Signal-to-Noise Ratio Advantage of Binaural Hearing Aids and Directional Microphones under Different Levels of Reverberation

1984 ◽  
Vol 49 (3) ◽  
pp. 278-286 ◽  
Author(s):  
David B. Hawkins ◽  
William S. Yacullo

The signal-to-noise ratio necessary for a constant performance level was determined for normally hearing and hearing-impaired subjects under three levels of reverberation (0.3, 0.6, and 1.2 s) with monaural and binaural hearing aids having directional and omnidirectional microphones. Results indicated (a) a significant binaural advantage (2–3 dB) which was independent of microphone type and reverberation time, (b) a significant directional microphone advantage (3–4 dB) which was independent of hearing aid arrangement (monaural or binaural) but dependent on level of reverberation, (c) a significant reverberation effect which was larger than either the binaural or directional microphone effect, and (d) additive binaural and directional microphone advantages. The results suggest that the signal-to-noise ratio is optimized when binaural hearing aids with directional microphones are used in rooms with short reverberation times.

2011 ◽  
Vol 22 (06) ◽  
pp. 375-386 ◽  
Author(s):  
Stella L. Ng ◽  
Christine N. Meston ◽  
Susan D. Scollie ◽  
Richard C. Seewald

Background: There is a need for objective pediatric hearing aid outcome measurement and thus a need for the evaluation of outcome measures. We explored a commercially available pediatric sentence-in-noise measure adapted for use as an aided outcome measure. Purpose: The purposes of the current study were (1) to administer an adapted BKB-SIN (Bamford-Kowal-Bench Speech-in-Noise test) to adults and children who have normal hearing and children who use hearing aids and (2) to evaluate the utility of this adapted BKB-SIN as an aided, within-subjects outcome measure for amplification strategies. Research Design: We used a mixed within and between groups design to evaluate speech recognition in noise for the three groups of participants. The children who use hearing aids were tested under the omnidirectional, directional, and digital noise reduction (DNR) conditions. Results from each group were compared to each other, and we compared results of each aided condition for the children who use hearing aids to evaluate the test utility as an aided outcome measure. Study Sample: The study sample consisted of 14 adults with normal hearing (aged 22–28 yr) and 15 children with normal hearing (aged 6–18 yr), recruited through word of mouth, and 14 children who use hearing aids (aged 9–16 yr) recruited from local audiology clinics. Data Collection and Analysis: List pairs of the BKB-SIN test were presented at 50 dB HL as follows: four list pairs to each participant with normal hearing, four list pairs in the omnidirectional condition, and two list pairs in the directional and DNR conditions. Children who use hearing aids were fitted bilaterally with laboratory devices and completed the BKB-SIN test aided. Data were plotted as mean percent of key words correct at each signal-to-noise ratio (SNR). Further, we conducted an analysis of variance for group differences and within-groups for the three aided conditions. Results: Adult participants outperformed children with normal hearing, who outperformed the children who use hearing aids. SNR-50 (signal-to-noise ratio at which listener can obtain a speech recognition score of 50% correct) scores demonstrated reliability of the adapted test implementation. The BKB-SIN test measured significant differences in performance for omnidirectional versus directional microphone conditions but not between omnidirectional and DNR conditions. Conclusions: We conclude that the adapted implementation of the BKB-SIN test can be administered reliably and feasibly. Further study is warranted to develop norms for the adapted implementation as well as to determine if an adapted implementation can be sensitive to age effects. Until such norms are developed, clinicians should refrain from comparing results from the adapted test to the test manual norms and should instead use the adapted implementation as a within-subject measure.


2005 ◽  
Vol 16 (09) ◽  
pp. 662-676 ◽  
Author(s):  
Brian E. Walden ◽  
Rauna K. Surr ◽  
Kenneth W. Grant ◽  
W. Van Summers ◽  
Mary T. Cord ◽  
...  

This study examined speech intelligibility and preferences for omnidirectional and directional microphone hearing aid processing across a range of signal-to-noise ratios (SNRs). A primary motivation for the study was to determine whether SNR might be used to represent distance between talker and listener in automatic directionality algorithms based on scene analysis. Participants were current hearing aid users who either had experience with omnidirectional microphone hearing aids only or with manually switchable omnidirectional/directional hearing aids. Using IEEE/Harvard sentences from a front loudspeaker and speech-shaped noise from three loudspeakers located behind and to the sides of the listener, the directional advantage (DA) was obtained at 11 SNRs ranging from -15 dB to +15 dB in 3 dB steps. Preferences for the two microphone modes at each of the 11 SNRs were also obtained using concatenated IEEE sentences presented in the speech-shaped noise. Results revealed that a DA was observed across a broad range of SNRs, although directional processing provided the greatest benefit within a narrower range of SNRs. Mean data suggested that microphone preferences were determined largely by the DA, such that the greater the benefit to speech intelligibility provided by the directional microphones, the more likely the listeners were to prefer that processing mode. However, inspection of the individual data revealed that highly predictive relationships did not exist for most individual participants. Few preferences for omnidirectional processing were observed. Overall, the results did not support the use of SNR to estimate the effects of distance between talker and listener in automatic directionality algorithms.


1993 ◽  
Vol 2 (2) ◽  
pp. 47-51 ◽  
Author(s):  
Edgar Villchur

Hearing aid design to alleviate the noise problem has concentrated on improving the signal-to-noise ratio with the aid, using devices such as directional microphones, adaptive filters, and circuits that discriminate between steady-state noise and speech. The design approach discussed here is directed at improving the speech recognition of hearing-impaired listeners at a given signal-to-noise ratio, by restoring to their perception speech cues they no longer hear because of their impairment. This allows them to retain more of the redundant information in speech after masking has taken its toll, and empowers their ability to separate desired from undesired signals (what Broadbent calls "selective listening" in persons with normal hearing). Experimental results are presented.


2020 ◽  
Vol 24 ◽  
pp. 233121652093339
Author(s):  
Els Walravens ◽  
Gitte Keidser ◽  
Louise Hickson

Trainable hearing aids let users fine-tune their hearing aid settings in their own listening environment: Based on consistent user-adjustments and information about the acoustic environment, the trainable aids will change environment-specific settings to the user’s preference. A requirement for effective fine-tuning is consistency of preference for similar settings in similar environments. The aim of this study was to evaluate consistency of preference for settings differing in intensity, gain-frequency slope, and directionality when listening in simulated real-world environments and to determine if participants with more consistent preferences could be identified based on profile measures. A total of 52 adults (63–88 years) with hearing varying from normal to a moderate sensorineural hearing loss selected their preferred setting from pairs differing in intensity (3 or 6 dB), gain-frequency slope (±1.3 or ± 2.7 dB/octave), or directionality (omnidirectional vs. cardioid) in four simulated real-world environments: traffic noise, a monologue in traffic noise at 5 dB signal-to-noise ratio, and a dialogue in café noise at 5 and at 0 dB signal-to-noise ratio. Forced-choice comparisons were made 10 times for each combination of pairs of settings and environment. Participants also completed nine psychoacoustic, cognitive, and personality measures. Consistency of preference, defined by a setting preferred at least 9 out of 10 times, varied across participants. More participants obtained consistent preferences for larger differences between settings and less difficult environments. The profile measures did not predict consistency of preference. Trainable aid users could benefit from counselling to ensure realistic expectations for particular adjustments and listening situations.


2019 ◽  
Vol 28 (1) ◽  
pp. 101-113 ◽  
Author(s):  
Jenna M. Browning ◽  
Emily Buss ◽  
Mary Flaherty ◽  
Tim Vallier ◽  
Lori J. Leibold

Purpose The purpose of this study was to evaluate speech-in-noise and speech-in-speech recognition associated with activation of a fully adaptive directional hearing aid algorithm in children with mild to severe bilateral sensory/neural hearing loss. Method Fourteen children (5–14 years old) who are hard of hearing participated in this study. Participants wore laboratory hearing aids. Open-set word recognition thresholds were measured adaptively for 2 hearing aid settings: (a) omnidirectional (OMNI) and (b) fully adaptive directionality. Each hearing aid setting was evaluated in 3 listening conditions. Fourteen children with normal hearing served as age-matched controls. Results Children who are hard of hearing required a more advantageous signal-to-noise ratio than children with normal hearing to achieve comparable performance in all 3 conditions. For children who are hard of hearing, the average improvement in signal-to-noise ratio when comparing fully adaptive directionality to OMNI was 4.0 dB in noise, regardless of target location. Children performed similarly with fully adaptive directionality and OMNI settings in the presence of the speech maskers. Conclusions Compared to OMNI, fully adaptive directionality improved speech recognition in steady noise for children who are hard of hearing, even when they were not facing the target source. This algorithm did not affect speech recognition when the background noise was speech. Although the use of hearing aids with fully adaptive directionality is not proposed as a substitute for remote microphone systems, it appears to offer several advantages over fixed directionality, because it does not depend on children facing the target talker and provides access to multiple talkers within the environment. Additional experiments are required to further evaluate children's performance under a variety of spatial configurations in the presence of both noise and speech maskers.


1986 ◽  
Vol 29 (2) ◽  
pp. 146-154 ◽  
Author(s):  
Reinier Plomp

This paper reviews the results of a series of investigations inspired by a model of the speech-reception threshold (SRT) of hearing-impaired listeners. The model contains two parameters accounting for the SRT of normal-hearing listeners (SRT in quiet and signal-to-noise ratio corresponding to the threshold at high noise levels), two parameters describing the hearing loss (attenuation and threshold elevation in terms of signal-to-noise ratio), and three parameters describing the hearing aid (acoustic gain, threshold elevation expressed in signal-to-noise ratio, and equivalent internal noise level). Experimental data are reported for three different types of hearing impairment: presbycusis, hearing losses with a pathological origin, and noise-induced losses. The model gives an excellent description of the data. It demonstrates that for many hearing-impaired persons speech intelligibility at noise levels beyond 50 to 60 dB(A) is their main problem, whereas hearing aids are most effective below that noise level.


Author(s):  
R. SHANTHA SELVA KUMARI ◽  
V. SADASIVAM

In this paper, an off-line double density discrete wavelet transform based de-noising and baseline wandering removal methods are proposed. Different levels decomposition is used depending upon the noise level, so as to give a better result. When the noise level is low, three levels decomposition is used. When the noise level is medium, four levels decomposition is used. When the noise level is high, five levels decomposition is used. Soft threshold technique is applied to each set of wavelet detail coefficients with different noise level. Donoho's estimator is used as a threshold for each set of wavelet detail coefficients. The results are compared with other classical filters and improvement of signal to noise ratio is discussed. Using the proposed method the output signal to noise ratio is 19.7628 dB for an input signal to noise ratio of -7.11 dB. This is much higher than other methods available in the literature. Baseline wandering removal is done by using double density discrete wavelet approximation coefficients of the whole signal. This is an unsupervised method allowing the process to be used in off-line automatic analysis of electrocardiogram. The results are more accurate than other methods with less effort.


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