Pure-tone Frequency Research Articles

Hyperbaric oxygen therapy and corticosteroids as combined treatment for acute acoustic trauma.

Acute acoustic trauma (AAT) is a sudden sensorineural hearing loss (SNHL) due to exposure to high intensity impulse noise. There are no acceptable treatment guidelines, although several studies showed steroids could be effective in restoring hearing levels. A recent report suggested that steroids combined with hyperbaric oxygen therapy (HBOT) are a superior regiment for AAT. The purpose of the current study is to investigate the effectiveness of steroids and HBOT for AAT treatment. the medical records 90 patients (118 ears) afflicted with AAT and treated with steroids and HBOT were retrospectively reviewed. Inclusion criteria were sensorineural hearing loss of at least 30 dB at the high frequency range (> 3,000Hz) following exposure to intense sound. Patients who started treatment within 7 days were classified as "Early treatment" group whereas patients who started treatment ≥ 8 days after AAT were classified as "Late treatment". The high frequency (3-8kHz) Pure Tone Average (hPTA) of the entire study population (n = 118) was 40.26 ± 15.42 dB pretreatment vs. 24.99 ± 15.83 dB post treatment (Wilcoxon matched-pairs test, P < 0.0001). Pre-treatment hPTA was not statistically different between early and late study groups, 39.87 ± 16.00 vs. 40.86 ± 14.35 dB in the early vs. late group, respectively (ANOVA, F[3,232] = 22.574, P > 0.05). The post-treatment hPTA on the other hand, was significantly lower in the early vs. late treatment groups (21.93 ± 15.38 vs.31.19 ± 15.09 dB, respectively; ANOVA, F[3,232] = 22.574, P < 0.05). Combination treatment with corticosteroids and HBOT is highly beneficial in improving hearing outcomes following AAT, when initiated within 7 days. This study was retrospectively registered on July 19th 2020 and assigned the identifier number NCT04482998.

Evaluating the Effect of Various Pure Tone Averages on Cochlear Implant Candidacy Screening.

To provide evidence to use an extended frequency pure tone average to screen for cochlear implant evaluation candidates as recommended by the American Cochlear Implant Alliance. Additionally, to determine whether traditional low frequency, high or low frequency, high frequency, or extended frequency pure tone average most accurately predicts cochlear implant candidates based on speech perception scores from aided AzBio sentence testing or aided consonant-nucleus-consonant (CNC) testing. Adults from a tertiary care center who completed aided sentence testing during cochlear implant evaluation between 2014 and 2024 were assessed. Pure tone averages at low, high, low or high, and extended frequency ranges were evaluated with individual ear's aided AzBio or aided CNC scores as an outcome. Sensitivity, specificity, negative predictive value, and positive predictive value were assessed and compared using a paired study design. There were 675 observations from 363 patients with AzBio as an outcome variable and 665 observations from 364 patients with CNC scores as an outcome variable. High or low frequency achieved the highest sensitivity at 96.3% AzBio as an outcome and 95.6% with CNC as an outcome, which was significantly better than low frequency (p < 0.001). Low frequency achieved the best specificity at 63.6% with AzBio as an outcome 76.9% with CNC as an outcome. Extended frequency pure tones resulted in greater sensitivity in predicting CI candidates compared with the traditionally used low frequency pure tone average. Screening with wider frequency values will lead to a greater number of patients being identified for a cochlear implant evaluation. Level 3 Laryngoscope, 2025.

Scala tympani drill-out technique for oval window atresia with malformed facial nerve:update

Background In some rare cases of congenital aplasia of the oval window (OW), malformed facial nerve (FN) locations covering the most or entire OW present a challenge to hearing reconstruction, there is no a highly effective surgical hearing reconstruction methods. Aims/objectives To update a Scala tympani drill-out technique (SDT) for abnormal FN course covering the OW. Material and methods All patients of congenital atresia of the OW was recruited between August 2014 and July 2023 in a tertiary-care center. When it’s inability to perform the vestibulotomy with FN covering the OW, The SDT surgery was made with a titanium TORP between the tympanic membrane and scala tympani fenestration for hearing reconstruction. Air conduction (AC) thresholds, bone conduction (BC) thresholds, and air-bone gap (ABG) at 0.5, 1, 2, 4 kHz pure tone frequencies were compared before and 3 months after surgery. Results A total of 11 patients underwent SDT surgery during the study period. All cases showed no bone conduction (BC) hearing loss, facial paralysis, tinnitus, or dizziness. The ABG has decreased by 21.2 ± 10.8 dB 3 month after operation. In the long term, three cases had the same hearing as pre-operative, three cases felt their hearing gradually decreased but better than pre-operative. Conclusions and significance As a new and optional method, our results suggest an effective way to reconstruct hearing for middle ear deformities with FN occlusion, the short-term effect can be confirmed, while the long-term effect is mixed, and a large amount of clinical research is still needed.

Delayed-X Harmonics Synthesizer algorithm for low frequency noise removal

As various technologies on noise reduction have improved their performances, slight low frequency noise has become more prominent in quiet environments. Since the traveling of low noise is difficult to be isolated by walls and earplugs, we aim an active noise control embedded in unoccluded headphones. In this case, both desired sounds (e.g., speech) and unwanted noises pass through the opened ears, so the algorithm is required to adapt only the noise separating from the speech (selective cancelation). Therefore, our selected procedure was Delayed-X Harmonics Synthesizer algorithm which produces pure tones in the opposite phase, because the generated pure tones in the low frequency can minimize the damage for the speech quality. To select the frequencies of pure tones, we focused on the fact that noise is more stationary than speech. The targets frequencies were determined by a small frame-variation on the spectra of the error signals. Our simulations demonstrated that the low noise (&lt; 100 Hz) could be reduced by 10dB even in the slight noise condition (SNR = 5dB), while the speech intelligibility (PESQ) was maintained. When our system is embedded in the unoccluded headphones, the users will take daily conversation without any troubles of low noise.

Analysis of the efficacy of fiber laser stapes fenestration in the treatment of 58 cases of otosclerosis and ossicular malformation

Objective: To explore the surgical efficacy of conductive deafness caused by otosclerosis and ossicular malformation with 980 nm fiber laser stapedial floor fenestration. Methods: Data of 58 patients (ears) who were diagnosed with conductive deafness caused by otosclerosis (49 ears) and ossicular malformation (9 ears) treated by 980 nm Diode laser small-fenestra stapedotomy were retrospectively analyzed. Air conduction (AC) thresholds, bone conduction (BC) thresholds, and air-bone gap (ABG) at 0.5, 1, 2, 4 kHz pure tone frequencies were compared before and 3 months after surgery, and the advantages and precautions of 980 nm fiber laser were summarized. Paired t-test (SPSS 26.0 software) was use to analyze the listening data. Results: Fiber optic laser stapes fenestration and artificial stapes implantation were successfully completed in all 57 cases (ears), the hearing of another one patient (ear) with floating malformation of detachment of stapedial floor was lower than that before surgery. Preoperative at 0.5, 1, 2, 4 kHz frequencies of AC thresholds, BC thresholds, and ABG were (65.4±9.7) dB, (27.2±8.9) dB, and (38.2±9.8) dB respectively. Postoperative 3 months at the same frequency of AC thresholds, BC thresholds, and ABG were (42.1±11.3) dB, (26.9±6.6) dB, and (15.2±9.1) dB. Preoperative and postoperative of AC threshold and ABG were statistically significant at 0.5, 1, 2, 4 kHz (t value was 13.270 and13.948, both P<0.01), and yet the BC threshold was not statistically significant before and after surgery at the same frequency (t=0.418, P>0.05). Conclusions: 980 nm fiber laser stapes floor fenestration is an effective treatment for conductive deafness caused by otosclerosis and ossicular malformation.

The association between skeletal muscle mass and sensorineural hearing loss upon cisplatin-based chemoradiotherapy in patients with head and neck squamous cell carcinoma.

Patients with head and neck squamous cell carcinoma (HNSCC) treated with cisplatin-based chemoradiotherapy (CRT) frequently experience irreversible sensorineural hearing loss (SNHL). Patients with low lumbar skeletal muscle index (LSMI) may experience higher serum peak dosages of cisplatin. This study investigated whether pre-treatment low LSMI is associated with increased SNHL upon cisplatin-based CRT. LSMI was assessed using routine pre-treatment CT scans. Pure tone audiometry was performed at baseline and at follow-up to assess treatment-related SNHL. Linear mixed models were used to reveal a potential association between the continuous variable LSMI and SNHL. This retrospective cohort study included 81 patients and found a significant association between low LSMI and increased treatment-related SNHL at pure tone frequencies vital for the perception of speech (averaged of 1, 2, and 4 kHz) (p = 0.048). HNSCC patients with low LSMI suffer increased treatment-related SNHL upon cisplatin-based CRT.

Psilocybin decreases neural responsiveness and increases functional connectivity while preserving pure-tone frequency selectivity in mouse auditory cortex.

Psilocybin is a serotonergic psychedelic believed to have therapeutic potential for neuropsychiatric conditions. Despite well-documented prevalence of perceptual alterations, hallucinations, and synesthesia associated with psychedelic experiences, little is known about how psilocybin affects sensory cortex or alters the activity of neurons in awake animals. To investigate, we conducted two-photon imaging experiments in auditory cortex of awake mice and collected video of free-roaming mouse behavior, both at baseline and during psilocybin treatment. In comparison with pre-dose neural activity, a 2 mg/kg ip dose of psilocybin initially increased the amplitude of neural responses to sound. Thirty minutes post-dose, behavioral activity and neural response amplitudes decreased, yet functional connectivity increased. In contrast, control mice given intraperitoneal saline injections showed no significant changes in either neural or behavioral activity across conditions. Notably, neuronal stimulus selectivity remained stable during psilocybin treatment, for both tonotopic cortical maps and single-cell pure-tone frequency tuning curves. Our results mirror similar findings regarding the effects of serotonergic psychedelics in visual cortex and suggest that psilocybin modulates the balance of intrinsic versus stimulus-driven influences on neural activity in auditory cortex.NEW & NOTEWORTHY Recent studies have shown promising therapeutic potential for psychedelics in treating neuropsychiatric conditions. Musical experience during psilocybin-assisted therapy is predictive of treatment outcome, yet little is known about how psilocybin affects auditory processing. Here, we conducted two-photon imaging experiments in auditory cortex of awake mice that received a dose of psilocybin. Our results suggest that psilocybin modulates the roles of intrinsic neural activity versus stimulus-driven influences on auditory perception.

PSYCHOACOUSTICS-WEB: A free online tool for the estimation of auditory thresholds

PSYCHOACOUSTICS-WEB is an online tool written in JavaScript and PHP that enables the estimation of auditory sensory thresholds via adaptive threshold tracking. The toolbox implements the transformed up-down methods proposed by Levitt (Journal of the Acoustical Society of America, 49, 467-477, (1971) for a set of classic psychoacoustical tasks: frequency, intensity, and duration discrimination of pure tones; duration discrimination and gap detection of noise; and amplitude modulation detection with noise carriers. The toolbox can be used through a common web browser; it works with both fixed and mobile devices, and requires no programming skills. PSYCHOACOUSTICS-WEB is suitable for laboratory, classroom, and online testing and is designed for two main types of users: an occasional user and, above all, an experimenter using the toolbox for their own research. This latter user can create a personal account, customise existing experiments, and share them in the form of direct links to further users (e.g., the participants of a hypothetical experiment). Finally, because data storage is centralised, the toolbox offers the potential for creating a database of auditory skills.

Acoustic stimulation of the human round window by laser-induced nonlinear optoacoustics.

The feasibility of low frequency pure tone generation in the inner ear by laser-induced nonlinear optoacoustic effect at the round window was demonstrated in three human cadaveric temporal bones (TB) using an integral pulse density modulation (IPDM). Nanosecond laser pulses with a wavelength in the near-infrared (NIR) region were delivered to the round window niche by an optical fiber with two spherical lenses glued to the end and a viscous gel at the site of the laser focus. Using IPDM, acoustic tones with frequencies between 20Hz and 1kHz were generated in the inner ear. The sound pressures in scala tympani and vestibuli were recorded and the intracochlear pressure difference (ICPD) was used to calculate the equivalent sound pressure level (eq. dB SPL) as an equivalent for perceived loudness. The results demonstrate that the optoacoustic effect produced sound pressure levels ranging from 140eq. dB SPL at low frequencies ≤ 200Hz to 90eq. dB SPL at 1kHz. Therefore, the produced sound pressure level is potentially sufficient for patients requiring acoustic low frequency stimulation. Hence, the presented method offers a potentially viable solution in the future to provide the acoustic stimulus component in combined electro-acoustic stimulation with a cochlear implant.

Digits-in-Noise Test as an Assessment Tool for Hearing Loss and Hearing Aids.

The aim of this study was to examine the relationship between an American English Digits in Noise (DIN) test and commonly used audiological measures to evaluate the DIN test's ability to detect hearing loss and validate hearing aid fitting. QuickSIN and DIN tests were completed by participants with untreated hearing loss (n = 46), prescription hearing aids (n = 15), and over-the-counter (OTC) hearing aids (n = 12). Performance on the QuickSIN showed moderate positive correlations with DIN for untreated hearing loss participants and prescription hearing aid users, but not for OTC hearing aid users. For untreated hearing loss participants, both QuickSIN and DIN tests showed positive moderate to strong correlations with high frequency puretone averages. In OTC users, DIN scores did not significantly change over a 6-month time period and were better when conducted remotely compared to in-person testing. Our results suggest that the DIN test may be a feasible monitoring option for individuals with hearing loss and those fitted with hearing aids. However, due to small sample size in this pilot study, future research is needed to examine DIN test's utility for fitting and validating OTC hearing aids.

Evaluating calcium channel blockers and bisphosphonates as otoprotective agents in cochlear implantation hearing preservation candidates

Objectives Evaluate potential effects of calcium channel blockers (CCB) and bisphosphonates (BP) on residual hearing following cochlear implantation. Methods Medications of 303 adult hearing preservation (HP) candidates (low frequency pure tone average [LFPTA] of 125, 250, and 500 Hz ≤80 dB HL) were reviewed. Postimplantation LFPTA of patients taking CCBs and BPs were compared to controls matched by age and preimplantation LFPTA. Results Twenty-six HP candidates were taking a CCB (N = 14) or bisphosphonate (N = 12) at implantation. Median follow-up was 1.37 years (range 0.22–4.64y). Among subjects with initial HP, 29% (N = 2 of 7) CCB users compared to 50% (N = 2 of 4) controls subsequently lost residual hearing 3–6 months later (OR = 0.40, 95% CI = 0.04–4.32, p = 0.58). None of the four BP patients with initial HP experienced delayed loss compared to 50% (N = 2 of 4) controls with initial HP (OR = 0.00, 95% CI = 0.00–1.95, P = 0.43). Two CCB and one BP patients improved to a LFPTA <80 dB HL following initial unaided thresholds that suggested loss of residual hearing. Discussion There were no significant differences in the odds of delayed loss of residual hearing with CCBs or BPs. Conclusion Further investigation into potential otoprotective adjuvants for maintaining residual hearing following initial successful hearing preservation is warranted, with larger cohorts and additional CCB/BP agents.

Smartphone-Facilitated In-Situ Hearing Aid Audiometry for Community-Based Hearing Testing.

Hearing loss prevalence is increasing, with an estimated 2.5 billion people affected globally by 2050. Scalable service delivery models using innovative technologies and task-shifting are World Health Organization priorities to improve access to hearing care, particularly in low- and middle-income countries. Smartphone-facilitated audiometry in the community using hearing aids covered by noise-attenuating ear cups ("in-situ") could support more accessible hearing care when provided by less trained individuals such as community health workers (CHWs). This study aimed to determine the validity of this method for potential hearing aid fitting. Study objectives included determining the maximum permissible ambient noise level (MPANL), inter-device reliability, clinical threshold accuracy, reliability, and performance in real-world settings. Experiment 1: 15 normal-hearing adult participants were evaluated to determine MPANLs for circumaural Peltor 3M earcups covering Lexie Lumen hearing aids with smartphone-facilitated in-situ audiometry. MPANLs were calculated by measuring the difference in attenuation between thresholds obtained with standard headphones and in-situ hearing aids. Experiment 2: Pure-tone frequency and intensity output of 14 same-model Lexie Lumen hearing aids were measured to determine inter-device reliability. Pure-tone stimuli were measured and analyzed to determine sound pressure levels in decibels and pure-tone frequency when connected to a test box 2cc coupler. Experiment 3: 85 adult participants were tested in a sound booth to determine the accuracy of automated in-situ pure-tone audiometry (PTA) compared to clinical PTA (500, 1000, 2000, 3000, 4000, 6000 Hz) facilitated by an audiologist. The first 39 participants were tested twice to determine test-retest reliability. Experiment 4: In a community setting, 144 adult participants were tested with automated in-situ audiometry facilitated by CHWs using a smartphone app. These participants were subsequently tested with automated mobile PTA (500, 1000, 2000, 4000 Hz). An additional 44 participants were tested twice to determine test-retest reliability. Experiment 1: MPANLs of the Peltor 3M earcup-covered hearing aids were higher than standard headphones across all frequencies, ranging from 24 to 47.3 dB SPL. Experiment 2: Inter-device performance reliability was high, with all inter-device differences across all intensities and frequencies less than 3 dB. Frequency output was consistent and differed less than 0.7% between devices. Experiments 3 and 4: 85.2% and 83.3% of automated in-situ audiometry thresholds were within 10 dB of thresholds obtained in the sound booth and in a community setting, respectively. Acceptable test-retest intraclass correlation coefficient (ICC) was evident across all thresholds obtained in a sound booth (ICC = 0.85 to 0.93) and in a community setting (ICC = 0.83 to 0.97). Smartphone-facilitated in-situ audiometry allows for reliable and valid community-based testing. A simple smartphone user interface and automated in-situ audiometry allow CHWs with minimal training to facilitate the testing. With the additional capability to program hearing aids via the smartphone after the initial test, this approach would have the potential to support widespread access to personalized hearing aid fittings facilitated by CHWs in low- and middle-income countries. This approach also supports self-fitting options based on in-situ thresholds, enabling testing and fitting via over the counter hearing aids.

Predictive model for aminoglycoside induced ototoxicity.

Irreversible hearing loss is a well-known adverse effect of aminoglycosides, however, inability to accurately predict ototoxicity is a major limitation in clinical care. We addressed this limitation by developing a prediction model for aminoglycoside ototoxicity applicable to the general population. We employed a prospective non-drug-resistant tuberculosis (TB), non-HIV/AIDS cohort of 153 adults on Streptomycin based anti-TB therapy. High frequency pure-tone audiometry was done at regular intervals throughout the study. Clinical and audiological predictors of ototoxicity were collated and ototoxic threshold shift from the baseline audiogram computed. The prediction model was developed with logistic regression method by examining multiple predictors of ototoxicity. Series of models were fitted sequentially; the best model was identified using Akaike Information Criterion and likelihood ratio test. Key variables in the final model were used to develop a logit model for ototoxicity prediction. Ototoxicity occurred in 35% of participants. Age, gender, weight, cumulative Streptomycin dosage, social class, baseline pure tone average (PTA) and prior hearing symptoms were explored as predictors. Multiple logistic regression showed that models with age, cumulative dosage and baseline PTA were best for predicting ototoxicity. Regression parameters for ototoxicity prediction showed that yearly age increment raised ototoxicity risk by 5% (AOR = 1.05; CI, 1.01-1.09), and a gram increase in cumulative dosage increased ototoxicity risk by 7% (AOR = 1.05; CI, 1.05-1.12) while a unit change in baseline log (PTA) was associated 254% higher risk of ototoxicity (AOR = 3.54, CI: 1.25, 10.01). Training and validation models had area under the receiver operating characteristic curve as 0.84 (CI, 0.76-0.92) and 0.79 (CI, 0.62-0.96) respectively, showing the model has discriminatory ability. This model can predict aminoglycoside ototoxicity in the general population.

Analysis of clinical audiological characteristics of noise-induced silent hearing loss

Objective: To explore the characteristics of audiology examination of Noise-Induced Hidden Hearing Loss (NIHHL), and then explore its valuable diagnostic methods.Methods: A total of 80 young men aged between 19 and 35 were selected. They were classified into the experimental group with noise exposure history and the control group without noise exposure history, with 40 men in each group. We carried out extended high-frequency audiometry test for good ears; conducted speech in noise measurement and distortion product emission for good ears; DPOAE test, compare and analyze the results of each test.Results: The extended high frequency hearing threshold test results showed that the hearing threshold of the experimental group was larger than that of the control group at the frequency above 8kHz, with significant statistical difference (p &lt; .01). The results of speech audiometry under noise showed that the signal-to-noise ratio loss in the experimental group was greater than that in the control group, with a significant statistical difference (p &lt; .01). The results of otoacoustic emission showed that the signal-to-noise ratio of the experimental group was lower than that of the control group at the frequency of 6 kHz and above, with a statistically significant difference (p &lt; .01). There is a correlation between pure tone audiometry and DPOAE test results at high frequencies (6 kHz: p &lt;. 0001, r = -.478; 8 kHz: p &lt; .0001, r = -.491;) ; There was a correlation between speech audiometry and DPOAE test results under noise (p = .031, r = -.299).Conclusion: Compared with the control group, the extended high frequency pure tone hearing threshold increased or could not be elicited in the experimental group, speech recognition ability decreased significantly under noise, DPOAE was normally elicited but signal-to-noise ratio decreased, and there was a certain correlation between them. The above three audiological examination methods have a certain reference value for early recognition of hidden hearing loss.

Electrically evoked compound action potentials in cochlear implant users with preoperative residual hearing.

Residual hearing in cochlear implant (CI) candidates requires the functional integrity of the nerve in particular regions of the cochlea. Nerve activity can be elicited as electrically evoked compound action potentials (ECAP) after cochlear implantation. We hypothesize that ECAP thresholds depend on preoperative residual hearing ability. In a retrospective study, we analyzed 84 adult cochlear implant users who had received a Nucleus® CI632 Slim Modiolar Electrode and who preoperatively had had residual hearing. Inclusion criteria were severe to profound hearing loss with preoperative measurable hearing in the ear to receive the implant, postlingual hearing loss, German as native language and correct placement of the electrode, inserted completely into the scala tympani. Electrically evoked compound action potential (ECAP) was recorded intraoperatively. The angular insertion was measured for each electrode contact from postoperative computed tomography to estimate the corresponding spiral ganglion frequency. Pure-tone audiometry and allocated ECAP thresholds were tested to investigate possible correlation. The average of hearing thresholds, tested at 0.5, 1, 2, and 4 kHz (4FPTA) was 82 ± 18 (range 47-129) dB HL. The success rate for recording ECAP thresholds was 96.9%. For all comparable pure-tone frequencies (1, 2, 4, and 8 kHz), there was significant correlation between preoperative hearing levels and intraoperative ECAP thresholds (p < 0.001). Higher hearing thresholds are associated with increased ECAP thresholds. In CI candidates with adequate residual hearing, intraoperative electrophysiological measurement records lower thresholds. This outcome may be explained by the neural survival density of the peripheral system, with less neural degeneration.

Extending existing models of cochlear mechanics to emphasize physiological mechanisms that support innate perception of harmonic relations among pure tone frequencies

Tonotopic mapping along the basilar membrane of the cochlear organ of Corti naturally supports a consistent relationship between the physical frequency of a tone and its perception of pitch. For example, higher frequencies tend to be mapped to higher pitch perceptions. Nevertheless, a precise perception of harmonic relations among pure tone frequencies apparently lacks a strong foundation on the tonotopic mapping mechanism alone. We are presenting a supplementary hypothesis based on temporal delays and cross-correlations between delayed signals in the cochlear fluids and the surrounding structures that provide a robust mechanism to establish innate perception of applicable harmonic relations among pure tone frequencies.

The effect of smoking on hearing: The invisible part of the iceberg

Objectives Previous studies have had conflicting results regarding the potential effect of smoking on hearing. One reason for the conflicting results may be the limited number of studies evaluating extended high-frequency hearing thresholds among these studies. Therefore, this study aims to evaluate the potential effect of smoking on hearing using extended high-frequency hearing thresholds. Materials and Methods A total of 80 participants aged 20-30 with normal hearing (0.125-8 kHz hearing thresholds ≤ 15 dB HL) were included in this study. Extended high-frequency hearing thresholds in each ear of all participants were evaluated in the range of 9-20 kHz. The cigarette consumption of smokers was determined according to the Brinkman Index. Results There was a significant difference between the study and control groups in pure-tone hearing thresholds. This difference started to increase after 9 kHz in the right ear and 10 kHz in the left ear. Also, there was a highly positive correlation between Brinkman Index and hearing thresholds at all extended high-frequencies. Conclusion The present study suggests that smoking has a potential effect on hearing, especially on high-frequency hearing thresholds. Also, this is the first study to show from which frequency pure tone hearing thresholds are affected in smoking. Clinicians should not be limited to the frequency range used in the routine audiological evaluation and should not ignore extended high-frequency hearing thresholds not to overlook possible conditions that may affect hearing.

Association between nineteen dietary fatty acids and hearing thresholds: findings from a nationwide survey

IntroductionHearing loss is a prevalent health concern, and dietary factors, such as fatty acid intake, may play a role in its development. The current study aimed to investigate the association between the intake of dietary fatty acids and hearing thresholds among U.S. adults.MethodsThe researchers examined data from the National Health and Nutrition Examination Survey (NHANES), including 7,623 participants with available dietary fatty acid intake and audiometry data. Dietary fatty acid intake was assessed using dietary recalls, and hearing thresholds were measured using pure-tone audiometry. Multivariate linear regression models and smoothing curve fitting were utilized to explore the associations between dietary fatty acid intake and hearing thresholds, adjusting for relevant covariates.ResultsThis study reveals a direct association between both low and high frequency pure tone average (PTA) hearing thresholds and the dietary intake of total saturated fatty acids (SFAs) and total polyunsaturated fatty acids (PUFAs). Conversely, the intake of total monounsaturated fatty acids (MUFAs) demonstrates an inverted U-shaped correlation with low-frequency and high-frequency PTA hearing thresholds, having inflection points at 11.91 (energy (%)) and 10.88 (energy (%)), respectively.ConclusionDietary intake of certain fatty acids may influence hearing thresholds in adults.

Frequency detection, frequency discrimination, and spectro-temporal pattern perception in older and younger typically hearing adults

Elderly adults often experience difficulties in speech understanding, possibly due to age-related deficits in frequency perception. It is unclear whether age-related deficits in frequency perception differ between the apical or basal regions of the cochlea. It is also unclear how aging might differently affect frequency discrimination or detection of a change in frequency within a stimulus. In the present study, pure-tone frequency thresholds were measured in 19 older (61–74 years) and 20 younger (22–28 years) typically hearing adults. Participants were asked to discriminate between reference and probe frequencies or to detect changes in frequency within a probe stimulus. Broadband spectro-temporal pattern perception was also measured using the spectro-temporal modulated ripple test (SMRT). Frequency thresholds were significantly poorer in the basal than in the apical region of the cochlea; the deficit in the basal region was 2 times larger for the older than for the younger group. Frequency thresholds were significantly poorer in the older group, especially in the basal region where frequency detection thresholds were 3.9 times poorer for the older than for the younger group. SMRT thresholds were 1.5 times better for the younger than for the older group. Significant age effects were observed for SMRT thresholds and for frequency thresholds only in the basal region. SMRT thresholds were significantly correlated with frequency thresholds only in the older group. The poorer frequency and spectro-temporal pattern perception may contribute to age-related deficits in speech perception, even when audiometric thresholds are nearly normal.

The National Institute for Occupational Safety and Health recommended exposure level for noise needs to be revised downwards

Noise-induced hearing loss (NIHL) is caused by cumulative occupational and non-occupational noise exposure. The National Institute for Occupational Safety and Health (NIOSH) developed recommendations for occupational noise exposure in 1972, revised in 1998. Fifty years after the NIOSH 85 dBA recommended exposure level (REL) was first published, it needs to be revised downwards. In its calculations, NIOSH assumed that workers have quiet (&amp;lt;60 dBA) when not at work, something no longer true. Everyday public noise exposure now exceeds the Environmental Protection Agency's safe noise level, a time-weighted average of 70 dB for 24 hours, with multiple studies reporting average exposures near 75 dBA. Also, NIOSH calculations were based on occupational studies of material hearing loss measured by limited frequency pure tone audiometry, an insensitive measure of noise-induced auditory damage. Modern audiology techniques include extended range audiometry, speech in noise testing, diffusion product otoacoustic emissions testing, and questions about tinnitus and hyperacusis. Doing the needed research to support downward REL revision, detecting auditory damage in noise-exposed workers with these newer techniques, is a daunting task, but this is necessary both to protect workers and because the NIOSH REL forms the basis for the world's recommendations for non-occupational noise exposure.