Extended High-frequency Thresholds Research Articles

Extended High-Frequency Thresholds: Associations With Demographic and Risk Factors, Cognitive Ability, and Hearing Outcomes in Middle-Aged and Older Adults.

This study had two objectives: to examine associations between extended high-frequency (EHF) thresholds, demographic factors (age, sex, race/ethnicity), risk factors (cardiovascular, smoking, noise exposure, occupation), and cognitive abilities; and to determine variance explained by EHF thresholds for speech perception in noise, self-rated workload/effort, and self-reported hearing difficulties. This study was a retrospective analysis of a data set from the MUSC Longitudinal Cohort Study of Age-related Hearing Loss. Data from 347 middle-aged adults (45 to 64 years) and 694 older adults (≥ 65 years) were analyzed for this study. Speech perception was quantified using low-context Speech Perception In Noise (SPIN) sentences. Self-rated workload/effort was measured using the effort prompt from the National Aeronautics and Space Administration-Task Load Index. Self-reported hearing difficulty was assessed using the Hearing Handicap Inventory for the Elderly/Adults. The Wisconsin Card Sorting Task and the Stroop Neuropsychological Screening Test were used to assess selected cognitive abilities. Pure-tone averages representing conventional and EHF thresholds between 9 and 12 kHz (PTA(9 - 12 kHz)) were utilized in simple linear regression analyses to examine relationships between thresholds and demographic and risk factors or in linear regression models to assess the contributions of PTA(9 - 12 kHz) to the variance among the three outcomes of interest. Further analyses were performed on a subset of individuals with thresholds ≤ 25 dB HL at all conventional frequencies to control for the influence of hearing loss on the association between PTA(9 - 12 kHz) and outcome measures. PTA(9 - 12 kHz) was higher in males than females, and was higher in White participants than in racial Minority participants. Linear regression models showed the associations between cardiovascular risk factors and PTA(9 - 12 kHz) were not statistically significant. Older adults who reported a history of noise exposure had higher PTA(9 - 12 kHz) than those without a history, while associations between noise history and PTA(9 - 12 kHz) did not reach statistical significance for middle-aged participants. Linear models adjusting for age, sex, race and noise history showed that higher PTA(9 - 12 kHz) was associated with greater self-perceived hearing difficulty and poorer speech recognition scores in noise for both middle-aged and older participants. Workload/effort was significantly related to PTA(9 - 12 kHz) for middle-aged, but not older, participants, while cognitive task performance was correlated with PTA(9 - 12 kHz) only for older participants. In general, PTA(9 - 12 kHz)did not account for additional variance in outcome measures as compared to conventional pure-tone thresholds, with the exception of self-reported hearing difficulties in older participants. Linear models adjusting for age and accounting for subject-level correlations in the subset analyses revealed no association between PTA(9 - 12 kHz)and outcomes of interest. EHF thresholds show age-, sex-, and race-related patterns of elevation that are similar to what is observed for conventional thresholds. The current results support the need for more research to determine the utility of adding EHF thresholds to routine audiometric assessment with middle-aged and older adults.

Hidden Hearing Loss–Subjective and Objective Correlation of Cochlear Physiology

Purpose: The study is aimed at identifying the co-relation of subjective and objective tests’ that reveal the site of lesion in Hidden Hearing Loss.Methods: A total of 40 participants, between the age range 18 to 25 years were included in this study. They were categorized into two groups. Group 1 – Subjects with extended high frequency (EHF) loss but normal thresholds at conventional frequencies. Group 2 with normal EHF and conventional audiogram results. EHF testing was performed at 10 kHz, 12.5 kHz, 14 kHz, and 16 kHz. Click evoked Auditory Brainstem Response was done to elicit Cochlear Microphonics (CM) and Peak I.Results: Participants with normal EHF thresholds exhibited presence of Peak I and CM, whereas absence of Peak 1 and CM at 70 dB HL and below was seen in the group 1 participants. Results revealed no significant relationship between both groups.Conclusions: The outcome of this study defines the physiology behind Hidden Hearing Loss as the insult to cochlear structures especially OHC’s. This led to a conclusion that there is a strong alliance between EHF loss, absence of CM and Peak I resulting in Auditory dys-synchrony in the far basal regions of the cochlea. This reveals an astonishing impact that alarms young adult population to prevent further incidence at the earliest.

Midlife Speech Perception Deficits: Impact of Extended High-Frequency Hearing, Peripheral Neural Function, and Cognitive Abilities.

The objectives of the present study were to investigate the effects of age-related changes in extended high-frequency (EHF) hearing, peripheral neural function, working memory, and executive function on speech perception deficits in middle-aged individuals with clinically normal hearing. We administered a comprehensive assessment battery to 37 participants spanning the age range of 20 to 56 years. This battery encompassed various evaluations, including standard and EHF pure-tone audiometry, ranging from 0.25 to 16 kHz. In addition, we conducted auditory brainstem response assessments with varying stimulation rates and levels, a spatial release from masking (SRM) task, and cognitive evaluations that involved the Trail Making test (TMT) for assessing executive function and the Abbreviated Reading Span test (ARST) for measuring working memory. The results indicated a decline in hearing sensitivities at EHFs and an increase in completion times for the TMT with age. In addition, as age increased, there was a corresponding decrease in the amount of SRM. The declines in SRM were associated with age-related declines in hearing sensitivity at EHFs and TMT performance. While we observed an age-related decline in wave I responses, this decline was primarily driven by age-related reductions in EHF thresholds. In addition, the results obtained using the ARST did not show an age-related decline. Neither the auditory brainstem response results nor ARST scores were correlated with the amount of SRM. These findings suggest that speech perception deficits in middle age are primarily linked to declines in EHF hearing and executive function, rather than cochlear synaptopathy or working memory.

Standard and Extend High-Frequency Audiometry in Sudden Sensorineural Hearing Loss: Impacts on Tinnitus and Mental Health.

To analyze the results of auditory assessment in standard (SA) and extended high-frequency (EHF) audiometry, associating the findings with sudden tinnitus and mental health of patients with unilateral sudden sensorineural hearing loss (SSNHL). Prospective, cohort study. Outpatient otology clinic in a tertiary care hospital. Patients experiencing unilateral SSNHL were evaluated with pure-tone audiometry performed at frequencies of 250 to16,000 Hz, tinnitus pitch and loudness matching tests, Tinnitus Handicap Inventory (THI), Analog and Visual Scale (AVS) for bothersome tinnitus, and the Hospital Anxiety and Depression Scale (HADS). Eighteen patients with unilateral SSNHL were assessed. After starting treatment, there was a significant improvement in the SA (71.1 dB to 50 dB; p < 0.001*) and EHF audiometry (64.5 dB to 54.4 dB; p < 0.001*) thresholds at 15 days, and this persisted at 30 days of follow-up. Significant improvements were seen for tinnitus in loudness, VAS, and THI and for mental health in the realms of anxiety and depression by HADS. Despite improvements in SA, persistent EHF hearing loss was accompanied by persistent tinnitus, but it was of diminished loudness. Despite improvement in pure-tone thresholds by SA, a subset of unilateral SSNHL patients did not experience hearing recovery in EHF thresholds and reported persistent tinnitus. We postulate that their diminished anxiety and better mental health may be related to both hearing improvement in standard audiometry and reduction in tinnitus loudness. This pilot prospective study investigates the utility of performing EHF audiometry to better understand outcomes in patients with SSNHL.

Effects of Stimulus Type on 16-kHz Detection Thresholds.

Audiometric testing typically does not include frequencies above 8 kHz. However, recent research suggests that extended high-frequency (EHF) sensitivity could affect hearing in natural communication environments. Clinical assessment of hearing often employs pure tones and frequency-modulated (FM) tones interchangeably regardless of frequency. The present study was designed to evaluate how the stimulus chosen to measure EHF thresholds affects estimates of hearing sensitivity. The first experiment used standard audiometric procedures to measure 8- and 16-kHz thresholds for 5- to 28-year olds with normal hearing in the standard audiometric range (250 to 8000 Hz). Stimuli were steady tones, pulsed tones, and FM tones. The second experiment tested 18- to 28-year olds with normal hearing in the standard audiometric range using psychophysical procedures to evaluate how changes in sensitivity as a function of frequency affect detection of stimuli that differ with respect to bandwidth, including bands of noise. Thresholds were measured using steady tones, pulsed tones, FM tones, narrow bands of noise, and one-third-octave bands of noise at a range of center frequencies in one ear. In experiment 1, thresholds improved with increasing age at 8 kHz and worsened with increasing age at 16 kHz. Thresholds for individual participants were relatively similar for steady, pulsed, and FM tones at 8 kHz. At 16 kHz, mean thresholds were approximately 5 dB lower for FM tones than for steady or pulsed tones. This stimulus effect did not differ as a function of age. Experiment 2 replicated this greater stimulus effect at 16 kHz than at 8 kHz and showed that the slope of the audibility curve accounted for these effects. Contrary to prior expectations, there was no evidence that the choice of stimulus type affected school-age children more than adults. For individual participants, audiometric thresholds at 16 kHz were as much as 20 dB lower for FM tones than for steady tones. Threshold differences across stimuli at 16 kHz were predicted by differences in audibility across frequency, which can vary markedly between listeners. These results highlight the importance of considering spectral width of the stimulus used to evaluate EHF thresholds.

The relationship between extended high-frequency hearing and the binaural spatial advantage in young to middle-aged firefightersa).

Relationships between extended high-frequency (EHF) thresholds and speech-in-spatialized noise were examined in firefighters with a history of occupational noise and airborne toxin exposure. Speech recognition thresholds were measured for co-located and spatially separated (±90° azimuth) sentences in a competing signal using the Listening in Spatialized Noise-Sentences test. EHF hearing was significantly correlated with the spatial advantage, indicating that firefighters with poorer EHF thresholds experienced less benefit from spatial separation. The correlation between EHF thresholds and spatial hearing remained significant after controlling for age. Deficits in EHF and spatial hearing suggest firefighters may experience compromised speech understanding in job-related complex acoustic environments.

Cooling the Cochlea: Slowing Down Metabolism May Be a Way of Protecting Hearing from Surgical Trauma.

Background and Objectives: This narrative review of the literature explores the effect of body temperature on hearing. In particular, its focus is on extended high frequency (EHF) hearing-the range beyond the standard audiometric limit of 8 kHz. Such high frequencies are the first to be affected by noise-induced hearing loss, and so monitoring them can provide an early warning sign of incipient damage. Materials and Methods: This review builds on a personal literature database of 216 references covering the general topic of EHF hearing; the procedure was to then identify papers related to whole-body or cochlear cooling. A starting point was the paper by Munjal et al. who in 2013 reported changes of up to 15-30 dB in the EHF thresholds of subjects who had undergone cardiopulmonary bypass (CBP) surgery, which typically involves mild to moderate hypothermia-cooling of the blood-to reduce cellular oxygen demand and minimise tissue damage. Results: Reviewing the surrounding literature, we find that although CBP surgery by itself can impair hearing thresholds, lower body and cochlear temperatures in general provide neuroprotective effects. A connection between hearing loss and CBP surgery has been periodically documented, but the mechanism behind it has yet to be conclusively identified. Conclusions: The observations reviewed here tend to confirm the otoprotective effects of cooling. We consider that the high sensitivity of EHF thresholds to temperature is a major factor that has not been sufficiently recognised, although it has important implications for otological research and practice. Two important inferences are that, first, monitoring EHF thresholds might have considerable value in audiology, and, second, that lowering temperature of the cochlea during cochlear implantation might provide substantially better hearing preservation, as some researchers have already suggested.

A Comparison of the Digits-in-Noise Test and Extended High Frequency Response between Formally Trained Musicians and Non-Musicians

Background and Aim: Musical training has been hypothesised to result in enhanced Speech Perception in Noise (SPIN) abilities, but prolonged exposure to music also increases the risk for Music-Induced Hearing Loss (MIHL). The Signal-to-Noise Ratios (SNR) and the Extended High Frequency (EHF) thresholds between formally trained musicians and non- musicians were compared to determine the effect of musical training on musicians’ SPIN and hearing abilities. Methods: This cross-sectional study included 40 musicians and 39 non-musicians 18–30 years, with mean age (SD) 22.43(2.71) years. EHF audiometry and the Digits-in-Noise (DIN) test were conducted via a smartphone. Results: Differences found between the two groups regarding the DIN test and EHF thresholds were statistically insignificant. Musicians displayed early signs of MIHL as the musicians reported significantly more (p=0.004) instances of tinnitus than non-musicians. A statistically significant correlation was found only for the non-musician group between the 12.5 kHz threshold left and the SNR obtained in the diotic listening condition (rs=-0.465; p=0.003). Conclusion: The results suggested that musicians did not display a significant advantage for SPIN and did not appear to have significantly poorer EHF hearing sensitivity. However, slight trends were noticeable in the musicians which gravitated more towards studies that found enhanced SPIN abilities and elevated EHF thresholds in the musician population. In the future, it may be useful to include additional speech tests (open-set) alongside the DIN test (closed-set). The present study suggests that EHF audiometry may be used for the early detection of MIHL. Keywords: Music; audiometry; hearing loss; noise-induced; pitch discrimination; sound localization

Extended High-Frequency Audiometry for Ototoxicity Monitoring: A Longitudinal Evaluation of Drug-Resistant Tuberculosis Treatment.

The aim of this study was to describe extended high-frequency (EHF) pure-tone audiometry monitoring of ototoxicity in a longitudinal treatment program for drug-resistant tuberculosis (DRTB). This was a retrospective record review of longitudinal conventional (0.25-8 kHz) and EHF (9-16 kHz) audiometry for ototoxicity monitoring of DRTB patients undergoing treatment at community-based clinics between 2013 and 2017. Data from 69 patients with an average age of 37.9 years (SD = 11.2, range: 16.0-63.8 years) were included. Patients were assessed by primary health care audiologists (87%) or community health workers (13%) using portable audiological equipment. The average length of time between initial and exit assessments was 84.6 days (SD = 74.2, range: 2-335 days). EHF ototoxicity of a mild or greater degree of hearing loss (> 25 dB HL in one or both ears across frequencies) was evident in 85.5% of patients' posttreatment, compared with 47.8% of patients across conventional frequencies. EHF audiometry demonstrated an ototoxic shift (American Speech-Language-Hearing Association criteria) in 56.5% of cases compared with 31.9% when only conventional audiometry was considered. Mean hearing deterioration for patients was significant across EHFs (9-16 kHz) bilaterally (p < .05). Absent EHF thresholds at the initial assessment, owing to maximum output limits, was a limitation that occurred most frequently at 16 kHz (17.4%, 24/138). EHF audiometry is most sensitive for the early detection of ototoxicity and should be included in monitoring programs. Clinical ototoxicity monitoring protocols should consider shortened assessment approaches that target frequencies most sensitive to ototoxicity, including EHFs. https://doi.org/10.23641/asha.21651242.

Binaural temporal coding and the middle ear muscle reflex in audiometrically normal young adults

Noise exposure may damage the synapses that connect inner hair cells with auditory nerve fibers, before outer hair cells are lost. In humans, this cochlear synaptopathy (CS) is thought to decrease the fidelity of peripheral auditory temporal coding. In the current study, the primary hypothesis was that higher middle ear muscle reflex (MEMR) thresholds, as a proxy measure of CS, would be associated with smaller values of the binaural intelligibility level difference (BILD). The BILD, which is a measure of binaural temporal coding, is defined here as the difference in thresholds between the diotic and the antiphasic versions of the digits in noise (DIN) test. This DIN BILD may control for factors unrelated to binaural temporal coding such as linguistic, central auditory, and cognitive factors. Fifty-six audiometrically normal adults (34 females) aged 18 – 30 were tested. The test battery included standard pure tone audiometry, tympanometry, MEMR using a 2 kHz elicitor and 226 Hz and 1 kHz probes, the Noise Exposure Structured Interview, forward digit span test, extended high frequency (EHF) audiometry, and diotic and antiphasic DIN tests. The study protocol was pre-registered prior to data collection. MEMR thresholds did not predict the DIN BILD. Secondary analyses showed no association between MEMR thresholds and the individual diotic and antiphasic DIN thresholds. Greater lifetime noise exposure was non-significantly associated with higher MEMR thresholds, larger DIN BILD values, and lower (better) antiphasic DIN thresholds, but not with diotic DIN thresholds, nor with EHF thresholds. EHF thresholds were associated with neither MEMR thresholds nor any of the DIN outcomes, including the DIN BILD. Results provide no evidence that young, audiometrically normal people incur CS with impacts on binaural temporal processing.

Comparison of otoacoustic emissions in tinnitus and hyperacusis in adults with normal hearing sensitivity

Objective To investigate the effect of tinnitus and/or hyperacusis on distortion product otoacoustic emission (DPOAE) measures in adults with normal hearing thresholds from 0.25 to 8 kHz, while accounting for extended high-frequency (EHF) thresholds. Design A behavioural study consisted of comprehensive audiological assessment, validated tinnitus and hyperacusis questionnaires, DPOAE amplitudes and input/output (I/O) functions. Study sample Data of 56 participants with normal hearing were included for the analysis. Participants were categorised into four groups: (1) without tinnitus or hyperacusis, (2) with tinnitus only, (3) with hyperacusis only, and (4) with both tinnitus and hyperacusis. Results The groups with tinnitus showed elevated EHF thresholds compared with those without tinnitus. DPOAE amplitudes were not significantly affected by tinnitus and/or hyperacusis status; however, they were significantly affected by EHF thresholds. Further, no appreciable differences in DPOAE I/O functions were found across groups. Conclusions The reported non-significant differences in DPOAEs in individuals with tinnitus and/or hyperacusis do not support a peripheral mechanism or an interaction between peripheral and central mechanisms underlying tinnitus or hyperacusis. Our findings, however, suggest the need to assess basal cochlear function (e.g. EHF thresholds) for a better understanding of differences in DPOAE measures in tinnitus and/or hyperacusis.

Extended high-frequency bone conduction audiometry Calibration of bone conductor transducers in the conventional and extended high-frequency range

Objective To monitor ototoxicity, air conduction (AC) extended high frequency (EHF) thresholds can be measured up to 16 kHz. However, conductive hearing loss might influence these results. This is unfortunate because the EHF thresholds are important to follow the impact of ototoxic medication during therapy. Therefore a suitable bone conduction (BC) transducer and norm values for EHF BC measurements are needed. Design In this study three different BC transducers were used: the B71 (Radioear), the KH70 (Präcitronic), and the KLH96 (Westra). Hearing thresholds were measured from 0.125 to 16 kHz using AC transducers (Telephonics TDH39, Sennheiser HDA200), and BC thresholds from 0.25 to 8 kHz with the B71, and from 0.25 to 16 kHz with the KLH96 and KH70. Study sample 60 ears of 30 normal hearing subjects were measured. Results The KLH96 showed the highest output for the high frequencies, and distortion measurements were similar to the KH70. The results show that EHF measurements are possible using the KLH96 and KH70 bone conductors. Conclusion EHF BC measurements are reliable when using the KLH96 and KH70 bone conductors. The extended force sensitivity of the used artificial mastoid should be determined for a proper EHF BC calibration.

Identifying subclinical hearing problems

Noise exposure and aging can cause subclinical hearing problems that are not identified with conventional audiometry. Potential clinical assessments were studied that could identify subclinical hearing deterioration: (1) Electrocochleography (ECoG); (2) Middle Ear Muscle Reflex (MEMR); (3) Extended High Frequency (EHF) thresholds (10–16 kHz); and (4) word recognition in noise. Sixty-one young, normal-hearing people were recruited. Each completed the four auditory assessments and the Life-Time Exposure to Noise Solvents Questionnaire (LENS-Q). ECoG and MEMR measurements were measured as a function of sound level using clinical equipment. Word recognition in noise was measured with a diotic, closed-set, 12-alternative spondees-in-noise test. It was hypothesized that normal-hearing individuals reporting more noise exposure would have slower growth of the ECoG measures and MEMR magnitudes with increasing levels. Individuals reporting higher noise exposure with the LENS-Q had significantly reduced MEMR magnitudes and smaller slopes, supporting the hypothesis. Gender effects were observed. No significant effect of self-report noise-exposure was seen with ECoG AP growth functions or SP/AP ratios, though modest age effects were observed. EHF thresholds were the only significant predictor of word recognition in noise. The results suggest that word recognition in noise, EHF audiometry, and MEMR could indicate subclinical hearing problems.

Early Diagnosis of Hearing Loss in Patients Under Methadone Maintenance Treatment.

Background and Objective: Methadone maintenance treatment (MMT) as the most effective treatment for opioid addictions could induce both reversible and permanent hearing loss. Therefore, early detection of methadone-induced hearing loss is necessary to prevent irreversible cochlear damage. The present study aims to identify the early onset of hearing loss in patients who underwent MMT and to compare them with the age and gender matched normal hearing peers.Methods: This was an analytic cross-sectional study conducted on patients (n = 27 males; age range: 18–53 years old) who received 3 months MMT course (MMT group) and a control group consisting of age and gender matched healthy individuals (n = 27 males). Before MMT, all patients underwent conventional audiometry (250–8,000 Hz) and those with normal hearing threshold participated into the study. One month after MMT termination, the patients were assessed for possible hearing loss using conventional pure tone audiometry (PTA), extended high frequency (EHF) audiometry, and distortion product otoacoustic emissions (DPOAEs).Results: Our results demonstrated that the mean EHF thresholds in the MMT patients were significantly greater than the age- and gender-matched healthy controls across all frequencies (p < 0.001). However, there was no statistically significant difference in conventional PTA thresholds between both groups (p > 0.05). DPOAE amplitudes significantly reduced at higher frequencies (3,000–8,000 Hz) in the MMT group, compared to the healthy control group. In contrast to the conventional PTA audiometry, the EHF and DPOAE assessments identified hearing impairments in 11 (40.74%), and 14 (51.85%) of the MMT patients, respectively. The main mechanisms proposed for methadone induced hearing loss are cochlear ischemia following vasospasm or vasculitis, direct effect of opioids on opioid receptors present in cochlear stria vascularis of inner ear, blood-labyrinth selective transport of opioidproteins and receptors, and genetic polymorphism and mutations.Conclusion: The EHF and DPOAE tests have the potential to detect earlier changes in auditory function than conventional frequency audiometry in the MMT patients.

Auditory Gating and Extended High-Frequency Thresholds in Normal-Hearing Adults With Minimal Tinnitus.

Purpose The goal of this study was to assess whether peripheral auditory sensitivity in frequency regions above 8 kHz is related to central inhibitory function, as measured through a sensory gating paradigm, in normal-hearing adults with tinnitus (TINN) and without tinnitus (NTINN). The contribution of gating processes and peripheral sensitivity in extended high frequencies to tinnitus severity was evaluated via a hierarchical multiple regression method. Method Cortical auditory evoked potentials (CAEPs) were recorded in response to pairs of tones in normal-hearing adults without tinnitus, NTINN ( n = 45), and adults with tinnitus, TINN ( n = 21). CAEP peak component amplitude, latency, and gating indices were compared and correlated with extended high-frequency (EHF) pure-tone averages (PTAs) across groups and with tinnitus severity. An exploratory analysis was performed to investigate gating variability within the TINN group. Based on Tinnitus Handicap Inventory (Newman, Jacobson, & Spitzer, 1996) median scores, the TINN group was categorized into low- and high-median subgroups, and gating indices were compared between these subgroups. A hierarchical multiple regression analysis was performed to determine the amount of variance accounted for in the TINN group. Results Decreased gating via the CAEP Pa component and increased gating via the N1 component correlated with increased tinnitus severity, even in individuals who would traditionally be classified as having no tinnitus handicap. In the TINN group, lower EHF PTA thresholds correlated with tinnitus severity and decreased Pa gating. Individuals with a greater severity of tinnitus demonstrated atypical gating function reflected in both Pa and N1 components. Gating function and EHF PTA accounted for significant variance regarding tinnitus severity. Conclusions A trade-off between lower and higher level gating function was observed in adults with normal hearing and tinnitus, indicative of higher order compensatory mechanisms. Better cochlear sensitivity in extended high frequencies was related to decreased lower level gating processes and increased tinnitus THI scores, suggestive of an interaction between decreased gating and heightened auditory awareness. We are currently exploring whether gating processes in this population are compensatory, and the role of gating in auditory awareness.

Relations between speech perception in noise, high-frequency audiometry, and physiological measures of cochlear synaptopathy

Cochlear synaptopathy, a loss of synapses between inner hair cells and auditory nerve fibers, is associated with age and noise exposure in animal models. However, the functional consequences of synaptopathy for humans are unclear. We pooled data from two recent studies to answer the question: are the common physiological measures of cochlear synaptopathy related to speech-perception-in-noise (SPiN) performance? Eighty-three audiometrically normal participants (ages 18–39) took part. Measures of synaptopathy were as follows: auditory brainstem response (ABR) wave I amplitude (102 dB peSPL click); ABR wave I:V amplitude ratio; envelope following response (EFR) amplitude (4 kHz carrier, 105 Hz modulation frequency); EFR amplitude growth with stimulus modulation depth; and middle ear muscle reflex threshold (1–4 kHz elicitors). We also conducted extended high-frequency (EHF) audiometry (10 and 14 kHz), suggested as a marker for synaptopathy in lower frequency regions. SPiN performance was assessed using the coordinate response measure with spatial maskers. None of the physiological measures of synaptopathy correlated significantly with SPiN. There was a significant correlation between EHF thresholds and SPiN, although it is unclear whether this is due to a direct relation between EHF hearing and SPiN, or whether elevated EHF thresholds are a marker for hidden damage at lower frequencies.

Extended High-Frequency Smartphone Audiometry: Validity and Reliability.

Extended high-frequency (EHF) audiometry (8-16 kHz) has an important role in audiological assessments such as ototoxicity monitoring, and for speech recognition and localization. Accurate and reliable EHF testing with smartphone technologies has the potential to provide more affordable and accessible hearing-care services, especially in underserved contexts. To determine the accuracy and test-retest reliability of EHF audiometry with a smartphone application, using calibrated headphones. Air-conduction thresholds (8-16 kHz) and test-retest reproducibility, recorded with conventional audiometry (CA) and smartphone audiometry (SA), using audiometric (Sennheiser HDA 300 circumaural) and nonstandard audiometric (Sennheiser HD202 II supra-aural) headphones, were compared in a repeated-measures design. A total of 61 participants (122 ears) were included in the study. Of these, 24 were adults attending a tuberculosis clinic (mean age = 36.8, standard deviation [SD] = 14.2 yr; 48% female) and 37 were adolescents and young adults recruited from a prospective students program (mean age = 17.6, SD = 3.2 yr; 76% female). Of these, 22.3% (n = 326) of EHF thresholds were ≥25 dB HL. Threshold comparisons were made between CA and SA, with audiometric headphones and nonstandard audiometric headphones. A paired samples t-test was used for comparison of threshold correspondence between conventional and smartphone thresholds, and test-retest reproducibility of smartphone thresholds. Conventional thresholds corresponded with smartphone thresholds at the lowest intensity (10 dB HL), using audiometric and nonstandard audiometric headphones in 59.4% and 57.6% of cases, respectively. Conventional thresholds (exceeding 10 dB HL) corresponded within 10 dB or less, with smartphone thresholds in 82.9% of cases using audiometric headphones and 84.1% of cases using nonstandard audiometric headphones. There was no significant difference between CA and SA, using audiometric headphones across all frequencies (p > 0.05). Test-retest comparison also showed no significant differences between conditions (p > 0.05). Smartphone test-retest thresholds corresponded within 10 dB or less in 86.7% and 93.4% of cases using audiometric and nonstandard audiometric headphones, respectively. EHF smartphone testing with calibrated headphones can provide an accurate and reliable option for affordable mobile audiometry. The validity of EHF smartphone testing outside a sound booth as a cost-effective and readily available option to detect high-frequency hearing loss in community-based settings should be established.

Personal music systems and hearing.

To measure the output sound pressure levels of personal music systems and evaluate their effect on hearing. Output sound pressure levels at preferred volume settings and listening environment were measured using a manikin. Effects of personal music system use on hearing were evaluated using pure tone audiometry (in conventional and extended high frequency ranges), transient evoked otoacoustic emissions, syllable identification in noise, intensity discrimination, frequency discrimination and temporal modulation transfer function. Results showed, alarmingly, that large proportions of young adults are using personal music systems at levels higher than the safety limits set by regulatory bodies. Individuals who listened to personal music systems at levels higher than 80 dB LAeq exhibited poorer extended high frequency thresholds, reduced transient evoked otoacoustic emission amplitudes, poorer frequency discrimination, reduced modulation detection thresholds at 32 Hz modulation frequency, and reduced syllable identification in noise at -5 dB signal-to-noise ratio. Listening levels were significantly correlated with extended high frequency thresholds and transient evoked otoacoustic emission amplitudes. These results suggest that listening to music through personal music systems at higher volume levels may be hazardous to hearing.

High-frequency audiometry reveals high prevalence of aminoglycoside ototoxicity in children with cystic fibrosis

BackgroundIntravenous aminoglycoside (IV AG) antibiotics, widely used in patients with cystic fibrosis (CF), are known to have ototoxic complications. Despite this, audiological monitoring is not commonly performed and if performed, uses only standard pure-tone audiometry (PTA). The aim of this study was to investigate ototoxicity in CF children, to determine the most appropriate audiological tests and to identify possible risk factors. MethodsAuditory assessment was performed in CF children using standard pure tone audiometry (PTA), extended high-frequency (EHF) audiometry and distortion-product otoacoustic emissions (DPOAE). Results70 CF children, mean (SD) age 10.7 (3.5) years, were recruited. Of the 63 children who received IV AG, 15 (24%) children had ototoxicity detected by EHF audiometry and DPOAE. Standard PTA only detected ototoxicity in 13 children. Eleven of these children had received at least 10 courses of IV AG courses. A 25 to 85dBHL hearing loss (mean±SD: 57.5±25.7dBHL) across all EHF frequencies and a significant drop in DPOAE amplitudes at frequencies 4 to 8kHz were detected. However, standard PTA detected a significant hearing loss (>20dBHL) only at 8kHz in 5 of these 15 children and none in 2 subjects who had significantly elevated EHF thresholds. The number of courses of IV AG received, age and lower lung function were shown to be risk factors for ototoxicity. ConclusionsCF children who had received at least 10 courses of IV AG had a higher risk of ototoxicity. EHF audiometry identified 2 more children with ototoxicity than standard PTA and depending on facilities available, should be the test of choice for detecting ototoxicity in children with CF receiving IV AG.

A Report of Extended High Frequency Audiometry Thresholds in School-Age Children with No Hearing Complaints

The aim of the study was to establish the extended high frequency thresholds (EHF) of school-age children with no hearing complaints. The study was conducted on 50 children aged 8 to 12 years with pure tone thresholds (0.5, 1 and 2 kHz) of 15 dB HL or less, with normal speech discrimination and tympanometry and with the presence of contralateral acoustic reflexes of 0.5, 1, 2 and 4 kHz. The children were tested for EHF at frequencies of 9, 10, 11.2, 12.5, 14 and 16 kHz. No significant differences were found between the right and left ear for female and male groups. The results allowed us to group the children into a single sample with mean thresholds (dB) of 8.6 (9 kHz), 6.2 (10 kHz), 8.2 (11.2 kHz), 7.1 (12.5 kHz), 0.4 (14 kHz), and -3.6 (16 kHz). We conclude that, for school-age children, the extended EHF below 15 dBHL could be used as an indication of normal hearing sensitivity.