Comparison of Multichannel Wide Dynamic Range Compression and ChannelFree Processing Strategies on Consonant Recognition

2015 ◽  
Vol 26 (07) ◽  
pp. 607-614 ◽  
Author(s):  
Patrick Plyler ◽  
Mark Hedrick ◽  
Brittany Rinehart ◽  
Rebekah Tripp
Keyword(s):  
Hearing Aids ◽  
Repeated Measures ◽  
Dynamic Range ◽  
Hearing Aid ◽  
Previous Experience ◽  
Wide Dynamic Range ◽  
Dynamic Range Compression ◽  
Processing Strategies ◽  
Hearing Aid Use ◽  
Subjective Preference

Background: Both wide dynamic range compression (WDRC) and ChannelFree (CF) processing strategies in hearing aids were designed to improve listener comfort and consonant identification, yet few studies have actually compared them. Purpose: To determine whether CF processing provides equal or better consonant identification and subjective preference than WDRC. Research Design: A repeated-measures randomized design was used in which each participant identified consonants from prerecorded nonsense vowel–consonant–vowel syllables in three conditions: unaided, aided using CF processing, and aided using WDRC processing. For each of the three conditions, syllables were presented in quiet and in a speech-noise background. Participants were also asked to rate the two processing schemes according to overall preference, preference in quiet and noise, and sound quality. Study Sample: Twenty adults (seven females; mean age 69.7 yr) with ≥1 yr of hearing aid use participated. Ten participants had previous experience wearing aids with WDRC, and 10 had previous experience with CF processing. Participants were tested with both WDRC and CF processing. Data Collection and Analysis: Number of consonants correct were measured and used as the dependent variable in analyses of variance with subsequent post hoc testing. For subjective preference, a listener rating form was employed with subsequent χ2 analysis. Results: Overall results showed that signal-processing strategy did not significantly affect consonant identification or subjective preference, nor did previous hearing aid use influence results. Listeners with audiometric slopes exceeding 11 dB per octave, however, preferred CF processing and performed better in noise with CF processing. Conclusion: CF processing is a viable alternative to WDRC for listeners with more severely sloping audiometric contours.

Comparison of Multichannel Wide Dynamic Range Compression and ChannelFree Processing in Open Canal Hearing Instruments

2013 ◽  
Vol 24 (02) ◽  
pp. 126-137 ◽  
Author(s):  
Patrick N. Plyler ◽  
Monika Bertges Reber ◽  
Amanda Kovach ◽  
Elisabeth Galloway ◽  
Elizabeth Humphrey
Keyword(s):  
Signal Processing ◽  
Hearing Loss ◽  
Hearing Aids ◽  
Repeated Measures ◽  
Dynamic Range ◽  
Wide Dynamic Range ◽  
Repeated Measures Design ◽  
Dynamic Range Compression ◽  
Processing Strategies ◽  
Hearing Instruments

Background: Multichannel wide dynamic range compression (WDRC) and ChannelFree processing have similar goals yet differ significantly in terms of signal processing. Multichannel WDRC devices divide the input signal into separate frequency bands; a separate level is determined within each frequency band; and compression in each band is based on the level within each band. ChannelFree processing detects the wideband level, and gain adjustments are based on the wideband signal level and adjusted up to 20,000 times per second. Although both signal processing strategies are currently available in hearing aids, it is unclear if differences in these signal processing strategies affect the performance and/or preference of the end user. Purpose: The purpose of the research was to determine the effects of multichannel wide dynamic range compression and ChannelFree processing on performance and/or preference of listeners using open-canal hearing instruments. Research Design: An experimental study in which subjects were exposed to a repeated measures design was utilized. Study Sample: Fourteen adult listeners with mild sloping to moderately severe sensorineural hearing loss participated (mean age 67 yr). Data Collection and Analysis: Participants completed two 5 wk trial periods for each signal processing strategy. Probe microphone, behavioral and subjective measures were conducted unaided and aided at the end of each trial period. Results: Behavioral and subjective results for both signal processing strategies were significantly better than unaided results; however, behavioral and subjective results were not significantly different between the signal processing strategies. Conclusions: Multichannel WDRC and ChannelFree processing are both effective signal processing strategies that provide significant benefit for hearing instrument users. Overall preference between the strategies may be related to the degree of hearing loss of the user, high-frequency in-situ levels, and/or acceptance of background noise.

scholarly journals Modeling and Predicting Hearing Aid Outcome

2003 ◽  
Vol 7 (2) ◽  
pp. 41-75 ◽  
Author(s):  
Larry E. Humes
Keyword(s):  
Factor Analysis ◽  
Individual Differences ◽  
Outcome Measures ◽  
Hearing Aids ◽  
Dynamic Range ◽  
Single Channel ◽  
Hearing Aid ◽  
Wide Dynamic Range ◽  
Dynamic Range Compression ◽  
Hearing Aid Use

Following a brief tutorial on the application of factor analysis to hearing aid outcome measures, three studies of hearing aid outcome measures in elderly adults are presented and analyzed. Two of the studies were completed at Indiana University (IU-1 and IU-2), and one was a collaborative multisite study by the Veterans Administration and the National Institute of Deafness and other Communication Disorders (NIDCD/VA). IU-1 measured hearing aid outcome in 173 elderly wearers of single-channel, linear, in-the-ear hearing aids with output-limiting compression, whereas IU-2 obtained the same extensive set of outcome measures from 53 elderly wearers of two-channel, wide-dynamic-range compression, in-the-canal hearing aids. In the NIDCD/VA study, 333 to 338 participants wore three single-channel circuits in succession, with each circuit housed within an in-the-ear shell. The three circuits included in that study and in this analysis were: (1) linear with peak clipping, (2) linear with output-limiting compression, and (3) single-channel, wide-dynamic-range compression. Evaluation of the many outcome measures completed in each study using principal components factor analysis revealed that from three (both IU studies) to five (NIDCD/VA study) principal components captured the individual differences in hearing aid outcome. This was independent of hearing aid type (in-the-ear or in-the-canal) and circuitry. Subsequent multiple regression analyses of individual differences in performance along each dimension of hearing aid outcome revealed that these individual differences could be accounted for reasonably well by various prefit variables for some dimensions of outcome, but not others. In general, measures of speech recognition performance were well accounted for by prefit measures, with the best predictors being hearing loss, cognitive performance, and age. Measures of hearing aid usage were less well accounted for by prefit measures, with the most accurate predictor of current hearing aid use being prior hearing aid use. The outcome dimension accounted for most poorly was that associated with hearing aid satisfaction, with subjective measures of aided sound quality being the best predictor of performance along this dimension of hearing aid outcome. Additional multicenter, large-scale studies are needed to develop more complete models of hearing aid outcome and to identify the variables that influence various aspects of hearing aid outcome. It is only through this additional research that it will be possible to optimize outcome for hearing aid wearers.

A Comparison of the Aided Performance and Benefit Provided by a Linear and a Two-Channel Wide Dynamic Range Compression Hearing Aid

1999 ◽  
Vol 42 (1) ◽  
pp. 65-79 ◽  
Author(s):  
Larry E. Humes ◽  
Laurel Christensen ◽  
Tara Thomas ◽  
Fred H. Bess ◽  
Andrea Hedley-Williams ◽  
...  
Keyword(s):  
Outcome Measures ◽  
Hearing Aids ◽  
Dynamic Range ◽  
Hearing Aid ◽  
Self Report ◽  
Volume Control ◽  
Listening Effort ◽  
Wide Dynamic Range ◽  
Dynamic Range Compression ◽  
Monosyllabic Words

The aided performance and benefit achieved with linear and two-channel wide dynamic range compression (WDRC) in-the-canal (ITC) hearing aids were established in 55 individuals. Study participants had been wearing either linear or adaptive-frequency-response (Bass Increase at Low Levels, BILL) ITC hearing aids for approximately one year before participation in this study. Outcome measures included aided performance and objective benefit in quiet and noise at a variety of speech levels (50, 60, and 75 dB SPL), at various levels of babble background (quiet, signal-to-babble ratios of +5 and +10 dB), and for various types of test materials (monosyllabic words and sentences in connected speech). Several subjective measures of aided performance (sound-quality judgments and magnitude estimates of listening effort) and relative benefit (improvement in listening effort and the Hearing Aid Performance Inventory, HAPI) were also obtained. Finally, self-report measures of hearing-aid use were also obtained using daily logs. Participants completed all outcome measures for the linear ITC hearing aids first, following 2 months of usage, and then repeated all outcome measures for the WDRC instruments after a subsequent 2-month period of use. In general, although both types of hearing aids demonstrated significant benefit, the results indicated that the WDRC instruments were superior to the linear devices for many of the outcome measures. This tended to be the case most frequently when low speech levels were used. Many of the performance differences between devices most likely can be ascribed to differences in gain, and prescriptive approaches (DSL[i/o] vs. NAL-R), for the fixed volume control testing performed in this study.

Loudness and Satisfaction Ratings for Hearing Aid Users

2009 ◽  
Vol 20 (04) ◽  
pp. 272-282 ◽  
Author(s):  
Peter J. Blamey ◽  
Lois F.A. Martin
Keyword(s):  
Hearing Aids ◽  
Dynamic Range ◽  
Hearing Aid ◽  
Strong Relationship ◽  
Impaired Hearing ◽  
Soft Or ◽  
Wide Dynamic Range ◽  
Dynamic Range Compression ◽  
Hearing Thresholds ◽  
Comfortable Loudness

Background: Hearing aids amplify low-intensity sounds to make them audible while keeping high-intensity sounds at an acceptable loudness for listeners with impaired hearing. Purpose: The purpose of this analysis was to assess loudness and satisfaction at the same time using a combined loudness and satisfaction questionnaire to rate 18 everyday environmental sounds. Research Design: Ten sets of data from four studies, covering three conditions, were analyzed. The three conditions were unaided, wide dynamic range compression (WDRC), and adaptive dynamic range optimization (ADRO®). In total, there were 61 subjects giving over 3,000 pairs of ratings for loudness and satisfaction. Results: The analysis found a strong relationship between loudness and satisfaction ratings for this set of listeners and conditions. The maximum satisfaction ratings corresponded to sounds with “comfortable” loudness ratings. Satisfaction was lowest for sounds that were “uncomfortably loud.” Sounds that were very soft or inaudible also received low satisfaction ratings unless the sounds were expected to be soft, such as the sound of one's own breathing. Conclusions: Hearing aid fittings that place most sounds at a comfortable level are likely to be more satisfactory than hearing aid fittings that produce more sounds close to hearing thresholds or discomfort levels. Aided conditions gave higher loudness and satisfaction ratings than the unaided condition, and the ADRO hearing aids gave significantly higher satisfaction ratings than the WDRC hearing aids.

Effect of a Single-Channel Wide Dynamic Range Compression Circuit on Perception of Stop Consonant Place of Articulation

2000 ◽  
Vol 43 (5) ◽  
pp. 1174-1184 ◽  
Author(s):  
Mark S. Hedrick ◽  
Tracie Rice
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Dynamic Range ◽  
Single Channel ◽  
Hearing Aid ◽  
Category Boundary ◽  
Frequency Region ◽  
Wide Dynamic Range ◽  
Place Of Articulation ◽  
Dynamic Range Compression

Previous studies have shown that altering the amplitude of a consonant in a specific frequency region relative to an adjacent vowel's amplitude in the same frequency region will affect listeners' perception of the consonant place of articulation. Hearing aids with single-channel, fast-acting wide dynamic range compression (WDRC) alter the overall consonant-vowel (CV) intensity ratio by increasing consonant energy. Perhaps one reason WDRC has had limited success in improving speech recognition performance is that the natural amplitude balances between consonant and vowel are altered in crucial frequency regions, thus disturbing the aforementioned amplitude cue for determining place of articulation. The current study investigated the effect of a WDRC circuit on listeners' perception of place of articulation when the relative amplitude of consonant and vowel was manipulated. The stimuli were a continuum of synthetic CV syllables stripped of all place cues except relative consonant amplitudes. Acoustic analysis of the CVs before and after hearing aid processing showed a predictable increase in high-frequency energy, particularly for the burst of the consonant. Alveolar bursts had more high-frequency energy than labial bursts. Twenty-five listeners with normal hearing and 5 listeners with sensorineural hearing loss labeled the consonant sound of the CV syllables in unaided form and after the syllables were recorded through a hearing aid with single-channel WDRC. There were significantly more listeners who were unable to produce a category boundary when labeling the aided stimuli. Of those listeners who did yield a category boundary for both aided and unaided stimuli, there were significantly more alveolar responses for the aided condition. These results can be explained by the acoustic analyses of the aided stimuli.

Speech and Music Quality Ratings for Linear and Nonlinear Hearing Aid Circuitry

2007 ◽  
Vol 18 (08) ◽  
pp. 688-699 ◽  
Author(s):  
Evelyn Davies-Venn ◽  
Pamela Souza ◽  
David Fabry
Keyword(s):  
Hearing Aids ◽  
Dynamic Range ◽  
Hearing Aid ◽  
Significant Preference ◽  
Wide Dynamic Range ◽  
Dynamic Range Compression ◽  
Quality Ratings ◽  
Linear And Nonlinear ◽  
Moderate Hearing Loss

This study evaluated quality ratings for speech and music stimuli processed using peak clipping (PC), compression limiting (CL), and wide-dynamic range compression (WDRC) hearing aid circuitry. Eighteen listeners with mild-to-moderate hearing loss were binaurally fitted with behind-the-ear (BTE) hearing aids and instructed to rate the quality of speech under various conditions in quiet and noise and two genres of music. Results for speech revealed a slight preference for WDRC at 80 dB SPL, and equivalent ratings for the three circuits under all other listening conditions. Music ratings revealed a marginally significant preference for WDRC and a preference for classical over popular music. For music, judgments on pleasantness were the most influential on overall circuit preference. Este estudio evalúa estimaciones de calidad para estímulos de lenguaje y música procesados usando corte de picos (PC), limitación de la compresión (CL) y compresión de rango dinámico amplio (WDRC) en los circuitos del auxiliar auditivo. Dieciocho sujetos con hipoacusia leve a moderada fueron adaptados binauralmente con auxiliares auditivos retroauriculares (BTE) e instruidos para juzgar la calidad del lenguaje bajo varias condiciones de silencio y ruido, y la de dos géneros de música. Los resultados para el lenguaje revelaron una ligera preferencia para el WDRC a 80 dB SPL, y estimaciones equivalentes para los tres circuitos en las otras condiciones de escucha. Las estimaciones para la música revelaron una preferencia marginalmente significativa para el WDRC y una preferencia para la música clásica por encima de la popular. Para la música, los juicios de agradabilidad fueron los que más influyeron en la preferencia global de los circuitos.

Reliability and Stability of Various Hearing-Aid Outcome Measures in a Group of Elderly Hearing-Aid Wearers

1996 ◽  
Vol 39 (5) ◽  
pp. 923-935 ◽  
Author(s):  
Larry E. Humes ◽  
Dan Halling ◽  
Maureen Coughlin
Keyword(s):  
Outcome Measures ◽  
Hearing Aids ◽  
Repeated Measures ◽  
Nonsense Syllable ◽  
Hearing Aid ◽  
Objective Measure ◽  
The Elderly ◽  
Elderly Persons ◽  
Hearing Aid Use ◽  
Hearing Handicap

Twenty elderly persons with hearing impairment were fit with binaural in-the-ear hearing aids and followed for a 6-month period post-fit. Several hearing-aid outcome measures were obtained at 0, 7, 15, 30, 60, 90, and 180 days post-fit. Outcome measures included (a) objective measures of benefit obtained with nonsense-syllable materials in quiet (CUNY Nonsense Syllable Test, NST) and sentences in multitalker babble (Hearing in Noise Test, HINT); (b) two subjective measures of benefit, one derived from pre-fit/post-fit comparisons on a general scale of hearing handicap (Hearing Handicap Inventory for the Elderly, HHIE) and the other based on a subjective scale of post-fit hearing-aid benefit (Hearing Aid Performance Inventory, HAPI); (c) a questionnaire on hearing-aid satisfaction; (d) an objective measure of hearing-aid use; and (e) a subjective measure of hearing-aid use. Reliability and stability of each measure were examined through repeated-measures analyses of variance, a series of test-retest correlations, and, where possible, scatterplots of the scores against their corresponding 95% critical differences. Many of the measures were found to be both reliable and stable indicators of hearing-aid outcome.

A 1-Channel 3-Band Wide Dynamic Range Compression Chip for Vibration Transducer of Implantable Hearing Aids

2014 ◽  
Vol 24 (1) ◽  
pp. 1009-1017 ◽  
Author(s):  
DongWook Kim ◽  
KiWoong Seong ◽  
MyoungNam Kim ◽  
JinHo Cho ◽  
JyungHyun Lee
Keyword(s):  
Hearing Aids ◽  
Dynamic Range ◽  
Wide Dynamic Range ◽  
Dynamic Range Compression ◽  
Vibration Transducer ◽  
Implantable Hearing Aids

Effects of Coordinated Compression and Pinna Compensation Features on Horizontal Localization Performance in Hearing Aid Users

2015 ◽  
Vol 26 (01) ◽  
pp. 080-092 ◽  
Author(s):  
Petri Korhonen ◽  
Chi Lau ◽  
Francis Kuk ◽  
Denise Keenan ◽  
Jennifer Schumacher
Keyword(s):  
Repeated Measures ◽  
Horizontal Plane ◽  
Dynamic Range ◽  
Hearing Aid ◽  
Hearing Impaired ◽  
Localization Accuracy ◽  
Repeated Measures Design ◽  
Dynamic Range Compression ◽  
Data Collection And Analysis ◽  
Localization Performance

Background: Hearing-impaired listeners localize sounds better unaided than aided. Wide dynamic range compression circuits operating independently at each ear in bilateral fittings, and microphone positions of different hearing aid styles, have been cited as a reason. Two hearing aid features, inter-ear coordinated compression (IE) and pinna compensation (PC), were developed to mitigate the compromised aided localization performance. Purpose: This study examined the effect of IE and PC on aided localization performance in the horizontal plane with hearing-impaired listeners. Research Design: A single-blind, repeated-measures design was used. Study Sample: A total of 10 experienced hearing aid users with bilaterally symmetrical sensorineural hearing loss who had previously participated in localization training were evaluated. Data Collection and Analysis: Localization performance was measured using 12 loudspeakers spaced 30° apart on the horizontal plane. Aided performance was evaluated using a behind-the-ear hearing aid at four settings: omnidirectional microphone (Omni), Omni microphone with the PC feature, Omni microphone with IE, and Omni microphone with the PC feature and IE together. In addition, unaided localization performance was measured. Results: Significant improvement in the localization accuracy was measured for sounds arriving from the back when comparing the PC with the Omni conditions. The use of IE reduced the magnitude of errors for some listeners for sounds originating from ±90°. The average reduction in the errors was 7.3°. Conclusions: This study confirmed that the use of the PC feature improved localization for sounds arriving from behind the listener. The use of IE may improve localization for some listeners for sounds arriving from the sides.

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