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1.
J Acoust Soc Am ; 155(5): 3254-3266, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38742964

ABSTRACT

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.


Subject(s)
Acoustic Stimulation , Auditory Threshold , Turtles , Animals , Turtles/physiology , Time Factors , Noise/adverse effects , Evoked Potentials, Auditory/physiology , Hearing Loss, Noise-Induced/physiopathology , Hearing Loss, Noise-Induced/etiology , Male , Female , Hearing/physiology
2.
Trends Hear ; 28: 23312165241242235, 2024.
Article in English | MEDLINE | ID: mdl-38738302

ABSTRACT

The objective of this project was to establish cutoff scores on the tinnitus subscale of the Tinnitus and Hearing Survey (THS) using a large sample of United States service members (SM) with the end goal of guiding clinical referrals for tinnitus evaluation. A total of 4,589 SM undergoing annual audiometric surveillance were prospectively recruited to complete the THS tinnitus subscale (THS-T). A subset of 1,304 participants also completed the Tinnitus Functional Index (TFI). The original 5-point response scale of the THS (THS-T16) was modified to an 11-point scale (THS-T40) for some participants, to align with the response scale of the TFI. Age, sex, hearing loss, and self-reported tinnitus bother were also recorded. The THS-T was relatively insensitive to hearing, but self-reported bothersome tinnitus was significantly associated with the THS-T40 score. Receiver operating characteristic analysis was used to determine cutoff scores on the THS-T that aligned with recommended cutoff values for clinical intervention on the TFI. A cutoff of 9 on the THS-T40 aligns with a TFI cutoff of 25, indicating a patient may need intervention for tinnitus. A cutoff of 15 aligns with a TFI cutoff of 50, indicating that more aggressive intervention for tinnitus is warranted. The THS-T is a viable tool to identify patients with tinnitus complaints warranting clinical evaluation for use by hearing conservation programs and primary care clinics. The THS-T40 cutoff scores of 9 and 15 provide clinical reference points to guide referrals to audiology.


Subject(s)
Tinnitus , Humans , Tinnitus/diagnosis , Female , Male , Middle Aged , Aged , Adult , Prospective Studies , United States , Hearing , Predictive Value of Tests , Reproducibility of Results , Severity of Illness Index , ROC Curve , Surveys and Questionnaires , Self Report , Audiometry/methods
3.
J Acoust Soc Am ; 155(5): 3183-3194, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38738939

ABSTRACT

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.


Subject(s)
Acoustic Stimulation , Auditory Threshold , Evoked Potentials, Auditory, Brain Stem , Mice, Knockout , Noise , Receptors, Nicotinic , Reflex, Startle , Animals , Noise/adverse effects , Receptors, Nicotinic/genetics , Receptors, Nicotinic/deficiency , Perceptual Masking , Behavior, Animal , Mice , Mice, Inbred C57BL , Cochlea/physiology , Cochlea/physiopathology , Male , Phenotype , Olivary Nucleus/physiology , Auditory Pathways/physiology , Auditory Pathways/physiopathology , Female , Auditory Perception/physiology , Hearing
4.
Trends Hear ; 28: 23312165241252240, 2024.
Article in English | MEDLINE | ID: mdl-38715410

ABSTRACT

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?


Subject(s)
Audiometry, Evoked Response , Auditory Threshold , Cochlea , Cochlear Implantation , Cochlear Implants , Hearing , Humans , Audiometry, Evoked Response/methods , Retrospective Studies , Cochlear Implantation/instrumentation , Female , Middle Aged , Male , Aged , Adult , Hearing/physiology , Cochlea/surgery , Cochlea/physiopathology , Treatment Outcome , Adolescent , Predictive Value of Tests , Young Adult , Child , Audiometry, Pure-Tone , Aged, 80 and over , Child, Preschool , Hearing Loss/diagnosis , Hearing Loss/physiopathology , Hearing Loss/surgery , Hearing Loss/rehabilitation
5.
Trends Hear ; 28: 23312165241248973, 2024.
Article in English | MEDLINE | ID: mdl-38717441

ABSTRACT

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.


Subject(s)
Audiometry, Evoked Response , Cochlea , Cochlear Implantation , Cochlear Implants , Humans , Cochlea/surgery , Cochlea/physiology , Cochlea/physiopathology , Cochlear Implantation/instrumentation , Cochlear Implantation/methods , Audiometry, Evoked Response/methods , Middle Aged , Aged , Male , Female , Hearing/physiology , Adult , Treatment Outcome , Predictive Value of Tests , Electric Stimulation , Persons With Hearing Impairments/rehabilitation , Persons With Hearing Impairments/psychology , Auditory Threshold/physiology
6.
Sci Rep ; 14(1): 10578, 2024 05 08.
Article in English | MEDLINE | ID: mdl-38719853

ABSTRACT

Hearing preservation (HP) during vestibular schwannomas (VSs) surgery poses a significant challenge. Although brainstem auditory evoked potentials (BAEPs) on the affected side are commonly employed to monitor cochlear nerve function, their low signal-to-noise ratio (SNR) renders them susceptible to interferences, compromising their reliability. We retrospectively analyzed the data of patients who underwent tumor resection, while binaural brainstem auditory evoked potentials (BAEPs) were simultaneously recorded during surgery. To standardize BAEPs on the affected side, we incorporated the synchronous healthy side as a reference (interval between affected and healthy side ≤ 3 min). A total of 127 patients were enrolled. Comparison of the raw BAEPs data pre- and post-tumor resection revealed that neither V-wave amplitude (Am-V) nor latency (La-V) could serve as reliable predictors of HP simultaneously. However, following standardization, V-wave latency (STIAS-La-V) and amplitude (STIAS-Am-V) emerged as stable predictors of HP. Furthermore, the intraoperative difference in V-wave amplitude (D-Am-V) predicted postoperative HP in patients with preoperative HP and remained predictive after standardization. The utilization of intraoperative synchronous healthy side BAEPs as a reference to eliminate interferences proves to be an effective approach in enhancing the reliability of BAEPs for predicting HP in VSs patients.


Subject(s)
Evoked Potentials, Auditory, Brain Stem , Neuroma, Acoustic , Humans , Neuroma, Acoustic/surgery , Neuroma, Acoustic/physiopathology , Female , Evoked Potentials, Auditory, Brain Stem/physiology , Male , Middle Aged , Adult , Retrospective Studies , Aged , Hearing , Young Adult
7.
Hear Res ; 447: 109021, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38703432

ABSTRACT

Understanding the complex pathologies associated with hearing loss is a significant motivation for conducting inner ear research. Lifelong exposure to loud noise, ototoxic drugs, genetic diversity, sex, and aging collectively contribute to human hearing loss. Replicating this pathology in research animals is challenging because hearing impairment has varied causes and different manifestations. A central aspect, however, is the loss of sensory hair cells and the inability of the mammalian cochlea to replace them. Researching therapeutic strategies to rekindle regenerative cochlear capacity, therefore, requires the generation of animal models in which cochlear hair cells are eliminated. This review discusses different approaches to ablate cochlear hair cells in adult mice. We inventoried the cochlear cyto- and histo-pathology caused by acoustic overstimulation, systemic and locally applied drugs, and various genetic tools. The focus is not to prescribe a perfect damage model but to highlight the limitations and advantages of existing approaches and identify areas for further refinement of damage models for use in regenerative studies.


Subject(s)
Cochlea , Disease Models, Animal , Hair Cells, Auditory , Regeneration , Animals , Hair Cells, Auditory/pathology , Hair Cells, Auditory/metabolism , Mice , Cochlea/pathology , Cochlea/physiopathology , Humans , Hearing , Hearing Loss, Noise-Induced/physiopathology , Hearing Loss, Noise-Induced/pathology , Hearing Loss/pathology , Hearing Loss/physiopathology , Acoustic Stimulation
8.
Hear Res ; 447: 109012, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38703433

ABSTRACT

Hearing loss is a common side effect of many tumor treatments. However, hearing loss can also occur as a direct result of certain tumors of the nervous system, the most common of which are the vestibular schwannomas (VS). These tumors arise from Schwann cells of the vestibulocochlear nerve and their main cause is the loss of function of NF2, with 95 % of cases being sporadic and 5 % being part of the rare neurofibromatosis type 2 (NF2)-related Schwannomatosis. Genetic variations in NF2 do not fully explain the clinical heterogeneity of VS, and interactions between Schwann cells and their microenvironment appear to be critical for tumor development. Preclinical in vitro and in vivo models of VS are needed to develop prognostic biomarkers and targeted therapies. In addition to VS, other tumors can affect hearing. Meningiomas and other masses in the cerebellopontine angle can compress the vestibulocochlear nerve due to their anatomic proximity. Gliomas can disrupt several neurological functions, including hearing; in fact, glioblastoma multiforme, the most aggressive subtype, may exhibit early symptoms of auditory alterations. Besides, treatments for high-grade tumors, including chemotherapy or radiotherapy, as well as incomplete resections, can induce long-term auditory dysfunction. Because hearing loss can have an irreversible and dramatic impact on quality of life, it should be considered in the clinical management plan of patients with tumors, and monitored throughout the course of the disease.


Subject(s)
Hearing Loss , Hearing , Neuroma, Acoustic , Humans , Neuroma, Acoustic/pathology , Neuroma, Acoustic/physiopathology , Neuroma, Acoustic/complications , Hearing Loss/physiopathology , Hearing Loss/etiology , Hearing Loss/pathology , Animals , Neurilemmoma/pathology , Neurilemmoma/complications , Neurilemmoma/therapy , Vestibulocochlear Nerve/pathology , Vestibulocochlear Nerve/physiopathology , Risk Factors , Neurofibromatosis 2/genetics , Neurofibromatosis 2/complications , Neurofibromatosis 2/pathology , Neurofibromatosis 2/physiopathology , Neurofibromatosis 2/therapy , Meningioma/pathology , Meningioma/physiopathology , Meningioma/complications
9.
Curr Biol ; 34(9): R346-R348, 2024 05 06.
Article in English | MEDLINE | ID: mdl-38714161

ABSTRACT

Animals including humans often react to sounds by involuntarily moving their face and body. A new study shows that facial movements provide a simple and reliable readout of a mouse's hearing ability that is more sensitive than traditional measurements.


Subject(s)
Face , Animals , Mice , Face/physiology , Auditory Perception/physiology , Hearing/physiology , Sound , Movement/physiology , Humans
10.
Hear Res ; 447: 109023, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38733710

ABSTRACT

Limited auditory input, whether caused by hearing loss or by electrical stimulation through a cochlear implant (CI), can be compensated by the remaining senses. Specifically for CI users, previous studies reported not only improved visual skills, but also altered cortical processing of unisensory visual and auditory stimuli. However, in multisensory scenarios, it is still unclear how auditory deprivation (before implantation) and electrical hearing experience (after implantation) affect cortical audiovisual speech processing. Here, we present a prospective longitudinal electroencephalography (EEG) study which systematically examined the deprivation- and CI-induced alterations of cortical processing of audiovisual words by comparing event-related potentials (ERPs) in postlingually deafened CI users before and after implantation (five weeks and six months of CI use). A group of matched normal-hearing (NH) listeners served as controls. The participants performed a word-identification task with congruent and incongruent audiovisual words, focusing their attention on either the visual (lip movement) or the auditory speech signal. This allowed us to study the (top-down) attention effect on the (bottom-up) sensory cortical processing of audiovisual speech. When compared to the NH listeners, the CI candidates (before implantation) and the CI users (after implantation) exhibited enhanced lipreading abilities and an altered cortical response at the N1 latency range (90-150 ms) that was characterized by a decreased theta oscillation power (4-8 Hz) and a smaller amplitude in the auditory cortex. After implantation, however, the auditory-cortex response gradually increased and developed a stronger intra-modal connectivity. Nevertheless, task efficiency and activation in the visual cortex was significantly modulated in both groups by focusing attention on the visual as compared to the auditory speech signal, with the NH listeners additionally showing an attention-dependent decrease in beta oscillation power (13-30 Hz). In sum, these results suggest remarkable deprivation effects on audiovisual speech processing in the auditory cortex, which partially reverse after implantation. Although even experienced CI users still show distinct audiovisual speech processing compared to NH listeners, pronounced effects of (top-down) direction of attention on (bottom-up) audiovisual processing can be observed in both groups. However, NH listeners but not CI users appear to show enhanced allocation of cognitive resources in visually as compared to auditory attended audiovisual speech conditions, which supports our behavioural observations of poorer lipreading abilities and reduced visual influence on audition in NH listeners as compared to CI users.


Subject(s)
Acoustic Stimulation , Attention , Cochlear Implantation , Cochlear Implants , Deafness , Electroencephalography , Persons With Hearing Impairments , Photic Stimulation , Speech Perception , Humans , Male , Female , Middle Aged , Cochlear Implantation/instrumentation , Adult , Prospective Studies , Longitudinal Studies , Persons With Hearing Impairments/psychology , Persons With Hearing Impairments/rehabilitation , Deafness/physiopathology , Deafness/rehabilitation , Deafness/psychology , Case-Control Studies , Aged , Visual Perception , Lipreading , Time Factors , Hearing , Evoked Potentials, Auditory , Auditory Cortex/physiopathology , Evoked Potentials
11.
Hear Res ; 447: 109024, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38735179

ABSTRACT

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.


Subject(s)
Auditory Threshold , Cochlear Implantation , Cochlear Implants , Spiral Ganglion , Cochlear Implantation/instrumentation , Cochlear Implantation/adverse effects , Humans , Spiral Ganglion/pathology , Spiral Ganglion/physiopathology , Hair Cells, Auditory, Inner/pathology , Time Factors , Cell Survival , Male , Hearing , Hearing Loss/physiopathology , Hearing Loss/pathology , Hearing Loss/surgery , Hearing Loss/etiology , Female , Hair Cells, Auditory/pathology , Aged , Nerve Degeneration , Middle Aged , Temporal Bone/pathology , Temporal Bone/surgery
12.
Trends Hear ; 28: 23312165241256721, 2024.
Article in English | MEDLINE | ID: mdl-38773778

ABSTRACT

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.


Subject(s)
Child Language , Hearing Aids , Hearing Loss, Bilateral , Language Development , Humans , Male , Child, Preschool , Female , Hearing Loss, Bilateral/rehabilitation , Hearing Loss, Bilateral/diagnosis , Hearing Loss, Bilateral/physiopathology , Hearing Loss, Bilateral/psychology , Speech Perception , Case-Control Studies , Correction of Hearing Impairment/instrumentation , Treatment Outcome , Persons With Hearing Impairments/rehabilitation , Persons With Hearing Impairments/psychology , Severity of Illness Index , Comprehension , Hearing , Audiometry, Pure-Tone , Age Factors , Auditory Threshold , Language Tests
13.
Otol Neurotol ; 45(5): e427-e434, 2024 Jun 01.
Article in English | MEDLINE | ID: mdl-38693092

ABSTRACT

OBJECTIVE: To examine the clinical features and surgical outcomes in patients with congenital absence of the oval window (CAOW), and to investigate the potential factors that affect audiologic results. STUDY DESIGN: A retrospective chart review. SETTING: A tertiary academic center. PATIENTS AND INTERVENTION: A total of 17 ears among 16 patients were confirmed to have CAOW. Among them, 13 ears underwent vestibulotomy for hearing reconstruction. Clinical parameters associated with the hearing outcomes were analyzed. MAIN OUTCOME MEASURES: A mean air-bone gap (ABG) after 6-month and long-term follow-up was compared with preoperative measurements. RESULTS: Intraoperative findings showed that anomalies of the malleus or incus were observed in 11 ears (64.7%), stapes anomalies were present in all ears (100%), and facial nerve anomalies were present in 10 ears (58.8%). Because of unfavorable facial nerve anomalies, hearing reconstruction was aborted in four cases (23.5%). In the hearing reconstruction group, the mean ABG at 6 months postoperation was significantly reduced after compared with the preoperative value (44.0 ± 8.4 dB versus 58.8 ± 9.1 dB, p = 0.006). After dividing ears into a success subgroup (ABG ≤ 30 dB, seven ears) and non-success subgroup (ABG > 30 dB, six ears), the use of a drill during vestibulotomy was significantly related to a poor hearing outcome (100% versus 16.7%, p = 0.015). The long-term follow-up result (mean, 60 mo) revealed no deterioration compared with the 6-month postoperative result. Five ears (29.4%) underwent revision surgery, and three of them showed ABG improvements. No serious complications were reported. CONCLUSION: Vestibulotomy is an effective and safe option for hearing restoration in patients with CAOW, particularly when the use of a drill is not required. The long-term audiologic outcome is also reliable.


Subject(s)
Oval Window, Ear , Humans , Male , Female , Retrospective Studies , Adult , Treatment Outcome , Oval Window, Ear/surgery , Oval Window, Ear/abnormalities , Adolescent , Child , Middle Aged , Otologic Surgical Procedures/methods , Facial Nerve/surgery , Facial Nerve/physiopathology , Facial Nerve/abnormalities , Young Adult , Bone Conduction/physiology , Stapes/abnormalities , Audiometry, Pure-Tone , Hearing/physiology , Malleus/surgery
14.
Hear Res ; 446: 109004, 2024 May.
Article in English | MEDLINE | ID: mdl-38608332

ABSTRACT

The naturally occurring amino acid, l-ergothioneine (EGT), has immense potential as a therapeutic, having shown promise in the treatment of other disease models, including neurological disorders. EGT is naturally uptaken into cells via its specific receptor, OCTN1, to be utilized by cells as an antioxidant and anti-inflammatory. In our current study, EGT was administered over a period of 6 months to 25-26-month-old CBA/CaJ mice as a possible treatment for age-related hearing loss (ARHL), since presbycusis has been linked to higher levels of cochlear oxidative stress, apoptosis, and chronic inflammation. Results from the current study indicate that EGT can prevent aging declines of some key features of ARHL. However, we found a distinct sex difference for the response to the treatments, for hearing - Auditory Brainstem Responses (ABRs) and Distortion Product Otoacoustic Emissions (DPOAEs). Males exhibited lower threshold declines in both low dose (LD) and high dose (HD) test groups throughout the testing period and did not display some of the characteristic aging declines in hearing seen in Control animals. In contrast, female mice did not show any therapeutic effects with either treatment dose. Further confirming this sex difference, EGT levels in whole blood sampling throughout the testing period showed greater uptake of EGT in males compared to females. Additionally, RT-PCR results from three tissue types of the inner ear confirmed EGT activity in the cochlea in both males and females. Males and females exhibited significant differences in biomarkers related to apoptosis (Cas-3), inflammation (TNF-a), oxidative stress (SOD2), and mitochondrial health (PGC1a).These changes were more prominent in males as compared to females, especially in stria vascularis tissue. Taken together, these findings suggest that EGT has the potential to be a naturally derived therapeutic for slowing down the progression of ARHL, and possibly other neurodegenerative diseases. EGT, while effective in the treatment of some features of presbycusis in aging males, could also be modified into a general prophylaxis for other age-related disorders where treatment protocols would include eating a larger proportion of EGT-rich foods or supplements. Lastly, the sex difference discovered here, needs further investigation to see if therapeutic conditions can be developed where aging females show better responsiveness to EGT.


Subject(s)
Aging , Antioxidants , Cochlea , Disease Models, Animal , Disease Progression , Ergothioneine , Evoked Potentials, Auditory, Brain Stem , Mice, Inbred CBA , Oxidative Stress , Presbycusis , Animals , Ergothioneine/pharmacology , Female , Evoked Potentials, Auditory, Brain Stem/drug effects , Male , Presbycusis/physiopathology , Presbycusis/pathology , Presbycusis/drug therapy , Presbycusis/metabolism , Presbycusis/prevention & control , Oxidative Stress/drug effects , Aging/drug effects , Aging/pathology , Antioxidants/pharmacology , Sex Factors , Cochlea/drug effects , Cochlea/metabolism , Cochlea/physiopathology , Cochlea/pathology , Age Factors , Apoptosis/drug effects , Otoacoustic Emissions, Spontaneous/drug effects , Superoxide Dismutase/metabolism , Auditory Threshold/drug effects , Hearing/drug effects , Mice , Anti-Inflammatory Agents/pharmacology
15.
Hear Res ; 447: 109008, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38636186

ABSTRACT

The auditory cortex is the source of descending connections providing contextual feedback for auditory signal processing at almost all levels of the lemniscal auditory pathway. Such feedback is essential for cognitive processing. It is likely that corticofugal pathways are degraded with aging, becoming important players in age-related hearing loss and, by extension, in cognitive decline. We are testing the hypothesis that surface, epidural stimulation of the auditory cortex during aging may regulate the activity of corticofugal pathways, resulting in modulation of central and peripheral traits of auditory aging. Increased auditory thresholds during ongoing age-related hearing loss in the rat are attenuated after two weeks of epidural stimulation with direct current applied to the surface of the auditory cortex for two weeks in alternate days (Fernández del Campo et al., 2024). Here we report that the same cortical electrical stimulation protocol induces structural and cytochemical changes in the aging cochlea and auditory brainstem, which may underlie recovery of age-degraded auditory sensitivity. Specifically, we found that in 18 month-old rats after two weeks of cortical electrical stimulation there is, relative to age-matched non-stimulated rats: a) a larger number of choline acetyltransferase immunoreactive neuronal cell body profiles in the ventral nucleus of the trapezoid body, originating the medial olivocochlear system.; b) a reduction of age-related dystrophic changes in the stria vascularis; c) diminished immunoreactivity for the pro-inflammatory cytokine TNFα in the stria vascularis and spiral ligament. d) diminished immunoreactivity for Iba1 and changes in the morphology of Iba1 immunoreactive cells in the lateral wall, suggesting reduced activation of macrophage/microglia; d) Increased immunoreactivity levels for calretinin in spiral ganglion neurons, suggesting excitability modulation by corticofugal stimulation. Altogether, these findings support that non-invasive neuromodulation of the auditory cortex during aging preserves the cochlear efferent system and ameliorates cochlear aging traits, including stria vascularis dystrophy, dysregulated inflammation and altered excitability in primary auditory neurons.


Subject(s)
Aging , Auditory Cortex , Auditory Pathways , Cochlea , Electric Stimulation , Presbycusis , Animals , Auditory Cortex/metabolism , Auditory Cortex/physiopathology , Cochlea/innervation , Cochlea/metabolism , Cochlea/physiopathology , Cochlea/pathology , Presbycusis/physiopathology , Presbycusis/metabolism , Presbycusis/pathology , Auditory Pathways/physiopathology , Auditory Pathways/metabolism , Male , Aging/pathology , Aging/metabolism , Disease Models, Animal , Age Factors , Neurons, Efferent/metabolism , Microglia/metabolism , Microglia/pathology , Auditory Threshold , Choline O-Acetyltransferase/metabolism , Olivary Nucleus/metabolism , Evoked Potentials, Auditory, Brain Stem , Hearing , Rats, Sprague-Dawley , Tumor Necrosis Factor-alpha/metabolism , Calcium-Binding Proteins , Microfilament Proteins
16.
Cell Rep ; 43(4): 114025, 2024 Apr 23.
Article in English | MEDLINE | ID: mdl-38564333

ABSTRACT

Type I spiral ganglion neurons (SGNs) convey sound information to the central auditory pathway by forming synapses with inner hair cells (IHCs) in the mammalian cochlea. The molecular mechanisms regulating the formation of the post-synaptic density (PSD) in the SGN afferent terminals are still unclear. Here, we demonstrate that brain-specific angiogenesis inhibitor 1 (BAI1) is required for the clustering of AMPA receptors GluR2-4 (glutamate receptors 2-4) at the PSD. Adult Bai1-deficient mice have functional IHCs but fail to transmit information to the SGNs, leading to highly raised hearing thresholds. Despite the almost complete absence of AMPA receptor subunits, the SGN fibers innervating the IHCs do not degenerate. Furthermore, we show that AMPA receptors are still expressed in the cochlea of Bai1-deficient mice, highlighting a role for BAI1 in trafficking or anchoring GluR2-4 to the PSDs. These findings identify molecular and functional mechanisms required for sound encoding at cochlear ribbon synapses.


Subject(s)
Cochlea , Hearing , Post-Synaptic Density , Receptors, AMPA , Receptors, G-Protein-Coupled , Spiral Ganglion , Animals , Receptors, AMPA/metabolism , Mice , Spiral Ganglion/metabolism , Hearing/physiology , Cochlea/metabolism , Post-Synaptic Density/metabolism , Mice, Knockout , Hair Cells, Auditory, Inner/metabolism , Mice, Inbred C57BL , Synapses/metabolism
17.
Int J Pediatr Otorhinolaryngol ; 180: 111956, 2024 May.
Article in English | MEDLINE | ID: mdl-38657426

ABSTRACT

OBJECTIVE: Trimming of perforation margins and external auditory canal (EAC) packing are basic procedures in underlay myringoplasty for repairing chronic perforations. The objective of this study was to compare the operation time, graft outcome, hearing improvement, and complications of endoscopic cartilage underlay myringoplasty with and without trimming of perforation margins and EAC packing in children. STUDY DESIGN: Prospective, randomized study. SETTING: Tertiary referral center. MATERIAL AND METHODS: Pediatric patients older than 12 years with chronic perforations were randomly divided into two groups: myringoplasty with trimming of perforation margin and EAC packing (TPME) group or no trimming of perforation margin and EAC packing (NTPME) group. The operation time, graft success rate, hearing improvement, and complications were compared between the two groups. RESULTS: Fifty-two patients were ultimately included in the study. The mean operation time was 31.4 ± 4.2 min in the TPME group and 23.6 ± 1.7 min in the NTPME group; the difference was significant (P < 0.01). The rate of aural fullness significantly differed between the TPME and NTPME groups (P = 0.000). All participants were followed up for 12 months; the graft success rate did not significantly differ between the groups (88.5% vs. 96.2%; P = 0.603). No patients developed adhesive otitis media. Between the preoperative and postoperative measurements, the mean air-bone gap improved by 10.2 ± 2.8 dB in the TPME group and 11.6 ± 0.7 dB in the NTPME group; this was significant (P < 0.001) in both groups. CONCLUSIONS: Endoscopic cartilage underlay myringoplasty NTPME shorted the operation time and avoided aural fullness and EAC discomfort compared with the TPME technique; however, graft success and hearing improvement were comparable between the two techniques for repairing large perforations in children.


Subject(s)
Myringoplasty , Operative Time , Tympanic Membrane Perforation , Humans , Myringoplasty/methods , Tympanic Membrane Perforation/surgery , Child , Female , Male , Prospective Studies , Treatment Outcome , Chronic Disease , Ear Canal/surgery , Endoscopy/methods , Adolescent , Cartilage/transplantation , Hearing
18.
Trends Hear ; 28: 23312165241246616, 2024.
Article in English | MEDLINE | ID: mdl-38656770

ABSTRACT

Negativity bias is a cognitive bias that results in negative events being perceptually more salient than positive ones. For hearing care, this means that hearing aid benefits can potentially be overshadowed by adverse experiences. Research has shown that sustaining focus on positive experiences has the potential to mitigate negativity bias. The purpose of the current study was to investigate whether a positive focus (PF) intervention can improve speech-in-noise abilities for experienced hearing aid users. Thirty participants were randomly allocated to a control or PF group (N = 2 × 15). Prior to hearing aid fitting, all participants filled out the short form of the Speech, Spatial and Qualities of Hearing scale (SSQ12) based on their own hearing aids. At the first visit, they were fitted with study hearing aids, and speech-in-noise testing was performed. Both groups then wore the study hearing aids for two weeks and sent daily text messages reporting hours of hearing aid use to an experimenter. In addition, the PF group was instructed to focus on positive listening experiences and to also report them in the daily text messages. After the 2-week trial, all participants filled out the SSQ12 questionnaire based on the study hearing aids and completed the speech-in-noise testing again. Speech-in-noise performance and SSQ12 Qualities score were improved for the PF group but not for the control group. This finding indicates that the PF intervention can improve subjective and objective hearing aid benefits.


Subject(s)
Correction of Hearing Impairment , Hearing Aids , Noise , Persons With Hearing Impairments , Speech Intelligibility , Speech Perception , Humans , Male , Female , Aged , Noise/adverse effects , Middle Aged , Correction of Hearing Impairment/instrumentation , Persons With Hearing Impairments/rehabilitation , Persons With Hearing Impairments/psychology , Perceptual Masking , Hearing Loss/rehabilitation , Hearing Loss/psychology , Hearing Loss/diagnosis , Audiometry, Speech , Surveys and Questionnaires , Aged, 80 and over , Time Factors , Acoustic Stimulation , Hearing , Treatment Outcome
19.
BMC Public Health ; 24(1): 1024, 2024 Apr 12.
Article in English | MEDLINE | ID: mdl-38609927

ABSTRACT

In this cross-sectional random survey among Thai adults living in Bangkok, we aimed to identify the prevalence of hearing problems and examine their relationship with individual factors. We administered a self-report questionnaire and performed pure-tone air conduction threshold audiometry. A total of 2463 participants (1728 female individuals) aged 15-96 years were included. The hearing loss prevalence was 53.02% and increased with age. The prevalence of a moderate or greater degree of hearing impairment was 2.8%. Participants aged 65 years and over had 8.56 and 6.79 times greater hearing loss and hearing impairment than younger participants, respectively. Male participants were twice as likely to have hearing loss and hearing impairment as female individuals. Participants with higher education levels showed less likelihood of having hearing loss and hearing impairment than those with no or a primary school education. Participants who ever worked under conditions with loud noise for > 8 h per day had 1.56 times greater hearing loss than those without such exposure. An inconsistent correlation was found between hearing loss, hearing impairment and noncommunicable diseases (diabetes, hypertension, and obesity). Although most participants had mild hearing loss, appropriate care and monitoring are necessary to prevent further loss in such individuals. The questionnaire-based survey found only people with hearing problems that affect daily communication.


Subject(s)
Deafness , Hearing , Adult , Female , Male , Humans , Cross-Sectional Studies , Thailand/epidemiology , Health Surveys
20.
J Clin Neurosci ; 124: 1-14, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38615371

ABSTRACT

BACKGROUND: Vestibular schwannomas (VS) are benign tumors arising from vestibular nerve's Schwann cells. Surgical resection via retrosigmoid (RS) or middle fossa (MF) is standard, but the optimal approach remains debated. This meta-analysis evaluated RS and MF approaches for VS management, emphasizing hearing preservation and Cranial nerve seven (CN VII) outcomes stratified by tumor size. METHODS: Systematic searches across PubMed, Cochrane, Web of Science, and Embase identified relevant studies. Hearing and CN VII outcomes were gauged using the American Academy of Otolaryngology-Head and Neck Surgery, Gardner Robertson, and House-Brackmann scores. RESULTS: Among 7228 patients, 56 % underwent RS and 44 % MF. For intracanalicular tumors, MF recorded 38 % hearing loss, compared to RS's 54 %. In small tumors (<1.5 cm), MF showed 41 % hearing loss, contrasting RS's lower 15 %. Medium-sized tumors (1.5 cm-2.9 cm) revealed 68 % hearing loss in MF and 55 % in RS. Large tumors (>3cm) were only reported in RS with a hearing loss rate of 62 %. CONCLUSION: Conclusively, while MF may be preferable for intracanalicular tumors, RS demonstrated superior hearing preservation for small to medium-sized tumors. This research underlines the significance of stratified outcomes by tumor size, guiding surgical decisions and enhancing patient outcomes.


Subject(s)
Neuroma, Acoustic , Neurosurgical Procedures , Neuroma, Acoustic/surgery , Humans , Neurosurgical Procedures/methods , Cranial Fossa, Middle/surgery , Hearing Loss/etiology , Hearing Loss/prevention & control , Hearing Loss/surgery , Facial Nerve/surgery , Hearing/physiology
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