scholarly journals Cochlear Implant Microphone Location Affects Speech Recognition in Diffuse Noise

2015 ◽  
Vol 26 (01) ◽  
pp. 051-058 ◽  
Author(s):  
Elizabeth R. Kolberg ◽  
Sterling W. Sheffield ◽  
Timothy J. Davis ◽  
Linsey W. Sunderhaus ◽  
René H. Gifford

Background: Despite improvements in cochlear implants (CIs), CI recipients continue to experience significant communicative difficulty in background noise. Many potential solutions have been proposed to help increase signal-to-noise ratio in noisy environments, including signal processing and external accessories. To date, however, the effect of microphone location on speech recognition in noise has focused primarily on hearing aid users. Purpose: The purpose of this study was to (1) measure physical output for the T-Mic as compared with the integrated behind-the-ear (BTE) processor mic for various source azimuths, and (2) to investigate the effect of CI processor mic location for speech recognition in semi-diffuse noise with speech originating from various source azimuths as encountered in everyday communicative environments. Research Design: A repeated-measures, within-participant design was used to compare performance across listening conditions. Study Sample: A total of 11 adults with Advanced Bionics CIs were recruited for this study. Data Collection and Analysis: Physical acoustic output was measured on a Knowles Experimental Mannequin for Acoustic Research (KEMAR) for the T-Mic and BTE mic, with broadband noise presented at 0 and 90° (directed toward the implant processor). In addition to physical acoustic measurements, we also assessed recognition of sentences constructed by researchers at Texas Instruments, the Massachusetts Institute of Technology, and the Stanford Research Institute (TIMIT sentences) at 60 dBA for speech source azimuths of 0, 90, and 270°. Sentences were presented in a semi-diffuse restaurant noise originating from the R-SPACE 8-loudspeaker array. Signal-to-noise ratio was determined individually to achieve approximately 50% correct in the unilateral implanted listening condition with speech at 0°. Performance was compared across the T-Mic, 50/50, and the integrated BTE processor mic. Results: The integrated BTE mic provided approximately 5 dB attenuation from 1500–4500 Hz for signals presented at 0° as compared with 90° (directed toward the processor). The T-Mic output was essentially equivalent for sources originating from 0 and 90°. Mic location also significantly affected sentence recognition as a function of source azimuth, with the T-Mic yielding the highest performance for speech originating from 0°. Conclusions: These results have clinical implications for (1) future implant processor design with respect to mic location, (2) mic settings for implant recipients, and (3) execution of advanced speech testing in the clinic.

2020 ◽  
Author(s):  
chaofeng lan ◽  
yuanyuan Zhang ◽  
hongyun Zhao

Abstract This paper draws on the training method of Recurrent Neural Network (RNN), By increasing the number of hidden layers of RNN and changing the layer activation function from traditional Sigmoid to Leaky ReLU on the input layer, the first group and the last set of data are zero-padded to enhance the effective utilization of data such that the improved reduction model of Denoise Recurrent Neural Network (DRNN) with high calculation speed and good convergence is constructed to solve the problem of low speaker recognition rate in noisy environment. According to this model, the random semantic speech signal with a sampling rate of 16 kHz and a duration of 5 seconds in the speech library is studied. The experimental settings of the signal-to-noise ratios are − 10dB, -5dB, 0dB, 5dB, 10dB, 15dB, 20dB, 25dB. In the noisy environment, the improved model is used to denoise the Mel Frequency Cepstral Coefficients (MFCC) and the Gammatone Frequency Cepstral Coefficents (GFCC), impact of the traditional model and the improved model on the speech recognition rate is analyzed. The research shows that the improved model can effectively eliminate the noise of the feature parameters and improve the speech recognition rate. When the signal-to-noise ratio is low, the speaker recognition rate can be more obvious. Furthermore, when the signal-to-noise ratio is 0dB, the speaker recognition rate of people is increased by 40%, which can be 85% improved compared with the traditional speech model. On the other hand, with the increase in the signal-to-noise ratio, the recognition rate is gradually increased. When the signal-to-noise ratio is 15dB, the recognition rate of speakers is 93%.


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.


Author(s):  
Jenny L. Pierce ◽  
Kristine Tanner ◽  
Ray M. Merrill ◽  
Lauren Shnowske ◽  
Nelson Roy

Purpose The primary aim of this study was to obtain high-quality acoustic normative data in natural field environments for female voices. A secondary aim was to examine acoustic measurement variability in field environments. Method This study employed a within-subject repeated-measures experimental design that included 45 young female adults with normal voices. Participants were stratified by age (18–23, 24–29, and 30–35 years). After initial evaluation and instruction, participants completed voice recordings during seven consecutive days using a standard protocol, including both connected speech and sustained vowels. Thirty-two cepstral-, spectral-, and time-based acoustic measures were acquired using Praat and the Analysis of Dysphonia in Speech and Voice. Results Among the 958 total recordings, greater than 90% satisfied inclusion criteria based on protocol compliance, peak clipping, and signal-to-noise ratio. Significant differences were observed for age ( p < .05). For 19 acoustic measures, values improved significantly as signal-to-noise ratio increased. Cepstral- and spectral-based measures demonstrated less measurement variability as compared with time-based measures. Conclusions With adequate training, field audio recordings represent a viable option for clinical voice management. The significant age effects observed in this study support the need for more specific criteria when collecting and applying normative data. Cepstral- and spectral-based measures demonstrated the least measurement variability. This study provides additional evidence for multiparameter acoustic voice measurement, specifically toward ecologically valid sampling in natural environments. Future studies should expand on these findings in other populations with normal and disordered voices.


2017 ◽  
Vol 28 (05) ◽  
pp. 404-414 ◽  
Author(s):  
Dorothy Neave-DiToro ◽  
Adrienne Rubinstein ◽  
Arlene C. Neuman

Background: Limited attention has been given to the effects of classroom acoustics at the college level. Many studies have reported that nonnative speakers of English are more likely to be affected by poor room acoustics than native speakers. An important question is how classroom acoustics affect speech perception of nonnative college students. Purpose: The combined effect of noise and reverberation on the speech recognition performance of college students who differ in age of English acquisition was evaluated under conditions simulating classrooms with reverberation times (RTs) close to ANSI recommended RTs. Research Design: A mixed design was used in this study. Study Sample: Thirty-six native and nonnative English-speaking college students with normal hearing, ages 18–28 yr, participated. Intervention: Two groups of nine native participants (native monolingual [NM] and native bilingual) and two groups of nine nonnative participants (nonnative early and nonnative late) were evaluated in noise under three reverberant conditions (0.03, 0.06, and 0.08 sec). Data Collection and Analysis: A virtual test paradigm was used, which represented a signal reaching a student at the back of a classroom. Speech recognition in noise was measured using the Bamford–Kowal–Bench Speech-in-Noise (BKB-SIN) test and signal-to-noise ratio required for correct repetition of 50% of the key words in the stimulus sentences (SNR-50) was obtained for each group in each reverberant condition. A mixed-design analysis of variance was used to determine statistical significance as a function of listener group and RT. Results: SNR-50 was significantly higher for nonnative listeners as compared to native listeners, and a more favorable SNR-50 was needed as RT increased. The most dramatic effect on SNR-50 was found in the group with later acquisition of English, whereas the impact of early introduction of a second language was subtler. At the ANSI standard’s maximum recommended RT (0.6 sec), all groups except the NM group exhibited a mild signal-to-noise ratio (SNR) loss. At the 0.8 sec RT, all groups exhibited a mild SNR loss. Conclusion: Acoustics in the classroom are an important consideration for nonnative speakers who are proficient in English and enrolled in college. To address the need for a clearer speech signal by nonnative students (and for all students), universities should follow ANSI recommendations, as well as minimize background noise in occupied classrooms. Behavioral/instructional strategies should be considered to address factors that cannot be compensated for through acoustic design.


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.


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