A Digital Processing Strategy to Optimize Hearing Aid Outputs Directly

2004 ◽  
Vol 15 (10) ◽  
pp. 716-728 ◽  
Author(s):  
Peter J. Blamey ◽  
Lois F.A. Martin ◽  
Hayley J. Fiket
Keyword(s):  
Hearing Loss ◽  
Confidence Interval ◽  
Hearing Aids ◽  
Dynamic Range ◽  
Digital Processing ◽  
Second Phase ◽  
Open Platform ◽  
Dynamic Range Compression ◽  
Hearing Instruments ◽  
Amplification Strategy

A new amplification strategy (ADRO™), based on 64 independently operating channels, was compared with a nine-channel wide dynamic range compression strategy (WDRC). Open-platform in-the-ear hearing instruments were configured either with ADRO or the manufacturer's WDRC strategy. Twenty-two subjects with mild to moderate hearing loss took home the ADRO or WDRC hearing aids. After three weeks' acclimatization, the aids were evaluated using monosyllables in quiet at 50 to 65 dB SPL and sentences in eight-talker babble. The acclimatization and evaluation were repeated in the second phase of the balanced reverse-block blind experimental design. The ADRO program showed a statistically significant mean advantage of 7.85% word score (95% confidence interval 3.19% to 12.51%; p = 0.002) and 6.41% phoneme score for the monosyllables in quiet (95% confidence interval 2.03% to 10.79%; p = 0.006). A statistically significant advantage of 7.25% was also found for the ADRO program in background noise (95% confidence interval 1.95% to 12.55%; p = 0.010). The results are consistent with earlier data for listeners with moderate to severe hearing loss.

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.

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

Low-level Speech Recognition of Children with Hearing Aids

2021 ◽  
Author(s):  
Jace Wolfe ◽  
Mila Duke ◽  
Sharon Miller ◽  
Erin Schafer ◽  
Christine Jones ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Speech Recognition ◽  
Word Recognition ◽  
Hearing Aids ◽  
Hearing Aid ◽  
Phase 1 ◽  
Second Phase ◽  
Phase 2 ◽  
Low Level ◽  
Children With Hearing Loss

Background: For children with hearing loss, the primary goal of hearing aids is to provide improved access to the auditory environment within the limits of hearing aid technology and the child’s auditory abilities. However, there are limited data examining aided speech recognition at very low (40 dBA) and low (50 dBA) presentation levels. Purpose: Due to the paucity of studies exploring aided speech recognition at low presentation levels for children with hearing loss, the present study aimed to 1) compare aided speech recognition at different presentation levels between groups of children with normal hearing and hearing loss, 2) explore the effects of aided pure tone average (PTA) and aided Speech Intelligibility Index (SII) on aided speech recognition at low presentation levels for children with hearing loss ranging in degree from mild to severe, and 3) evaluate the effect of increasing low-level gain on aided speech recognition of children with hearing loss. Research Design: In phase 1 of this study, a two-group, repeated-measures design was used to evaluate differences in speech recognition. In phase 2 of this study, a single-group, repeated-measures design was used to evaluate the potential benefit of additional low-level hearing aid gain for low-level aided speech recognition of children with hearing loss. Study Sample: The first phase of the study included 27 school-age children with mild to severe sensorineural hearing loss and 12 school-age children with normal hearing. The second phase included eight children with mild to moderate sensorineural hearing loss. Intervention: Prior to the study, children with hearing loss were fitted binaurally with digital hearing aids. Children in the second phase were fitted binaurally with digital study hearing aids and completed a trial period with two different gain settings: 1) gain required to match hearing aid output to prescriptive targets (i.e., primary program), and 2) a 6-dB increase in overall gain for low-level inputs relative to the primary program. In both phases of this study, real-ear verification measures were completed to ensure the hearing aid output matched prescriptive targets. Data Collection and Analysis: Phase 1 included monosyllabic word recognition and syllable-final plural recognition at three presentation levels (40, 50, and 60 dBA). Phase 2 compared speech recognition performance for the same test measures and presentation levels with two differing gain prescriptions. Results and Conclusions: In phase 1 of the study, aided speech recognition was significantly poorer in children with hearing loss at all presentation levels. Higher aided SII in the better ear (55 dB SPL input) was associated with higher CNC word recognition at a 40 dBA presentation level. In phase 2, increasing the hearing aid gain for low-level inputs provided a significant improvement in syllable-final plural recognition at very low-level inputs and resulted in a non-significant trend toward better monosyllabic word recognition at very low presentation levels. Additional research is needed to document the speech recognition difficulties children with hearing aids may experience with low-level speech in the real world as well as the potential benefit or detriment of providing additional low-level hearing aid gain

Effect of Slow-Acting Wide Dynamic Range Compression on Measures of Intelligibility and Ratings of Speech Quality in Simulated-Loss Listeners

2005 ◽  
Vol 48 (3) ◽  
pp. 702-714 ◽  
Author(s):  
Peninah S. Rosengard ◽  
Karen L. Payton ◽  
Louis D. Braida
Keyword(s):  
Hearing Loss ◽  
Speech Intelligibility ◽  
Dynamic Range ◽  
Speech Quality ◽  
Subjective Ratings ◽  
Subjective Measures ◽  
Wide Dynamic Range ◽  
Dynamic Range Compression ◽  
Amplitude Compression ◽  
Moderate Hearing Loss

The purpose of this study was twofold: (a) to determine the extent to which 4-channel, slow-acting wide dynamic range amplitude compression (WDRC) can counteract the perceptual effects of reduced auditory dynamic range and (b) to examine the relation between objective measures of speech intelligibility and categorical ratings of speech quality for sentences processed with slow-acting WDRC. Multiband expansion was used to simulate the effects of elevated thresholds and loudness recruitment in normal hearing listeners. While some previous studies have shown that WDRC can improve both speech intelligibility and quality, others have found no benefit. The current experiment shows that moderate amounts of compression can provide a small but significant improvement in speech intelligibility, relative to linear amplification, for simulated-loss listeners with small dynamic ranges (i.e., flat, moderate hearing loss). This benefit was found for speech at conversational levels, both in quiet and in a background of babble. Simulated-loss listeners with large dynamic ranges (i.e., sloping, mild-to-moderate hearing loss) did not show any improvement. Comparison of speech intelligibility scores and subjective ratings of intelligibility showed that listeners with simulated hearing loss could accurately judge the overall intelligibility of speech. However, in all listeners, ratings of pleasantness decreased as the compression ratio increased. These findings suggest that subjective measures of speech quality should be used in conjunction with either objective or subjective measures of speech intelligibility to ensure that participant-selected hearing aid parameters optimize both comfort and intelligibility.

scholarly journals Principles of Digital Dynamic-Range Compression

2005 ◽  
Vol 9 (2) ◽  
pp. 45-76 ◽  
Author(s):  
James M. Kates
Keyword(s):  
Hearing Aids ◽  
Auditory Perception ◽  
Dynamic Range ◽  
Side Branch ◽  
Frequency Resolution ◽  
Compression Behavior ◽  
Digital Hearing Aids ◽  
Dynamic Range Compression ◽  
Digital Compression ◽  
Digital Hearing Aid

This article provides an overview of dynamic-range compression in digital hearing aids. Digital technology is becoming increasingly common in hearing aids, particularly because of the processing flexibility it offers and the opportunity to create more-effective devices. The focus of the paper is on the algorithms used to build digital compression systems. Of the various approaches that can be used to design a digital hearing aid, this paper considers broadband compression, multi-channel filter banks, a frequency-domain compressor using the FFT, the side-branch design that separates the filtering operation from the frequency analysis, and the frequency-warped version of the side-branch approach that modifies the analysis frequency spacing to more closely match auditory perception. Examples of the compressor frequency resolution, group delay, and compression behavior are provided for the different design approaches.

scholarly journals Hearing Aid Treatment for Patients with Mixed Hearing Loss. Part II: Speech Recognition in Comparison to Direct Acoustic Cochlear Stimulation

2020 ◽  
Vol 25 (3) ◽  
pp. 133-142
Author(s):  
Nina Wardenga ◽  
Ad F.M. Snik ◽  
Eugen Kludt ◽  
Bernd Waldmann ◽  
Thomas Lenarz ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Speech Recognition ◽  
Middle Ear ◽  
Hearing Aids ◽  
Dynamic Range ◽  
Hearing Aid ◽  
Middle Ear Surgery ◽  
Promising Alternative ◽  
Mixed Hearing Loss ◽  
Technical Specifications

Background: The conventional therapy for severe mixed hearing loss is middle ear surgery combined with a power hearing aid. However, a substantial group of patients with severe mixed hearing loss cannot be treated adequately with today’s state-of-the-art (SOTA) power hearing aids, as predicted by the accompanying part I of this publication, where we compared the available maximum power output (MPO) and gain from technical specifications to requirements for optimum benefit using a common fitting rule. Here, we intended to validate the theoretical assumptions from part I experimentally in a mixed hearing loss cohort fitted with SOTA power hearing aids. Additionally, we compared the results with an implantable hearing device that circumvents the impaired middle ear, directly stimulating the cochlea, as this might be a better option. Objectives: Speech recognition outcomes obtained from patients with severe mixed hearing loss supplied acutely with a SOTA hearing aid were studied to validate the outcome predictions as described in part I. Further, the results obtained with hearing aids were compared to those in direct acoustic cochlear implant (DACI) users. Materials and Methods: Twenty patients (37 ears with mixed hearing loss) were provided and fitted with a SOTA power hearing aid. Before and after an acclimatization period of at least 4 weeks, word recognition scores (WRS) in quiet and in noise were studied, as well as the speech reception threshold in noise (SRT). The outcomes were compared retrospectively to a second group of 45 patients (47 ears) using the DACI device. Based on the severity of the mixed hearing loss and the available gain and MPO of the SOTA hearing aid, the hearing aid and DACI users were subdivided into groups with prediction of sufficient, partially insufficient, or very insufficient hearing aid performance. Results: The patients with predicted adequate SOTA hearing aid performance indeed showed the best WRS in quiet and in noise when compared to patients with predicted inferior outcomes. Insufficient hearing aid performance at one or more frequencies led to a gradual decrease in hearing aid benefit, validating the criteria used here and in the accompanying paper. All DACI patients showed outcomes at the same level as the adequate hearing aid performance group, being significantly better than those of the groups with inadequate hearing aid performance. Whereas WRS in quiet and noise were sensitive to insufficient gain or output, showing significant differences between the SOTA hearing aid and DACI groups, the SRT in noise was less sensitive. Conclusions: Limitations of outcomes in mixed hearing loss individuals due to insufficient hearing aid performance can be accurately predicted by applying a commonly used fitting rule and the 35-dB dynamic range rule on the hearing aid specifications. Evidently, when outcomes in patients with mixed hearing loss using the most powerful hearing aids are insufficient, bypassing the middle ear with a powerful active middle ear implant or direct acoustic implant can be a promising alternative treatment.

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