Hearing Aid Distortion and Consonant Identification

1971 ◽  
Vol 14 (2) ◽  
pp. 323-331 ◽  
Author(s):  
Daniel L. Bode ◽  
Roger N. Kasten
Keyword(s):  
Frequency Response ◽  
High Frequency ◽  
Hearing Aid ◽  
Harmonic Distortion ◽  
Normal Hearing ◽  
Test Material ◽  
High Fidelity ◽  
Sensation Level ◽  
Experimental Conditions ◽  
High Frequency Response

An experiment was conducted with 34 normal-hearing listeners to determine the effects of distortion (generated by a single hearing aid) on consonant identification in noise. Five experimental conditions were employed in which measured harmonic distortion ranged from approximately 1% (high fidelity) to 35%. Each listening condition involved playback of recorded test material at a constant sensation level. Results showed that average consonant identification scores, relative to the high-fidelity condition, decreased 15–29% as a function of increased distortion. Initial consonants were discriminated best across all distortion conditions, and progressive increases in distortion tended to most affect final consonants. The data also suggested possible talker/hearing aid interactions. Reduced high-frequency response and altered speech-to-noise ratio, together with harmonic distortion, were postulated as mutually inclusive causes of the observed decrements in consonant differentiation.

Performance of Individual Hearing Aids Utilizing Microphone and Induction Coil Input

1971 ◽  
Vol 14 (2) ◽  
pp. 365-371 ◽  
Author(s):  
Richard J. Sung ◽  
William R. Hodgson
Keyword(s):  
Frequency Response ◽  
Hearing Aids ◽  
Speech Intelligibility ◽  
Hearing Aid ◽  
Harmonic Distortion ◽  
Physical Characteristics ◽  
Induction Coil ◽  
Body Type ◽  
High Frequency Response ◽  
Physical Measurements

Physical measurements of gain, maximum power output, frequency response, and harmonic distortion were made on each of two body-type hearing aids on both the microphone and induction coil settings. In addition, we investigated speech intelligibility through each aid, for both acoustic and magnetic input, using 32 normal-hearing subjects. Our findings indicated that different hearing aids provide different sensitivity for loop induction. For a given hearing aid, physical characteristics varied between the microphone and the telephone coil settings. The intelligibility of speech produced by a given mode of signal input, either microphone or telephone coil, was dependent on physical characteristics of the hearing aid. The usable high-frequency response and the configuration of the response curve in the region of 1500 to 3000 Hz appeared to be associated with the intelligibility of monosyllabic words.

scholarly journals Evaluation of Hearing Aid Frequency Response Fittings in Pediatric and Young Adult Bimodal Recipients

2015 ◽  
Vol 26 (04) ◽  
pp. 393-407 ◽  
Author(s):  
Lisa S. Davidson ◽  
Jill B. Firszt ◽  
Chris Brenner ◽  
Jamie H. Cadieux
Keyword(s):  
Young Adults ◽  
Word Recognition ◽  
Frequency Response ◽  
High Frequency ◽  
Outcome Measure ◽  
Hearing Aid ◽  
Sentence Recognition ◽  
High Frequency Response ◽  
Frequency Responses ◽  
Group Data

Background: A coordinated fitting of a cochlear implant (CI) and contralateral hearing aid (HA) for bimodal device use should emphasize balanced audibility and loudness across devices. However, guidelines for allocating frequency information to the CI and HA are not well established for the growing population of bimodal recipients. Purpose: The study aim was to compare the effects of three different HA frequency responses, when fitting a CI and an HA for bimodal use, on speech recognition and localization in children/young adults. Specifically, the three frequency responses were wideband, restricted high frequency, and nonlinear frequency compression (NLFC), which were compared with measures of word recognition in quiet, sentence recognition in noise, talker discrimination, and sound localization. Research Design: The HA frequency responses were evaluated using an A B1 A B2 test design: wideband frequency response (baseline-A), restricted high-frequency response (experimental-B1), and NLFC-activated (experimental-B 2 ). All participants were allowed 3–4 weeks between each test session for acclimatization to each new HA setting. Bimodal benefit was determined by comparing the bimodal score to the CI-alone score. Study Sample: Participants were 14 children and young adults (ages 7–21 yr) who were experienced users of bimodal devices. All had been unilaterally implanted with a Nucleus CI24 internal system and used either a Freedom or CP810 speech processor. All received a Phonak Naida IX UP behind-the-ear HA at the beginning of the study. Data Collection and Analysis: Group results for the three bimodal conditions (HA frequency response with wideband, restricted high frequency, and NLFC) on each outcome measure were analyzed using a repeated measures analysis of variance. Group results using the individual “best bimodal” score were analyzed and confirmed using a resampling procedure. Correlation analyses examined the effects of audibility (aided and unaided hearing) in each bimodal condition for each outcome measure. Individual data were analyzed for word recognition in quiet, sentence recognition in noise, and localization. Individual preference for the three bimodal conditions was also assessed. Results: Group data revealed no significant difference between the three bimodal conditions for word recognition in quiet, sentence recognition in noise, and talker discrimination. However, group data for the localization measure revealed that both wideband and NLFC resulted in significantly improved bimodal performance. The condition that yielded the “best bimodal” score varied across participants. Because of this individual variability, the “best bimodal” score was chosen for each participant to reassess group data within word recognition in quiet, sentence recognition in noise, and talker discrimination. This method revealed a bimodal benefit for word recognition in quiet after a randomization test was used to confirm significance. The majority of the participants preferred NLFC at the conclusion of the study, although a few preferred a restricted high-frequency response or reported no preference. Conclusions: These results support consideration of restricted high-frequency and NLFC HA responses in addition to traditional wideband response for bimodal device users.

High Frequency Response of Magnetization of Thin-Film Heads

1992 ◽  
Vol 7 (10) ◽  
pp. 773-778
Author(s):  
S. Narumi ◽  
S. Sudo ◽  
M. Aihara ◽  
H. Fukui
Keyword(s):  
Thin Film ◽  
Frequency Response ◽  
High Frequency ◽  
High Frequency Response

Fitting Frequency-Lowering Signal Processing Applying the American Academy of Audiology Pediatric Amplification Guideline: Updates and Protocols

2016 ◽  
Vol 27 (03) ◽  
pp. 219-236 ◽  
Author(s):  
Susan Scollie ◽  
Danielle Glista ◽  
Julie Seto ◽  
Andrea Dunn ◽  
Brittany Schuett ◽  
...  
Keyword(s):  
Signal Processing ◽  
Frequency Response ◽  
Hearing Aids ◽  
Hearing Aid ◽  
Fine Tuning ◽  
Sensation Level ◽  
Response Level ◽  
Strong Basis ◽  
Wide Range ◽  
Signal Processors

Background: Although guidelines for fitting hearing aids for children are well developed and have strong basis in evidence, specific protocols for fitting and verifying technologies can supplement such guidelines. One such technology is frequency-lowering signal processing. Children require access to a broad bandwidth of speech to detect and use all phonemes including female /s/. When access through conventional amplification is not possible, the use of frequency-lowering signal processing may be considered as a means to overcome limitations. Fitting and verification protocols are needed to better define candidacy determination and options for assessing and fine tuning frequency-lowering signal processing for individuals. Purpose: This work aims to (1) describe a set of calibrated phonemes that can be used to characterize the variation in different brands of frequency-lowering processors in hearing aids and the verification with these signals and (2) determine whether verification with these signal are predictive of perceptual changes associated with changes in the strength of frequency-lowering signal processing. Finally, we aimed to develop a fitting protocol for use in pediatric clinical practice. Study Sample: Study 1 used a sample of six hearing aids spanning four types of frequency lowering algorithms for an electroacoustic evaluation. Study 2 included 21 adults who had hearing loss (mean age 66 yr). Data Collection and Analysis: Simulated fricatives were designed to mimic the level and frequency shape of female fricatives extracted from two sources of speech. These signals were used to verify the frequency-lowering effects of four distinct types of frequency-lowering signal processors available in commercial hearing aids, and verification measures were compared to extracted fricatives made in a reference system. In a second study, the simulated fricatives were used within a probe microphone measurement system to verify a wide range of frequency compression settings in a commercial hearing aid, and 27 adult listeners were tested at each setting. The relation between the hearing aid verification measures and the listener’s ability to detect and discriminate between fricatives was examined. Results: Verification measures made with the simulated fricatives agreed to within 4 dB, on average, and tended to mimic the frequency response shape of fricatives presented in a running speech context. Some processors showed a greater aided response level for fricatives in running speech than fricatives presented in isolation. Results with listeners indicated that verified settings that provided a positive sensation level of /s/ and that maximized the frequency difference between /s/ and /∫/ tended to have the best performance. Conclusions: Frequency-lowering signal processors have measureable effects on the high-frequency fricative content of speech, particularly female /s/. It is possible to measure these effects either with a simple strategy that presents an isolated simulated fricative and measures the aided frequency response or with a more complex system that extracts fricatives from running speech. For some processors, a more accurate result may be achieved with a running speech system. In listeners, the aided frequency location and sensation level of fricatives may be helpful in predicting whether a specific hearing aid fitting, with or without frequency-lowering, will support access to the fricatives of speech.

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