Standard Audiograms Research Articles

The Noise Reduction Algorithm May Not Compensate for the Degradation in Output Signal-to-Noise Ratio Caused by Wide Dynamic Range Compression.

Most modern hearing aids (HAs) employ wide dynamic range compression (WDRC) and noise reduction (NR) algorithms. It is known that the nonlinear effects of WDRC and NR cause changes to the output signal-to-noise ratio (SNR) of an HA. However, the relative contributions of WDRC and NR to the nonlinear effects are not fully understood. The current study investigated (a) whether WDRC or NR dominates the nonlinear effects measured at the output of a digital HA and (b) whether the electroacoustic effectiveness of NR depends on WDRC parameters while input SNR and background noise are systematically varied. Test stimuli were Connected Speech Test sentences in multitalker babble noise (2- or 20-talker), presented at input SNRs ranging from -10 to +10 dB. The HA was programmed using multiband WDRC set according to the National Acoustic Laboratories for Nonlinear HA fitting formula 2 prescriptive fits for four standard audiograms and two compression speeds. The NR algorithm of the HA was switched on or off in separate conditions. Nonlinear electroacoustic effects from the WDRC and NR algorithms were assessed by measuring the output SNR of the HA using a phase-inversion technique. To investigate whether there are other factors that may be important besides the output SNR, the Hearing Aid Speech Intelligibility Index and the Hearing Aid Speech Quality Index were applied to the recordings to generate inferences on aided speech intelligibility and perceived speech quality. Results showed that WDRC dominated the net nonlinear effect at low-input SNRs, and the net nonlinear effect of WDRC and NR was reduced at high-input SNRs. Results also showed that the effectiveness of NR depended on compression parameters. The effectiveness of NR was partially explained by the trend of Hearing Aid Speech Intelligibility Index and Hearing Aid Speech Quality Index scores, potentially indicating that the Hearing Aid Speech Intelligibility Index and Hearing Aid Speech Quality Index scores may capture factors that cannot be captured by the output SNR metric. Results suggest that the individual signal-processing stages in an HA should not be considered as independent. Electroacoustic evaluation of WDRC and NR algorithms in isolation is not sufficient to capture the combined nonlinear effect of the two algorithms. https://doi.org/10.23641/asha.25962541.

Extended High-frequency Hearing Impairment Despite a Normal Audiogram: Relation to Early Aging, Speech-in-noise Perception, Cochlear Function, and Routine Earphone Use.

Humans can hear up to 20 kHz. Emerging evidence suggests that hearing in the extended high frequencies (EHFs; >8 kHz) contributes to speech perception in noise. The objective of the present study was to describe the features of EHF hearing impairment in young adults with normal standard audiograms (0.25-8 kHz). Specifically, the study goals were to: (1) characterize the EHF hearing impairment and identify potential risk factors; (2) elucidate the age-related changes in EHF hearing; (3) determine the effect of EHF hearing impairment on speech-in-noise recognition; and (4) examine the extent to which EHF hearing impairment influences cochlear functioning in the standard frequencies. Hearing thresholds at standard frequencies and EHFs (10, 12.5, 14, and 16 kHz), and speech recognition thresholds (SRTs) using digit triplets in multi-talker babble were measured in both ears from 222 participants (19-38 years; n = 444 ears) with normal audiograms (≤20 dB HL at standard frequencies). Test-retest measurement of hearing thresholds was obtained in a subset of 50 participants (100 ears), and clinical distortion product otoacoustic emissions (f2 frequency = 2, 3, 4, and 5 kHz) were recorded in 49 participants (98 ears). Forty-two of 222 participants had EHF hearing impairment (>20 dB HL for at least one EHF in either ear). Only seven individuals with EHF impairment had significant case history and/or listening-in-noise complaints. A breakpoint in the threshold-age function was observed for the EHFs for males but not for females. Linear mixed models revealed a significant effect of age, pure-tone averages for speech frequencies (0.5, 1, 2, and 4 kHz), and EHFs and group (NH versus EHF hearing impairment) independent of each other on the SRTs. Individuals with EHF hearing impairment had less measurable emissions and when present, had a lower magnitude of otoacoustic emissions relative to NH controls. There was no difference in hearing thresholds, SRTs, or otoacoustic emissions between earphone users and nonusers. The hearing thresholds for the EHFs exhibit signs of early auditory aging. Age-related deterioration in auditory function can be observed in the third decade of human life. A breakpoint in the threshold-age function suggests that rapid aging processes are operational at a relatively younger age (21 years) for males. The audibility of EHFs contributes to speech-in-noise recognition. EHF hearing impairment independent of age and speech frequencies can affect speech-in-noise recognition. Reduced distortion product otoacoustic emissions in the standard frequencies may suggest preclinical cochlear degeneration in individuals with EHF hearing impairment.

Efficacy of cartilage conduction hearing aids in children

ObjectivesCartilage conduction hearing aids (CC-HAs) are novel hearing aids that use the third hearing pathway of cartilage conduction. We assessed the efficacy of CC-HAs and the hearing effects and safety of additional tape compression over the transducer in children with hearing loss. MethodsThe patients (n = 42) underwent a one-month free trial of CC-HAs. Forty of them were patients with auditory canal atresia or stenosis. CC-HA-aided and unaided hearing thresholds (48 fitted ears) were determined using standard audiograms, after which participants could choose to purchase the device or not. We calculated the purchase rates and compared the patient characteristics between the purchase and non-purchase groups along with the purchase reason (or not). We applied additional tape compression over the CC-HA transducer and assessed the hearing effects and side effects. ResultsCC-HA led to hearing improvements at all frequencies. Overall, 72.92% of participants purchased a CC-HA after the trial. By applying additional tape compression over the CC-HA transducer, the stability and hearing gains were improved mainly at low frequencies, and no side effects such as dermatitis were observed. ConclusionsCC-HAs are efficacious in producing hearing improvements in children, especially in patients with atresia or canal stenosis who cannot use air conduction hearing aids. Furthermore, we found that the additional tape compression over the transducer was an easy and a safe method for improving the hearing effects and stability of the CC-HA.

From Acute to Chronic Tinnitus: Pilot Data on Predictors and Progression.

Little is known about the transition from acute tinnitus to chronic tinnitus. By means of this study, we are attempting to close this gap by presenting prospective pilot data of patients with acute tinnitus, followed by tracking their condition's trajectory over a period of 6 months. Forty-nine patients presenting with acute tinnitus (duration < 28 days) were recruited in two clinics. We recorded demographic and clinical tinnitus-related data as well as data on personality, health, treatments, and life-style, during patients' first appearance in the clinic and again three and 6 months thereafter. Standard audiograms were performed at the first and the second visit. Nine (18.4%) patients showed full remission of their tinnitus. These patients differed from patients with a chronic course of tinnitus by shorter tinnitus duration, lower fear-related hyperacusis, higher proportion of female gender, increased ear pressure, and lower levels of alcohol consumption. Among the patients with a chronification of tinnitus, there was no change in tinnitus characteristics. However, their tinnitus distress improved moderately over time. These preliminary data are in line with earlier studies that have shown that only a small proportion of those patients presenting in the clinic with acute tinnitus experience a full remission. The results of this study can be of service in deducing hypotheses for the transition from acute to chronic tinnitus and in developing designs for interventional studies.

Who are good adult candidates for cartilage conduction hearing aids?

Cartilage conduction hearing aids (CC-HAs) are novel hearing aids using the third hearing pathway of cartilage conduction. We assessed the efficacy of CC-HAs in adult hearing-loss patients who had various anatomical conditions of their ear canal(s) and determined who are good candidates for CC-HAs. Patients (n = 37) were categorised into three groups of participants based on ear canal anatomy: (1) canal stenosis; (2) abnormal canal; (3) normal canal. After a 1-month free trial of normal usage, CC-HA-aided and unaided hearing thresholds (43 fitted ears) were determined using standard audiograms, after which participants could choose to purchase the device or not. Group and subgroup purchase rates were calculated along with the purchase reason (or not). Subgroup binary analysis of purchase rates was done according to hearing loss severity (< 70dB and ≥ 70dB) of unaided average air conduction (AC) hearing thresholds. CC-HA provided hearing improvements in all frequencies within each group. Overall, 60.47% of participants purchased a CC-HA after the trial. Over 70% participants with canal stenosis purchased CC-HAs, regardless of their AC hearing thresholds (severe vs. mild), and significantly more mild-loss participants in the abnormal canal group purchased their trial CC-HA compared to severe-loss participants (85.71% vs. 20%). Adult patients with ear canal stenosis or closure are the best candidates for CC-HAs, regardless of their hearing thresholds. Patients with more severe hearing loss accompanied by ear canal anomalies and patients with normal canal anatomy may not be good candidates.

Speech recognition with hearing aids for 10 standard audiograms

BackgroundImprovement of speech perception in quiet is an important goal of hearing aid provision. In practice, results are highly variable. The aim of this study was to investigate the relationship between type and extent of hearing loss (audiogram type), maximum word recognition score, and aided speech perception.Materials and methodsPure tone and speech audiometric data of 740 ears in 370 patients were reviewed. All subjects visited our hearing center for hearing aid evaluation between 2012 and 2017. The maximum word recognition score (WRSmax) and the monosyllabic speech recognition score with hearing aids, WRS65(HA) were analyzed for 10 different standard audiogram types.ResultsThe WRS65(HA) with hearing aids for different degrees of hearing loss is, within error boundaries, comparable to previous investigations and shows a difference of 10–20 percentage points to the WRSmax. This difference tends to be larger for flat and moderately sloping audiograms compared to steep-sloping audiograms. The ratio WRS65(HA)/WRSmax can be interpreted as an efficiency factor for hearing aid provision, since it relates speech recognition with hearing aids to the maximally achievable information carrying capacity of the hearing impaired.ConclusionThe expectation regarding hearing aid provision has to be adjusted according to maximum word recognition score, the derived quality measures, degree of hearing loss, and audiogram type.

Limitations of the Envelope Difference Index as a Metric for Nonlinear Distortion in Hearing Aids.

The envelope difference index (EDI) compares the envelopes of two signals. It has been used to measure nonlinear distortion in hearing aids, but it also responds to linear processing. This article compares linear and nonlinear processing effects on the EDI. The EDI for spectral tilt and peak clipping distortion is computed to illustrate the effects of linear and nonlinear signal modifications. The EDI for wide dynamic-range compression is then compared with that obtained for linear amplification for a set of standard audiograms to show the expected range of EDI values for linear and nonlinear hearing aid processing. The EDI for hearing aid amplification and compression is also compared with a measure of time-frequency envelope modulation distortion for the same conditions. The EDI is shown to be as sensitive to linear amplification as it is to nonlinear processing. The EDI values for spectral tilt can exceed those for peak clipping, and the EDI values for linear amplification exceed those for wide dynamic-range compression for four of the nine audiograms considered. The agreement of the EDI with a nonlinear envelope distortion measure is shown to depend on the long-term spectra of the signals being compared when computing the EDI. The accuracy of the EDI as an indicator of nonlinear distortion for sentence materials can be improved by equalizing the long-term spectrum of the processed signal to match that of the unprocessed input. However, the EDI does not have a clear interpretation because of the confound between linear and nonlinear processing effects and the lack of an auditory model in calculating the signal differences.

Standard Audiograms for Koreans Derived through Hierarchical Clustering Using Data from the Korean National Health and Nutrition Examination Survey 2009\u20132012

Assessments of standardized region/population-specific audiological characteristics are needed for provision of effective rehabilitative services through reducing costs associated with hearing aids. This study aims to propose a set of standard audiograms representing the Korean population that were derived by analyzing data from the 2009–2012 Korea National Health and Nutrition Examination Survey (KNHANES), a nationwide epidemiologic study conducted by Korean government organizations. Standard audiograms were derived by applying a hierarchical clustering method from recorded audiologic data that were obtained independently at 6 frequencies for each ear: 0.5, 1.0, 2.0, 3.0, 4.0, and 6.0 kHz (in dB HL). To derive the optimal number of clusters of the desired standard audiograms, cubic clustering criterion, pseudo-F-, and pseudo-t2-statistics were calculated. These analyses resulted in 29 clusters representing a standard audiogram of the South Korean population. Eighteen of the clusters represented normal hearing audiograms (73.11%), while 11 represented hearing-impaired (HI) standard audiograms (27.89%). Of the 11 HI audiograms, 7 were defined as flat-type (17.81%), while the remaining 4 were defined as sloping-type (9.08%). In conclusion, 29 audiograms representing standard audiograms for the Korean population have been derived using KNHANES data. Improved understanding of the characteristics of each cluster may be helpful for development of more personalized, fixed-setting hearing aids.

Effectiveness of Auditory Measures for Detecting Hidden Hearing Loss and/or Cochlear Synaptopathy: A Systematic Review.

Standard audiometric evaluations are not sensitive enough to identify hidden hearing loss (HHL) and/or cochlear synaptopathy (CS). Patients with either of these conditions frequently present with difficulty understanding speech in noise or other complaints such as tinnitus. The purpose of this systematic review is to identify articles in peer-reviewed journals that assessed the sensitivity of audiologic measures for detecting HHL and/or CS, and which showed potential for use in a clinical test battery for these disorders. A reference librarian submitted specific boolean terminology to MEDLINE, Embase, and Web of Science. The authors used a consensus approach with specially designed score sheets for the selection of titles, abstracts, and then articles for inclusion in the systematic review and for quality assessment. Fifteen articles were included in the systematic review. Seven articles involved humans; seven involved animals, and one study used both humans and animals. Results showed that pure-tone audiometry to 20 kHz, otoacoustic emissions, electrocochleography, auditory brainstem response (ABR), electrophysiological tests, speech recognition in noise with and without temporal distortion, interviews, and self-report measures have been used to assess HHL and/or CS. For HHL, ultra-high-frequency audiometry may help identify persons with sensory hair cell loss that does not show up on standard audiograms. Promising nonbehavioral measures for CS included ABR wave I amplitude, the summating potential-to-action potential ratio, and speech recognition in noise with and without temporal distortion. Self-report questionnaires also may help identify auditory dysfunction in persons with normal hearing.

The Influence of Hearing Loss Represented by Standard Audiogram Types to Unaided APHAB Scores

Questionnaires as the APHAB (Abbreviated Profile of Hearing Aid Benefit) are besides pure-tone and speech-audiometry the third method of diagnostics in audiology. Up to now there has been no research on the influence of individual hearing loss, represented by standard audiograms, on the scores of the unaided APHAB (APHABu) done with a big number of subjects. This study will investigate whether there does exist such a relationship or not. A total of 2 745 records provided by a database were analysed. First, the subjects' audiograms (air conduction) were allocated to 7 standardised audiogram types. By using a multivariant mixed linear model a potential connection was examined between these standard audiograms and particular APHABu scores for its four subscales: EC - ease of communication, BN - background noise, RV - reverberation, AV - aversiveness of sounds. There was no evidence for a dependency between any type of hearing loss dependence and unaided APHAB-scores. The values on the EC-scale vary between 49.8 and 58.0, on the BN-scale between 45.3 and 46.6, on the RV-scale between 44.4 and 52.4, and on the AV-scale between 47.6 and 50.1. This result confirms earlier studies with other questionnaires. Therefore, the APHABu can be used as an initial instrument for the diagnostics of individual hearing loss independently on whether hearing aids will be fitted subsequently or not.

Standard Audiograms for the IEC 60118-15 Measurement Procedure

For the characterization of hearing aids, a new test method has been defined in the new International Electrotechnical Commission (IEC) standard 60118-15. For this characterization, the hearing aid will be set to actual user settings as programmed by standard fitting software from the hearing aid manufacturer. To limit the variation of programming outcomes, 10 standard audiograms, which cover the entire range of audiograms met in clinical practice, have been defined. This article describes how the set of standard audiograms has been developed. This set of standard audiogram has been derived by a vector quantization analysis method on a database of 28,244 audiograms. Using this analysis method, sets of typical audiograms have been obtained of sizes 12 and 60. It turned out that the smaller set could not be used for selecting audiograms as sloping audiograms were absent. Therefore, the larger set has been analyzed to provide seven standard audiograms for flat and moderately sloping hearing loss and three standard audiograms for steep hearing loss.