Directional Processing and Noise Reduction in Hearing Aids: Individual and Situational Influences on Preferred Setting

2016 ◽  
Vol 27 (08) ◽  
pp. 628-646 ◽  
Author(s):  
Tobias Neher ◽  
Kirsten C. Wagener ◽  
Rosa-Linde Fischer

Background: A better understanding of individual differences in hearing aid (HA) outcome is a prerequisite for more personalized HA fittings. Currently, knowledge of how different user factors relate to response to directional processing (DIR) and noise reduction (NR) is sparse. Purpose: To extend a recent study linking preference for DIR and NR to pure-tone average hearing thresholds (PTA) and cognitive factors by investigating if (1) equivalent links exist for different types of DIR and NR, (2) self-reported noise sensitivity and personality can account for additional variability in preferred DIR and NR settings, and (3) spatial target speech configuration interacts with individual DIR preference. Research Design: Using a correlational study design, overall preference for different combinations of DIR and NR programmed into a commercial HA was assessed in a complex speech-in-noise situation and related to PTA, cognitive function, and different personality traits. Study Sample: Sixty experienced HA users aged 60–82 yr with controlled variation in PTA and working memory capacity took part in this study. All of them had participated in the earlier study, as part of which they were tested on a measure of “executive control” tapping into cognitive functions such as working memory, mental flexibility, and selective attention. Data Collection and Analysis: Six HA settings based on unilateral (within-device) or bilateral (across-device) DIR combined with inactive, moderate, or strong single-microphone NR were programmed into a pair of behind-the-ear HAs together with individually prescribed amplification. Overall preference was assessed using a free-field simulation of a busy cafeteria situation with either a single frontal talker or two talkers at ±30° azimuth as the target speech. In addition, two questionnaires targeting noise sensitivity and the “Big Five” personality traits were administered. Data were analyzed using multiple regression analyses and repeated-measures analyses of variance with a focus on potential interactions between the HA settings and user factors. Results: Consistent with the earlier study, preferred HA setting was related to PTA and executive control. However, effects were weaker this time. Noise sensitivity and personality did not interact with HA settings. As expected, spatial target speech configuration influenced preference, with bilateral and unilateral DIR “winning” in the single- and two-talker scenario, respectively. In general, participants with higher PTA tended to more strongly prefer bilateral DIR than participants with lower PTA. Conclusions: Although the current study lends some support to the view that PTA and cognitive factors affect preferred DIR and NR setting, it also indicates that these effects can vary across noise management technologies. To facilitate more personalized HA fittings, future research should investigate the source of this variability.

2013 ◽  
Vol 24 (10) ◽  
pp. 980-991 ◽  
Author(s):  
Kristi Oeding ◽  
Michael Valente

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.


2013 ◽  
Vol 24 (08) ◽  
pp. 649-659 ◽  
Author(s):  
Kristy Jones Lowery ◽  
Patrick N. Plyler

Background: Directional microphones (D-Mics) and digital noise reduction (DNR) algorithms are used in hearing aids to reduce the negative effects of background noise on performance. Directional microphones attenuate sounds arriving from anywhere other than the front of the listener while DNR attenuates sounds with physical characteristics of noise. Although both noise reduction technologies are currently available in hearing aids, it is unclear if the use of these technologies in isolation or together affects acceptance of noise and/or preference for the end user when used in various types of background noise. Purpose: The purpose of the research was to determine the effects of D-Mic, DNR, or the combination of D-Mic and DNR on acceptance of noise and preference when listening in various types of background noise. Research Design: An experimental study in which subjects were exposed to a repeated measures design was utilized. Study Sample: Thirty adult listeners with mild sloping to moderately severe sensorineural hearing loss participated (mean age 67 yr). Data Collection and Analysis: Acceptable noise levels (ANLs) were obtained using no noise reduction technologies, D-Mic only, DNR only, and the combination of the two technologies (Combo) for three different background noises (single-talker speech, speech-shaped noise, and multitalker babble) for each listener. In addition, preference rankings of the noise reduction technologies were obtained within each background noise (1 = best, 3 = worst). Results: ANL values were significantly better for each noise reduction technology than baseline; and benefit increased significantly from DNR to D-Mic to Combo. Listeners with higher (worse) baseline ANLs received more benefit from noise reduction technologies than listeners with lower (better) baseline ANLs. Neither ANL values nor ANL benefit values were significantly affected by background noise type; however, ANL benefit with D-Mic and Combo was similar when speech-like noise was present while ANL benefit was greatest for Combo when speech spectrum noise was present. Listeners preferred the hearing aid settings that resulted in the best ANL value. Conclusion: Noise reduction technologies improved ANL for each noise type, and the amount of improvement was related to the baseline ANL value. Improving an ANL with noise reduction technologies is noticeable to listeners, at least when examined in this laboratory setting, and listeners prefer noise reduction technologies that improved their ability to accept noise.


2013 ◽  
Vol 24 (09) ◽  
pp. 845-858 ◽  
Author(s):  
Petri Korhonen ◽  
Francis Kuk ◽  
Chi Lau ◽  
Denise Keenan ◽  
Jennifer Schumacher ◽  
...  

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.


2011 ◽  
Vol 22 (05) ◽  
pp. 265-273 ◽  
Author(s):  
Francis Kuk ◽  
Heidi Peeters ◽  
Chi Lau ◽  
Petri Korhonen

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.


Author(s):  
Francis Kuk ◽  
Christopher Slugocki ◽  
Petri Korhonen

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.


2020 ◽  
Vol 31 (04) ◽  
pp. 262-270
Author(s):  
Francis Kuk ◽  
Christopher Slugocki ◽  
Petri Korhonen

Abstract Background Many studies on the efficacy of directional microphones (DIRMs) and noise-reduction (NR) algorithms were not conducted under realistic signal-to-noise ratio (SNR) conditions. A Repeat-Recall Test (RRT) was developed previously to partially address this issue. Purpose This study evaluated whether the RRT could provide a more comprehensive understanding of the efficacy of a DIRM and NR algorithm under realistic SNRs. Possible interaction with listener working memory capacity (WMC) was assessed. Research Design This study uses a double-blind, within-subject repeated measures design. Study Sample Nineteen listeners with a moderate degree of hearing loss participated. Data Collection and Analysis The RRT was administered with participants wearing the study hearing aids (HAs) under two microphones (omnidirectional versus directional) by two NR (on versus off) conditions. Speech was presented from 0° at 75 dB SPL and a continuous noise from 180° at SNRs of 0, 5, 10, and 15 dB. The order of SNR and HA conditions was counterbalanced across listeners. Each test condition was completed twice in two 2-hour sessions separated by one month. Results The recall scores of listeners were used to group listeners into good and poor WMC groups. Analysis using linear mixed-effects models revealed significant effects of context, SNR, and microphone for all four measures (repeat, recall, listening effort, and tolerable time). NR was only significant on the listening effort scale in the DIRM mode at an SNR of 5 dB. Listeners with good WMC performed better on all measures of the RRT and benefitted more from context. Although DIRM benefitted listeners with good and poor WMC, the benefits differed by context and SNR. Conclusions The RRT confirmed the efficacy of DIRM and NR on several outcome measures under realistic SNRs. It also highlighted interactions between WMC and sentence context on feature efficacy.


2013 ◽  
Author(s):  
Kathryn Arehart ◽  
Pamela Souza ◽  
Thomas Lunner ◽  
Michael Syskind Pedersen ◽  
James Kates

2013 ◽  
Vol 133 (5) ◽  
pp. 3382-3382 ◽  
Author(s):  
Kathryn Arehart ◽  
Pamela Souza ◽  
Thomas Lunner ◽  
Michael Syskind Pedersen ◽  
James M. Kates

2019 ◽  
Vol 30 (02) ◽  
pp. 103-114
Author(s):  
Patrick N. Plyler ◽  
Brittney Tardy ◽  
Mark Hedrick

AbstractNonlinear frequency compression (NLFC) and digital noise reduction (DNR) are hearing aid features often used simultaneously in the adult population with hearing loss. Although each feature has been studied extensively in isolation, the effects of using them in combination are unclear.The effects of NLFC and DNR in noise on word recognition and satisfaction ratings in noise in adult hearing aid users were evaluated.A repeated measures design was used.Two females and 13 males between the ages of 55 and 83 yr who were experienced hearing aid users participated. Thirteen were experienced with NLFC and all were experienced with DNR. Each participant was fit with Phonak Bolero Q90-P hearing instruments using their specific audiometric data and the Desired Sensation Level v5.0 (adult) fitting strategy. Fittings were verified with probe microphone measurements using speech at 65-dB sound pressure level (SPL). NLFC verification was performed using the Protocol for the Provision of Amplification, Version 2014.01.All testing was conducted in a double-walled sound booth. Four hearing aid conditions were used for all testing: Baseline (NLFC off, DNR off), NLFC only, DNR only, and Combination (NLFC on, DNR on). A modified version of the Pascoe’s High-Frequency Word List was presented at 65-dB SPL with speech spectrum noise at 6-dB signal-to-noise ratio (SNR) and 1-dB SNR for each hearing aid condition. Listener satisfaction ratings were obtained after each listening condition in terms of word comfort, word clarity, and average satisfaction. Two-way repeated measures analyses of variance were conducted to assess listener performance. Pairwise comparisons were then completed for significant main effects.Word recognition results indicated a significant SNR effect only (6 dB SNR > 1 dB SNR). Satisfaction ratings results indicated a significant SNR and hearing aid condition effect for clarity, comfort, and average satisfaction. Clarity ratings were significantly higher for DNR and Combination than NLFC. Comfort ratings were significantly higher for DNR than NLFC. Average satisfaction was significantly higher for DNR and Combination than for NLFC. Also, average ratings were significantly higher for Combination than Baseline.Activating NLFC or DNR in isolation or in combination did not significantly impact word recognition in noise. Activating NLFC in isolation reduced satisfaction ratings relative to the DNR or Combination conditions. The isolated use of DNR significantly improved all satisfaction ratings when compared with the isolated use of NLFC. These findings suggest NLFC should not be used in isolation and should be coupled with DNR for best results. Future research should include a field trial as this was a limitation of the study.


1988 ◽  
Vol 31 (2) ◽  
pp. 156-165 ◽  
Author(s):  
P. A. Busby ◽  
Y. C. Tong ◽  
G. M. Clark

The identification of consonants in a/-C-/a/nonsense syllables, using a fourteen-alternative forced-choice procedure, was examined in 4 profoundly hearing-impaired children under five conditions: audition alone using hearing aids in free-field (A),vision alone (V), auditory-visual using hearing aids in free-field (AV1), auditory-visual with linear amplification (AV2), and auditory-visual with syllabic compression (AV3). In the AV2 and AV3 conditions, acoustic signals were binaurally presented by magnetic or acoustic coupling to the subjects' hearing aids. The syllabic compressor had a compression ratio of 10:1, and attack and release times were 1.2 ms and 60 ms. The confusion matrices were subjected to two analysis methods: hierarchical clustering and information transmission analysis using articulatory features. The same general conclusions were drawn on the basis of results obtained from either analysis method. The results indicated better performance in the V condition than in the A condition. In the three AV conditions, the subjects predominately combined the acoustic parameter of voicing with the visual signal. No consistent differences were recorded across the three AV conditions. Syllabic compression did not, therefore, appear to have a significant influence on AV perception for these children. A high degree of subject variability was recorded for the A and three AV conditions, but not for the V condition.


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