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Hearing aids are commonly fit with ear canals partially or fully open-a condition that increases the risk of acoustic feedback. Feedback limits the audiometric fitting range of devices by limiting usable gain. To guide clinical decision making and device selection, we developed the Peak Height Insertion Gain (PHIG) method to detect feedback spikes in the short-term insertion gain derived from audio recordings. Using a manikin, 145 audio recordings of a speech signal were obtained from seven hearing aids. Each hearing aid was programmed for a moderate high-frequency hearing loss with systematic variations in frequency response, gain, and feedback suppression; this created audio recordings that varied the presence and strength of feedback. Using subjective ratings from 13 expert judges, the presence of feedback was determined and then classified according to its temporal and tonal qualities. These classifications were used to optimize parameters for two versions of the PHIG method based on global and local analyses. When specificity was fixed at 0.95, the sensitivity of the global analysis was 0.86 and increased to 0.95 when combined with the local analysis. Without compromising performance, a clinically expedient version of the PHIG method can be obtained using only a single measurement.

Purpose: To calculate the real-ear insertion gain (REIG) according to the types of hearing aids, we evaluated the preferred REIGs of Korean hearing-impaired listeners and psychoacoustic differences between open-canal fitting (OF) and closed-canal fitting (CF).Methods: The subjects with sensorineural hearing loss were divided into OF group (4 monaural fittings, 15 binaural fittings with 34 ears), and CF group (8 monaural fittings, 13 binaural fittings with 34 ears). There were no statistical differences in hearing threshold level (HTL) at each octave frequencies, word recognition score (WRS) and Korean Adaptation of the International Outcome Inventory for Hearing Aids (K-IOI-HA) between the two groups. When there was no need for further electroacoustic adjustment of the hearing aid, sharpness and occlusion of amplified sound, clarity of sentence, and loudness of noise were evaluated based on the everyday experience. And REIGs with international speech test signal and WRS in sound-treated room were measured.Results: Preferred REIG for HTL was low for OF compared to CF in 0.5 kHz and 0.75 kHz at input SPL of 55 dB, 0.5 kHz at 60 dB SPL, 0.25 kHz and 0.5 kHz at 80 dB SPL. However, there were no differences in aided WRS and psychoacoustics between the two groups.Conclusion: In this study, the preferred REIG of OF and CF groups showed a difference under 0.75 kHz although there were no psychoacoustic differences between the two groups. Therefore, the results of this study should be considered when formulating Korean-type hearing aid fitting formula.

Background Hearing aid fitting guidelines recommend real ear measures (REM) to verify hearing aid performance. Unfortunately, approximately 70 to 80% of clinicians do not use REM, but instead download manufacturer first-fit. Studies report differences in performance between first-fit and programmed-fit with greatest differences in the higher frequencies. Recently, hearing aid and real ear analyzer (REA) manufacturers allow REA communication with hearing aid software feature to automatically program hearing aids to target. Little research is available reporting the accuracy of this feature. Purpose The aim of the study is to examine whether differences exist at 50, 65, and 80 dB SPL between two ReSound first-fit formulae (Audiogram+ and NAL-NL2) using ReSound AutoREM and Aurical NAL-NL2 Research Design The study design is of repeated measure type. Study Sample The study sample includes 48 ears. Data Collection and Analysis For the two fitting formulae, AutoREM real ear insertion gain (REIG) was measured at 50, 65, and 80 dB SPL and compared with measures from Aurical NAL-NL2. Results Mean AutoREM REIG for ReSound NAL-NL2 was 3 to 8 dB below Aurical NAL-NL2 for 50 dB SPL, within 1 to 3 dB for 65 dB SPL and 1 to 5 dB above for 80 dB SPL. Mean AutoREM REIG for Audiogram + was 1 to 12 dB below Aurical NAL-NL2 for 50 dB SPL, within 2 to 5 dB for 65 dB SPL and 1 to 7 dB above NAL-NL2 for 80 dB SPL. Conclusion Relative to the Aurical NAL-NL2, AutoREM REIG50 for Audiogram + and ReSound NAL-NL2 was lower. Relative to the Aurical NAL-NL2, AutoREM REIG65 for Audiogram + was higher at 1,000 Hz and lower at 4,000 to 6,000 Hz and for ReSound NAL-NL2 it was lower at 500 Hz and 4,000 Hz and higher at 3,000 Hz. Relative to the Aurical NAL-NL2, AutoREM REIG80 for Audiogram + was higher at 500 to 3,000 Hz and 6,000 Hz and ReSound NAL-NL2 was higher at 500 to 6,000 Hz. Because of wide intersubject variability clinicians should continue to use REM as a “check and balance” when using AutoREM.

Purpose: This study aimed to compare the preferred real-ear insertion gain for Korean (PREIG-K) wearing multi-channel hearing aid with the National Acoustics Laboratories-Non-Linear version 2 (NAL-NL2; National Acoustic Laboratories) gains in order to develop Korean hearing aid fitting formula.Methods: A total of thirty one (62 ears) Korean hearing aid users were included in this study. All subjects wore in-the-canal or custom hearing aids in both ears. Individual hearing aid fitting procedures involved to adjust the gains for 50, 65, and 80 dB sound pressure level of speech across low, high, and wideband frequency bands based on participant’s subjective responses. In addition, only the high frequency bands of 1 kHz or more of the PREIG-K were re-adjusted to be the same as NAL-NL2 gain and then the word recognition scores (WRSs) were compared before and after the adjusting gain. Results: The results showed that the PREIG-K increased up to 1.5 kHz with the maximum amount, then the PREIG-K decreased across the frequencies. For all half octave frequencies, the PREIG-Ks were substantially less than the NAL-NL2. When the PREIG-K of high frequencies were re-adjusted same as the NAL-NL2 gains, the WRSs of the PREIG-K were not significantly different before and after gain adjustment. The slopes up to 1.5 kHz frequencies of the PREIG-K were steeper than the slopes of NAL-NL2 gain, however similar to the slope of manufactures’ fitting formulae.Conclusion: The development of an effective hearing aid fitting formula for improving the communication abilities of hearing-impaired Korean will require further experiments considering the language, physical characteristics, and word recognition used by Koreans.

Purpose The initial-fit provided by the hearing aid manufacturer’s software is generally a display of measurement done in the ear simulators. The need for verification of hearing aid output and gain in the real ear using probe-microphone measurement to match the prescriptive target is highlighted. The objective of the study was to evaluate the difference in real-ear aided response (REAR), real-ear insertion gain (REIG), aided thresholds, articulation index (AI) and word recognition score (WRS) in quiet, with hearing aid programmed to NAL-NL1 first-fit and NAL-NL1 optimized-fit using the probe-microphone technique. Methods In a repeated measure experimental design, 11 participants with a mean age of 41.09 (SD=±9.95) years having moderate and moderately-severe sensorineural hearing loss were tested monaurally in two aided conditions, with a 16-channel hearing aid programmed for manufacturer’s NAL-NL1 first-fit and optimized-fit to NAL-NL1 using probe-microphone verification. The REAR, REIG, aided threshold, articulation index and word recognition scores in quiet were obtained for both aided conditions. Results The REAR, REIG, aided threshold, AI and WRS in quiet were significantly better with the NAL-NL1 optimized-fit compared to manufacturer’s NAL-NL1 first-fit. Conclusion The optimized-fit yields better audibility and improved word recognition in quiet. This supports best practice guidelines of many professional organizations regarding the use of probe-microphone measurement as the “Gold standard” for verification of hearing aid fitting, thereby providing better satisfaction and quality of life to hearing aid users.

Objective. Speech perception in cocktail party scenarios has been the concern of a group of researchers who are involved with the design of hearing-aid devices.Approach. In this paper, a new unified ear-EEG-based binaural speech enhancement system is introduced for hearing-impaired (HI) listeners. The proposed model, which is based on auditory attention detection (AAD) and individual hearing threshold (HT) characteristics, has four main processing stages. In the binaural processing stage, a system based on the deep neural network is trained to estimate auditory ratio masks for each of the speakers in the mixture signal. In the EEG processing stage, AAD is employed to select one ratio mask corresponding to the attended speech. Here, the same EEG data is also used to predict the HTs of listeners who participated in the EEG recordings. The third stage, called insertion gain computation, concerns the calculation of a special amplification gain based on individual HTs. Finally, in the selection-resynthesis-amplification stage, the attended speech signals of the target are resynthesized based on the selected auditory mask and then are amplified using the computed insertion gain.Main results. The detection of the attended speech and the HTs are achieved by classifiers that are trained with features extracted from the scalp EEG or the ear EEG signals. The results of evaluating AAD and HT detection show high detection accuracies. The systematic evaluations of the proposed system yield substantial intelligibility and quality improvements for the HI and normal-hearingaudiograms.Significance. The AAD method determines the direction of attention from single-trial EEG signals without access to audio signals of the speakers. The amplification procedure could be adjusted for each subject based on the individual HTs. The present model has the potential to be considered as an important processing tool to personalize the neuro-steered hearing aids.

Objective We used real-ear insertion gain (REIG), with the international speech test signal (ISTS), to evaluate the amplifying characteristics of hearing aids, set for patients who have been wearing such aids for a long time in a stable manner. We further compared this to the target values of the DSLv5 and NAL-NL2 methods. Methods The subjects were adults with moderate sensorineural hearing loss. We examined 40 ears in 25 individuals (15 people wearing hearing aids in both ears and ten people wearing aid in only one ear). Fit assessments were performed based on the speech performance-intensity functions and tolerance of environmental noise, and the ears studied were categorized as either ears with sufficient benefit or ears with insufficient benefit. Additionally, we evaluated the REIG for international speech test signals at 65-dB and 80-dB sound pressure level (SPL). We compared the REIG and target values for voice input at 65-dB and 80-dB SPL, calculated from the DSLv5 and NAL-NL2 methods. Results Among the 40 ears, 34 received sufficient benefit and six received an insufficient benefit from hearing aids. The REIG for ISTS at 65-dB in the sufficient benefit ears, at frequencies of 1,000 Hz and 2,000 Hz, were similar to the target values of NAL-NL2 and DSLv5 but were significantly lower at 250 Hz, 500 Hz, and 4,000 Hz frequencies. The compression ratio of REIG for sufficient benefit ears was similar to that of DSLv5. The REIG for ISTS at 65-dB in the insufficient benefit ears was smaller than that in the sufficient benefit ears at frequencies of 2,000 Hz and 4,000 Hz. Conclusion This study suggested that the target values of NAL-NL2 and DSLv5 are appropriate, even for Japanese-speaking individuals, at mid-pitch sounds. Although it is necessary to investigate the necessity for low-pitch and high-pitch gains further in the future, this study provides meaningful data regarding the amplifying characteristics in Japanese-speaking individuals who have been wearing hearing aids in a stable manner.

The American Speech-Language-Hearing Association (ASHA) and American Academy of Audiology (AAA) have created Best Practice Guidelines for fitting hearing aids to adult patients. These guidelines recommend using real-ear measures (REM) to verify that measured output/gain of hearing aid(s) match a validated prescriptive target. Unfortunately, approximately 70–80% of audiologists do not routinely use REM when fitting hearing aids, instead relying on a manufacturer default “first-fit” setting. This is problematic because numerous studies report significant differences in REM between manufacturer first-fit and the same hearing aids using a REM or programmed-fit. These studies reported decreased prescribed gain/output in the higher frequencies for the first-fit compared with the programmed fit, which are important for recognizing speech. Currently, there is little research in peer-reviewed journals reporting if differences between hearing aids fitted using a manufacturer first-fit versus a programmed-fit result in significant differences in speech recognition in quiet, noise, and subjective outcomes.To examine if significant differences were present in monosyllabic word and phoneme recognition (consonant-nucleus-consonant; CNC) in quiet, sentence recognition in noise (Hearing in Noise Test; HINT), and subjective outcomes using the Abbreviated Profile of Hearing Aid Benefit (APHAB) and the Speech, Spatial and Qualities of Hearing (SSQ) questionnaires between hearing aids fit using one manufacturer’s first-fit and the same hearing aids with a programmed-fit using REM to National Acoustic Laboratories Nonlinear Version 2 (NAL-NL2) prescriptive target.A double-blind randomized crossover design was used. Throughout the study, one investigator performed all REM whereas a second investigator measured speech recognition in quiet, noise, and scored subjective outcome measures.Twenty-four adults with bilateral normal sloping to moderately severe sensorineural hearing loss with no prior experience with amplification.The hearing aids were fit using the proprietary manufacturer default first-fit and a programmed-fit to NAL-NL2 using real-ear insertion gain measures. The order of the two fittings was randomly assigned and counterbalanced. Participants acclimatized to each setting for four weeks and returned for assessment of performance via the revised CNC word lists, HINT, APHAB, and SSQ for the respective fitting.(1) A significant median advantage of 15% (p < 0.001; 95% CI: 9.7–24.3%) for words and 7.7% (p < 0.001; 95% CI: 5.9–10.9%) for phonemes for the programmed-fit compared with first-fit at 50 dB sound pressure level (SPL) and 4% (p < 0.01; 95% CI: 1.7–6.3%) for words at 65 dB SPL; (2) No significant differences for the HINT reception threshold for sentences (RTS); (3) A significant median advantage of 4.2% [p < 0.04; 95% confidence interval (CI): −0.6–13.2%] for the programmed-fit compared with the first-fit for the background noise subscale problem score for the APHAB; (4) No significant differences on the SSQ.Improved word and phoneme recognition for soft and words for average speech in quiet were reported for the programmed-fit. Seventy-nine percent of the participants preferred the programmed-fitting versus first-fit. Hearing aids, therefore, should be verified and programmed using REM to a prescriptive target versus no verification using a first-fit.

Objectives/Hypothesis The purpose of this study was to measure the degree of coupling between the floating mass transducer (FMT) and the round window membrane (RWM) in patients with conductive and mixed hearing loss implanted with the Vibrant Soundbridge (VSB) device. The efficiency of direct and indirect coupling of the FMT to the RWM was compared by measuring differences between the initial prescription targets and the final settings of the VSB audio processor after fine-tuning. Study Design Retrospective study. Methods Investigation of a group of subjects with either conductive or mixed hearing loss implanted with the VSB, a device that uses a FMT coupled to the RWM. There were two subgroups: subjects in which coupling was direct (no interposed material) or indirect (interposed material). The functional gain, insertion gain, and compression characteristics of the device were measured to assess the efficiency of coupling and to investigate the proximity of the fitting to prescriptive targets. Results Coupling for the subgroup with indirect coupling of the RWM was higher (better) than for the subgroup with direct coupling. The gain deviation from prescriptive targets was smaller for the subgroup with indirect coupling. Conclusions The coupling method can have an effect on the coupling efficiency and the final electroacoustic settings of the device. The prescription targets were not accurate for the majority of subjects from either subgroup. Indirect coupling appears to provide more effective stimulation of the cochlea. Level of Evidence 4. Laryngoscope, 127:2843–2849, 2017

Unilateral auditory deprivation or stimulation can induce changes in loudness and modify the sound level required to elicit the acoustic reflex. This has been explained in terms of a change in neural response, or gain, for a given sound level. However, it is unclear if these changes are driven by the asymmetry in auditory input or if they will also occur following bilateral changes in auditory input. The present study used a cross-over trial of unilateral and bilateral amplification to investigate changes in the acoustic reflex thresholds (ARTs) and the auditory brainstem response (ABR) in normal hearing listeners. Each treatment lasted 7 days and there was a 7-day washout period between the treatments. There was no significant change in the ART or ABR with either treatment. This null finding may have occurred because the amplification was insufficient to induce experience-related changes to the ABR and ART. Based on the null findings from the present study, and evidence of a change in ART in previous unilateral hearing aid use in normal hearing listeners, the threshold to trigger adaptive changes appears to be around 5 days of amplification with real ear insertion gain greater than 13-17 dB.

Supplemental Digital Content is available in the text., Objectives: The objective of this study was to test the ability to achieve, maintain, and subjectively benefit from extended high-frequency amplification in a real-world use scenario, with a device that restores audibility for frequencies up to 10 kHz. Design: A total of 78 participants (149 ears) with mild to moderately-severe sensorineural hearing loss completed one of two studies conducted across eight clinical sites. Participants were fitted with a light-driven contact hearing aid (the Earlens system) that directly drives the tympanic membrane, allowing extended high-frequency output and amplification with minimal acoustic feedback. Cambridge Method for Loudness Equalization 2 - High Frequency (CAM2)-prescribed gains for experienced users were used for initial fitting, and adjustments were made when required according to participant preferences for loudness and comfort or when measures of functional gain (FG) indicated that more or less gain was needed. Participants wore the devices for an extended period. Prescribed versus adjusted output and gain, frequency-specific FG, and self-perceived benefit assessed with the Abbreviated Profile of Hearing Aid Benefit, and a custom questionnaire were documented. Self-perceived benefit results were compared with those for unaided listening and to ratings with participants’ own acoustic hearing aids. Results: The prescribed low-level insertion gain from 6 to 10 kHz averaged 53 dB across all ears, with a range from 26 to 86 dB. After adjustment, the gain from 6 to 10 kHz decreased to an average of 45 dB with a range from 16 to 86 dB. Measured FG averaged 39 dB from 6 to 10 kHz with a range from 11 to 62 dB. Abbreviated Profile of Hearing Aid Benefit results revealed a significant improvement in communication relative to unaided listening, averaging 28 to 32 percentage points for the background noise, reverberation, and ease of communication subscales. Relative to participants’ own hearing aids, the subscales ease of communication and aversiveness showed small but significant improvements for Earlens ranging from 6 to 7 percentage points. For the custom satisfaction questionnaire, most participants rated the Earlens system as better than their own hearing aids in most situations. Conclusions: Participants used and reported subjective benefit from the Earlens system. Most participants preferred slightly less gain at 6 to 10 kHz than prescribed for experienced users by CAM2, preferring similar gains to those prescribed for inexperienced users, but gains over the extended high frequencies were high relative to those that are currently available with acoustic hearing aids.

The tranquil solution for the hearing impaired subjects to get rid of the impairment is to wear the appropriate hearing aid to increase the hearing level and clarity of the perceived speech. Though the present day hearing aids are inbuilt with a suitable noise removing algorithm to get a clear speech signal, the satisfaction among the users is low. The satisfaction of the hearing aid users will be enhanced only with the fixation of appropriate Real Ear Insertion Gain (REIG) values for different frequency bands of the perceived speech signal. Various prescriptive procedures were developed so far in prescribing these values. But, the strenuous task for the audiologists is in selecting the best procedure and to suggest required modifications. The present work focuses this problem faced by the audiologists by analyzing the various technical snags and arrived with suitable solutions. In the present work, an expert system was developed to predict gain values without the need of the prescriptive procedures and reduced the trial and error time of the audiologists. A gain suggestion database of the satisfied subjects was developed, and later it was used by the correlation algorithm in the gain prediction process. The successful gain suggestions of the most correlated subject for different frequencies in the database are recommended for the new subject. The developed expert system was validated by performing hearing aid trials with 256 hearing impaired subjects and 93.7% of them received satisfaction. The successful gain suggestions made by the expert system are stored continuously to strengthen the database, so as to recommend the most appropriate gain values for the new subject.

Purpose A model was developed to examine variables that influence signal-to-noise ratio (SNR) at the tympanic membrane (TM) when using a hearing aid (HA) and frequency modulated (FM) system. The model was used to explore how HA coupling influences SNR. Method To generate the model, HA output was measured in a coupler. Known coupler to real-ear transformations and known values for vent (gain) loss as a function of coupling were also used. The model was verified by measuring sound pressure level (SPL) at the TM in 6 ears. Results The model predicts similar overall SNRs at the TM regardless of coupling method when HA and FM microphones are active. The primary difference in SNR is in the low frequencies and depends on the amount of low frequency insertion gain and the noise levels at the HA and FM microphones. Conclusions A model was developed to explore how complex variables contribute to SNR at the TM. One variable, HA coupling, is predicted to have only a minimal effect on SNR at the TM when there is HA gain. Further studies will be needed to assess the real-world effectiveness of an FM system coupled to an open- versus closed-fit HA.

Summary Introduction: Old age is associated with changes in the characteristics of the middle ear transmission system and in external ear resonance, and these carry implications for the hearing aid (HA) verification process for which targets and measures of the real ear insertion gain (REIG) are used. Aim: To compare the real ear unaided gain (REUG) and the equivalent volumes of the external ear (VeqEE) and the middle ear (VeqME) between elderly and adult patients. Methods: This is a retrospective study in which the medical records of 28 elderly patients (aged between 61 and 102 years, average hearing thresholds between 38.75 and 85 dB HL) and 23 adult patients (aged 20–59, mean hearing thresholds between 31.25 and 116.25 dB HL) with bilateral sensorineural hearing loss and no history of middle ear abnormalities were analyzed. Immittance measurements (VeqEE, VeqME, and pressure of the peak of maximum compliance) and the REUG (frequency and amplitude of the primary peak) were recovered for a total of 40 ears. These data were compared between elderly and adults as well as between men and women, using Student's t test. Correlations (Pearson) between immittance and REUG data were also verified. Results: No statistically significant differences (p

Background: In the past, bilateral contralateral routing of signals (BICROS) amplification incorporated omnidirectional microphones on the transmitter and receiver sides and some models utilized noise reduction (NR) on the receiver side. Little research has examined the performance of BICROS amplification in background noise. However, previous studies examining contralateral routing of signals (CROS) amplification have reported that the presence of background noise on the transmitter side negatively affected speech recognition. Recently, NR was introduced as a feature on the receiver and transmitter sides of BICROS amplification, which has the potential to decrease the impact of noise on the wanted speech signal by decreasing unwanted noise directed to the transmitter side. Purpose: The primary goal of this study was to examine differences in the reception threshold for sentences (RTS in dB) using the Hearing in Noise Test (HINT) in a diffuse listening environment between unaided and three aided BICROS conditions (no NR, mild NR, and maximum NR) in the Tandem 16 BICROS. A secondary goal was to examine real-world subjective impressions of the Tandem 16 BICROS compared to unaided. Research Design: A randomized block repeated measures single blind design was used to assess differences between no NR, mild NR, and maximum NR listening conditions. Study Sample: Twenty-one adult participants with asymmetric sensorineural hearing loss (ASNHL) and experience with BICROS amplification were recruited from Washington University in St. Louis School of Medicine. Data Collection and Analysis: Participants were fit with the National Acoustic Laboratories’ Nonlinear version 1 prescriptive target (NAL-NL1) with the Tandem 16 BICROS at the initial visit and then verified using real-ear insertion gain (REIG) measures. Participants acclimatized to the Tandem 16 BICROS for 4 wk before returning for final testing. Participants were tested utilizing HINT sentences examining differences in RTS between unaided and three aided listening conditions. Subjective benefit was determined via the Abbreviated Profile of Hearing Aid Benefit (APHAB) questionnaire between the Tandem 16 BICROS and unaided. A repeated measures analysis of variance (ANOVA) was utilized to analyze the results of the HINT and APHAB. Results: Results revealed no significant differences in the RTS between unaided, no NR, mild NR, and maximum NR. Subjective impressions using the APHAB revealed statistically and clinically significant benefit with the Tandem 16 BICROS compared to unaided for the Ease of Communication (EC), Background Noise (BN), and Reverberation (RV) subscales. Conclusions: The RTS was not significantly different between unaided, no NR, mild NR, and maximum NR. None of the three aided listening conditions were significantly different from unaided performance as has been reported for previous studies examining CROS hearing aids. Further, based on comments from participants and previous research studies with conventional hearing aids, manufacturers of BICROS amplification should consider incorporating directional microphones and independent volume controls on the receiver and transmitter sides to potentially provide further improvement in signal-to-noise ratio (SNR) for patients with ASNHL.

Various prescriptive procedures have been developed, for calculating the real ear insertion gain of a digital hearing aid based either on loudness equalization or speech intelligibility. But the problem for audiologists lies in selecting an appropriate procedure for particular types of hearing impairment. The aim of this work is to analyze various linear and nonlinear prescriptive procedures, by performing various audiological investigations on hearing impaired subjects, so as to select an optimum procedure for a specific type of impairment. An audiological test was carried out on 237 hearing impaired subjects in the age group of 23 to 75 years, and they were given appropriate hearing aids with gain recommendations, using different formulae by audiologists. The degrees of success of the recommended formulae were analyzed, based on the speech discrimination score. Subjects with mild and moderate losses were found satisfied with the gain suggestions of linear prescriptive procedures, in addition to procedures based on loudness equalization NAL-RP (National Acoustics Laboratory-Revised Profound), POGO II (prescription of Gain Output), and DSL (Desired Sensation Level). Subjects with sensorineural loss were satisfied only with the gain recommendations of non linear prescriptive procedures NAL-NL1 (National Acoustics Laboratory-Non Linear), NAL-NL2 and DSL I/O (Desired Sensation Level Input/Output). An appropriate prescriptive procedure for a specific audiogram could be successfully suggested in future based on the results obtained from the total population on whom the study was carried out. In the case of those subjects who were not satisfied with the suggested procedure, a revised formula would be arrived at, by suitably varying the gains by the audiologists.

Background: Hearing aid prescriptive recommendations for hearing losses having a conductive component have received less clinical and research interest than for losses of a sensorineural nature; as a result, much variation remains among current prescriptive methods in their recommendations for conductive and mixed hearing losses (Johnson and Dillon, 2011). Purpose: The primary intent of this brief clinical note is to demonstrate differences between two algebraically equivalent expressions of hearing loss, which have been approaches used historically to generate a prescription for hearing losses with a conductive component. When air and bone conduction thresholds are entered into hearing aid prescriptions designed for nonlinear hearing aids, it was hypothesized that that two expressions would not yield equivalent amounts of prescribed insertion gain and output. These differences are examined for their impact on the maximum power output (MPO) requirements of the hearing aid. Subsequently, the MPO capabilities of two common behind-the-ear (BTE) receiver placement alternatives, receiver-in-aid (RIA) and receiver-in-canal (RIC), are examined. Study Samples: The two expressions of hearing losses examined were the 25% ABG + AC approach and the 75% ABG + BC approach, where ABG refers to air-bone gap, AC refers to air-conduction threshold, and BC refers to bone-conduction threshold. Example hearing loss cases with a conductive component are sampled for calculations. The MPO capabilities of the BTE receiver placements in commercially-available products were obtained from hearing aids on the U.S. federal purchasing contract. Results: Prescribed gain and the required MPO differs markedly between the two approaches. The 75% ABG + BC approach prescribes a compression ratio that is reflective of the amount of sensorineural hearing loss. Not all hearing aids will have the MPO capabilities to support the output requirements for fitting hearing losses with a large conductive component particularly when combined with significant sensorineural hearing loss. Generally, current RIA BTE products have greater output capabilities than RIC BTE products. Conclusions: The 75% ABG + BC approach is more appropriate than the 25% ABG + AC approach because the latter approach inappropriately uses AC thresholds as the basis for determining the compression ratio. That is, for hearing losses with a conductive component, the AC thresholds are not a measure of sensorineural hearing loss and cannot serve as the basis for determining the amount of desired compression. The Australian National Acoustic Laboratories has been using the 75% ABG + BC approach in lieu of the 25% ABG + AC approach since its release of the National Acoustic Laboratories—Non-linear 1 (NAL-NL1) prescriptive method in 1999. Future research may examine whether individuals with conductive hearing loss benefit or prefer more than 75% restoration of the conductive component provided adequate MPO capabilities to support such restoration.

The various gain calculating formulae for digital h earing aids is analyzed for different subjects to f ind out suitable adaptive gain formula for most successful gain reco mmendations. The object of the work is to design and develop an adaptive expert system, which could be effective ly used to perform screening tests to identify the level of hearing impairment and recommend suitable gain suggestions for frequency bands of digital hearing aid. Initially, the design requirements for a digital hearing aid a re being arrived by using the standard gain formula e followed such as National Acoustic Laboratory Revised (NAL-R) and Prescription of Gain Output (POGO II). The test is carried with 272 subjects aging from 25 to 72 and 2 21 male and 51 female. Of which gain is recommended for 127 subjects with the standard gain formula. When t he recommendations are verified for satisfaction among the hearing aid users only 28 received satisfaction wit h NAL-R and 25 received satisfactions with POGO II. Remaining subjects received satisfaction only after fine tuning the gain value and recommended gains are stored in adaptive expert system. Subsequently, based on t he suggested value of gains and additional data fro m expert audiologists, gain formula could be made distinct f or every language.

The last decade has offered a multitude of instant fi t coupling systems to be fi tted with behind-the-ear (BTE) hearing aids. The impact of these designs on the reliability of real ear measurements (REMs) has not been reported. The purpose of this study was to obtain REM reliability data for instant fi t coupling systems. Design: REM reliability data was obtained for four different instant-fi t coupling systems and for standard size 13 tubing and custom earmolds. REMs were performed for all fi ve coupling systems two times and by two examiners. Study sample: Ten normal-hearing individuals (20 ears) served as participants. Results: The REM test-retest reliability is high for the four instant fi t coupling systems as well as for the custom earmolds. The REM inter-examiner reliability is high for three of the four instant fi t coupling systems. Conclusions: Carrying out REMs with instant fi t coupling systems appears to be fundamentally no different than performing REMs with conventional hearing aids. For either, care should be taken in probe tube placement in terms of insertion depth and maintaining the probe tube placement, and other best practices regarding test environment and test setup should be observed.

Preferences between low delays and phase-frequency responses of behind-the-ear, open-canal hearing aids were investigated with acoustic conditions deemed sensitive to delay effects by normal-hearing listeners.Hearing aids with the following selectable delay and phase response options were fitted at low insertion gain: (1) 1.4 ms delay, minimum phase; (2) 3.4 ms delay, minimum phase; and (3) 3.4 ms delay, linear phase. Blind paired comparisons were made between processing options and between each option and a muted hearing-aid output with two music stimuli. The three alternative forced choice responses were "Slightly prefer", "Prefer", or "Strongly prefer".Twelve hearing-impaired musicians.At the 3.4-ms delay, the minimum-phase response was significantly preferred to the linear-phase response for one music sample and vice-versa for the other sample with a sign test (p0.04) but not a Wilcoxon signed rank test that accounted for the low preference strength. Preferences between all other processing conditions were not significant.In acoustic conditions sensitive to delay effects, delays of 1.4 or 3.4 ms were either not detected or no less preferable than no delayed aided signal. It is unclear whether different phase-frequency responses may be preferred with different music stimuli.

OBJETIVO: avaliar as medidas repetidas da resposta de ressonância da orelha externa sem (REUR) e com uso de amplificação (REAR) e o ganho de inserção (REIG), realizados face a face e via teleconsulta. MÉTODO: estudo prospectivo longitudinal. Foram realizadas quatro repetições da REUR, REAR e REIG (com estímulo speech noise apresentado em 65 dB NPS e 0º azimute) em 19 orelhas de adultos ouvintes normais, via face a face (F) e teleconsulta síncrona por controle remoto de aplicativo (T) e vídeo interativo. O software Polycom PVX foi utilizado para compartilhamento e transmissão de áudio e vídeo. A conexão foi realizada via LAN (Local Area Network) USP na velocidade de 384 kbps Foi calculado o erro causal (Dalhberg) entre as quatro medidas para frequências de 250 a 8000 Hz. RESULTADOS: os erros casuais entre as medidas F e T foram muito semelhantes, sendo maiores nas frequências acima de 4 kHz. As diferenças e variações entre as medidas F e T estavam dentro da magnitude de variabilidade do procedimento de medidas com microfone sonda. CONCLUSÃO: as medidas com microfone sonda via teleconsulta fornece resultados confiáveis e similares aos obtidos pelo procedimento padrão. PURPOSE: to evaluate the repeated measurements of the real ear unaided response (REUR), real ear aided response (REAR) and insertion gain (REIG) conducted as face to face (F) and via telecounselling (T). METHOD: longitudinal prospective study. Four measures of REUR, REAR and REIG (carried out with speech noise stimulus presented at 65 dB SPL at 0° azimuth) were obtained in 19 ears in normal hearing adults, face to face and via synchronous telecounsellings with remote control of the real ear equipment and interactive video. Polycom PVX software was used for desktop sharing and video and audio transmission. The Loca Area Network (LAN) USP was used for the connection (transmission rate: 384 kbps). Dahlberg’s casual errors were calculated for obtaining the measures for frequencies from 250 to 8000 Hz. RESULTS: casual errors between F and T measures were very similar, being greater for frequencies above 4 kHz. The differences between F and T measures were no greater than the variability reported for real ear measures. CONCLUSION: probe microphone measures obtained via telecounselling provides reliable results and similar to those obtained by standard procedures.

Background: Prescriptive methods have been at the core of modern hearing aid fittings for the past several decades. Every decade or so, there have been revisions to existing methods and/or the emergence of new methods that become widely used. In 2001 Byrne et al provided a comparison of insertion gain for generic prescriptive methods available at that time. Purpose: The purpose of this article was to compare National Acoustic Laboratories—Non-linear 1 (NAL-NL1), National Acoustic Laboratories—Non-linear 2 (NAL-NL2), Desired Sensation Level Multistage Input/Output (DSL m[i/o]), and Cambridge Method for Loudness Equalization 2—High-Frequency (CAMEQ2-HF) prescriptive methods for adults on the amplification characteristics of prescribed insertion gain and compression ratio. Following the differences observed in prescribed insertion gain among the four prescriptive methods, analyses of predicted specific loudness, overall loudness, and bandwidth of cochlear excitation and effective audibility as well as speech intelligibility of the international long-term average speech spectrum (ILTASS) at an average conversational input level were completed. These analyses allow for the discussion of similarities and differences among the present-day prescriptive methods. Research Design: The impact of insertion gain differences among the methods is examined for seven hypothetical hearing loss configurations using models of loudness perception and speech intelligibility. Study Sample: Hearing loss configurations for adults of various types and degrees were selected, five of which represent sensorineural impairment and were used by Byrne et al; the other two hearing losses provide an example of mixed and conductive impairment. Data Collection and Analysis: Prescribed insertion gain data were calculated in 1/3-octave frequency bands for each of the seven hearing losses from the software application of each prescriptive method over multiple input levels. The insertion gain data along with a diffuse field-to-eardrum transfer function were used to calculate output levels at the eardrums of the hypothetical listeners. Levels of hearing loss and output were then used in the Moore and Glasberg loudness model and the ANSI S3.5-1997 Speech Intelligibility Index model. Results: NAL-NL2 and DSL m[i/o] provided comparable overall loudness of approximately 8 sones for the five sensorineural hearing losses for a 65 dB SPL ILTASS input. This loudness was notably less than that perceived by a normal-hearing person for the same input signal, 18.6 sones. NAL-NL2 and DSL m[i/o] also provided comparable predicted speech intelligibility in quiet and noise. CAMEQ2-HF provided a greater average loudness, similar to NAL-NL1, with more high-frequency bandwidth but no significant improvement to predicted speech intelligibility. Conclusions: Definite variation in prescribed insertion gain was present among the prescriptive methods. These differences when averaged across the hearing losses were, by and large, negligible with regard to predicted speech intelligibility at normal conversational speech levels. With regard to loudness, DSL m[i/o] and NAL-NL2 provided the least overall loudness, followed by CAMEQ2-HF and NAL-NL1 providing the most loudness. CAMEQ2-HF provided the most audibility at high frequencies; even so, the audibility became less effective for improving speech intelligibility as hearing loss severity increased.

When hearing aid gain is prescribed by software, gain is calculated based on the average acoustics for the age of patient, gender, mold type, and so on. The acoustics of the individual's ear often vary from the average values, so there will be a mismatch between the prescribed gain and the real-ear gain. Real-ear measurement can be used to verify the gain and adjust it to meet targets, but the quality of the match will be limited by the number of channels and the flexibility of the hearing aid. A potential way to improve this process is to generate a filter that compensates for variations in real-ear insertion gain due to individual ear acoustics. Such a filter could be included in the processing path of a digital hearing aid. This article describes how such a filter can be generated using the windowing method, and the principle is demonstrated in a real ear. The approach requires communication between the real-ear measurement and hearing aid programming software. A finite impulse response filter with group delay just over 2 ms matched insertion gain to target values within the acceptable tolerance defined by British Society of Audiology guidelines.

補聴器適合中の80症例を対象に, 試聴中の補聴器を用いて5周波数における実耳挿入利得 (REIG) とファンクショナルゲイン (FG) を測定し比較した。非線形増幅補聴器では, 補聴閾値と等しい入力音圧レベルにおけるREIGを比較に用いた。その結果, 高利得のCIC補聴器を装用する1症例でのみ, ハウリングのためREIGの測定が行えなかった。これ以外の症例においては, 250 Hzから2 kHzの周波数では, 2つの測定値は比較的よく一致した。4 kHzでは, REIGはFGより平均約5 dB小さくなり, 差の標準偏差も他の周波数より大きかった。REIG測定における補聴器挿入時のプローブチューブ位置のずれが, この不一致の一因である可能性が示唆された。いくつかの特殊な場合にはFGの測定が必須であるものの, REIGの測定結果から補聴閾値 (FG) を推定することはノンリニア補聴器でも可能であり, 通常の補聴器の利得評価においては, REIGはFGに比べ利点が多いことが確かめられた。

The present study investigated the possible use of the auditory steady state response (ASSR) technique in hearing aid fitting. The relationship between the real ear insertion gain (REIG) and ASSR gain (unaided ASSR threshold vs. aided ASSR threshold) was examined. Thirty subjects with mild to moderately severe sensorineural hearing loss with age range of 15 years to 50 years (mean age 32 years) participated in the study. Based on the degree, configuration and type of hearing loss, two digital BTE hearing aids were preselected. For each subject insertion gain and ASSR gain were measured at 500 Hz, 1 kHz, 2 kHz and 4 kHz. The hearing aid that best matched with the target curve during insertion gain measurement was selected for the ASSR measurement. ASSR gain and REIG were highly correlated with significance values p < .05. Paired sample t tests revealed that there was no significant difference at all test frequencies. The ASSR technique shows great promise in hearing aid fitting for those who can not reliably respond on behavioral testing.

Real-ear measurements using the modified pressure method with concurrent (real-time) equalization can be inaccurate, when amplified sound leaks out of the ear canal and reaches the reference microphone. In such situations the reference microphone will detect an increased sound level and reduce the output of the loudspeaker to maintain the desired level. The risk of having errors due to leaks increases if digital feedback suppression (DFS) is used, thus achieving higher feedback-free gain levels. The following hypotheses were tested: a) using the concurrent equalization method for fitting hearing instruments with DFS may result in underestimated real-ear insertion gain (especially when using open fittings) and b) as the benefit of the DFS system increases, this error also increases. Real-ear measurements were carried out in twenty-one subjects using the modified pressure method with stored equalization as well as with concurrent equalization. The results of the study supports both hypotheses. As a consequence it is recommended to use a stored equalization method for real-ear measurements of hearing instruments with DFS and open fitting.

Background: The bilateral contralateral routing of signals (BICROS) system has provided limited benefit for speech recognition in noise for patients with asymmetric sensorineural hearing loss, even when an automatic adaptive multichannel directional microphone (DM) is in the receiver (Rx) and an omnidirectional microphone (OM) is in the transmitter (Tx). A recent BICROS system was introduced that can be programmed with a DM in the Rx and an OM or a DM in the Tx. Purpose: To examine if significant differences in sentence recognition in noise and subjective preferences are present between an OM and an adaptive broadband DM programmed in the Tx of a BICROS system with an automatic adaptive multichannel DM programmed in the Rx. Research Design: A randomized crossover single-blind design was used to assess differences between the OM and DM programmed in the Tx. Study Sample: Eighteen adult experienced BICROS system users were recruited. Data Collection and Analysis: The BICROS system was fit using real-ear insertion gain measures. The Tx was programmed with an OM and a DM and the Rx was always programmed with an automatic adaptive multichannel DM. The order of microphone condition in the Tx was counterbalanced. Participants acclimatized to the BICROS system for 4 weeks and returned and completed the Abbreviated Profile of Hearing Aid Benefit (APHAB) for the respective microphone condition. The Tx was then programmed with the other microphone condition and participants acclimatized for another four weeks. At the final visit, the APHAB was completed for the respective microphone condition. After eight weeks of acclimatization, Hearing in Noise Test sentences were presented in the R-Space™ system with the Tx in either the OM or DM condition for three listening conditions: (1) speech from 90° to the Rx and noise from 0°, 90°, and 180° to the Tx (Sp Rx/N Tx), (2) speech from 90° to the Tx and noise from 0°, 90°, and 180° to the Rx (Sp Tx/N Rx), and (3) speech from 0° and noise from eight surrounding loudspeakers separated by 45° (diffuse). Results: A two-factor repeated measures analysis of variance revealed no significant differences between the OM and DM microphone conditions for Sp Rx/N Tx listening condition. A significant mean disadvantage of 1.9 dB (p < 0.01) was revealed for the DM compared to the OM for Sp Tx/N Rx listening condition and a mean advantage of 2.6 dB (p < 0.001) for the DM compared to the OM in a diffuse listening condition. There were no significant differences in the APHAB aided problem and resulting benefit scores between the OM and DM for the following subscales: ease of communication, background noise, reverberation, and aversiveness of sounds. Conclusions: No significant differences were revealed between OM and DM for Sp Rx/N Tx. The DM performed significantly poorer than OM for the Sp Tx/N Rx listening condition. Results revealed significant benefit for the DM compared to OM for the diffuse listening condition. No significant differences were revealed between the OM and DM on the APHAB.

Matching a prescription gain target at 60-65 dB SPL does not ensure audibility of lower input levels, nor does it mean the fitted frequency response slope is conducive to good sound quality. The aim of the present study was to evaluate the use of probe-microphone measurements to match target gain and slope, as a function of earmould style, frequency, and input level.The real-ear insertion gain was calculated for an input of 50, 65, and 80 dB SPL for the manufacturer's 'initial fit' (IF) settings and after adjustment to target in 49 and 51 open slim-tube and custom earmould fittings, respectively.One hundred adults with median age 74 years (range 32-93).Some 18%-67% of the IF settings were within 10 dB of the target gain but this increased to 85% after adjustment. Some 47%-71% of the IF settings were within 10 dB of the target slope but, with the exception of 2-4 kHz, this increased to 88% after adjustment.The results indicate that IF settings are inadequate, at least for the model of hearing aid used in the present study; however, significant discrepancies remained, even after adjustment.

Objective The methods to evaluate the efficacy of the adjusted hearing aid for a hearing-impaired person are fitting tests. The tests include those presently carried out for evaluating hearing aid fitting, and the methods of testing and evaluation have been published as “Guidelines for the evaluation of hearing aid fitting (2010)” by the Japan Audiological Society. Methods Guidelines for the following 8 test methods are presented. (1) Measurements of speech performance-intensity functions and speech recognition scores; (2) Assessment of hearing aid fitting from the aspect of tolerance of environmental noise; (3) Measurement of real-ear insertion gain (measurement of sound pressure levels at the eardrum); (4) Measurement of the hearing threshold level and the uncomfortable loudness level (UCL) in sound pressure level (SPL) with an inserted earphone; (5) Aided threshold test in a sound field (functional gain measurement); (6) Prediction of insertion gain and aided threshold from hearing aid characteristics and the pure tone audiogram; (7) Measurement of speech recognition in noise; (8) Assessment of hearing aid fitting using questionnaires. In the above tests, (1) and (2) are mandatory tests, and (3) to (8) are informative tests. Results By performing test combinations properly selected from the above 8 tests, the benefits of a hearing aid could be determined. Conclusion The above test methods were useful and valuable in determining the efficacy of the adjusted hearing aid for a hearing-impaired person during clinical practice.

The time course of changes in perceived sound quality after hearing instrument fitting has not been studied systematically It is possible, for example, that patients may object to additional high frequency gain when fitted, but not after a period of auditory acclimatisation. The aim of this study was to utilise sound quality judgements to compare two frequency responses in new users at 4-week intervals over a 24-week post-fitting period. The null hypothesis was that there would be no change in sound quality judgements over time. A total of 16 elderly subjects were fitted monaurally with the same model of linear, programmable hearing instrument. This was set to a standard response that provided 26-29 dB of real-ear insertion gain at 2000 4000 Hz. This program was worn by the subjects for the duration of the study. All subjects reported greater than four hours of daily use. The alternative response which was used in a paired comparison paradigm, provided a mean gain reduction of 3, 8, 13, and 16 dB at 2000, 3000, 4000 and 6000 Hz, respectively. Subjects compared the standard and the alternative responses for sound quality along dimensions of comfort, clarity, and overall preference while listening to running speech presented in quiet, steady noise, and speech babble. At the time of fitting there was a small preference for the standard response when judging clarity, but the alternative response was preferred for comfort and preferred overall. Repeated-measures analysis of variance (ANOVA) for each quality dimension did not reveal any statistically significant change over time. It is concluded that this pattern of preference is unaffected by acclimatisation to amplification, at least over the initial 24 weeks of instrument use.

This paper describes the outcome of a clinical trial of a low-cost high power compression behind-the ear-hearing aid (BTE-HA), performed in order to assure the quality of the product. Twenty-one experienced HA users, 14 males and 7 females at a median age of 77 years, (range 50–86 years) were recruited among persons fitted with HAs within a period of 6–12 months prior to recruitment. Seventeen had been fitted previously with binaural DSP-HAs, whereas four had a monaural fitting with analogue HAs. All subjects had a hearing loss >50 db at 2 kHz. Validation of the fitting according to the NAL-R prescription or POGO prescription was performed by insertion gain measurements, showing that the HA meets the frequency and amplification characteristics required according to an individual hearing loss. The immediate improvement in SRS in quiet on an individual basis was median 52% (range 8–96) and in background noise (S/N=5 dB) median 43% (range 0–76). A comparison between the benefits obtained with the test-HA and...

Closed-set word tests can be implemented with or without trial-by-trial visual feedback. Feedback is considered to increase subject motivation yet its influence on performance is unknown. The aim of this study was to compare performance on the Four Alternative Auditory Feature (FAAF) test with and without visual feedback over a 24-week period following fitting of a hearing aid. A total of 32 elderly subjects were recruited as new users and fitted monaurally with the same model of linear, programmable hearing aid that provided in excess of 20 dB insertion gain at 2-4 kHz. Half of the subjects were provided with visual feedback. In these subjects, mean performance increased by 5% across the study period. The improvement in performance over time was statistically significant on analysis of variance (p < 0.05). Mean performance did not increase in the remaining subjects who were not provided with feedback. If closed-set word tests are to be used with visual feedback to measure changes over time, the potentially confounding effects of practice must be controlled carefully. Alternatively, omitting feedback leads to simpler experimental designs.

In July 2001 the World Health Organization (WHO) launched their "Guidelines for hearing aids and services for developing countries". The objective of this study was to evaluate the clinical outcome of an analogue, low-cost, behind-the-ear hearing aid (BTE-HA) that met the minimum technical requirements outlined by the WHO.A total of 25 subjects (17 males, 8 females; median age 74 years; range 50-86 years) were recruited among patients referred for audiological evaluation who consented to participate in the trial. All subjects had a hearing loss ofor = 60 dB HL at 2 kHz, were mobile and mentally unimpaired; 13 were experienced users of HAs, 3 suffered from mixed conductive/sensorineural hearing impairment (HI) and the remainder had pure sensorineural HI. Based on pure-tone, speech and impedance audiometry the BTE-HAs were fitted, using the National Acoustic Laboratories-R (NAL-R) prescription rule, 21 binaurally and 4 monaurally. All fittings were validated by insertion gain measurements, and the immediate benefit was measured by means of the speech recognition score in background noise (SRSN; signal:noise ratio = 10 dB) without and with the HA. After a 6-week trial period a structured interview based on the International Outcome Inventory for Hearing Aids (IOI-HAs) was performed.The results showed that the amplification of the HA deviated significantly from the NAL-R target at all frequencies, giving significantly more amplification at 500 and 1000 Hz despite maximum bass-cut, whenever relevant, and significantly less amplification as required at 2, 3 and 4 kHz. The median SRSN without HA was 48% (range 0-96%), which improved significantly to 80% (range 24-100%) with HA. The median individual difference in SRSN without and with HA was 20% (range 0-72%). The total IOI-HA score with the test HA was 4.1 (range 2.6-4.6), showing that it offered subjectively high satisfaction and reduction in limitations of activity.The low-cost HA: (i) provides benefit to the hearing-impaired person; (ii) offers poor amplification in the high frequencies; and (iii) gives subjective satisfaction similar to that for modern available HAs.

People of Chinese ethnicity account for more than 20% of the world's population. A substantial number of hearing aid fittings occur in Chinese adults each year, often involving real ear insertion gain measures initially developed with Western populations. These measures may not be appropriate for non-Western persons. To determine the suitability of standard Western data, real ear unaided response (REUR) was measured for 40 Chinese young adults aged 20–32 years. Measurements were made with a speech-weighted composite signal generated from a 45° azimuth. The average maximum amplitude was 17.92 dB SPL (range: 12.25–22.55 dB), and the average peak resonant frequency was 3042 Hz (range: 2300–6700 Hz). Intra-tester test-retest reliability revealed mean differences of less than 0.2 dB in amplitude at each octave frequency from 250 Hz to 4000 Hz, and the average peak resonant frequency was within 13 Hz for two consecutive measurements. The intersubject variability of the peak resonant frequency of the REU...

Hypothesis The aim of this review is to present 19th century mechanical hearing devices that were designed for concealment or camouflage. Background Extensive literature, past and current, along with museum catalogs, trade catalogs, and advertisements, were examined to identify mechanical devices designed for concealment. Methods Several mechanical devices were selected for acoustic gain measurements. Measurements were made in an anechoic chamber using a Knowles Electronics Manikin for Acoustic Research fitted with a Zwislocki coupler and a pressure microphone in the right ear. One-third-octave bands of noise were presented via a KLH Model 6 loudspeaker placed at a distance of 2.23 m on-axis. The sound level at the ear of the Knowles Electronics Manikin for Acoustic Research was recorded with and without the device in place. Results A wide variety of 19th century hearing devices designed for concealment were identified. Some hearing devices, such as fans, parasols, lorgnettes, water canteens, walking sticks, chairs/thrones, hats, and books, were concealed within everyday items. Other hearing devices, such as artificial conchae, bouquet holders, and hair and beard receptors, wereconcealed on the person. The insertion gain of a representative concealed device, the Aurolese Phone, averaged approximately 3.5 dB in the range of frequencies most relevant for speech communication. Conclusions The ingenuity behind the design of 19th century mechanical hearing devices created for concealment or camouflage is to be commended. For the Aurolese Phone, some acoustic benefit was possible despite design constraints imposed by its concealed nature.

The goal of this study is to quantify a given hearing aid insertion gain using a consonant recognition based measure, for ears having sensorineural hearing loss. The basic question addressed is how a treatment impacts phone recognition, relative to a normal-hearing insertion gain. These tests are directed at (1) fine-tuning a treatment, with the ultimate goal of improving speech perception, and (2) to identify when a hearing level based treatment degrades speech recognition. Eight subjects with hearing loss were tested under two conditions: Flat-gain and a Treatment insertion gain based on subject's hearing level. The speech corpus consisted of consonant-vowel tokens at different signal to speech-weighted noise (SNR) conditions, presented at subjects’ most comfortable level. The tokens used in this study were selected from those having less than 3% error at -2 [dB] SNR, from 30 Normal Hearing subjects. The Treatment caused token score to improve for 31% of the trials and decrease for 12%. An analysis meth...

Objective: The practical importance of the simplex procedure, a subjective technique used to refine the frequency gain characteristic (FGC) of a hearing aid according to listener preference, was determined for individual listeners by measuring hearing aid benefit using both laboratory studies and field studies. Design: A digital research hearing aid with two memories was used as the test hearing aid. The modified simplex procedure was used to select the FGC judged to yield the best speech clarity in the presence of low-level vent noise and again in higher-level cafeteria noise by 10 experienced hearing aid users. The FGCs assessed by the listeners varied systematically from The National Acoustic Laboratories Revised (NAL-R) response in the amount of low-frequency or high-frequency amplification. The benefit obtained with these two simplex-selected settings was compared with that obtained using the NAL-R FGC. Measures of benefit included speech recognition testing in the laboratory and ratings of speech intelligibility in the field. In the first field study, the two simplex settings were compared. In the second field study, the simplex-selected setting for higher level noise and the NAL-R setting were compared. Results: In the laboratory, the majority of listeners selected an increase in the low-frequency channel gain compared with the NAL-R. Desired high-frequency channel gain was correlated with degree of hearing loss and type of background noise. The benefit as measured using nonsense syllables did not differ significantly among the three fittings, but differences in benefit were measurable with the rating procedure. Five of eight participants noticed a significant difference in their speech understanding in the real world for the FGCs selected in different background noises. Two of seven participants reported significantly better speech intelligibility with a simplex-selected FGC compared with the NAL-R FGC in the real world. The remaining subjects reported similar speech understanding capabilities with both hearing aid settings. Conclusions: The majority of subjects included in this study selected an FGC with real ear insertion gain different than the NAL-R prescription to improve subjective speech understanding in the laboratory. A small number of these listeners rated the selected FGC as providing improved speech intelligibility over the NAL-R FGC in the real world. This finding indicates that the simplex procedure should be used selectively to modify the NAL-R prescription. A screening technique would be useful in selecting those who might benefit from a modified fitting. The simplex procedure may also prove to be useful in selecting listeners who would benefit from multiple memory hearing aids.

Wind noise was measured in four behind-the-ear hearing instruments with different microphone openings. A silent airflow of 7 m/s was directed toward the ear of a Kemar head and the resulting wind noise was measured. The amplification was set to an insertion gain of 35 dB at 1.6 kHz. The wind noise amplitude at the position of the drum ranged from 84 to 97 dB(A). The hearing instrument with a partially covered microphone entrance proved best, whereas one with an open microphone entrance had the poorest performance. A reduction in wind noise of 6-17 dB could be achieved in all hearing instruments by using a simple windscreen made of Styrofoam. The windscreen affected the frequency response by less than 2 dB. By subtracting the insertion gain from the wind noise, an equivalent wind noise could be presented as a function of frequency. A considerable difference was found between the wind noise sensitivity in different hearing instruments. All could be improved by a windscreen without adversely affecting the frequency response.

Although hearing aid fitting by insertion gain measurement is known to be an accurate and reliable technique, it is rarely used routinely in the UK National Health Service (NHS) because of high demands on staff and time. This study investigated whether an alternative, more practical procedure of fitting by median ear corrected coupler measurements would be as beneficial to NHS patients. Forty patients took part in a double-blind cross-over study comparing the two fitting methods. Results show that the insertion gain fittings were significantly better than the coupler fittings in terms of both patient preference and speech discrimination in noise. It is concluded that, even with the limited response adjustments available, individual deviations from the median ear make routine hearing aid fitting by insertion gain measurement indeed desirable in the NHS.

It is chiefly in schools for the deaf, kindergartens for the hard of hearing, and other facilities where hearing aids are fitted to children in Japan. Persons in charge of hearing aids in each school or facility, execute fitting to their own opinions, without a standard method of fitting. However, it is the general view that children should wear hearing aids regardless of hearing level and that they should learn to use their ears. In this paper, I described the fitting method in Japan. In addition, I explained in detail the fitting method that considers the functional gain which is becoming the main measurement, and introduce examples. I also explain that the effect of the hearing aid is measured by the functional gain, without the measure of insertion gain in Japan.

When a sound producing device is sealed in the ear canal, acoustical compliances resulting from pressurization of the trapped volume lead to dramatic boosts in SPL, up to 60 dB, especially at low frequencies. This has been found to result in listener fatigue, and to trigger the acoustic (stapedius) reflex, as well as producing temporary threshold shift. Repeated exposure can cause temporary threshold shift to become permanent. Hearing aids avoid this problem by suppressing frequencies below about 300 Hz, where the effect is most pronounced. Other devices such as ear buds and professional in-ear monitors, offer wider frequency response and thus expose listeners to potentially dangerous sound pressures. The trapped volume insertion gain is measured for ear buds by comparing SPL, measured in the ear canal, for sealed and unsealed conditions. New ear sealing technology is demonstrated that allows release of the excess acoustical compliance and thus mitigates the trapped volume insertion gain: (1) a vent cover...

Previous work has shown that a normally aided ear tested without the hearing aid is better able to identify speech-in-noise than the unaided ear at high sound levels, while performance for the unaided ear is superior at lower sound levels [S. Gatehouse, J. Acoust. Soc. Am. 86, 2103-6 (1989); J. Acoust. Soc. Am. 92, 1258-68 (1992)]. This effect was further explored using intensity discrimination for complex stimuli. Stimuli were half-octave bandpass-filtered tone complexes centered at 0.25 and 3 kHz. Four bilateral, symmetric hearing-impaired listeners with mean HL of 24 dB at 0.25 kHz, and 58 dB at 3 kHz were tested. Intensity discrimination was performed across the dynamic range of the listeners. At sound-pressure levels greater than 85 dB, the normally aided ear tested without the aid was more sensitive to changes in intensity than the unaided ear, whereas at lower levels, the converse occurred. This pattern was observed only for the 3-kHz center frequency, and not for the 0.25-kHz center frequency. Insertion gain measurements using the aids at normal volume showed an average of 20 dB gain at 3 kHz, and -2 dB gain at 0.25 kHz. The changes in intensity discrimination in the normally aided ear are consistent with the frequency-gain characteristics of the hearing aid, and suggest that a change in intensity coding occurred.

In a previous study, we investigated slow cortical potential (SCP) N1-P2 amplitudes and N1 latencies in aided and unaided conditions, with the finding that despite being set to provide 20 or 40 dB of gain, none of the hearing aids resulted in a reliable increase in SCP response amplitude relative to the unaided (Marynewich et al., in press). The current study investigates the effects of hearing-aid processing on acoustic measures for two 1000-Hz tonal stimuli: short (60 ms) and long (757 ms), presented at three intensities (30, 50, 70 dB SPL) in aided and unaided conditions using three hearing aids (Analog, DigitalA, DigitalB) with two gain settings (20, 40 dB). Acoustic results indicate that gain achieved by the hearing aids, measured at 30 ms after stimulus onset, for both the short and long stimuli, was less than real-ear insertion gain measured with standard hearing aid test signals. Additionally, the digital hearing aids altered the rise time of the stimuli such that maximum gain was reached well past 30 ms after stimulus onset; rise times differed between the digital aids. These results indicate that aided SCP results must be cautiously interpreted and that further research is required for clinical application.

The development of hearing aid (HA) software programming does not replace the analysis of real ears with probe microphones. AIM: To compare simulated insertion gain in HA software programming and real ear insertion gain. METHOD: A prospective study of 62 patients (aged from 29 to 93 years; 30 male and 32 female). All patients presented unilateral (n=14) or bilateral (n=48) and mild to profound sensorineural hearing impairment. 110 ears assessed. Data was gathered from medical records and the insertion gain was obtained in real ears for comparison with the simulated insertion gain in HA software programming. Statistical tests were applied to analyze the correlation of data - difference of real ear and simulated insertion gain. RESULTS: HA software programming simulated insertion gain was higher than real ear insertion gain obtained with probe microphone measures. There were statistically significant frequency differences. Age did not correlate with the difference of real ear and simulated measures. CONCLUSION: The use of real ear measures is important during verification of HA. Profissionais vêm utilizando as simulações dos softwares de programação de Aparelhos de Amplificação Sonora Individuais (AASI) em substituição à verificação do desempenho medido em ouvido real. OBJETIVO: Comparar o ganho de inserção simulado nos softwares de programação dos AASI com as medidas reais do ganho de inserção. MATERIAL E MÉTODO: Estudo retrospectivo com 62 pacientes (idade entre 29 e 93 anos; 30 homens e 32 mulheres) com deficiência auditiva neurossensorial unilateral (n=14) ou bilateral (n=48) de grau leve a profundo, totalizando 110 orelhas avaliadas. As simulações e medidas em ouvido real foram comparadas por meio do teste t pareado. Foi analisada a correlação entre a diferença do ganho real e o ganho simulado e a idade. RESULTADOS: O ganho simulado no software de programação foi significativamente maior do que o ganho de inserção real. Não houve correlação entre a idade e a diferença entre estas medidas. CONCLUSÃO: A despeito da maior sofisticação dos softwares de programação do AASI, os dados de simulação não substituem a realização da verificação com as medidas com microfone sonda.

Eine gewissenhafte Horgerateanpassung erfordert neben der frequenzspezifischen Korrektur der Schwerhorigkeit auch die Berucksichtigung der uberschwelligen Eigenschaften des geschadigten Ohres. Das meist vorhandene Rekruitment schrankt die Dynamikbreite des Horens deutlich ein und erhoht die Anforderungen an das Horgerat. Fur die Einschatzung des Verhaltens der Horgerate bei sehr lauten Schallen verlies man sich lange Zeit auf die Angaben der Horgeratehersteller in den Datenblattern. Diese Horgeratemerkmale sind aber alle an Ohrsimulatoren erhoben. Da es bereits bei niedrigeren Pegeln zwischen der Messung am Trommelfell und der Kuppler-Messung deutliche Unterschiede gibt, wurden in dieser Studie bei hohen Eingangspegeln die Ausgangsleistungen der Horgerate mit der In-situ-Messung aufgezeichnet und mit den Kuppler-Messungen verglichen. Zwischen den beiden Mesverfahren zeigten sich teilweise stark divergierende Resultate, im Einzelfall bis zu 30 dB. Hierbei gab der Kuppler teilweise eine hohere und teilweise eine niedrigere Kompression als die In-situ-Messung an. Die durchschnittlich hochste Kompressionsleistung lag bei beiden Mesverfahren im mittleren und hohen Frequenzbereich und damit in einer fur die Spracherkennung wichtigen Region. Die Ergebnisse unterstreichen die Bedeutung der In-situ-Messung bei der Horgerateanpassung zur Kontrolle der Wirkung von Regelschaltungen. Mit mehrkanaligen Horgeraten ist der ungunstige Effekt der tiefen Frequenzen auf die Spracherkennung am sichersten zu minimieren. A careful hearing aid fitting requires consideration of various characteristics of inner ear pathology. The recruitment phenomenon restricts the dynamic range of the impaired hearing and this increases the demands on the hearing aids for a satisfactory correction of the frequency characteristics as well as for an intensity reduction at higher sound pressure level SPL. For years data from coupler or KEMAR (Knowles Electronics Manikin of Acoustical Research) have served to estimate the real ear gain of a hearing aid at higher input levels. In previous papers we reported on some of the differences between coupler measurement and probe tube measurement. The object of this study was to investigate the differences between these two methods at higher input SPL. Therefore, we measured the real ear insertion gain as well as the output characteristics with a 2 cm3 coupler in 80 patients at input levels of 60 dB, 80 dB and 100 dB. The results show differences between the two methods up to 30 dB in both directions in the single patient. Furthermore, the highest compression rate was found in the middle and high frequency range which are crucial for speech discrimination. Consequently, probe tube measurement should be used not only to adjust the frequency characteristics of the hearing aid but also to characterise the real effect of Automatic Gain Control AGC and Peak Clipping PC on insertion gain at higher input SPL. Multichannel hearing aids should be used whenever possible to reduce the disturbances to speech discrimination at low frequencies.

補聴器を日常生活で常用しているレクルートメント現象陽性の感音難聴症例を対象として, 実耳挿入利得と子音明瞭度の関係を検討した。 対象を60歳以上の高齢者に限定したため, 1回の検査の負担が大きい57式語表は用いず67式語表を2回施行しその結果から子音明瞭度を検討した。 また今回は裸耳でもある程度は聞き取れる語音を補聴器装用によりどの程度聞き取りが良くなるかを検討する目的で, 検査語音の基準音を測定耳の平均聴力+10dBに設定した。 その結果有声子音群の明瞭度の改善には1500Hzの実耳挿入利得, 無声子音群の明瞭度の改善には3000Hz, 4000Hzの実耳挿入利得が必要であることを示唆する結果を得た。 補聴器装用に伴う有声子音群の明瞭度の改善は語音や症例により異なった傾向を示すものと考えた。

The purpose of this investigation was to determine what subjective factors may influence the success of fitting in-the-canal hearing instruments (ITCs). Four different types of ITC were fitted to four matched groups of 20 experienced ITC users. In addition to the subjective experiences of the users, the results were checked using insertion gain (IG) measurements. The results indicate that too sharp sound quality from paper rustle, from running water and from use of kitchen utensils is a common problem that it is important to be aware of. The possibility of maximal venting is of special importance in order to avoid autophony. Feedback may be a problem, especially when maximal venting is necessary. However, for several models of ITC, feedback is, in reality, a minor problem. High cost of batteries may be a problem for persons with ITC using 10/230 batteries. IG measurements indicated that a gain of approximately 0.3 in relation to the hearing losses was preferred. It may be advantageous to choose a model of ITC that has extensive flexibility.

This paper presents a digital hearing aid chip designed for Mandarin user to enhance speech quality and intelligibility. The hearing aid consists of an 18 subbands analysis and synthesis filter bank, insertion gain stage, and three channels wide dynamic range control for the new Mandarin-specific auditory compensation algorithm. A noise reduction block based on multiband spectral subtraction and enhanced entropy voice activity detection is also included to enhance quality. We reduce the power consumption of these algorithms through algorithmic and architecture optimization. In addition, for the data storage requirement, a low power SRAM that can operate at 0.6V and below is developed. Moreover, several strategies such as multi-clock domain, bypass mode, and voltage scaling are also adopted for power reduction. The chip measurement shows that the hearing aid consumes 314uW at 0.6V.

A unilateral hearing loss is characterized by reduced hearing in one ear. The problems caused by sensory deprivation can be minimized with the use of hearing aids (HA). AIM: To analyze the correlation between the prescribed grain and the insertion gain difference and with the results obtained regarding the benefit and satisfaction with the use of hearing aids in unilateral hearing impaired patients. MATERIALS AND METHODS: Prospective study with 15 subjects, mean age of 41.6 years, of both genders, users of hearing aids effectively. We used the International Questionnaire Results for hearing aids (International Outcome Inventory for Hearing Aids - IOI-HA), measured with a probe microphone. RESULTS: The mean values in the analyses of the IOI-HA per item were positive and higher than four points. In relation to the objective measures, the frequencies in which we obtained the gain values which were closer to the target were: 1K Hz, 2K Hz and 500 Hz, respectively. CONCLUSION: The satisfaction of individuals using hearing aid unilaterally is not completely correlated to the prescribed gain, because even if the target is not being reached in some frequencies, the individuals were pleased as to the use of their hearing aids.