Reducing the Device Delay Mismatch Can Improve Sound Localization in Bimodal Cochlear Implant/Hearing-Aid Users

In users of a cochlear implant (CI) together with a contralateral hearing aid (HA), so-called bimodal listeners, differences in processing latencies between digital HA and CI up to 9 ms constantly superimpose interaural time differences. In the present study, the effect of this device delay mismatch on sound localization accuracy was investigated. For this purpose, localization accuracy in the frontal horizontal plane was measured with the original and minimized device delay mismatch. The reduction was achieved by delaying the CI stimulation according to the delay of the individually worn HA. For this, a portable, programmable, battery-powered delay line based on a ring buffer running on a microcontroller was designed and assembled. After an acclimatization period to the delayed CI stimulation of 1 hr, the nine bimodal study participants showed a highly significant improvement in localization accuracy of 11.6% compared with the everyday situation without the delay line ( p < .01). Concluding, delaying CI stimulation to minimize the device delay mismatch seems to be a promising method to increase sound localization accuracy in bimodal listeners.

Download Full-text

Comparing the Effect of Different Hearing Aid Fitting Methods in Bimodal Cochlear Implant Users

American Journal of Audiology ◽

10.1044/2018_aja-18-0067 ◽

2019 ◽

Vol 28 (1) ◽

pp. 1-10 ◽

Cited By ~ 3

Author(s):

Jantien L. Vroegop ◽

J. Gertjan Dingemanse ◽

Marc P. van der Schroeff ◽

André Goedegebure

Keyword(s):

Cochlear Implant ◽

Sound Localization ◽

Hearing Aid ◽

Hearing Aid Fitting ◽

Speech In Noise ◽

Localization Test ◽

Fitting Procedures ◽

Auditory Performance ◽

Contralateral Ear ◽

Noise Test

PurposeThe aim of the study was to investigate the effect of 3 hearing aid fitting procedures on provided gain of the hearing aid in bimodal cochlear implant users and their effect on bimodal benefit.MethodThis prospective study measured hearing aid gain and auditory performance in a cross-over design in which 3 hearing aid fitting methods were compared. Hearing aid fitting methods differed in initial gain prescription rule (NAL-NL2 and Audiogram+) and loudness balancing method (broadband vs. narrowband loudness balancing). Auditory functioning was evaluated by a speech-in-quiet test, a speech-in-noise test, and a sound localization test. Fourteen postlingually deafened adult bimodal cochlear implant users participated in the study.ResultsNo differences in provided gain and in bimodal performance were found for the different hearing aid fittings. For all hearing aid fittings, a bimodal benefit was found for speech in noise and sound localization.ConclusionOur results confirm that cochlear implant users with residual hearing in the contralateral ear substantially benefit from bimodal stimulation. However, on average, no differences were found between different types of fitting methods, varying in prescription rule and loudness balancing method.

Download Full-text

Sensitivity to interaural time differences and localization accuracy in cochlear implant users with combined electric-acoustic stimulation

PLoS ONE ◽

10.1371/journal.pone.0241015 ◽

2020 ◽

Vol 15 (10) ◽

pp. e0241015

Author(s):

Monika Körtje ◽

Uwe Baumann ◽

Timo Stöver ◽

Tobias Weissgerber

Keyword(s):

Cochlear Implant ◽

Acoustic Stimulation ◽

Interaural Time Differences ◽

Localization Accuracy ◽

Electric Acoustic Stimulation

Download Full-text

Amount of Frequency Compression in Bimodal Cochlear Implant Users Is a Poor Predictor for Audibility and Spatial Hearing

Journal of Speech Language and Hearing Research ◽

10.1044/2021_jslhr-20-00653 ◽

2021 ◽

pp. 1-14

Author(s):

Snandan Sharma ◽

Waldo Nogueira ◽

A. John van Opstal ◽

Josef Chalupper ◽

Lucas H. M. Mens ◽

...

Keyword(s):

Speech Recognition ◽

Cochlear Implant ◽

Sound Localization ◽

High Frequency ◽

Hearing Aid ◽

Spatial Hearing ◽

Meaningful Improvement ◽

Frequency Compression ◽

Knee Point ◽

Localization Performance

Purpose Speech understanding in noise and horizontal sound localization is poor in most cochlear implant (CI) users with a hearing aid (bimodal stimulation). This study investigated the effect of static and less-extreme adaptive frequency compression in hearing aids on spatial hearing. By means of frequency compression, we aimed to restore high-frequency audibility, and thus improve sound localization and spatial speech recognition. Method Sound-detection thresholds, sound localization, and spatial speech recognition were measured in eight bimodal CI users, with and without frequency compression. We tested two compression algorithms: a static algorithm, which compressed frequencies beyond the compression knee point (160 or 480 Hz), and an adaptive algorithm, which aimed to compress only consonants leaving vowels unaffected (adaptive knee-point frequencies from 736 to 2946 Hz). Results Compression yielded a strong audibility benefit (high-frequency thresholds improved by 40 and 24 dB for static and adaptive compression, respectively), no meaningful improvement in localization performance (errors remained > 30 deg), and spatial speech recognition across all participants. Localization biases without compression (toward the hearing-aid and implant side for low- and high-frequency sounds, respectively) disappeared or reversed with compression. The audibility benefits provided to each bimodal user partially explained any individual improvements in localization performance; shifts in bias; and, for six out of eight participants, benefits in spatial speech recognition. Conclusions We speculate that limiting factors such as a persistent hearing asymmetry and mismatch in spectral overlap prevent compression in bimodal users from improving sound localization. Therefore, the benefit in spatial release from masking by compression is likely due to a shift of attention to the ear with the better signal-to-noise ratio facilitated by compression, rather than an improved spatial selectivity. Supplemental Material https://doi.org/10.23641/asha.16869485

Download Full-text

Horizontal sound localization in cochlear implant users with a contralateral hearing aid

Hearing Research ◽

10.1016/j.heares.2016.04.008 ◽

2016 ◽

Vol 336 ◽

pp. 72-82 ◽

Cited By ~ 8

Author(s):

Lidwien C.E. Veugen ◽

Maartje M.E. Hendrikse ◽

Marc M. van Wanrooij ◽

Martijn J.H. Agterberg ◽

Josef Chalupper ◽

...

Keyword(s):

Cochlear Implant ◽

Sound Localization ◽

Hearing Aid

Download Full-text

Sound Localization and Binaural Hearing in Children with a Hearing Aid and a Cochlear Implant

Audiology and Neurotology ◽

10.1159/000218361 ◽

2010 ◽

Vol 15 (1) ◽

pp. 36-43 ◽

Cited By ~ 8

Author(s):

J. Beijen ◽

A.F.M. Snik ◽

L.V. Straatman ◽

E.A.M. Mylanus ◽

L.H.M. Mens

Keyword(s):

Cochlear Implant ◽

Sound Localization ◽

Hearing Aid ◽

Binaural Hearing

Download Full-text

Impact of Reverberation on Speech Perception and Sound Localization Accuracy in Cochlear Implant Users With Single-Sided Deafness

Otology & Neurotology ◽

10.1097/mao.0000000000003335 ◽

2021 ◽

Vol Publish Ahead of Print ◽

Author(s):

Monika Körtje ◽

Anja Eichenauer ◽

Timo Stöver ◽

Uwe Baumann ◽

Tobias Weissgerber

Keyword(s):

Speech Perception ◽

Cochlear Implant ◽

Sound Localization ◽

Localization Accuracy ◽

Single Sided Deafness

Download Full-text

Chronic Bilateral Cochlear Implant Stimulation in Early-Deaf Rabbits Restores Neural Binaural Sensitivity

10.1101/803627 ◽

2019 ◽

Author(s):

Woongsang Sunwoo ◽

Bertrand Delgutte ◽

Yoojin Chung

Keyword(s):

Cochlear Implant ◽

Sound Localization ◽

Temporal Coding ◽

Functional Restoration ◽

Single Neurons ◽

Chronic Stimulation ◽

Interaural Time Differences ◽

Speech Reception ◽

Bilateral Cochlear Implant ◽

Auditory Experience

AbstractCochlear implant (CI) users with a pre-lingual onset of hearing loss show poor sensitivity to interaural time differences (ITD), an important cue for sound localization and speech reception in noise. Similarly, neural ITD sensitivity in the inferior colliculus (IC) of neonatally-deafened animals is degraded compared to animals deafened as adults. Here, we show that chronic bilateral CI stimulation during development can partly reverse the effect of early-onset deafness on ITD sensitivity. The prevalence of ITD sensitive neurons was restored to the level of adult-deaf rabbits in the early-deaf rabbits that received chronic stimulation with wearable bilateral sound processors during development. In contrast, chronic CI stimulation did not improve temporal coding in early-deaf rabbits. The present study is the first report showing functional restoration of ITD sensitivity with CI stimulation in single neurons and highlights the importance of auditory experience during development.

Download Full-text

Predictors of Purchasing a Hearing Aid After an Evaluation Period: A Prospective Study in Dutch Older Hearing Aid Candidates

American Journal of Audiology ◽

10.1044/2019_aja-heal18-18-0163 ◽

2019 ◽

Vol 28 (3S) ◽

pp. 802-805 ◽

Cited By ~ 1

Author(s):

Marieke Pronk ◽

Janine F. J. Meijerink ◽

Sophia E. Kramer ◽

Martijn W. Heymans ◽

Jana Besser

Keyword(s):

Help Seeking ◽

Hearing Aid ◽

Model Performance ◽

Area Under The Curve ◽

Secondary Data ◽

Support Program ◽

Evaluation Period ◽

A Prospective Study ◽

Study Participants ◽

Baseline Covariates

Purpose The current study aimed to identify factors that distinguish between older (50+ years) hearing aid (HA) candidates who do and do not purchase HAs after having gone through an HA evaluation period (HAEP). Method Secondary data analysis of the SUpport PRogram trial was performed ( n = 267 older, 1st-time HA candidates). All SUpport PRogram participants started an HAEP shortly after study enrollment. Decision to purchase an HA by the end of the HAEP was the outcome of interest of the current study. Participants' baseline covariates (22 in total) were included as candidate predictors. Multivariable logistic regression modeling (backward selection and reclassification tables) was used. Results Of all candidate predictors, only pure-tone average (average of 1, 2, and 4 kHz) hearing loss emerged as a significant predictor (odds ratio = 1.03, 95% confidence interval [1.03, 1.17]). Model performance was weak (Nagelkerke R 2 = .04, area under the curve = 0.61). Conclusions These data suggest that, once HA candidates have decided to enter an HAEP, factors measured early in the help-seeking journey do not predict well who will and will not purchase an HA. Instead, factors that act during the HAEP may hold this predictive value. This should be examined.

Download Full-text