Hearing Thresholds Research Articles

Brainstem auditory evoked responses: Objective hearing threshold assessment in Holstein cows.

Animal audiology utilizes brainstem auditory evoked responses (BAER) as a non-invasive tool to assess hearing in animals, including Holstein dairy cows. Understanding cows' auditory capabilities is critical for their welfare, especially given their exposure to farm noise. This study provides preliminary normative BAER data for Holstein cows by focusing on absolute and interpeak wave latencies. The objective is to assess the impact of farm noise and expand audiologists' practice scope. Ten Holstein cows were tested using monoaural broadband click stimuli with contralateral masking. Earphones with foam ear tips were used to minimize environmental noise interference. The BAER responses were recorded via subdermal needle electrodes placed at standardized locations on the cows' heads. The data were analysed using descriptive statistics to determine auditory thresholds and wave latencies. The cows exhibited auditory thresholds at 90 dB SPL (55 dB nHL). Detailed wave and interpeak latencies were recorded at intensities from 85 to 105 dB SPL. At 90 dB SPL, the average latency for wave V was 5.17 ms, marking the auditory threshold for Holstein cows. These findings provide key insights into the auditory sensitivity of Holstein cows, highlighting BAER's potential for monitoring auditory health and evaluating the effects of noise pollution on animal welfare. This research underscores the value of integrating animal audiology into the audiologist's scope, ultimately enhancing both animal welfare and farming sustainability.Contribution:This study adds to the limited literature on farm animal auditory health and suggests strategies to improve welfare through better auditory management.

Improving speech intelligibility in noise and spatial perception: the critical role of hearing aid microphone position.

Hearing aid (HA) manufacturers have introduced behind-the-ear (BTE) models where the microphone is positioned in the ear canal, which could impact auditory performance by distorting the pinna's acoustic cues. This study aimed to compare two different BTE HAs with varying microphone positions: the receiver in the ear (RITE) and the transducer in the ear (TIE). The study involved 10 participants who had never used HAs before. They used both RITE and TIE HAs bilaterally for 3 weeks. Auditory performance was assessed through free field hearing assessments (hearing thresholds, speech recognition threshold, and speech discrimination score), the Turkish Matrix Sentence Test (TURMatrix), a sound localization test, and the Satisfaction with Amplification in Daily Living (SADL) questionnaire. There was no significant difference between TIE and RITE in the free field hearing assessments. However, TIE outperformed RITE in non-adaptive TURMatrix scores in quiet, adaptive TURMatrix scores in noise, and sound localization accuracy at various angles. SADL sub-scores (Positive Effect, Service and Cost, and Personal Image) and overall satisfaction scores were significantly better for TIE. The microphone position in HAs can influence auditory performance. This study demonstrated that TIE provided better speech intelligibility, localization accuracy, and user satisfaction compared to RITE.

Impairment of Internal Auditory Canal Barrier in Meniere'sDisease.

The aim of this investigation was to explore the potential correlation between the signal intensity ratio (SIR) at the internal auditory canal (IAC) fundus and hearing impairment in Meniere's disease (MD), thereby providing a foundation to further understand the mechanisms underlying hearing loss. Fifty patients diagnosed with unilateral definite MD were enrolled in the study. 3D-FLAIR MRI was conducted 4 h after intravenous administration of gadobutrol to determine the SIR of the bilateral IAC fundus. The difference in the SIR of the IAC fundus between the affected and unaffected sides was assessed, followed by an analysis of its correlation with low-, middle-, and high-tone hearing thresholds. Correlation analysis was also conducted between the degree of endolymphatic hydrops (EH) in the vestibule and cochlea and the SIR on the affected side. The degree of EH in MD can be clearly visualised using 3D-FLAIR MRI. The SIR on the affected side was significantly higher than that on the unaffected side (p = 0.000). Furthermore, a positive correlation was observed between the SIR at the affected and low (r = 0.692, p = 0.000), middle (r = 0.615, p = 0.000) and high-tone (r = 0.440, p = 0.001) hearing thresholds, while the SIR showed no significant correlation with cochlear (r = 0.315, p = 0.088) or vestibular hydrops (r = 0.215, p = 0.244). The IAC fundus barrier may be damaged in patients with MD, representing one of the factors affecting the level of hearing.

The evaluation of auditory processing skills and late latencies in children with ventilation tube history

Objective(s): This study aims to evaluate the changes in temporal auditory processing skills in children who underwent bilateral ventilation tube insertion (VTI) due to Otitis Media with Effusion (OME) and the effect of these changes on speech comprehension in noisy environments. MethodsThis is a case-control study. In total, 60 children were included in the study in two groups. The control group included 30 children aged 11 to 15, who had normal hearing thresholds and normal immitancemetric evaluation, and were not diagnosed with OME. The study group included 30 children, aged 11–15 who underwent bilateral VTI surgery after their diagnosis of OME during the ages of 3–10 and currently had normal hearing thresholds and normal immitancemetric values. Each group underwent the Turkish Matrix Test (TMT), Random Gap Detection Test (RGDT), Frequency Pattern Test (FPT), Duration Pattern Test (DPT), and Cortical Auditory Evoked Potential Test (CAEP). ResultsWhen the temporal processing tests (FPT, DPT, RGDT) were compared, a significant difference was obtained between the study group and the control group (p < 0.05). With the TMT, significantly lower scores were obtained in the study group compared to the control group (p < 0.01). In addition, the latency values in the cortical auditory evoked potential test were longer in the study group compared to the control group, but these results were not statistically significant (p > 0.05). ConclusionAs a result of the study, it is concluded that the central auditory processing skills were affected in children with a history of bilateral VTI due to OME. Temporal processing tests, Turkish Matrix Test and Cortical Auditory Evoked Potential tests can be recommended as reliable and easily applicable tests, together with traditional hearing test methods in children with a history of OME, in order to evaluate comprehension skills in classroom noise.

Lipid metabolism and hearing loss: association of non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR) with adolescent hearing health

BackgroundThe ratio of non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol (NHHR) is a novel lipid measure for assessing the risk of cardiovascular disease. Lipid metabolism disorders are reportedly associated with hearing impairment. This study aimed to investigate the potential association between NHHR and hearing.MethodsThe data used in this study were obtained from the National Health and Nutrition Examination Survey (NHANES) cycles of 2005–2010 and 2017–2018, including 4,296 participants aged 6–19 years. The NHHR was calculated from lipid profiles, and hearing was assessed using pure-tone audiometry. Weighted multivariate logistic regression analyses were used to investigate the association between the NHHR and hearing loss. Subgroup and sensitivity analyses were performed to verify the robustness of the results.ResultsUnivariate analysis revealed significant associations between the NHHR and hearing threshold at all categorized frequency (low, speech, or high-frequency) (P < 0.001). Three models were used: an unadjusted model, a model adjusted for age, sex, and race, and a model further adjusted for PIR, BMI, and diabetes. Multiple regression analysis confirmed these associations consistently across all models. When considered as a continuous variable, NHHR had a significant association with enhanced hearing thresholds at all categorized frequencies: low-frequency (β:0.56, 95% CI: 0.36–0.75), speech-frequency (β:0.55, 95% CI: 0.36–0.7), and high-frequency (β:0.55, 95% CI: 0.36–0.74). The adjusted models showed persistent positive correlations after controlling for covariates. The NHHR was consistently positively associated with hearing loss. The NHHR and auditory thresholds showed a general dose-response association across all frequencies.ConclusionsNHHR is a promising biomarker for predicting adolescent hearing threshold shifts and hearing loss. The study highlights the importance of early lipid monitoring and management as strategies to prevent or reduce hearing impairment.

Hearing loss and its relation to longitudinal changes in white matter microstructure in older adults: The Rotterdam Study

Hearing loss is considered a potentially modifiable risk factor for dementia. The sensory deprivation theory postulates that hearing loss adversely affects cognition in older adults through structural brain changes, but longitudinal studies are scarce. To find evidence for a possible detrimental effect of hearing loss on white matter microstructure, we carried out a longitudinal study in the population-based Rotterdam Study. A total of 1877 participants with a median age at baseline of 56.4 years (IQR: [52.2–60.0]) underwent audiometry and had longitudinal diffusion imaging data available with a mean follow-up of 4.0 years. A lower level of hearing acuity was associated with worse white matter microstructure in the left uncinate fasciculus and superior longitudinal fasciculus at baseline. Poorer hearing acuity was also associated with faster microstructural deterioration over time in the left superior longitudinal fasciculus. The strongest effects were observed for low-frequency hearing thresholds, while the high-frequency thresholds showed the weakest associations. These results suggest that hearing loss may contribute to the age-related decline in brain structure, consistent with the sensory deprivation theory.

Critical role of hepsin/TMPRSS1 in hearing and tectorial membrane morphogenesis: Insights from transgenic mouse models

Mutations in various type II transmembrane serine protease (TMPRSS) family members are associated with non-syndromic hearing loss, with some mechanisms still unclear. For instance, the mechanism underlying profound hearing loss and tectorial membrane (TM) malformations in hepsin/TMPRSS1 knockout (KO) mice remains elusive. In this study, we confirmed significantly elevated hearing thresholds and abnormal TM morphology in hepsin KO mice, characterized by enlarged TM with gaps and detachment from the spiral limbus. Transgenic mouse lines were created to express either wild-type or a serine protease-dead mutant of human hepsin in the KO background. The Tg68;KO line, expressing moderate levels of wild-type human hepsin in the cochlea, showed partial restoration of hearing function. Conversely, the Tg5;KO or TgRS;KO lines, with undetectable hepsin or protease-dead hepsin, did not show such improvement. Histological analyses revealed that Tg68;KO mice, but not Tg5;KO or TgRS;KO mice, had a more compact TM structure, partially attached to the spiral limbus. These results indicate that hepsin expression levels correlate with improvements in hearing and TM morphology, and its protease activity is critical for these effects. Hepsin's role was further examined by studying its relationship with α-tectorin (TECTA) and β-tectorin (TECTB), non-collagenous proteins crucial for TM formation. Hepsin was co-expressed with TECTA and TECTB in the developing cochlear epithelium. Immunostaining showed decreased levels of TECTA and TECTB in hepsin KO TM, partially restored in Tg68;KO mice. These findings suggest that hepsin is essential for proper TM morphogenesis and auditory function, potentially by proteolytic processing/maturation of TECTA and TECTB and their incorporation into the TM.

Central Auditory Processing Abilities in Children with Non-Syndromic Cleft Lip and Palate: An Electrophysiological Study.

The present study compared the central auditory processing abilities using electrophysiological tests in children with non-syndromic cleft lip and palate (NSCLP) and their age-matched control group. Thirty children aged 7 to 15 years were recruited for the study. Participants were divided into 2 groups. The clinical group (children with NSCLP) comprised 15 children, while the control group (craniofacially typical peers) comprised 15 children with normal hearing sensitivity and auditory processing skills. Electrophysiological tests, including auditory brainstem responses (ABR), binaural interaction component (BIC) of ABR, auditory late latency responses (ALLR), and P300 were assessed. The results showed deviant responses in ABR, BIC, and ALLR in children with NSCLP compared to craniofacially typical counterparts. However, no significant difference was observed in P300 between the two groups. Children with NSCLP may be at a higher risk of central auditory processing disorder due to their abnormal neural transmission in the auditory nervous system. Also, assessing auditory processing abilities in children with NSCLP should include electrophysiological tests in the test battery for additional information regarding neural transmission.

ATP-gated P2x7 receptor is a major channel type at type II auditory nerves and required for hearing sensitivity efferent controlling and noise protection.

Hearing sensitivity and noise protection are mediated and determined by negative feedback of the cochlear efferent system. Type II auditory nerves (ANs) innervate outer hair cells (OHCs) in the cochlea and provide an input to this efferent control. However, little is known about underlying channel information. Here, we report that ATP-gated P2x7 receptor had a predominant expression at type II ANs and the synaptic areas under inner hair cells and OHCs with lateral and medial olivocochlear efferent nerves. Knockout (KO) of P2x7 increased hearing sensitivity with enhanced acoustic startle response (ASR), auditory brainstem response (ABR), and cochlear microphonics (CM) by increasing OHC electromotility, an active cochlear amplifier in mammals. P2x7 KO also increased susceptibility to noise. Middle level noise exposure could impair active cochlear mechanics resulting in permanent hearing loss in P2x7 KO mice. These data demonstrate that P2x7 receptors have a critical role in type II AN function and the cochlear efferent system to control hearing sensitivity; deficiency of P2x7 receptors can impair the cochlear efferent suppression leading to hearing oversensitivity and susceptibility to noise.

Evaluating the accuracy of a self-administered smartphone hearing test application in a geriatric population.

As the global population ages, hearing loss becomes increasingly prevalent, and is associated with neurocognitive and psychiatric comorbidities, impacting quality of life. Early screening and timely intervention might prevent or delay cognitive decline, a gap in care that can potentially be addressed by self-administered smartphone hearing tests. This study aims to evaluate the accuracy of Mimi™ (Berlin, Germany), a commercially available self-administered smartphone hearing test compared to pure tone audiogram (PTA) in terms of both hearing levels and hearing thresholds in our local geriatric population > 65 years-old. Fifty-two participants above 65 years of age requiring conventional audiograms were recruited from a National Referral University Hospital Otolaryngology clinic from March to June 2022. All participants were administered the conventional PTA tests in a sound-proof booth conducted by audiology technicians followed by Mimi™ Hearing Test in a quiet clinic room. Comparisons between the hearing levels of both tests were analyzed using Spearman's rank correlation coefficient, Bland-Altman plots and Gwet's Kappa which looked at concordance. Hearing thresholds were then analysed using the Wilcoxon signed rank (SR) test. Mimi™ showed strong to very strong correlation with good agreement compared to readings obtained from formal PTA. Concordance in determining hearing loss also showed substantial to almost perfect agreement at each individual frequency, with values of kappa falling between 0.735-0.857. In terms of thresholds, there were no significant differences in thresholds given by both tests except for 2.0 kHz, HFPTA and 4FPTA (p < 0.05). Mimi™ serves as a good screening tool for detection of moderate hearing loss for early pickup and treatment except at higher frequencies. The smartphone hearing test is also less accurate in determining the extent of hearing loss and formal PTA after hearing loss is detected on screening should still be standard of care.

Auditory characteristics and disease progression trends of patients with common recessive deafness genes GJB2 and SLC26A4

Patients who aged≥6 years and had hearing loss due to GJB2 or SLC26A4 mutation from the Chinese Deafness Genome Project between January 2020 and December 2023 were included. A total of 43 patients with GJB2 mutation were detected, including 25 males and 18 females, with a mean age of (20.4±11.4) years. There were 20 patients with SLC26A4 mutation, including 9 males and 11 females, with a mean age of (15.7±9.1) years. The mean hearing threshold of GJB2 and SLC26A4 mutation patients was 54.1 (95%CI: 49.1-59.1) decibel hearing level (dB HL) and 66.1 (95%CI: 58.6-73.6) dB HL, respectively. The hearing threshold of GJB2 and SLC26A4 mutation patients increased at a rate of 0.21 (95%CI:-0.15-0.57) dB HL/year and 2.22 (95%CI: 1.46-2.99) dB HL/year, respectively. The current study indicates that patients with SLC26A4 mutation show a progressive trend of hearing decline with the increase of age.

Effect of Age on Distortion Product Otoacoustic Emissions at Extended High Frequencies.

The inner ear is most susceptible to the aging effects. Distortion product otoacoustic emissions (DPOAEs) are a good indicator for interpreting the age effects but are usually recorded at up to 8000 Hz frequencies in routine audiologic testing. The present study was designed to assess and compare the DPOAEs at conventional frequencies and at extended high frequencies (EHFs) across different age groups. Extended high-frequency audiometry (9000-16000 Hz) and DPOAEs from 500-16000 Hz were recorded on 80 adult (160 ears) participants (15-55 years) with normal hearing sensitivity. The participants were categorized into 4 groups: group I (15-<25 years), group II (25-<35 years), group III (35-<45 years), and group IV (45-55 years). A statistically significant reduction in EHF thresholds was observed from group III onward. However, the thresholds were comparatively better for group III at frequencies 9000, 10000, and 11500Hz than group IV. No significant difference was observed for EHF DPOAEs in groups I and II (except at 16000 Hz) and III and IV. Distortion product otoacoustic emissions at conventional frequencies in group IV were significantly poorer than the other 3 groups. A weak negative correlation was observed between the DPOAE parameters and EHF thresholds. The effect of age was more pronounced on EHF DPOAEs than EHF thresholds for frequencies 9000, 10000, and 11500 Hz. Distortion product otoacoustic emissions at EHF started deteriorating below the age of 30 years and showed a rapid decline above 35 years. Extended high-frequency DPOAEs can be used as screening tools to assess the function of the basal part of the cochlea.

Exploring the optimal plateau durations of tone burst to elicit masseteric vestibular evoked myogenic potentials: a within-subjects study

ObjectiveThe purpose of the present study was to explore the effect of plateau duration in eliciting masseter vestibular evoked myogenic potentials (mVEMPs) in healthy individuals with hearing sensitivity ≤ 15dBHL.MethodA within-subjects design was utilized in the study. Therefore, ipsilateral tone burst evoked mVEMPs were obtained from 30 healthy individuals using the zygomatic montage at 500 Hz tone bursts. Self-monitoring biofeedback was given during the procedure to confirm the tension of the masseter muscle. mVEMPs were recorded across three different plateau duration from 0 to 2 ms with rise/fall time of 2 ms at 95dBnHL. Hence the median and interquartile range were calculated for descriptive analysis of the data followed by non-parametric inferential statistics.ResultsTone burst evoked mVEMPs were found to be 100% present across all three plateau durations for both ears at 95 dBnHL. P11 and N21 latencies increased with longer plateau durations in both ears. There were no significant differences in P11-N21 peak-to-peak amplitude or interaural amplitude ratio (IAAR) observed across different plateau durations. IAAR was lowest for a 2 ms plateau duration in the 2–2-2 cycle. No significant variations were found across the three plateau durations.ConclusionSignificant differences in P11 and N21 latencies were observed across the three stimulus cycles, while no significant differences were found for P11N21 amplitude and IAAR. Yet, there was found to have the highest amplitude and lowest IAAR for 2–2-2 cycle than 2–0-2 and 2–1-2, suggesting it to be the optimal stimulus among the three of them.

Hydrogel Matrix Containing Microcarriers for Dexamethasone Delivery to Protect Against Cisplatin-Induced Hearing Loss.

A functional hydrogel containing biopolymer microcarriers loaded with dexamethasone was developed to address the hearing loss that results from cisplatin ototoxicity. The drug delivery platform was tested both in vitro in the HEI-OC1 inner ear cell line and in vivo in a rat animal model. The newly described formula offered prolonged release of the contained dexamethasone for up to six days and transformed into a solid state at body temperature, thus counteracting its clearing through the Eustachian tube when injected into the middle ear. When tested in vitro, the inner ear cells exposed to cisplatin showed significantly higher viability at 48 hours when seeded on hydrogel containing dexamethasone-loaded microparticles than the cells treated with free dexamethasone. In the rat in vivo model, the ears of the rats treated with the hydrogel formulation presented better hearing thresholds after cisplatin administration than contralateral ears treated with free dexamethasone. The ears of the rats treated with microcarriers without inclusion in the functional hydrogel obtained better results than the dexamethasone treatment group but not as good as the hydrogel-containing microcarrier group. Histological assessment of the rats' inner ears showed better integrity of the structures and lower apoptosis in the microcarrier-treated groups than in the control group. Overall, the newly described microcarrier of dexamethasone offers better protection against cisplatin-induced hearing loss than free dexamethasone, especially when contained in a functional hydrogel formulation.

Hidden hearing loss in a Charcot-Marie-Tooth type 1A mouse model.

Hidden hearing loss (HHL), a recently described auditory neuropathy characterized by normal audiometric thresholds but reduced sound-evoked cochlear compound action potentials, has been proposed to contribute to hearing difficulty in noisy environments in people with normal hearing thresholds and has become a widespread complaint. While most studies on HHL pathogenesis have focused on inner hair cell (IHC) synaptopathy, we recently showed that transient auditory nerve (AN) demyelination also causes HHL in mice. To test the effect of myelinopathy on hearing in a clinically relevant model, we studied a mouse model of Charcot-Marie-Tooth type 1A (CMT1A), the most prevalent hereditary peripheral neuropathy in humans. CMT1A mice exhibited the functional hallmarks of HHL together with disorganization of AN heminodes near the IHCs with minor loss of AN fibers. These results support the hypothesis that mild disruptions of AN myelination can cause HHL and that heminodal defects contribute to the alterations in the sound-evoked cochlear compound action potentials seen in this mouse model. Furthermore, these findings suggest that patients with CMT1A or other mild peripheral neuropathies are likely to suffer from HHL. Furthermore, these results suggest that studies of hearing in patients with CMT1A might help develop robust clinical tests for HHL, which are currently lacking.

Acoustic measurement around the pinna in the VHF region using a dummy head

We investigated the azimuth and vertical angle characteristics of head related transfer function (HRTF) at very high frequency region using head and torso simulator (HATS). The VHF sounds contain potential hazards for young people who can hear such sounds. Therefore, the relationship between hearing thresholds in very-high frequency (VHF) region and intensity of VHF sounds are very important for considering human impact. The former means sound pressure level (SPL) at eardrum, and the latter is SPL at center of two ears without a head. The difference between two SPLs means head-related transform function (HRTF). In this paper, we reported the HRTFs measured in VHF region for the azimuth and vertical angles by using a HATS. The complicated contour maps of HRTFs for angle and frequency show that the SPLs at eardrum in VHF region depend on among material, size and figure of a pinna.

Anthropogenic noise and impact on marine species : Acoustic metamaterials as a reduction solution

Anthropogenic underwater noise generated by offshore maritime activities poses a significant threat to nearby ecosystems due to elevated sound levels. Efforts have to be undertaken on noise reduction solutions, depending both on the offshore activities and on the marine species. In this context, leveraging the recent advances in underwater acoustic metamaterials seems crucial, due to their special properties in terms of scattering and absorption. This endeavor aligns with advancing Marine Renewable Energies while minimizing environmental impact. In this communication, a synthetic review is first proposed to define the various maritime works targeted, as well as their associated sound levels and frequency ranges of emission. In a second part, a cartography is outlined by classifying different marine species according to their hearing type, depth of immersion and auditory threshold. Then, in relation with the two previous analyses, solutions based on metamaterials for deep sea immersions are proposed. In particular, a multi-periodic arrangement of bars is proposed that exhibits several band gaps (i.e. frequency ranges in which propagation is forbidden), in order to limit the transmission of sound waves in a large frequency range. The concept can be easily extended depending on the targeted offshore activities and marine species.

Subjective and functional outcome measures to evaluate performance of pediatric cochlear implant

BackgroundThe majority of research on the effects of cochlear implants has been on clinical evaluations of efficacy (hearing and speech skills and auditory thresholds). But it is unclear how much clinical efficacy metrics (speech, hearing, and language tests) actually demonstrate how beneficial cochlear implants (CI) are in everyday circumstances. In this study, we aim to assess the performance of a child’s current CI with both subjective and functional outcomes measures. Also, we aimed to assess factors affecting these outcomes after CI.MethodsThe study group included 45 cochlear-implanted children, and their chronological age ranges between 4 and 12 years. Children were divided according to their language age into three groups: group 1 (G1) includes15 children with a language age of less than 2 years, group 2 (G2) includes 15 children with a language age of 2 to less than 4 years, and group 3 (G3) includes 15 children with language age 4 to 6 years. Assessment was done in two sessions: one for phoniatric evaluation and another for audiological evaluation.ResultsCI enabled children to develop speech perception in a closed manner evidenced by the early speech perception (ESP) test with pattern perception being the easiest and monosyllabic words being the most difficult and the least to develop. Most children with CI were able to control their voice, to a lesser extent to use speech in meaningful use in social situations and to develop communication strategies in oral situations which were the least to develop, and this was evident by Meaningful Use of Speech Scale. Children with CI were able to acquire language, and their receptive language was better than expressive language, but their language age was below their chronological age.ConclusionThe cochlear implant is an effective rehabilitative tool for the treatment of prelingually deafened children, and this was evident by our results. A hierarchal approach of speech assessment according to the language age of the child and selection of age-appropriate speech perception test is very important to assess cochlear-implanted children Speech recognition had a high degree of variability. Early implantation age and increased duration of implant experience were the most important factors associated with good performance with CI, better speech perception, and better language outcomes.

Issues and recent research on VHF sound exposure with consideration for young people's hearing perception

We define VHF sound as airborne sound that may be audible to humans above 16 kHz. It has been reported in recent studies that VHF sounds can be annoying when audible. We have therefore carried out various research studies to ensure the safe use of VHF sounds. One of the aim of this study is to obtain basic data for developing guidelines for VHF sound exposure, if necessary.These include measurements of hearing thresholds in the VHF range, ABR measurements, HRTF measurements and acoustic measurements for simulation and current situation of exposure regarding the effect of hair. This paper reports on recent trends in VHF sound exposure in Japan and several studies on the perceptions of young people's hearing of VHF sounds.

Assessment of hearing and balance functions in patients with acromegaly by the use of an audiovestibular test battery: a cross-sectional study.

Patients with acromegaly may have abnormalities in their hearing and balance as a result of modifications in body composition and involvement of the temporal bone. The objective of this study is to examine if there are any changes in the auditory and vestibular systems in individuals with acromegaly by using audiogram and vestibular function tests. This prospective study included 33 healthy controls and 33 acromegaly patients who were matched for age and gender distribution. A pure-tone audiometry test was conducted, including frequencies ranging from 250Hz to 8000Hz. Videonystagmography (VNG) was employed to assess nystagmus, an essential parameter used for assessing vestibular functions. The Video Head Impulse Test (v-HIT) was used to assess the vestibulo-ocular reflex (VOR). The Dizziness Handicap Inventory (DHI) was applied to evaluate the subjective complaints of the participants. The acromegaly patients had significantly elevated hearing thresholds at all frequencies (250, 500, 1000, 2000, 4000, and 6000Hz) compared to the control group (p < 0.005). The VNG tests, including gaze horizontal, gaze vertical, saccade, spontaneous nystagmus, optokinetic, smooth pursuit, and positioning tests, did not show any statistically significant difference between the two groups (p values > 0.05). The patient group demonstrated reduced VOR gains compared to the control group in the anterior and posterior channels (p < 0.005). There was no statistically significant difference between the two groups for the occurrence of aberrant eye movements (p values > 0.05). The patient group had a total DHI score of 6.6 ± 3.2, while the control group had a score of 3.2 ± 2.6 (independent samples t-test; p < 0.001). Therefore, The patient group exhibited significantly greater subjective vestibular symptoms. Patients with acromegaly experience impaired auditory function. The central vestibular system remains unaffected, while the gains of the vestibulo-ocular reflex (VOR) in the posterior and anterior semicircular canals are decreased. Additionally, these patients report experiencing subjective dizziness. Screening for hearing and balance in patients with acromegaly may improve the quality of life of patients and prevent problems related to balance disorders at an early stage.