scholarly journals The effect of a coding strategy that removes temporally masked pulses on speech perception by cochlear implant users

2020 ◽  
Author(s):  
Wiebke Lamping ◽  
Tobias Goehring ◽  
Jeremy Marozeau ◽  
Robert P. Carlyon

Speech recognition in noisy environments remains a challenge for cochlear implant (CI) recipients. Unwanted charge interactions between current pulses in the same and across different electrode channels are likely to impair performance. Here we investigate the effect of reducing the number of current pulses on speech perception. This was achieved by implementing a psychoacoustic temporal-masking model where current pulses in each channel were passed through a temporal integrator to identify and remove pulses that were less likely to be perceived by the recipient. The decision criterion of the temporal integrator was varied to control the percentage of pulses removed in each condition. In experiment 1, speech in quiet was processed with a standard Continuous Interleaved Sampling (CIS) strategy and with 25, 50 and 75% of pulses removed. In experiment 2, performance was measured for speech in noise with the CIS reference and with 50 and 75% of pulses removed. Speech intelligibility in quiet revealed no significant difference between reference and test conditions. For speech in noise, results showed a significant improvement of 2.4 dB when removing 50% of pulses. Performance both in quiet and in noise was not significantly different between the reference and when 75% of pulses were removed. Further, by reducing the overall amount of current pulses by 25, 50, and 75% but accounting for the increase in charge necessary to compensate for the decrease in loudness, estimated average power savings of 21.15, 40.95, and 63.45%, respectively, could be possible for this set of listeners. In conclusion, removing temporally masked pulses may improve speech perception in noise and result in substantial power savings.

2021 ◽  
Vol 10 (16) ◽  
pp. 3666
Author(s):  
Tytti Willberg ◽  
Ville Sivonen ◽  
Pia Linder ◽  
Aarno Dietz

Background: A large number of different speech-in-noise (SIN) tests are available for testing cochlear implant (CI) recipients, but few studies have compared the different tests in the same patient population to assess how well their results correlate. Methods: A clinically representative group of 80 CI users conducted the Finnish versions of the matrix sentence test, the simplified matrix sentence test, and the digit triplet test. The results were analyzed for correlations between the different tests and for differences among the participants, including age and device modality. Results: Strong and statistically significant correlations were observed between all of the tests. No floor or ceiling effects were observed with any of the tests when using the adaptive test procedure. Age or the length of device use showed no correlation to SIN perception, but bilateral CI users showed slightly better results in comparison to unilateral or bimodal users. Conclusions: Three SIN tests that differ in length and complexity of the test material provided comparable results in a diverse CI user group.


2019 ◽  
Vol 30 (07) ◽  
pp. 579-589 ◽  
Author(s):  
Hillary A. Snapp ◽  
Michael E. Hoffer ◽  
Anthony Spahr ◽  
Suhrud Rajguru

AbstractThe aim of the study was to determine if contralateral routing of signal (CROS) technology results in improved hearing outcomes in unilateral cochlear implant (CI) patients and provides similar gains in speech perception in noise to traditional monaural listeners (MLs).The study is a prospective, within-subject repeated-measures experiment.Adult, English-speaking patients with bilateral severe–profound sensorineural hearing loss using an Advanced Bionics CI (n = 12) in one ear were enrolled for the study.Hearing performance in the monaural listening condition (CI only) was compared with the CROS-aided (unilateral CI + CROS) condition. Participants were tested for speech-in-noise performance using the Bamford-Kowal-Bench Speech-in-Noise™ test materials in the speech front/noise front (0 degrees/0 degrees azimuth), speech front/noise back (0 degrees/180 degrees azimuth), speech deaf ear/noise monaural ear (90 degrees/270 degrees azimuth), and speech monaural ear/noise deaf ear (90 degrees/270 degrees azimuth) configurations. Localization error was assessed using three custom stimuli consisting of 1/3 octave narrowband noises centered at 500 and 4000 Hz and a broadband speech stimulus. Localization stimuli were presented at random in the front hemifield by 19 speakers spatially separated by 10 degrees. Outcomes were compared with a previously described group of traditional MLs in the CROS-aided condition (normal hearing ear + CROS).All participants were tested acutely with no adaptation to the CROS device. Statistical analyses were performed using Wilcoxon signed rank tests for nonparametric data and paired sample. Statistical significance was set to p < 0.00625 after Bonferroni adjustment for eight tests.Significant benefit was observed from unaided to the CI + CROS–aided condition for listening in noise across most listening conditions with the greatest benefit observed in the speech deaf ear/noise monaural ear (90 degrees/270 degrees azimuth) condition (p < 0.0005). When compared with traditional MLs, no significant difference in decibel gain from the unaided to CROS-aided conditions was observed between participant groups. There was no improvement in localization ability in the CROS-aided condition for either participant group and no significant difference in performance between traditional MLs and unilateral CI listeners.These findings support that unilateral CI users are capable of achieving similar gains in speech perception to that of traditional MLs with wireless CROS. These results indicate that the use of wireless CROS stimulation in unilateral CI recipients provides increased benefit and an additional rehabilitative option for this population when bilateral implantation is not possible. The results suggest that noninvasive CROS solutions can successfully rehabilitate certain monaural listening deficits, provide improved hearing outcomes, and expand the reach of treatment in this population.


2013 ◽  
Vol 24 (02) ◽  
pp. 105-120 ◽  
Author(s):  
Ann E. Perreau ◽  
Ruth A. Bentler ◽  
Richard S. Tyler

Background: Frequency-lowering signal processing in hearing aids has re-emerged as an option to improve audibility of the high frequencies by expanding the input bandwidth. Few studies have investigated the usefulness of the scheme as an option for bimodal users (i.e., combined use of a cochlear implant and a contralateral hearing aid). In this study, that question was posed. Purpose: The purposes of this study were (1) to determine if frequency compression was a better bimodal option than conventional amplification and (2) to determine the impact of a frequency-compression hearing aid on speech recognition abilities. Research Design: There were two separate experiments in this study. The first experiment investigated the contribution of a frequency-compression hearing aid to contralateral cochlear implant (CI) performance for localization and speech perception in noise. The second experiment assessed monaural consonant and vowel perception in quiet using the frequency-compression and conventional hearing aid without the use of a contralateral CI or hearing aid. Study Sample: Ten subjects fitted with a cochlear implant and hearing aid participated in the first experiment. Seventeen adult subjects with a cochlear implant and hearing aid or two hearing aids participated in the second experiment. To be included, subjects had to have a history of postlingual deafness, a moderate or moderate-to-severe hearing loss, and have not worn this type of frequency-lowering hearing aid previously. Data Collection and Analysis: In the first experiment, performance using the frequency-compression and conventional hearing aids was assessed on tests of sound localization, speech perception in a background of noise, and two self-report questionnaires. In the second experiment, consonant and vowel perception in quiet was assessed monaurally for the two conditions. In both experiments, subjects alternated daily between a frequency-compression and conventional hearing aid for 2 mo. The parameters of frequency compression were set individually for each subject, and audibility was measured for the frequency compression and conventional hearing aid programs by comparing estimations of the Speech Intelligibility Index (SII) using a modified algorithm (Bentler et al, 2011). In both experiments, the outcome measures were administered following the hearing aid fitting to assess performance at baseline and after 2 mo of use. Results: For this group of subjects, the results revealed no significant difference between the frequency-compression and conventional hearing aid on tests of localization and consonant recognition. Spondee-in-noise and vowel perception scores were significantly higher with the conventional hearing aid compared to the frequency-compression hearing aid after 2 mo of use. Conclusions: These results suggest that, for the subjects in this study, frequency compression is not a better bimodal option than conventional amplification. In addition, speech perception may be negatively influenced by frequency compression because formant frequencies are too severely compressed and can no longer be distinguished.


2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Chi Yhun Lo ◽  
Catherine M. McMahon ◽  
Valerie Looi ◽  
William F. Thompson

Cochlear implant (CI) recipients generally have good perception of speech in quiet environments but difficulty perceiving speech in noisy conditions, reduced sensitivity to speech prosody, and difficulty appreciating music. Auditory training has been proposed as a method of improving speech perception for CI recipients, and recent efforts have focussed on the potential benefits of music-based training. This study evaluated two melodic contour training programs and their relative efficacy as measured on a number of speech perception tasks. These melodic contours were simple 5-note sequences formed into 9 contour patterns, such as “rising” or “rising-falling.” One training program controlled difficulty by manipulating interval sizes, the other by note durations. Sixteen adult CI recipients (aged 26–86 years) and twelve normal hearing (NH) adult listeners (aged 21–42 years) were tested on a speech perception battery at baseline and then after 6 weeks of melodic contour training. Results indicated that there were some benefits for speech perception tasks for CI recipients after melodic contour training. Specifically, consonant perception in quiet and question/statement prosody was improved. In comparison, NH listeners performed at ceiling for these tasks. There was no significant difference between the posttraining results for either training program, suggesting that both conferred benefits for training CI recipients to better perceive speech.


2010 ◽  
Vol 10 ◽  
pp. 329-339 ◽  
Author(s):  
Torsten Rahne ◽  
Michael Ziese ◽  
Dorothea Rostalski ◽  
Roland Mühler

This paper describes a logatome discrimination test for the assessment of speech perception in cochlear implant users (CI users), based on a multilingual speech database, the Oldenburg Logatome Corpus, which was originally recorded for the comparison of human and automated speech recognition. The logatome discrimination task is based on the presentation of 100 logatome pairs (i.e., nonsense syllables) with balanced representations of alternating “vowel-replacement” and “consonant-replacement” paradigms in order to assess phoneme confusions. Thirteen adult normal hearing listeners and eight adult CI users, including both good and poor performers, were included in the study and completed the test after their speech intelligibility abilities were evaluated with an established sentence test in noise. Furthermore, the discrimination abilities were measured electrophysiologically by recording the mismatch negativity (MMN) as a component of auditory event-related potentials. The results show a clear MMN response only for normal hearing listeners and CI users with good performance, correlating with their logatome discrimination abilities. Higher discrimination scores for vowel-replacement paradigms than for the consonant-replacement paradigms were found. We conclude that the logatome discrimination test is well suited to monitor the speech perception skills of CI users. Due to the large number of available spoken logatome items, the Oldenburg Logatome Corpus appears to provide a useful and powerful basis for further development of speech perception tests for CI users.


2021 ◽  
Vol 37 (1) ◽  
Author(s):  
Younes Lotfi ◽  
Mahdieh Hasanalifard ◽  
Abdollah Moossavi ◽  
Enayatollah Bakhshi ◽  
Mohammad Ajalloueyan

Abstract Background The objective of this study was to evaluate the effect of “Spatially separated speech in noise” auditory training on the ability of speech perception in noise among bimodal fitting users. The assumption was that the rehabilitation can enhance spatial hearing and hence speech in noise perception. This study was an interventional study, with a pre/post-design. Speech recognition ability was assessed with the specific tests. After performing the rehabilitation stages in the intervention group, the speech tests were again implemented, and by comparing the pre- and post-intervention data, the effect of auditory training on the speech abilities was assessed. Twenty-four children of 8–12 years who had undergone cochlear implantation and continuously used bimodal fitting were investigated in two groups of control and intervention. Results The results showed a significant difference between the groups in different speech tests after the intervention, which indicated that the intervention group have improved more than the control group. Conclusion It can be concluded that “Spatially separated speech in noise” auditory training can improve the speech perception in noise in bimodal fitting users. In general, this rehabilitation method is useful for enhancing the speech in noise perception ability.


2019 ◽  
Author(s):  
Mark D. Fletcher ◽  
Amatullah Hadeedi ◽  
Tobias Goehring ◽  
Sean R Mills

Cochlear implant (CI) users receive only limited sound information through their implant, which means that they struggle to understand speech in noisy environments. Recent work has suggested that combining the electrical signal from the CI with a haptic signal that provides crucial missing sound information (“electro-haptic stimulation”; EHS) could improve speech-in-noise performance. The aim of the current study was to test whether EHS could enhance speech-in-noise performance in CI users using: (1) a tactile signal derived using an algorithm that could be applied in real time, (2) a stimulation site appropriate for a real-world application, and (3) a tactile signal that could readily be produced by a compact, portable device. We measured speech intelligibility in multi-talker noise with and without vibro-tactile stimulation of the wrist in CI users, before and after a short training regime. No effect of EHS was found before training, but after training EHS was found to improve the number of words correctly identified by an average of 8.3 %-points, with some users improving by more than 20 %-points. Our approach could offer an inexpensive and non-invasive means of improving speech-in-noise performance in CI users.


2016 ◽  
Vol 21 (6) ◽  
pp. 383-390 ◽  
Author(s):  
Rebecca L. Heywood ◽  
Deborah A. Vickers ◽  
Francesca Pinto ◽  
George Fereos ◽  
Azhar Shaida

The objectives of this study were to assess: (i) patient expectations met as a measure of outcome in early-deafened, late-implanted (non-traditional) cochlear implant recipients and (ii) pre-implantation predictive factors for postoperative speech perception. The notes of 13 recipients were retrospectively reviewed. The mean age at onset of profound deafness was 1.5 years (range 0-6). The mean age at implantation was 37 years (range 22-51 years). Patient expectations were assessed pre-operatively and 1 year after implantation. They were met or exceeded in 129/140 (92%) domains overall. A higher Speech Intelligibility Rating and audiovisual City University of New York sentence score before implantation were found to be positive predictive factors for improved speech discrimination after cochlear implantation.


2018 ◽  
Author(s):  
N Freimann ◽  
D Polterauer ◽  
S Gollwitzer ◽  
J Müller ◽  
ME Schuster

2014 ◽  
Vol 25 (04) ◽  
pp. 367-379 ◽  
Author(s):  
Lisa G. Potts ◽  
Kelly A. Kolb

Background: Difficulty understanding speech in the presence of background noise is a common report among cochlear implant (CI) recipients. Several speech-processing options designed to improve speech recognition, especially in noise, are currently available in the Cochlear Nucleus CP810 speech processor. These include adaptive dynamic range optimization (ADRO), autosensitivity control (ASC), Beam, and Zoom. Purpose: The purpose of this study was to evaluate CI recipients’ speech-in-noise recognition to determine which currently available processing option or options resulted in best performance in a simulated restaurant environment. Research Design: Experimental study with one study group. The independent variable was speech-processing option, and the dependent variable was the reception threshold for sentences score. Study Sample: Thirty-two adult CI recipients. Intervention: Eight processing options were tested: Beam, Beam + ASC, Beam + ADRO, Beam + ASC + ADRO, Zoom, Zoom + ASC, Zoom + ADRO, and Zoom + ASC + ADRO. Data Collection and Analysis: Participants repeated Hearing in Noise Test sentences presented at a 0° azimuth, with R-Space restaurant noise presented from a 360° eight-loudspeaker array at 70 dB sound pressure level. A one-way repeated-measures analysis of variance was used to analyze differences in Beam options, Zoom options, and Beam versus Zoom options. Results: Among the Beam options, Beam + ADRO was significantly poorer than Beam only, Beam + ASC, and Beam + ASC + ADRO. A 1.6-dB difference was observed between the best (Beam only) and poorest (Beam + ADRO) options. Among the Zoom options, Zoom only and Zoom + ADRO were significantly poorer than Zoom + ASC. A 2.2-dB difference was observed between the best (Zoom + ASC) and poorest (Zoom only) options. The comparison between Beam and Zoom options showed one significant difference, with Zoom only significantly poorer than Beam only. No significant difference was found between the other Beam and Zoom options (Beam + ASC vs Zoom + ASC, Beam + ADRO vs Zoom + ADRO, and Beam + ASC + ADRO vs Zoom + ASC + ADRO). The best processing option varied across subjects, with an almost equal number of participants performing best with a Beam option (n = 15) compared with a Zoom option (n = 17). There were no significant demographic or audiological moderating variables for any option. Conclusions: The results showed no significant differences between adaptive directionality (Beam) and fixed directionality (Zoom) when ASC was active in the R-Space environment. This finding suggests that noise-reduction processing is extremely valuable in loud semidiffuse environments in which the effectiveness of directional filtering might be diminished. However, there was no significant difference between the Beam-only and Beam + ASC options, which is most likely related to the additional noise cancellation performed by the Beam option (i.e., two-stage directional filtering and noise cancellation). In addition, the processing options with ADRO resulted in the poorest performances. This could be related to how the CI recipients were programmed or the loud noise level used in this study. The best processing option varied across subjects, but the majority performed best with directional filtering (Beam or Zoom) in combination with ASC. Therefore in a loud semidiffuse environment, the use of either Beam + ASC or Zoom + ASC is recommended.


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