Effect of Maximum Power Output and Noise Reduction on Speech Recognition in Noise

2011 ◽  
Vol 22 (05) ◽  
pp. 265-273 ◽  
Author(s):  
Francis Kuk ◽  
Heidi Peeters ◽  
Chi Lau ◽  
Petri Korhonen
Keyword(s):  
Noise Reduction ◽  
Hearing Aids ◽  
Power Output ◽  
Noise Level ◽  
Repeated Measures ◽  
Speech Intelligibility ◽  
Hearing Aid ◽  
Maximum Power ◽  
Maximum Power Output ◽  
Bonferroni Adjustment

Background: The maximum power output (MPO) of a hearing aid was typically discussed in the context of avoiding loudness discomfort. However, an MPO that is too low, as in the cases to avoid discomfort for people with a severe loudness tolerance problem and hearing losses that exceed the fitting range of the hearing aids, could negatively affect sound quality and speech intelligibility in noise. Purpose: The current study was designed to demonstrate the degradation in speech intelligibility in noise on the HINT (Hearing in Noise Test) when the MPO of the wearers' hearing aids was lowered by 10 dB from the default. The interactions with noise reduction (NR) algorithms (classic [NR-classic] and Speech Enhancer [NR-SE]) were also examined. Research Design: A single-blinded, factorial repeated-measures design was used to study the effect of noise input level (68 dBC, 75 dBC), MPO setting (default and default-10), and NR algorithm (off, classic, SE) on HINT performance. Study Sample: Eleven adults with a severe sensorineural hearing loss participated. Intervention: Participants were fit with the Widex m4-19 behind-the-ear hearing aids binaurally in the default frequency response and MPO settings. The hearing aids were adjusted to six MPO (default, default-10) by NR (off, classic, SE conditions). Testing was completed within one 2 hr session. Data Collection and Analysis: The RTS (reception threshold for speech) for 50% correct on the HINT was measured in each of the six hearing aid conditions at two input levels (68 and 75 dBC) with speech and noise stimuli presented from the front. Repeated-measures ANOVAs were conducted using SPSS software to examine significant differences. Results: A repeated-measures ANOVA showed that noise level was not significant while NR algorithm and MPO were significant. The interaction between noise level and NR algorithm was also significant. Post hoc analysis with Bonferroni adjustment for the effect of NR algorithm showed that performance with NR-off was significantly poorer than performance with NR-classic and NR-SE (p < 0.05). However, NR-classic and NR-SE were not significantly different from each other (p > 0.05). Conclusions: An MPO that was 10 dB lower than the default could negatively affect the signal-to-noise ratio (SNR) of the listening environment. However, NR could compensate for the degradation in SNR.

Performance Improvement of Digital Hearing Aid Systems

2015 ◽  
Vol 1 ◽  
pp. 27
Author(s):  
Isiaka Ajewale Alimi
Keyword(s):  
Noise Reduction ◽  
Hearing Aids ◽  
Digital Signal Processor ◽  
Speech Intelligibility ◽  
Communication Systems ◽  
Hearing Aid ◽  
Spectral Subtraction ◽  
Residual Spectrum ◽  
Digital Hearing Aids ◽  
Digital Hearing Aid

Digital hearing aids addresses the issues of noise and speech intelligibility that is associated with the analogue types. One of the main functions of the digital signal processor (DSP) of digital hearing aid systems is noise reduction which can be achieved by speech enhancement algorithms which in turn improve system performance and flexibility. However, studies have shown that the quality of experience (QoE) with some of the current hearing aids is not up to expectation in a noisy environment due to interfering sound, background noise and reverberation. It is also suggested that noise reduction features of the DSP can be further improved accordingly. Recently, we proposed an adaptive spectral subtraction algorithm to enhance the performance of communication systems and address the issue of associated musical noise generated by the conventional spectral subtraction algorithm. The effectiveness of the algorithm has been confirmed by different objective and subjective evaluations. In this study, an adaptive spectral subtraction algorithm is implemented using the noise-estimation algorithm for highly non-stationary noisy environments instead of the voice activity detection (VAD) employed in our previous work due to its effectiveness. Also, signal to residual spectrum ratio (SR) is implemented in order to control the amplification distortion for speech intelligibility improvement. The results show that the proposed scheme gives comparatively better performance and can be easily employed in digital hearing aid system for improving speech quality and intelligibility.

scholarly journals Sentence Recognition in Noise and Perceived Benefit of Noise Reduction on the Receiver and Transmitter Sides of a BICROS Hearing Aid

2013 ◽  
Vol 24 (10) ◽  
pp. 980-991 ◽  
Author(s):  
Kristi Oeding ◽  
Michael Valente
Keyword(s):  
Noise Reduction ◽  
Hearing Aids ◽  
Repeated Measures ◽  
Background Noise ◽  
Signal To Noise Ratio ◽  
Hearing Aid ◽  
Directional Microphones ◽  
Sentence Recognition ◽  
Clinically Significant ◽  
The Impact

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.

Effects of a Transient Noise Reduction Algorithm on Speech Understanding, Subjective Preference, and Preferred Gain

2013 ◽  
Vol 24 (09) ◽  
pp. 845-858 ◽  
Author(s):  
Petri Korhonen ◽  
Francis Kuk ◽  
Chi Lau ◽  
Denise Keenan ◽  
Jennifer Schumacher ◽  
...  
Keyword(s):  
Noise Reduction ◽  
Hearing Aids ◽  
Repeated Measures ◽  
Speech Intelligibility ◽  
Repeated Measures Design ◽  
Subjective Preference ◽  
Listening Environments ◽  
Speech Identification ◽  
Noise Reduction Algorithm ◽  
Phoneme Identification

Background: Today's compression hearing aids with noise reduction systems may not manage transient noises effectively because of the short duration of these sounds compared to the onset times of the compressors and/or noise reduction algorithms. Purpose: The current study was designed to evaluate the effect of a transient noise reduction (TNR) algorithm on listening comfort, speech intelligibility in quiet, and preferred wearer gain in the presence of transients. Research Design: A single-blinded, repeated-measures design was used. Study Sample: Thirteen experienced hearing aid users with bilaterally symmetrical (≤7.5 dB) sensorineural hearing loss participated in the study. Results: Speech identification in quiet (no transient noise) was identical between the TNR On and the TNR Off conditions. The participants showed subjective preference for the TNR algorithm when “comfortable listening” was used as the criterion. Participants preferred less gain than the default prescription in the presence of transient noise sounds. However, the preferred gain was 2.9 dB higher when the TNR was activated than when it was deactivated. This translated to 12.1% improvement in phoneme identification over the TNR Off condition for soft speech. Conclusions: This study demonstrated that the use of the TNR algorithm would not negatively affect speech identification. The results also suggested that this algorithm may improve listening comfort in the presence of transient noise sounds and ensure consistent use of prescribed gain. Such an algorithm may ensure more consistent audibility across listening environments.

scholarly journals Relation Between Suitable Maximum Power output (MPO) of Hearing Aids and Unconfatable Loudness Level (UCL).

1993 ◽  
Vol 36 (1) ◽  
pp. 42-47
Author(s):  
Shinichi Okada ◽  
Kumi Ishii ◽  
Yuji Ase ◽  
Takashi Arai ◽  
Masami Usami
Keyword(s):  
Hearing Aids ◽  
Power Output ◽  
Maximum Power ◽  
Maximum Power Output ◽  
Loudness Level

Prescriptive Amplification Recommendations for Hearing Losses with a Conductive Component and Their Impact on the Required Maximum Power Output: An Update with Accompanying Clinical Explanation

2013 ◽  
Vol 24 (06) ◽  
pp. 452-460 ◽  
Author(s):  
Earl E. Johnson
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Compression Ratio ◽  
Hearing Aids ◽  
Power Output ◽  
Hearing Aid ◽  
Bone Conduction ◽  
Sensorineural Hearing ◽  
Maximum Power Output ◽  
Conductive Component

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.

scholarly journals Detection, Speech Recognition, Loudness, and Preference Outcomes With a Direct Drive Hearing Aid: Effects of Bandwidth

2021 ◽  
Vol 25 ◽  
pp. 233121652199913
Author(s):  
Paula Folkeard ◽  
Maaike Van Eeckhoutte ◽  
Suzanne Levy ◽  
Drew Dundas ◽  
Parvaneh Abbasalipour ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Hearing Aids ◽  
Repeated Measures ◽  
Speech Intelligibility ◽  
Hearing Aid ◽  
Outcome Measurement ◽  
Direct Drive ◽  
Hearing Devices ◽  
Within Subjects ◽  
Study Participants

Direct drive hearing devices, which deliver a signal directly to the middle ear by vibrating the tympanic membrane via a lens placed in contact with the umbo, are designed to provide an extension of audible bandwidth, but there are few studies of the effects of these devices on preference, speech intelligibility, and loudness. The current study is the first to compare aided speech understanding between narrow and extended bandwidth conditions for listeners with hearing loss while fitted with a direct drive hearing aid system. The study also explored the effect of bandwidth on loudness perception and investigated subjective preference for bandwidth. Fifteen adult hearing aid users with symmetrical sensorineural hearing loss participated in a prospective, within-subjects, randomized single-blind repeated-measures study. Participants wore the direct drive hearing aids for 4 to 15 weeks (average 6 weeks) prior to outcome measurement. Outcome measures were completed in various bandwidth conditions achieved by reducing the gain of the device above 5000 Hz or by filtering the stimuli. Aided detection thresholds provided evidence of amplification to 10000 Hz. A significant improvement was found in high-frequency consonant detection and recognition, as well as for speech in noise performance in the full versus narrow bandwidth conditions. Subjective loudness ratings increased with provision of the full bandwidth available; however, real-world trials showed most participants were able to wear the full bandwidth hearing aids with only small adjustments to the prescription method. The majority of participants had either no preference or a preference for the full bandwidth setting.

Using the Repeat-Recall Test to Examine Factors Affecting Context Use

2021 ◽  
Author(s):  
Francis Kuk ◽  
Christopher Slugocki ◽  
Petri Korhonen
Keyword(s):  
Noise Reduction ◽  
Hearing Aids ◽  
Speech Processing ◽  
Repeated Measures ◽  
Recall Test ◽  
Outcome Measure ◽  
Hearing Aid ◽  
Listening Effort ◽  
Double Blind ◽  
Repeated Measures Design

Abstract Background The effect of context on speech processing has been studied using different speech materials and response criteria. The Repeat-Recall Test (RRT) evaluates listener performance using high context (HC) and low context (LC) sentences; this may offer another platform for studying context use (CU). Objective This article aims to evaluate if the RRT may be used to study how different signal-to-noise ratios (SNRs), hearing aid technologies (directional microphone and noise reduction), and listener working memory capacities (WMCs) interact to affect CU on the different measures of the RRT. Design Double-blind, within-subject repeated measures design. Study Sample Nineteen listeners with a mild-to-moderately severe hearing loss. Data Collection The RRT was administered with participants wearing the study hearing aids under two microphone (omnidirectional vs. directional) by two noise reduction (on vs. off) conditions. Speech was presented from 0 degree at 75 dB sound pressure level and a continuous speech-shaped noise from 180 degrees at SNRs of 0, 5, 10, and 15 dB. The order of SNR and hearing aid conditions was counterbalanced across listeners. Each test condition was completed twice in two 2-hour sessions separated by 1 month. Results CU was calculated as the difference between HC and LC sentence scores for each outcome measure (i.e., repeat, recall, listening effort, and tolerable time). For all outcome measures, repeated measures analyses of variance revealed that CU was significantly affected by the SNR of the test conditions. For repeat, recall, and listening effort measures, these effects were qualified by significant two-way interactions between SNR and microphone mode. In addition, the WMC group significantly affected CU during recall and rating of listening effort, the latter of which was qualified by an interaction between the WMC group and SNR. Listener WMC affected CU on estimates of tolerable time as qualified by significant two-way interactions between SNR and microphone mode. Conclusion The study supports use of the RRT as a tool for measuring how listeners use sentence context to aid in speech processing. The degree to which context influenced scores on each outcome measure of the RRT was found to depend on complex interactions between the SNR of the listening environment, hearing aid features, and the WMC of the listeners.

scholarly journals The Effect of Digital Noise Reduction on Annoyance and Speech Perception in Low and High Acceptable Noise Level Groups

2019 ◽  
Vol 23 (04) ◽  
pp. e433-e439
Author(s):  
Hemanth Narayan Shetty ◽  
Navya Bilijagalemole Nanjundaswamy
Keyword(s):  
Speech Perception ◽  
Noise Reduction ◽  
Hearing Aids ◽  
Noise Level ◽  
Signal To Noise Ratio ◽  
Hearing Aid ◽  
Strong Negative Correlation ◽  
Acceptable Noise Level ◽  
Group A ◽  
Hearing Aid Benefit

Introduction Studies have reported that although speech perception in noise was unaltered with and without digital noise reduction (DNR), the annoyance toward noise measured by acceptable noise level (ANL) was significantly improved by DNR with the range between 2.5 and 4.5 dB. It is unclear whether a similar improvement would be observed in those individuals who have an ANL ≥ 14 dB (predictive of poor hearing aid user) often rejects their aid because of annoyance toward noise. Objectives (a) To determine the effect of activation of DNR on the improvement in the aided ANL from low- and high-ANL groups; and (b) to predict the change in ANL when DNR was activated. Method Ten bilateral mild to severe sloping sensorineural hearing loss (SNHL) participants in each of the low- and high-ANL groups were involved. These participants were bilaterally fitted with receiver in canal (RIC) hearing aids (Oticon, Smorum, Egedal, Denmark) with a DNR processor. Both SNR-50% (Signal to noise ratio (in dB) required to achieve 50 % speech recognition) and ANL were assessed in DNR-on and DNR-off listening conditions. Results Digital noise reduction has no effect on SNR-50 in each group. The annoyance level was significantly reduced in the DNR-on than DNR-off condition in the low-ANL group. In the high-ANL group, a strong negative correlation was observed between the ANL in DNR off and a change in ANL after DNR was employed in the hearing aid (benefit). The benefit of DNR on annoyance can be effectively predicted by baseline-aided ANL by linear regression. Conclusion Digital noise reduction reduced the annoyance level in the high-ANL group, and the amount of improvement was related to the baseline-aided ANL value.

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