A Patient-Centered, Provider-Facilitated Approach to the Refinement of Nonlinear Frequency Compression Parameters Based on Subjective Preference Ratings of Amplified Sound Quality

Purpose: To evaluate sound quality preferences of participants wearing hearing aids with different strengths of nonlinear frequency compression (NFC) processing versus no NFC processing. Two analysis methods, one without and one with a qualifier as to the magnitude of preferences, were compared for their percent agreement to differentiate a small difference in perceived sound quality as a result of applied NFC processing. Research Design: A single-blind design was used with participants unaware of the presence or strength of NFC processing (independent variable). The National Acoustic Laboratories-Nonlinear 2 (NAL-NL2) prescription of amplification was chosen because audibility is intentionally not prescribed in the presence of larger sensorineural hearing loss thresholds. A lack of prescribed audibility, when present, was deemed an objective qualifier for NFC. NFC is known to improve the input bandwidth available to listeners when high-frequency audibility is not otherwise available and increasing strengths of NFC were examined. Experimental condition 3 (EC3) was stronger than the manufacturer default (EC2). More aggressive strengths (e.g., EC4 and EC5), however, were expected to include excessive distortion and even reduce the output bandwidth that had been prescribed as audible by NAL-NL2 (EC1). Study Sample: A total of 14 male Veterans with severe high-frequency sensorineural hearing loss. Data Collection and Analysis: Participant sound quality preference ratings (dependent variable) without a qualifier as to the magnitude of preference were analyzed based on binomial probability theory, as is traditional with paired comparison data. The ratings with a qualifier as to the magnitude of preference were analyzed based on the nonparametric statistic of the Wilcoxon signed rank test. Results: The binomial probability analysis method identified a sound quality preference as well as the nonparametric probability test method. As the strength of NFC increased, more participants preferred the EC with less NFC. Fourteen of 14 participants showed equal preference between EC1 and EC2 perhaps, in part, because EC2 showed no objective improvement in audibility for six of the 14 participants (42%). Thirteen of the 14 participants showed no preference between NAL-NL2 and EC3, but all participants had an objective improvement in audibility. With more NFC than EC3, more and more participants preferred the other EC with less NFC in the paired comparison. Conclusions: By referencing the recommended sensation levels of amplitude compression (e.g., NAL-NL2) in the ear canal of hearing aid wearers, the targeting of NFC parameters can likely be optimized with respect to improvements in effective audibility that may contribute to speech recognition without adversely impacting sound quality. After targeting of NFC parameters, providers can facilitate decisions about the use of NFC parameters (strengths of processing) via sound quality preference judgments using paired comparisons.

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Speech Perception and Sound-Quality Rating with an Adaptive Nonlinear Frequency Compression Algorithm in Mandarin-Speaking Hearing Aid Users

Journal of the American Academy of Audiology ◽

10.1055/s-0040-1709450 ◽

2020 ◽

Vol 31 (08) ◽

pp. 590-598

Author(s):

Li Xu ◽

Solveig C. Voss ◽

Jing Yang ◽

Xianhui Wang ◽

Qian Lu ◽

...

Keyword(s):

Hearing Loss ◽

Hearing Aids ◽

Detection Threshold ◽

Sound Quality ◽

Hearing Impaired ◽

Nonlinear Frequency ◽

Frequency Compression ◽

Speech Reception ◽

Quality Ratings ◽

Phoneme Detection

Abstract Background Mandarin Chinese has a rich repertoire of high-frequency speech sounds. This may pose a remarkable challenge to hearing-impaired listeners who speak Mandarin Chinese because of their high-frequency sloping hearing loss. An adaptive nonlinear frequency compression (adaptive NLFC) algorithm has been implemented in contemporary hearing aids to alleviate the problem. Purpose The present study examined the performance of speech perception and sound-quality rating in Mandarin-speaking hearing-impaired listeners using hearing aids fitted with adaptive NLFC (i.e., SoundRecover2 or SR2) at different parameter settings. Research Design Hearing-impaired listeners' phoneme detection thresholds, speech reception thresholds, and sound-quality ratings were collected with various SR2 settings. Study Sample The participants included 15 Mandarin-speaking adults aged 32 to 84 years old who had symmetric sloping severe-to-profound sensorineural hearing loss. Intervention The participants were fitted bilaterally with Phonak Naida V90-SP hearing aids. Data Collection and Analysis The outcome measures included phoneme detection threshold using the Mandarin Phonak Phoneme Perception test, speech reception threshold using the Mandarin hearing in noise test (M-HINT), and sound-quality ratings on human speech in quiet and noise, bird chirps, and music in quiet. For each test, five experimental settings were applied and compared: SR2-off, SR2-weak, SR2-default, SR2-strong 1, and SR2-strong 2. Results The results showed that listeners performed significantly better with SR2-strong 1 and SR2-strong 2 settings than with SR2-off or SR2-weak settings for speech reception threshold and phoneme detection threshold. However, no significant improvement was observed in sound-quality ratings among different settings. Conclusions These preliminary findings suggested that the adaptive NLFC algorithm provides perceptual benefit to Mandarin-speaking people with severe-to-profound hearing loss.

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Effects of Adaptive Non-linear Frequency Compression in Hearing Aids on Mandarin Speech and Sound-Quality Perception

Frontiers in Neuroscience ◽

10.3389/fnins.2021.722970 ◽

2021 ◽

Vol 15 ◽

Author(s):

Shuang Qi ◽

Xueqing Chen ◽

Jing Yang ◽

Xianhui Wang ◽

Xin Tian ◽

...

Keyword(s):

Hearing Loss ◽

Sensorineural Hearing Loss ◽

Hearing Aids ◽

Sound Quality ◽

Compression Algorithm ◽

Frequency Compression ◽

Quality Perception ◽

Linear Frequency ◽

Sentence Recognition ◽

Non Linear

ObjectiveThis study was aimed at examining the effects of an adaptive non-linear frequency compression algorithm implemented in hearing aids (i.e., SoundRecover2, or SR2) at different parameter settings and auditory acclimatization on speech and sound-quality perception in native Mandarin-speaking adult listeners with sensorineural hearing loss.DesignData consisted of participants’ unaided and aided hearing thresholds, Mandarin consonant and vowel recognition in quiet, and sentence recognition in noise, as well as sound-quality ratings through five sessions in a 12-week period with three SR2 settings (i.e., SR2 off, SR2 default, and SR2 strong).Study SampleTwenty-nine native Mandarin-speaking adults aged 37–76 years old with symmetric sloping moderate-to-profound sensorineural hearing loss were recruited. They were all fitted bilaterally with Phonak Naida V90-SP BTE hearing aids with hard ear-molds.ResultsThe participants demonstrated a significant improvement of aided hearing in detecting high frequency sounds at 8 kHz. For consonant recognition and overall sound-quality rating, the participants performed significantly better with the SR2 default setting than the other two settings. No significant differences were found in vowel and sentence recognition among the three SR2 settings. Test session was a significant factor that contributed to the participants’ performance in all speech and sound-quality perception tests. Specifically, the participants benefited from a longer duration of hearing aid use.ConclusionFindings from this study suggested possible perceptual benefit from the adaptive non-linear frequency compression algorithm for native Mandarin-speaking adults with moderate-to-profound hearing loss. Periods of acclimatization should be taken for better performance in novel technologies in hearing aids.

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The Effect of Nonlinear Frequency Compression on Acoustic Change Complex Responses in High-Frequency Dead-Regioned Hearing Loss

Journal of the American Academy of Audiology ◽

10.1055/s-0041-1722948 ◽

2021 ◽

Author(s):

Ebru Kösemihal ◽

Ferda Akdas

Keyword(s):

Hearing Loss ◽

Hearing Aids ◽

High Frequency ◽

Normal Hearing ◽

Nonlinear Frequency ◽

Frequency Compression ◽

Frequency Information ◽

Cortical Level ◽

Significant Difference ◽

Acoustic Change Complex

Abstract Purpose The study is concern with the distinguishing of the stimuli containing high frequency information with the frequency compression feature at the cortical level using the acoustic change complex (ACC) and the comparison of such with the ACC answers of individuals with normal hearing. Research Design This is a case–control study. Study Sample Thirty adults (21 males and nine females) with normal hearing, ranging in age between 16 and 63 years (mean: 36.7 ± 12.9 years) and 20 adults (16 males and four females) with hearing loss ranging in age between 16 and 70 years (mean:49.0 ± 19.8 years) have been included in this study. Data Collection and Analysis A total of 1,000 ms long stimulus containing 500 and 4,000 Hz tonal stimuli was used for ACC recording. The start frequency (SF) and compression ratio (CR) parameters of the hearing aids were programmed according to the default settings (SFd, CRd) in the device software, the optimal setting (SFo, CRo), and the extra compression (SFe, CRe) requirements and ACC has been recorded for each condition. Evaluation has been performed according to P1-N1-P2 wave complex and ACC complex wave latencies. Independent samples t-test was used to test the significance of the differences between the groups. Results In all individuals ACC has been observed. There was a significant difference between the wave latencies in normal hearing- and hearing-impaired groups. All wave latency averages of the individuals with hearing impairment were longer than the individuals with normal hearing. There were statistically significant differences between SFd-SFo, SFd-SFe, and SFo-SFe parameters. But there was no difference between CRd, CRo, and CRe in terms of CRs. Conclusion In order to discriminate high frequency information at the cortical level we should not rely on default settings of the SF and CR of the hearing aids. Optimal bandwidth must be adjusted without performing insufficient compression or over-compression. ACC can be used besides the real ear measurement for hearing aid fitting.

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An Initial-Fit Comparison of Two Generic Hearing Aid Prescriptive Methods (NAL-NL2 and CAM2) to Individuals Having Mild to Moderately Severe High-Frequency Hearing Loss

Journal of the American Academy of Audiology ◽

10.3766/jaaa.24.2.7 ◽

2013 ◽

Vol 24 (02) ◽

pp. 138-150 ◽

Cited By ~ 1

Author(s):

Earl E. Johnson

Keyword(s):

Hearing Loss ◽

High Frequency ◽

Speech Intelligibility ◽

Paired Comparison ◽

Hearing Aid ◽

Sound Quality ◽

Individual Subject ◽

Model Calculations ◽

High Frequency Hearing Loss

Background: Johnson and Dillon (2011) provided a model-based comparison of current generic hearing aid prescriptive methods for adults with hearing loss based on the attributes of speech intelligibility, loudness, and bandwidth. Purpose: This study compared the National Acoustic Laboratories—Non-linear 2 (NAL-NL2) and Cambridge Method for Loudness Equalization 2—High-Frequency (CAM2) prescriptive methods using adult participants with less high-frequency hearing loss than Johnson and Dillon (2011). Of study interest was quantification of prescribed audibility, speech intelligibility, and loudness. The preferences of participants for either NAL-NL2 or CAM2 and preferred deviations from prescribed settings are also reported. Research Design: Using a single-blind, counter-balanced, randomized design, preference judgments for the prescriptive methods with regard to sound quality of speech and music stimuli were obtained. Preferred gain adjustments from the prescription within the 4–10 kHz frequency range were also obtained from each participant. Speech intelligibility and loudness model calculations were completed on the prescribed and adjusted amplification. Study Sample: Fourteen male Veterans, whose average age was 65 yr and whose hearing sensitivity averaged normal to borderline normal through 1000 Hz sloping to a moderately severe sensorineural loss, served as participants. Data Collection and Analysis: Following a brief listening time (˜10 min), typical of an initial fitting visit, the participants made paired comparison of sound quality between the NAL-NL2 and CAM2 prescriptive settings. Participants were also asked to modify each prescription in the range of 4–10 kHz using an overall gain control and make subsequent comparisons of sound quality preference between prescriptive and adjusted settings. Participant preferences were examined with respect to quantitative analysis of loudness modeling, speech intelligibility modeling, and measured high-frequency bandwidth audibility. Results: Consistent with the lack of difference in predicted speech intelligibility between the two prescriptions, sound quality preferences on the basis of clarity were split across participants while some participants did not have a discernable preference. Considering sound quality judgments of pleasantness, the majority of participants preferred the sound quality of the NAL-NL2 (8 of 14) prescription instead of the CAM2 prescription (2 of 14). Four of the 14 participants showed no preference on the basis of pleasantness for either prescription. Individual subject preferences were supported by loudness modeling that indicated NAL-NL2 was the softer of the two prescriptions and CAM2 was the louder. CAM2 did provide more audibility to the higher frequencies (5–8 kHz) than NAL-NL2. Participants turned the 4–10 kHz gain recommendation of CAM2 lower, on average, by a significant amount of 4 dB when making adjustments while no significant adjustment was made to the initial NAL-NL2 recommendation. Conclusions: NAL-NL2 prescribed gains were more often preferred at the initial fitting by the majority of participating veterans. For those patients with preference for a louder fitting than NAL-NL2, CAM2 is a good alternative. When the participant adjustment from the prescription between 4 and 10 kHz exceeded 4 dB from either NAL-NL2 (2 of 14) or CAM2 (11 of 14), the participants demonstrated a later preference for that adjustment 69% of the time. These findings are viewed as limited evidence that some individuals may have a preference for high-frequency gain that differs from the starting prescription.

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Evaluation of Nonlinear Frequency Compression for School-Age Children with Moderate to Moderately Severe Hearing Loss

Journal of the American Academy of Audiology ◽

10.3766/jaaa.21.10.2 ◽

2010 ◽

Vol 21 (10) ◽

pp. 618-628 ◽

Cited By ~ 44

Author(s):

Jace Wolfe ◽

Andrew John ◽

Erin Schafer ◽

Myriel Nyffeler ◽

Michael Boretzki ◽

...

Keyword(s):

Hearing Loss ◽

Speech Recognition ◽

Hearing Aids ◽

High Frequency ◽

Nonlinear Frequency ◽

Speech Sounds ◽

Severe Hearing Loss ◽

Frequency Compression ◽

Digital Hearing Aids ◽

Significant Difference

Background: Previous research has indicated that children with moderate hearing loss experience difficulty with recognition of high-frequency speech sounds, such as fricatives and affricates. Conventional behind-the-ear (BTE) amplification typically does not provide ample output in the high frequencies (4000 Hz and beyond) to ensure optimal audibility for these sounds. Purpose: To evaluate nonlinear frequency compression (NLFC) as a means to improve speech recognition for children with moderate to moderately severe hearing loss. Research Design: Within subject, crossover design with repeated measures across test conditions. Study Sample: Fifteen children, aged 5–13 yr, with moderate to moderately severe high-frequency sensorineural hearing loss were fitted with Phonak Nios, microsized, BTE hearing aids. These children were previous users of digital hearing aids and communicated via spoken language. Their speech and language abilities were age-appropriate. Data Collection and Analysis: Aided thresholds and speech recognition in quiet and in noise were assessed after 6 wk of use with NLFC and 6 wk of use without NLFC. Participants were randomly assigned to counter-balanced groups so that eight participants began the first 6 wk trial with NLFC enabled and the other seven participants started with NLFC disabled. Then, the provision of NLFC was switched for the second 6 wk trial. Speech recognition in quiet was assessed via word recognition assessments with the University of Western Ontario (UWO) Plural Test and recognition of vowel-consonant-vowel nonsense syllables with the Phonak Logatome test. Speech recognition in noise was assessed by evaluating the signal-to-noise ratio in dB for 50% correct performance on the Bamford-Kowal-Bench Speech-in-Noise (BKB-SIN) test, an adaptive test of speech perception in a multitalker babble background. Results: Aided thresholds for high-frequency stimuli were significantly better when NLFC was enabled, and use of NLFC resulted in significantly better speech recognition in quiet for the UWO Plural Test and for the phonemes /d/ and /s/ on the Phonak Logatome test. There was not a statistically significant difference in performance on the BKB-SIN test between the NLFC enabled and disabled conditions. Conclusions: These results indicate that NLFC improves audibility for and recognition of high-frequency speech sounds for children with moderate to moderately severe hearing loss in quiet listening situations.

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Evaluation of Wideband Frequency Responses and Nonlinear Frequency Compression for Children with Cookie-Bite Audiometric Configurations

Journal of the American Academy of Audiology ◽

10.3766/jaaa.25.10.10 ◽

2014 ◽

Vol 25 (10) ◽

pp. 1022-1033 ◽

Cited By ~ 8

Author(s):

Andrew John ◽

Jace Wolfe ◽

Susan Scollie ◽

Erin Schafer ◽

Mary Hudson ◽

...

Keyword(s):

Hearing Loss ◽

Speech Recognition ◽

Hearing Aids ◽

High Frequency ◽

Repeated Measures ◽

Nonsense Syllable ◽

Nonlinear Frequency ◽

Frequency Compression ◽

Sentence Recognition ◽

Phoneme Perception

Background: Previous research has suggested that use of nonlinear frequency compression (NLFC) can improve audibility for high-frequency sounds and speech recognition of children with moderate to profound high-frequency hearing loss. Furthermore, previous studies have generally found no detriment associated with the use of NLFC. However, there have been no published studies examining the effect of NLFC on the performance of children with cookie-bite audiometric configurations. For this configuration of hearing loss, frequency-lowering processing will likely move high-frequency sounds to a lower frequency range at which a greater degree of hearing loss exists. Purpose: The purpose of this study was to evaluate and compare the effects of wideband amplification and NLFC on high-frequency audibility and speech recognition of children with cookie-bite audiometric configurations. Research Design: This study consisted of a within-participant design with repeated measures across test conditions. Study Sample: Seven children, ages 6–13 yr, with cookie-bite audiometric configurations and normal hearing or mild hearing loss at 6000 and 8000 Hz, were recruited. Intervention: Participants were fitted with Phonak Nios S H2O III behind-the-ear hearing aids and Oticon Safari 300 behind-the-ear hearing aids. Data Collection: The participants were evaluated after three 4-to 6-wk intervals: (1) Phonak Nios S H2O III without NLFC, (2) Phonak Nios S H2O III with NLFC, and (3) Oticon Safari 300 with wideband frequency response extending to 8000 Hz. The order in which each technology was used was counterbalanced across participants. High-frequency audibility was evaluated by assessing aided thresholds (dB SPL) for warble tones and the high-frequency phonemes /sh/ and /s/. Speech recognition in quiet was measured with the University of Western Ontario (UWO) Plurals Test, the UWO Distinctive Features Difference (DFD) Test, and the Phoneme Perception Test vowel-consonant-vowel nonsense syllable test. Sentence recognition in noise was evaluated with the Bamford-Kowal-Bench Speech-In-Noise (BKB-SIN) Test. Analysis: Repeated-measures analyses of variance were used to analyze the data collected in this study. The results across the three different conditions were compared. Results: No difference in performance across conditions was observed for detection of high-frequency warble tones and the speech sounds /sh/ and /s/. No significant difference was seen across conditions for speech recognition in quiet when measured with the UWO Plurals Test, the UWO-DFD Test, and the Phoneme Perception Test vowel-consonant-vowel nonsense syllable test. Finally, there were also no differences across conditions on the BKB-SIN Test. Conclusions: These results suggest that NLFC does not degrade or improve audibility for and recognition of high-frequency speech sounds as well as sentence recognition in noise when compared with wideband amplification for children with cookie-bite audiometric configurations.

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