questions now are: do gains justify the effort, and do other procedures or possible combinations lead to greater benefits for patients?

Intracochlear Recording of Electrocochleography During and After Cochlear Implant Insertion Dependent on the Location in the Cochlea.

To preserve residual hearing during cochlear implant (CI) surgery it is desirable to use intraoperative monitoring of inner ear function (cochlear monitoring). A promising method is electrocochleography (ECochG). Within this project the relations between intracochlear ECochG recordings, position of the recording contact in the cochlea with respect to anatomy and frequency and preservation of residual hearing were investigated. The aim was to better understand the changes in ECochG signals and whether these are due to the electrode position in the cochlea or to trauma generated during insertion. During and after insertion of hearing preservation electrodes, intraoperative ECochG recordings were performed using the CI electrode (MED-EL). During insertion, the recordings were performed at discrete insertion steps on electrode contact 1. After insertion as well as postoperatively the recordings were performed at different electrode contacts. The electrode location in the cochlea during insertion was estimated by mathematical models using preoperative clinical imaging, the postoperative location was measured using postoperative clinical imaging. The recordings were analyzed from six adult CI recipients. In the four patients with good residual hearing in the low frequencies the signal amplitude rose with largest amplitudes being recorded closest to the generators of the stimulation frequency, while in both cases with severe pantonal hearing losses the amplitude initially rose and then dropped. This might be due to various reasons as discussed in the following. Our results indicate that this approach can provide valuable information for the interpretation of intracochlearly recorded ECochG signals.

Delayed hearing loss after cochlear implantation: Re-evaluating the role of hair cell degeneration.

Delayed loss of residual acoustic hearing after cochlear implantation is a common but poorly understood phenomenon due to the scarcity of relevant temporal bone tissues. Prior histopathological analysis of one case of post-implantation hearing loss suggested there were no interaural differences in hair cell or neural degeneration to explain the profound loss of low-frequency hearing on the implanted side (Quesnel et al., 2016) and attributed the threshold elevation to neo-ossification and fibrosis around the implant. Here we re-evaluated the histopathology in this case, applying immunostaining and improved microscopic techniques for differentiating surviving hair cells from supporting cells. The new analysis revealed dramatic interaural differences, with a > 80 % loss of inner hair cells in the cochlear apex on the implanted side, which can account for the post-implantation loss of residual hearing. Apical degeneration of the stria further contributed to threshold elevation on the implanted side. In contrast, spiral ganglion cell survival was reduced in the region of the electrode on the implanted side, but apical counts in the two ears were similar to that seen in age-matched unimplanted control ears. Almost none of the surviving auditory neurons retained peripheral axons throughout the basal half of the cochlea. Relevance to cochlear implant performance is discussed.

Alpha9alpha10 knockout mice show altered physiological and behavioral responses to signals in masking noise.

Medial olivocochlear (MOC) efferents modulate outer hair cell motility through specialized nicotinic acetylcholine receptors to support encoding of signals in noise. Transgenic mice lacking the alpha9 subunits of these receptors (α9KOs) have normal hearing in quiet and noise, but lack classic cochlear suppression effects and show abnormal temporal, spectral, and spatial processing. Mice deficient for both the alpha9 and alpha10 receptor subunits (α9α10KOs) may exhibit more severe MOC-related phenotypes. Like α9KOs, α9α10KOs have normal auditory brainstem response (ABR) thresholds and weak MOC reflexes. Here, we further characterized auditory function in α9α10KO mice. Wild-type (WT) and α9α10KO mice had similar ABR thresholds and acoustic startle response amplitudes in quiet and noise, and similar frequency and intensity difference sensitivity. α9α10KO mice had larger ABR Wave I amplitudes than WTs in quiet and noise. Other ABR metrics of hearing-in-noise function yielded conflicting findings regarding α9α10KO susceptibility to masking effects. α9α10KO mice also had larger startle amplitudes in tone backgrounds than WTs. Overall, α9α10KO mice had grossly normal auditory function in quiet and noise, although their larger ABR amplitudes and hyperreactive startles suggest some auditory processing abnormalities. These findings contribute to the growing literature showing mixed effects of MOC dysfunction on hearing.

Towards ASSR-based hearing assessment using natural sounds.

Objective. The auditory steady-state response (ASSR) allows estimation of hearing thresholds. The ASSR can be estimated from electroencephalography (EEG) recordings from electrodes positioned on both the scalp and within the ear (ear-EEG). Ear-EEG can potentially be integrated into hearing aids, which would enable automatic fitting of the hearing device in daily life. The conventional stimuli for ASSR-based hearing assessment, such as pure tones and chirps, are monotonous and tiresome, making them inconvenient for repeated use in everyday situations. In this study we investigate the use of natural speech sounds for ASSR estimation.Approach.EEG was recorded from 22 normal hearing subjects from both scalp and ear electrodes. Subjects were stimulated monaurally with 180 min of speech stimulus modified by applying a 40 Hz amplitude modulation (AM) to an octave frequency sub-band centered at 1 kHz. Each 50 ms sub-interval in the AM sub-band was scaled to match one of 10 pre-defined levels (0-45 dB sensation level, 5 dB steps). The apparent latency for the ASSR was estimated as the maximum average cross-correlation between the envelope of the AM sub-band and the recorded EEG and was used to align the EEG signal with the audio signal. The EEG was then split up into sub-epochs of 50 ms length and sorted according to the stimulation level. ASSR was estimated for each level for both scalp- and ear-EEG.Main results. Significant ASSRs with increasing amplitude as a function of presentation level were recorded from both scalp and ear electrode configurations.Significance. Utilizing natural sounds in ASSR estimation offers the potential for electrophysiological hearing assessment that are more comfortable and less fatiguing compared to existing ASSR methods. Combined with ear-EEG, this approach may allow convenient hearing threshold estimation in everyday life, utilizing ambient sounds. Additionally, it may facilitate both initial fitting and subsequent adjustments of hearing aids outside of clinical settings.

A single dose of AC102 restores hearing in a guinea pig model of noise-induced hearing loss to almost prenoise levels.

Although sudden sensorineural hearing loss (SSNHL) is a serious condition, there are currently no approved drugs for its treatment. Nevertheless, there is a growing understanding that the cochlear pathologies that underlie SSNHL include apoptotic death of sensory outer hair cells (OHCs) as well as loss of ribbon synapses connecting sensory inner hair cells (IHCs) and neurites of the auditory nerve, designated synaptopathy. Noise-induced hearing loss (NIHL) is a common subtype of SSNHL and is widely used to model hearing loss preclinically. Here, we demonstrate that a single interventive application of a small pyridoindole molecule (AC102) into the middle ear restored auditory function almost to prenoise levels in a guinea pig model of NIHL. AC102 prevented noise-triggered loss of OHCs and reduced IHC synaptopathy suggesting a role of AC102 in reconnecting auditory neurons to their sensory target cells. Notably, AC102 exerted its therapeutic properties over a wide frequency range. Such strong improvements in hearing have not previously been demonstrated for other therapeutic agents. In vitro experiments of a neuronal damage model revealed that AC102 protected cells from apoptosis and promoted neurite growth. These effects may be explained by increased production of adenosine triphosphate, indicating improved mitochondrial function, and reduced levels of reactive-oxygen species which prevents the apoptotic processes responsible for OHC death. This action profile of AC102 might be causal for the observed hearing recovery in in vivo models.

On the Feasibility of Using Behavioral Listening Effort Test Methods to Evaluate Auditory Performance in Cochlear Implant Users.

Realistic outcome measures that reflect everyday hearing challenges are needed to assess hearing aid and cochlear implant (CI) fitting. Literature suggests that listening effort measures may be more sensitive to differences between hearing-device settings than established speech intelligibility measures when speech intelligibility is near maximum. Which method provides the most effective measurement of listening effort for this purpose is currently unclear. This study aimed to investigate the feasibility of two tests for measuring changes in listening effort in CI users due to signal-to-noise ratio (SNR) differences, as would arise from different hearing-device settings. By comparing the effect size of SNR differences on listening effort measures with test-retest differences, the study evaluated the suitability of these tests for clinical use. Nineteen CI users underwent two listening effort tests at two SNRs (+4 and +8 dB relative to individuals' 50% speech perception threshold). We employed dual-task paradigms-a sentence-final word identification and recall test (SWIRT) and a sentence verification test (SVT)-to assess listening effort at these two SNRs. Our results show a significant difference in listening effort between the SNRs for both test methods, although the effect size was comparable to the test-retest difference, and the sensitivity was not superior to speech intelligibility measures. Thus, the implementations of SVT and SWIRT used in this study are not suitable for clinical use to measure listening effort differences of this magnitude in individual CI users. However, they can be used in research involving CI users to analyze group data.

[Mechanism of noise induced hidden hearing loss based on proteomics].

Objective: To explore the mechanism of noise-induced hidden hearing loss by proteomics. Methods: In October 2022, 64 SPF male C57BL/6J mice were divided into control group and noise exposure group with 32 mice in each group according to random sampling method. The noise exposure group was exposed to 100 dB sound pressure level, 2000-16000 Hz broadband noise for 2 h, and the mouse hidden hearing loss model was established. Auditory brainstem response (ABR) was used to test the change of hearing threshold of mice on the 7th day after noise exposure, the damage of basal membrane hair cells was observed by immunofluorescence, and the differentially expressed proteins in the inner ear of mice in each group were identified and analyzed by 4D-Label-free quantitative proteomics, and verified by Western blotting. The results were statistically analyzed by ANOVA and t test. Results: On the 7th day after noise exposure, there was no significant difference in hearing threshold between the control group and the noise exposure group at click and 8000 Hz acoustic stimulation (P>0.05) . The hearing threshold in the noise exposure group was significantly higher than that in the control group under 16000 Hz acoustic stimulation (P<0.05) . Confocal immunofluorescence showed that the basal membrane hair cells of cochlear tissue in noise exposure group were arranged neatly, but the relative expression of C-terminal binding protein 2 antibody of presynaptic membrane in middle gyrus and basal gyrus was significantly lower than that in control group (P<0.05) . GO enrichment analysis showed that the functions of differentially expressed proteins were mainly concentrated in membrane potential regulation, ligand-gated channel activity, and ligand-gated ion channel activity. KEGG pathway enrichment analysis showed that differentially expressed proteins were significantly enriched in phosphatidylinositol 3 kinase-protein kinase B (PI3K-Akt) signaling pathway, NOD-like receptor signaling pathway, calcium signaling pathway, etc. Western blotting showed that the expression of inositol 1, 4, 5-trisphosphate receptor 3 (Itpr3) was increased and the expression of solute carrier family 38 member 2 (Slc38a2) was decreased in the noise exposure group (P<0.05) . Conclusion: Through proteomic analysis, screening and verification of the differential expression proteins Itpr3 and Slc38a2 in the constructed mouse noise-induced hidden hearing loss model, the glutaminergic synaptic related pathways represented by Itpr3 and Slc38a2 may be involved in the occurrence of hidden hearing loss.

Electrocochleographic frequency-following responses as a potential marker of age-related cochlear neural degeneration.

Auditory nerve (AN) fibers that innervate inner hair cells in the cochlea degenerate with advancing age. It has been proposed that age-related reductions in brainstem frequency-following responses (FFR) to the carrier of low-frequency, high-intensity pure tones may partially reflect this neural loss in the cochlea (Märcher-Rørsted et al., 2022). If the loss of AN fibers is the primary factor contributing to age-related changes in the brainstem FFR, then the FFR could serve as an indicator of cochlear neural degeneration. In this study, we employed electrocochleography (ECochG) to investigate the effects of age on frequency-following neurophonic potentials, i.e., neural responses phase-locked to the carrier frequency of the tone stimulus. We compared these findings to the brainstem-generated FFRs obtained simultaneously using the same stimulation. We conducted recordings in young and older individuals with normal hearing. Responses to pure tones (250 ms, 516 and 1086 Hz, 85 dB SPL) and clicks were recorded using both ECochG at the tympanic membrane and traditional scalp electroencephalographic (EEG) recordings of the FFR. Distortion product otoacoustic emissions (DPOAE) were also collected. In the ECochG recordings, sustained AN neurophonic (ANN) responses to tonal stimulation, as well as the click-evoked compound action potential (CAP) of the AN, were significantly reduced in the older listeners compared to young controls, despite normal audiometric thresholds. In the EEG recordings, brainstem FFRs to the same tone stimulation were also diminished in the older participants. Unlike the reduced AN CAP response, the transient-evoked wave-V remained unaffected. These findings could indicate that a decreased number of AN fibers contributes to the response in the older participants. The results suggest that the scalp-recorded FFR, as opposed to the clinical standard wave-V of the auditory brainstem response, may serve as a more reliable indicator of age-related cochlear neural degeneration.

Age Impacts Speech-in-Noise Recognition Differently for Nonnative and Native Listeners.

PURPOSE: The purpose of this study was to explore potential differences in suprathreshold auditory function among native and nonnative speakers of English as a function of age. METHOD: Retrospective analyses were performed on three large data sets containing suprathreshold auditory tests completed by 5,572 participants who were self-identified native and nonnative speakers of English between the ages of 18-65 years, including a binaural tone detection test, a digit identification test, and a sentence recognition test. RESULTS: The analyses show a significant interaction between increasing age and participant group on tests involving speech-based stimuli (digit strings, sentences) but not on the binaural tone detection test. For both speech tests, differences in speech recognition emerged between groups during early adulthood, and increasing age had a more negative impact on word recognition for nonnative compared to native participants. Age-related declines in performance were 2.9 times faster for digit strings and 3.3 times faster for sentences for nonnative participants compared to native participants. CONCLUSIONS: This set of analyses extends the existing literature by examining interactions between aging and self-identified native English speaker status in several auditory domains in a cohort of adults spanning young adulthood through middle age. The finding that older nonnative English speakers in this age cohort may have greater-than-expected deficits on speech-in-noise perception may have clinical implications on how these individuals should be diagnosed and treated for hearing difficulties.