Contribution of low-frequency acoustic information to Chinese speech recognition in cochlear implant simulations

2006 ◽  
Vol 120 (4) ◽  
pp. 2260-2266 ◽  
Author(s):  
Xin Luo ◽  
Qian-Jie Fu
2011 ◽  
Vol 22 (09) ◽  
pp. 586-600 ◽  
Author(s):  
King Chung ◽  
Nicholas McKibben

Background: Wind noise can be a nuisance or a debilitating masker for cochlear implant users in outdoor environments. Previous studies indicated that wind noise at the microphone/hearing aid output had high levels of low-frequency energy and the amount of noise generated is related to the microphone directionality. Currently, cochlear implants only offer either directional microphones or omnidirectional microphones for users at-large. As all cochlear implants utilize pre-emphasis filters to reduce low-frequency energy before the signal is encoded, effective wind noise reduction algorithms for hearing aids might not be applicable for cochlear implants. Purpose: The purposes of this study were to investigate the effect of microphone directionality on speech recognition and perceived sound quality of cochlear implant users in wind noise and to derive effective wind noise reduction strategies for cochlear implants. Research Design: A repeated-measure design was used to examine the effects of spectral and temporal masking created by wind noise recorded through directional and omnidirectional microphones and the effects of pre-emphasis filters on cochlear implant performance. A digital hearing aid was programmed to have linear amplification and relatively flat in-situ frequency responses for the directional and omnidirectional modes. The hearing aid output was then recorded from 0 to 360° at flow velocities of 4.5 and 13.5 m/sec in a quiet wind tunnel. Study Sample: Sixteen postlingually deafened adult cochlear implant listeners who reported to be able to communicate on the phone with friends and family without text messages participated in the study. Intervention: Cochlear implant users listened to speech in wind noise recorded at locations that the directional and omnidirectional microphones yielded the lowest noise levels. Data Collection and Analysis: Cochlear implant listeners repeated the sentences and rated the sound quality of the testing materials. Spectral and temporal characteristics of flow noise, as well as speech and/or noise characteristics before and after the pre-emphasis filter, were analyzed. Correlation coefficients between speech recognition scores and crest factors of wind noise before and after pre-emphasis filtering were also calculated. Results: Listeners obtained higher scores using the omnidirectional than the directional microphone mode at 13.5 m/sec, but they obtained similar speech recognition scores for the two microphone modes at 4.5 m/sec. Higher correlation coefficients were obtained between speech recognition scores and crest factors of wind noise after pre-emphasis filtering rather than before filtering. Conclusion: Cochlear implant users would benefit from both directional and omnidirectional microphones to reduce far-field background noise and near-field wind noise. Automatic microphone switching algorithms can be more effective if the incoming signal were analyzed after pre-emphasis filters for microphone switching decisions.


2020 ◽  
Vol 63 (5) ◽  
pp. 1561-1571 ◽  
Author(s):  
David M. Kessler ◽  
Jace Wolfe ◽  
Michelle Blanchard ◽  
René H. Gifford

Purpose The purpose of this study was to investigate the relationship between speech recognition benefit derived from the addition of a hearing aid (HA) to the nonimplanted ear (i.e., bimodal benefit) and spectral modulation detection (SMD) performance in the nonimplanted ear in a large clinical sample. An additional purpose was to investigate the influence of low-frequency pure-tone average (PTA) of the nonimplanted ear and age at implantation on the variance in bimodal benefit. Method Participants included 311 unilateral cochlear implant (CI) users who wore an HA in the nonimplanted ear. Participants completed speech recognition testing in quiet and in noise with the CI-alone and in the bimodal condition (i.e., CI and contralateral HA) and SMD in the nonimplanted ear. Results SMD performance in the nonimplanted ear was significantly correlated with bimodal benefit in quiet and in noise. However, this relationship was much weaker than previous reports with smaller samples. SMD, low-frequency PTA of the nonimplanted ear from 125 to 750 Hz, and age at implantation together accounted for, at most, 19.1% of the variance in bimodal benefit. Conclusions Taken together, SMD, low-frequency PTA, and age at implantation account for the greatest amount of variance in bimodal benefit than each variable alone. A large portion of variance (~80%) in bimodal benefit is not explained by these variables. Supplemental Material https://doi.org/10.23641/asha.12185493


2021 ◽  
pp. 1-11
Author(s):  
Stefanie Bruschke ◽  
Uwe Baumann ◽  
Timo Stöver

Background: The cochlear implant (CI) is a standard procedure for the treatment of patients with severe to profound hearing loss. In the past, a standard healing period of 3–6 weeks occurred after CI surgery before the sound processor was initially activated. Advancements of surgical techniques and instruments allow an earlier initial activation of the processor within 14 days after surgery. Objective: Evaluation of the early CI device activation after CI surgery within 14 days, comparison to the first activation after 4–6 weeks, and assessment of the feasibility and safety of the early fitting over a 12 month observation period were the objectives of this study. Method: In a prospective study, 127 patients scheduled for CI surgery were divided into early fitting group (EF, n = 67) and control group (CG, n = 60). Individual questionnaires were used to evaluate medical and technical outcomes of the EF. Medical side effects, speech recognition, and follow-up effort were compared with the CG within the first year after CI surgery. Results: The early fitting was feasible in 97% of the EF patients. In the EF, the processor was activated 25 days earlier than in the CG. No major complications were observed in either group. At the follow-up appointments, side effects such as pain and balance problems occurred with comparable frequency in both groups. At initial fitting, the EF showed a significantly higher incidence of medical minor complications (p < 0.05). When developing speech recognition within the first year of CI use, no difference was observed. Furthermore, the follow-up effort within the first year after CI surgery was comparable in both groups. Conclusions: Early fitting of the sound processor is a feasible and safe procedure with comparable follow-up effort. Although more early minor complications were observed in the EF, there were no long-term wound healing problems caused by the early fitting. Regular inspection of the magnet strength is recommended as part of the CI follow-up since postoperative wound swelling must be expected. The early fitting procedure enabled a clear reduction in the waiting time between CI surgery and initial sound processor activation.


2021 ◽  
Vol 404 ◽  
pp. 108206
Author(s):  
Kelly Vasconcelos Chaves Martins ◽  
Maria Valéria Schmidt Goffi-Gomez ◽  
Robinson Koji Tsuji ◽  
Ricardo Ferreira Bento

Author(s):  
Claire Marcus Bernstein ◽  
Diane Majerus Brewer ◽  
Matthew H. Bakke ◽  
Anne D. Olson ◽  
Elizabeth Jackson Machmer ◽  
...  

Abstract Background Increasing numbers of adults are receiving cochlear implants (CIs) and many achieve high levels of speech perception and improved quality of life. However, a proportion of implant recipients still struggle due to limited speech recognition and/or greater communication demands in their daily lives. For these individuals a program of aural rehabilitation (AR) has the potential to improve outcomes. Purpose The study investigated the effects of a short-term AR intervention on speech recognition, functional communication, and psychosocial outcomes in post lingually deafened adult CI users. Research Design The experimental design was a multisite clinical study with participants randomized to either an AR treatment or active control group. Each group completed 6 weekly 90-minute individual treatment sessions. Assessments were completed pretreatment, 1 week and 2 months post-treatment. Study Sample Twenty-five post lingually deafened adult CI recipients participated. AR group: mean age 66.2 (48–80); nine females, four males; months postactivation 7.7 (3–16); mean years severe to profound deafness 18.4 (2–40). Active control group: mean age 62.8 (47–85); eight females, four males; months postactivation 7.0 (3–13); mean years severe to profound deafness 18.8 (1–55). Intervention The AR protocol consisted of auditory training (words, sentences, speech tracking), and psychosocial counseling (informational and communication strategies). Active control group participants engaged in cognitive stimulation activities (e.g., crosswords, sudoku, etc.). Data Collection and Analysis Repeated measures ANOVA or analysis of variance, MANOVA or multivariate analysis of variance, and planned contrasts were used to compare group performance on the following measures: CasperSent; Hearing Handicap Inventory; Nijmegen Cochlear Implant Questionnaire; Client Oriented Scale of Improvement; Glasgow Benefit Inventory. Results The AR group showed statistically significant improvements on speech recognition performance, psychosocial function, and communication goals with no significant improvement seen in the control group. The two groups were statistically equivalent on all outcome measures at preassessment. The robust improvements for the AR group were maintained at 2 months post-treatment. Conclusion Results of this clinical study provide evidence that a short-term AR intervention protocol can maximize outcomes for adult post lingually deafened CI users. The impact of this brief multidimensional AR intervention to extend CI benefit is compelling, and may serve as a template for best practices with adult CI users.


2021 ◽  
Author(s):  
Alexander T. Murr ◽  
Michael W. Canfarotta ◽  
Brendan P. O'Connell ◽  
Emily Buss ◽  
English R. King ◽  
...  

2020 ◽  
Vol 24 ◽  
pp. 233121652098029
Author(s):  
Allison Trine ◽  
Brian B. Monson

Several studies have demonstrated that extended high frequencies (EHFs; >8 kHz) in speech are not only audible but also have some utility for speech recognition, including for speech-in-speech recognition when maskers are facing away from the listener. However, the contribution of EHF spectral versus temporal information to speech recognition is unknown. Here, we show that access to EHF temporal information improved speech-in-speech recognition relative to speech bandlimited at 8 kHz but that additional access to EHF spectral detail provided an additional small but significant benefit. Results suggest that both EHF spectral structure and the temporal envelope contribute to the observed EHF benefit. Speech recognition performance was quite sensitive to masker head orientation, with a rotation of only 15° providing a highly significant benefit. An exploratory analysis indicated that pure-tone thresholds at EHFs are better predictors of speech recognition performance than low-frequency pure-tone thresholds.


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