The relationship between age, acceptable noise level, and listening effort in middle-aged and older-aged individuals.

Objective: The purpose of the study was to evaluate listening effort in adults who experience varied annoyance towards noise. Materials and methods: Fifty native Kannada-speaking adults aged 41-68 years participated. We evaluated the participant's acceptable noise level while listening to speech. Further, a sentence-final word-identification and recall test at 0 dB SNR (less favorable condition) and 4 dB SNR (relatively favorable condition) was used to assess listening effort. The repeat and recall scores were obtained for each condition. Results: The regression model revealed that the listening effort increased by 0.6% at 0 dB SNR and by 0.5% at 4 dB SNR with every one-year advancement in age. Listening effort increased by 0.9% at 0 dB SNR and by 0.7% at 4 dB SNR with every one dB change in the value of Acceptable Noise Level (ANL). At 0 dB SNR and 4 dB SNR, a moderate and mild negative correlation was noted respectively between listening effort and annoyance towards noise when the factor age was controlled. Conclusion: Listening effort increases with age, and its effect is more in less favorable than in relatively favorable conditions. However, if the annoyance towards noise was controlled, the impact of age on listening effort was reduced. Listening effort correlated with the level of annoyance once the age effect was controlled. Furthermore, the listening effort was predicted from the ANL to a moderate degree.

Reasons for ceiling ratings in real-life evaluations of hearing aids: the relationship between SNR and hearing aid ratings.

Introduction: In past Ecological Momentary Assessment (EMA) studies, hearing aid outcome ratings have often been close to ceiling. Methods: To analyze the underlying reasons for the very positive ratings, we conducted a study with 17 experienced hearing aid wearers who were fitted with study hearing aids. The acceptable noise level and the noise level where participants were unable to follow speech were measured. The participants then rated hearing aid satisfaction, speech understanding and listening effort for pre-defined SNRs between -10 and +20 dB SPL in the laboratory. These ratings were compared to ratings of a two-week EMA trial. Additionally, estimates of SNRs were collected from hearing aids during the EMA trial and we assessed whether the participants experienced those SNRs rated poorly in the laboratory in real life. Results: The results showed that for hearing aid satisfaction and speech understanding, the full rating scale was used in the laboratory, while the ratings in real life were strongly skewed towards the positive end of the scale. In the laboratory, SNRs where participants indicated they could not follow the narrator ("unable to follow" noise level) were rated clearly better than the lowest possible ratings. This indicates that very negative ratings may not be applicable in real-life testing. The lower part of the distribution of real-life SNR estimates was related to participants' individual "unable to follow" noise levels and the SNRs which were rated poorly in the laboratory made up less than 10% of the speech situations experienced in real life. Discussion: This indicates that people do not seem to frequently experience listening situations at SNRs where they are dissatisfied with their hearing aids and this could be the reason for the overly positive hearing aid outcome ratings in EMA studies. It remains unclear to what extent the scarcity of such situations is due lack of encounters or intentional avoidance.

Performance of older normal-hearing listeners on the tracking of noise tolerance (TNT) test.

OBJECTIVE: To gather preliminary reference data on older normal-hearing (NH) adults for the refined Tracking of Noise Tolerance (TNT) test. DESIGN: Within-subject repeated measures. Participants were tested on the TNT in the sound-field and under headphones. In the sound-field, speech stimuli were presented at 75 dB SPL and 82 dB SPL from 0° with a speech-shaped noise presented either from 0° or 180° at a level controlled by the participants. The order of signal level, mode of presentation, noise azimuth, and TNT passages were counterbalanced across listeners. Testing was repeated for one condition after 1-3 weeks to estimate within-session and between-session reliability. STUDY SAMPLE: Twenty-five NH listeners (51-82 yrs of age). RESULTS: Mean TNT scores (TNTAve) were about 4 dB at a speech input of 75 dB SPL and 3 dB at 82 dB SPL. The TNTAve was similar between the headphone and sound-field presentations in the co-located noise. TNTAve scores measured with noise-back were about 1 dB better than those measured from the front. The 95% confidence intervals of absolute test-retest differences were about 1.2 dB within-session and 2.0 dB between sessions. CONCLUSIONS: The refined TNT may be a reliable tool to measure noise acceptance and subjective speech intelligibility.

[Correlation between Mandarin acceptable noise level and cortical auditory evoked potential in young normal-hearing listeners].

Objective:To investigate the correlation between Mandarin acceptable noise level （M-ANL） and cortical auditory evoked potential （CAEP）, and to explore the possible mechanism leading to individual differences in M-ANL values. Methods:Thirty listeners aged 22-33 years with normal hearing were selected as the study subjects, and the M-ANL test and CAEP test were performed respectively. The most comfortable level （MCL）, maximum background noise level （BNL）, M-ANL and CAEP values of each subject were recorded. The latency of each wave of P1, N1, P2, N2, P300 and the amplitude of P1-N1, P2-N2, P300 in CAEP were recorded for each subject. SPSS 25.0 was used for statistical analysis to explore the correlation between the MCL value, BNL value and M-ANL values and the latency of P1, N1, P2, N2, P300 and P1-N1, P2-N2, P300 amplitudes of CAEP. Results:①The MCL value and M-ANL value were positively correlated with the P2 latency of CAEP, and the correlation coefficients were 0.404 and 0.400, respectively, and the differences were statistically significant （P<0.05）. There was no correlation with P1, N1, N2, and P300 latencies of CAEP （P>0.05）. ②The MCL value, BNL value and M-ANL value had no significant difference with the CAEP wave amplitudes of P1-N1, P2-N2, and P300 （P>0.05）. Conclusion:There was a certain correlation between M-ANL and CAEP in young adults with normal hearing, suggesting that the central auditory cortex might play a potential regulatory role in the background noise tolerance. Individuals with a greater background noise acceptance might have stronger central efferent mechanisms and/or less active central afferent mechanisms.

Effect of adaptive beamforming and noise reduction algorithms on speech intelligibility and noise tolerance in bimodal cochlear implant users.

OBJECTIVE: To evaluate the effect of a directional microphone (beamformer) and continuous noise reduction algorithms (CNRs) in bimodally aided cochlear implant (CI) users and to find the optimum hearing aid (HA) and CI settings of the beamformer and CNRs. METHODS: Speech reception threshold (SRT) and acceptable noise level (ANL) were assessed in twelve adult CI users for unilateral CI, unilateral HA and bimodal listening. To assess the effect of the UltraZoom beamformer and the ClearVoice™ and NoiseBlock CNRs on SRT and ANL, speech was presented from the front in multi-source speech-shaped noise. RESULTS: With unilateral CI, application of UltraZoom resulted in a significant improvement of the median SRT and ANL by 3.8 and 4.3 dB, respectively. For bimodal listening with UltraZoom, a significant improvement of 3.5 dB in median SRT was found. There was no significant effect of using the CNRs on speech intelligibility in noise or noise tolerance in either listening condition. CONCLUSION: UltraZoom should be applied on the CI to improve speech intelligibility in face to face conversations with multi-source background noise. However, due to the heterogeneous data, no recommendations for the settings of UltraZoom on the HA or of ClearVoice/NoiseBlock on either device can be given. TRIAL REGISTRATION: German Clinical Trials Register identifier: DRKS00010807.

Subjective criteria underlying noise-tolerance in the presence of speech.

OBJECTIVE: The objective was to determine the relative contribution of four criteria (loudness, annoyance, distraction, speech interference) to participants' noise-tolerance thresholds (NTT). DESIGN: While listening to speech in noise set at the highest signal-to-noise ratio at which noise became unacceptable (noise tolerance threshold), participants completed paired-comparison judgments of loudness, annoyance, distraction, and speech interference to determine the noise domain(s) that were most important in their noise tolerance judgments. Participants also completed absolute ratings of the noise using the same noise domains, which were combined with the paired comparison data for analysis. STUDY SAMPLE: Sixty-three adults with normal hearing participated. RESULTS: For the entire group, speech interference and distraction were the largest contributors to noise tolerance. A cluster analysis indicated three distinct groups: criteria were dominated by either annoyance (33%); distraction (48%), or speech interference (19%). Significant differences in NTT among the groups revealed the highest mean NTT for the annoyance group and lowest NTT for the speech interference group. CONCLUSION: The majority of participants based NTTs on criteria related to the noise itself (annoyance or distraction) and had greater noise sensitivity than the smaller group of participants who focused more on speech intelligibility in the noise.

The relation of hearing-specific patient-reported outcome measures with speech perception measures and acceptable noise levels in cochlear implant users.

Objective: To investigate the relation of a hearing-specific patient-reported outcome measure (PROM) with speech perception and noise tolerance measurements. It was hypothesised that speech intelligibility in noise and noise tolerance may explain a larger part of the variance in PROM scores than speech intelligibility in quiet.Design: This cross-sectional study used the Speech, Spatial, Qualities (SSQ) questionnaire as a PROM. Speech recognition in quiet, the Speech Reception Threshold in noise and noise tolerance as measured with the acceptable noise level (ANL) were measured with sentences.Study sample: A group of 48 unilateral post-lingual deafened cochlear implant (CI) users.Results: SSQ scores were moderately correlated with speech scores in quiet and noise, and also with ANLs. Speech scores in quiet and noise were strongly correlated. The combination of speech scores and ANL explained 10-30% of the variances in SSQ scores, with ANLs adding only 0-9%.Conclusions: The variance in the SSQ as hearing-specific PROM in CI users was not better explained by speech intelligibility in noise than by speech intelligibility in quiet, because of the remarkably strong correlation between both measures. ANLs made only a small contribution to explain the variance of the SSQ. ANLs seem to measure other aspects than the SSQ.

Preferences for digital noise reduction and microphone mode settings in hearing-impaired listeners with low and high tolerances for background noise.

Objective: To examine whether people with low and high acceptable noise levels (ANLs) have different preferences for aggressiveness of noise reduction (NR) and microphone mode, and whether they get different noise tolerance benefit with these two features.Design: Participants completed laboratory tests of unaided ANL and aided modified ANLs (with speech fixed at two levels) and preferences (at two SNRs) while listening to four levels of NR, three microphone modes and four combinations of NR/directionality.Study sample: Twenty adults with hearing loss; 10 with low ANLs and 10 with high ANLs.Results: Seven individuals with low ANLs and 10 individuals with high ANLs preferred the maximum NR setting; the remaining three individuals with low ANLs had inconsistent preference for NR. Eight people in each ANL group preferred the maximum directional setting (broadband (BB) directionality), the remaining two people in each group had inconsistent preferences for microphone mode.Conclusions: Because most participants preferred the maximum NR and directionality settings, ANLs could not be used to differentially prescribe these hearing aid settings.

Top-Down Auditory Plasticity: Acceptable Noise Level Predicts and Reflects the Effect of Perceptual Learning in Experience-Induced Plasticity.

OBJECTIVE: In the auditory system, tinnitus and superior speech perception in noise are examples of negative and positive plasticity that can result from sensory neural hearing loss and life experiences dealing with more complex stimuli and learning, respectively. The main objective of this study was to determine the relationship between acceptable noise level (ANL) values and perceptual learning in individuals exposed to unavoidable occupational noise. MATERIALS & METHODS: Here we document a form of plasticity in top-down auditory pathways through the measurement of the acceptable noise level in 60 adults, 27 females and 33 males, with normal hearing (Amiraalam state Hospital, Tehran, Iran 2016). Individuals were assigned to one of two groups: those with and without the occupational experience of speech perception in noise. RESULTS: The test group had statistically significant lower acceptable noise level and significantly higher background noise level scores compared with the control group. CONCLUSION: Using acceptable noise level, we attributed differences in individuals' abilities to tolerate varying amounts of background noise and speech perception in noise function to the auditory efferent system. Working in crowded locations due to job nature can influence differences in speech perception in noise function.

Efficacy of a Hearing Aid Noise Reduction Function.

Noise reduction systems have been implemented in hearing aids to improve signal-to-noise ratio and listening comfort. The aim of this study was to evaluate the efficacy of hearing aid noise reduction for Mandarin speakers. The results showed a significant improvement in acceptable noise levels and speech reception thresholds with noise reduction turned on. Sound quality ratings also suggested that most listeners preferred having noise reduction turned on for listening effort, listening comfort, speech clarity, and overall sound quality. These results suggest that the noise reduction system used in this study might improve sentence perception in steady-state noise, noise tolerance, and sound quality, although not all listeners preferred aggressive noise reduction. However, due to large interindividual variation, clinical application of the results should be on an individual basis.

The Effects of Hearing Aid Digital Noise Reduction and Directionality on Acceptable Noise Level.

OBJECTIVES: Two main digital signal processing technologies inside the modern hearing aid to provide the best conditions for hearing aid users are directionality (DIR) and digital noise reduction (DNR) algorithms. There are various possible settings for these algorithms. The present study evaluates the effects of various DIR and DNR conditions (both separately and in combination) on listening comfort among hearing aid users. METHODS: In 18 participants who received hearing aid fitting services from the Rehabilitation School of Shahid Beheshti University of Medical Sciences regularly, we applied acceptable noise level (ANL) as our subjective measure of listening comfort. We evaluated both of these under six different hearing aid conditions: omnidirectional-baseline, omnidirectional-broadband DNR, omnidirectional-multichannel DNR, directional, directional-broadband DNR, and directional-multichannel DNR. RESULTS: The ANL results ranged from -3 dB to 14 dB in all conditions. The results show, among all conditions, both the omnidirectional-baseline condition and the omnidirectional-broadband DNR condition are the worst conditions for listening in noise. The DIR always reduces the amount of noise that patients received during testing. The DNR algorithm does not improve listening in noise significantly when compared with the DIR algorithms. Although both DNR and DIR algorithms yielded a lower ANL, the DIR algorithm was more effective than the DNR. CONCLUSION: The DIR and DNR technologies provide listening comfort in the presence of noise. Thus, user benefit depends on how the digital signal processing settings inside the hearing aid are adjusted.

The Acceptable Noise Level Benefit From Directionality for Listeners With Severe Hearing Loss.

OBJECTIVES: Directional microphone technology can enhance the speech intelligibility and listening comfort of listeners with hearing impairment. The main aim of this study is to investigate and compare the benefit derived by listeners with severe hearing loss from directional microphone technology with that derived by listeners with moderate hearing loss. METHODS: The acceptable noise levels (ANLs) of two groups of listeners with moderate or severe hearing impairment (17 subjects in each group) were measured under unaided, omnidirectional-baseline-aided, and directional-aided conditions. RESULTS: Although the absolute ANL of the listeners in the severe hearing loss group was significantly higher than that of the listeners in the moderate hearing loss group, their derived benefit was equivalent to that derived by the listeners in the moderate hearing loss group. ANL and hearing loss degree were significantly related. Specifically, the ANL increased with the severity of hearing loss. CONCLUSION: Directional microphone technology can provide the benefits of listening comfort to listeners with severe hearing loss.

Effects of a transient noise reduction algorithm on speech intelligibility in noise, noise tolerance and perceived annoyance in cochlear implant users.

OBJECTIVE: To evaluate the validity and efficacy of a transient noise reduction algorithm (TNR) in cochlear implant processing and the interaction of TNR with a continuous noise reduction algorithm (CNR). DESIGN: We studied the effects of TNR and CNR on the perception of realistic sound samples with transients, using subjective ratings of annoyance, a speech-in-noise test and a noise tolerance test. STUDY SAMPLE: Participants were 16 experienced cochlear implant recipients wearing an Advanced Bionics Naida Q70 processor. RESULTS: CI users rated sounds with transients as moderately annoying. Annoyance was slightly, but significantly reduced by TNR. Transients caused a large decrease in speech intelligibility in noise and a moderate decrease in noise tolerance, measured on the Acceptable Noise Level test. The TNR had no significant effect on noise tolerance or on speech intelligibility in noise. The combined application of TNR and CNR did not result in interactions. CONCLUSIONS: The TNR algorithm was effective in reducing annoyance from transient sounds, but was not able to prevent a decreasing effect of transients on speech understanding in noise and noise tolerance. TNR did not reduce the beneficial effect of CNR on speech intelligibility in noise, but no cumulated improvement was found either.

Optimising the effect of noise reduction algorithm ClearVoice in cochlear implant users by increasing the maximum comfort levels.

OBJECTIVE: ClearVoice is a single-microphone noise reduction algorithm in Advanced Bionics cochlear implant(CI) systems with the aim to improve performance in background noise. The present study investigated a hypothesised increased effect of ClearVoice if combined with a structural increase of maximum comfort stimulation levels (M-levels) in the CI fitting. DESIGN: We tested performance with ClearVoice (Medium) in four conditions, defined by combined settings of ClearVoice off/on and with/without 5% increase of M-levels. The main outcome measures were the Acceptable Noise Level (ANL) and the speech reception threshold in continuous background noise (SRTn). STUDY SAMPLE: Participants were 16 experienced cochlear implant recipients with Advanced Bionics implants and a Naida Q70 processor. RESULTS: The ANL significantly improved by using either ClearVoice or an increase of M-levels. Combining both settings gave the largest improvement in ANL. For the SRTn, we found a small, but significant interaction between ClearVoice and an increase of M-levels, implying that ClearVoice improved speech understanding slightly, but only if combined with a 5% increase of M-levels. CONCLUSIONS: Optimal profit from ClearVoice is obtained if combined with a structural 5% increase of M-levels.

The Acceptable Noise Level Benefit From Directionality for Listeners With Severe Hearing Loss

OBJECTIVES: Directional microphone technology can enhance the speech intelligibility and listening comfort of listeners with hearing impairment. The main aim of this study is to investigate and compare the benefit derived by listeners with severe hearing loss from directional microphone technology with that derived by listeners with moderate hearing loss. METHODS: The acceptable noise levels (ANLs) of two groups of listeners with moderate or severe hearing impairment (17 subjects in each group) were measured under unaided, omnidirectional-baseline-aided, and directional-aided conditions. RESULTS: Although the absolute ANL of the listeners in the severe hearing loss group was significantly higher than that of the listeners in the moderate hearing loss group, their derived benefit was equivalent to that derived by the listeners in the moderate hearing loss group. ANL and hearing loss degree were significantly related. Specifically, the ANL increased with the severity of hearing loss. CONCLUSION: Directional microphone technology can provide the benefits of listening comfort to listeners with severe hearing loss.

The Effects of Hearing Aid Digital Noise Reduction and Directionality on Acceptable Noise Level

OBJECTIVES: Two main digital signal processing technologies inside the modern hearing aid to provide the best conditions for hearing aid users are directionality (DIR) and digital noise reduction (DNR) algorithms. There are various possible settings for these algorithms. The present study evaluates the effects of various DIR and DNR conditions (both separately and in combination) on listening comfort among hearing aid users. METHODS: In 18 participants who received hearing aid fitting services from the Rehabilitation School of Shahid Beheshti University of Medical Sciences regularly, we applied acceptable noise level (ANL) as our subjective measure of listening comfort. We evaluated both of these under six different hearing aid conditions: omnidirectional-baseline, omnidirectional-broadband DNR, omnidirectional-multichannel DNR, directional, directional-broadband DNR, and directional-multichannel DNR. RESULTS: The ANL results ranged from −3 dB to 14 dB in all conditions. The results show, among all conditions, both the omnidirectional-baseline condition and the omnidirectional-broadband DNR condition are the worst conditions for listening in noise. The DIR always reduces the amount of noise that patients received during testing. The DNR algorithm does not improve listening in noise significantly when compared with the DIR algorithms. Although both DNR and DIR algorithms yielded a lower ANL, the DIR algorithm was more effective than the DNR. CONCLUSION: The DIR and DNR technologies provide listening comfort in the presence of noise. Thus, user benefit depends on how the digital signal processing settings inside the hearing aid are adjusted.

Application of International Speech Test Signal on Acceptable Noise Level Test in Mandarin Adults with Normal Hearing / 听力学及言语疾病杂志

Objective To study the use of the international speech test signal(ISTS) on acceptable noise level (ANL)test in Mandarin adults.Methods The Mandarin test materials and ISTS were used as test materials.The ANL test was performed on 40 normal hearing adults.For each case,the most comfortable loudness(MCL)and background noise level(BNL)were obtained.MCL minus BNL equal to ANL.Results The values of ANL under the Mandarin test materials and ISTS test materials were 39.31±6.97 and 41.85±7.60 dB HL,respectively.The values of BNL were 37.59±8.45 and 39.27±8.66 dB HL,respectively.The values of ANL were 1.53±5.61 and 2.45±5.58 dB,respectively in 40 normal hearing adults.There was no significant difference in the MCL,BNL and ANL between the test materials of Mandarin and ISTS (P＞ 0.05).Conclusion International speech test signal (ISTS) can be used on ANL test in Mandarin adults with normal hearing.

Encoding of speech sounds at auditory brainstem level in good and poor hearing aid performers / Codificação dos sons da fala no nível do tronco encefálico auditivo em bons e maususuários de aparelhos auditivos

Abstract Introduction: Hearing aids are prescribed to alleviate loss of audibility. It has been reported that about 31% of hearing aid users reject their own hearing aid because of annoyance towards background noise. The reason for dissatisfaction can be located anywhere from the hearing aid microphone till the integrity of neurons along the auditory pathway. Objectives: To measure spectra from the output of hearing aid at the ear canal level and frequency following response recorded at the auditory brainstem from individuals with hearing impairment. Methods: A total of sixty participants having moderate sensorineural hearing impairment with age range from 15 to 65 years were involved. Each participant was classified as either Good or Poor Hearing aid Performers based on acceptable noise level measure. Stimuli /da/ and /si/ were presented through loudspeaker at 65 dB SPL. At the ear canal, the spectra were measured in the unaided and aided conditions. At auditory brainstem, frequency following response were recorded to the same stimuli from the participants. Results: Spectrum measured in each condition at ear canal was same in good hearing aid performers and poor hearing aid performers. At brainstem level, better F0 encoding; F0 and F1 energies were significantly higher in good hearing aid performers than in poor hearing aid performers. Though the hearing aid spectra were almost same between good hearing aid performers and poor hearing aid performers, subtle physiological variations exist at the auditory brainstem. Conclusion: The result of the present study suggests that neural encoding of speech sound at the brainstem level might be mediated distinctly in good hearing aid performers from that of poor hearing aid performers. Thus, it can be inferred that subtle physiological changes are evident at the auditory brainstem in a person who is willing to accept noise from those who are not willing to accept noise.

Resumo Introdução: Os aparelhos auditivos são prescritos para aliviar a perda de audibilidade. Tem sido relatado que 31% dos usuários rejeitam seu aparelho auditivo devido ao desconforto com o ruído de fundo. A razão para a insatisfação pode estar situada em qualquer local desde o microfone do aparelho auditivo até a integridade de neurônios ao longo da via auditiva. Objetivos: Medir espectros desde a saída do aparelho auditivo no nível do meato acústico externo e frequência de resposta (FFR) registrada no tronco encefálico de indivíduos com deficiência auditiva. Método: Foram selecionados 60 participantes com deficiência auditiva neurossensorial moderada, de 15 a 65 anos. Cada participante foi classificado como usuário bom ou mau de prótese auditiva (GHP ou PHP) com base na medida de nível de ruído aceitável (ANL). Estímulos/da/e/si/foram apresentados em alto-falante a 65 dB SPL. No meato acústico externo, os espectros foram medidos nas condições sem aparelho e com aparelho. No tronco encefálico auditivo, FFR foram registradas para os mesmos estímulos dos participantes. Resultados: Os espectros medidos em cada condição no meato acústico externo foram os mesmos em GHP e PHP. No nível do tronco cerebral, melhor codificação F0; energias de F0 e F1 foram significativamente maiores em GHP do que em PHP. Embora os espectros do aparelho auditivo fossem quase os mesmos entre GHP e PHP, existem variações fisiológicas sutis no tronco encefálico auditivo. Conclusão: O resultado do presente estudo sugere que a codificação neural do som da fala no nível do tronco encefálico pode ser mediada distintamente em GHP em comparação com PHP. Assim, pode-se inferir que mudanças fisiológicas sutis são evidentes no tronco encefálico em uma pessoa que está disposta a aceitar o ruído em comparação com aqueles que não estão dispostos a aceitar o ruído.

Encoding of speech sounds at auditory brainstem level in good and poor hearing aid performers.

INTRODUCTION: Hearing aids are prescribed to alleviate loss of audibility. It has been reported that about 31% of hearing aid users reject their own hearing aid because of annoyance towards background noise. The reason for dissatisfaction can be located anywhere from the hearing aid microphone till the integrity of neurons along the auditory pathway. OBJECTIVES: To measure spectra from the output of hearing aid at the ear canal level and frequency following response recorded at the auditory brainstem from individuals with hearing impairment. METHODS: A total of sixty participants having moderate sensorineural hearing impairment with age range from 15 to 65 years were involved. Each participant was classified as either Good or Poor Hearing aid Performers based on acceptable noise level measure. Stimuli /da/ and /si/ were presented through loudspeaker at 65dB SPL. At the ear canal, the spectra were measured in the unaided and aided conditions. At auditory brainstem, frequency following response were recorded to the same stimuli from the participants. RESULTS: Spectrum measured in each condition at ear canal was same in good hearing aid performers and poor hearing aid performers. At brainstem level, better F0 encoding; F0 and F1 energies were significantly higher in good hearing aid performers than in poor hearing aid performers. Though the hearing aid spectra were almost same between good hearing aid performers and poor hearing aid performers, subtle physiological variations exist at the auditory brainstem. CONCLUSION: The result of the present study suggests that neural encoding of speech sound at the brainstem level might be mediated distinctly in good hearing aid performers from that of poor hearing aid performers. Thus, it can be inferred that subtle physiological changes are evident at the auditory brainstem in a person who is willing to accept noise from those who are not willing to accept noise.

The Use of Acceptable Noise Level on Monaural and Binaural Amplification in Hearing Aids Fitting / 听力学及言语疾病杂志

Objective To compare the relationship of acceptable noise level (ANL) between monaural and binaural hearing aid in patients with bilateral moderate-to-severe hearing loss, and to investigate the clinical significance of the ANL in binaural hearing aid fitting and the predictive role in the hearing aid effect assessment.Methods A total of 15 patients with bilateral moderate-to-severe hearing loss were selected, and the most comfortable levels (MCL), background noise level (BNL) and calculate ANL were tested, respectively, in 4 conditions: without hearing aids, fitted only left ears, fitted only right ears and binaural fitting.Results The ANL in 15 subjects measured at 4 conditions were 18.87±5.26, 12.60±2.47, 12.00±2.90, and 5.13±1.25 dB S/N, respectively.The MCLs were 80.40±9.28, 63.73±5.15, 62.27±5.36, and 61.80±6.05 dB HL, respectively.The BNLs were 61.67±6.14, 51.13±3.94, 50.27±4.50, and 56.67±5.16 dB HL.The ANL difference between the only left and right fitting groups was not statistically significant(P>0.05).The ANL difference between the monaural or the binaural hearing aid group and without hearing aids group were statistically significant (P<0.05), respectively.Compared with the monaural hearing aid group, the binaural hearing aid group had significantly lower ANL(P<0.05).Conclusion For people with bilateral hearing loss, hearing aids can improve their ability to manage the background noise, and binaural hearing aid fitting is better than monaural.