Localization and Speech Understanding by a Patient With Bilateral Cochlear Implants and Bilateral Hearing Preservation

PurposeThe aim of this article is to summarize recent published and unpublished research from our 2 laboratories on improving speech understanding in complex listening environments by listeners fit with cochlear implants (CIs).MethodCI listeners were tested in 2 listening environments. One was a simulation of a restaurant with multiple, diffuse noise sources, and the other was a cocktail party with 2 spatially separated point sources of competing speech. At issue was the value of the following sources of information, or interventions, on speech understanding: (a) visual information, (b) adaptive beamformer microphones and remote microphones, (c) bimodal fittings, that is, a CI and contralateral low-frequency acoustic hearing, (d) hearing preservation fittings, that is, a CI with preserved low-frequency acoustic in the same ear plus low-frequency acoustic hearing in the contralateral ear, and (e) bilateral CIs.ResultsA remote microphone provided the largest improvement in speech understanding. Visual information and adaptive beamformers ranked next, while bimodal fittings, bilateral fittings, and hearing preservation provided significant but less benefit than the other interventions or sources of information. Only bilateral CIs allowed listeners high levels of speech understanding when signals were roved over the frontal plane.ConclusionsThe evidence supports the use of bilateral CIs and hearing preservation surgery for best speech understanding in complex environments. These fittings, when combined with visual information and microphone technology, should lead to high levels of speech understanding by CI patients in complex listening environments.Presentation Videohttp://cred.pubs.asha.org/article.aspx?articleid=2601622

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Experiments on Auditory-Visual Perception of Sentences by Users of Unilateral, Bimodal, and Bilateral Cochlear Implants

Journal of Speech Language and Hearing Research ◽

10.1044/2016_jslhr-h-15-0312 ◽

2016 ◽

Vol 59 (6) ◽

pp. 1505-1519 ◽

Cited By ~ 15

Author(s):

Michael F. Dorman ◽

Julie Liss ◽

Shuai Wang ◽

Visar Berisha ◽

Cimarron Ludwig ◽

...

Keyword(s):

Cochlear Implants ◽

Low Frequency ◽

Normal Hearing ◽

Relative Strength ◽

Speech Understanding ◽

Bilateral Cochlear Implants ◽

Place Of Articulation ◽

Percentage Points ◽

Test Conditions ◽

Lexical Segmentation

Purpose Five experiments probed auditory-visual (AV) understanding of sentences by users of cochlear implants (CIs). Method Sentence material was presented in auditory (A), visual (V), and AV test conditions to listeners with normal hearing and CI users. Results (a) Most CI users report that most of the time, they have access to both A and V information when listening to speech. (b) CI users did not achieve better scores on a task of speechreading than did listeners with normal hearing. (c) Sentences that are easy to speechread provided 12 percentage points more gain to speech understanding than did sentences that were difficult. (d) Ease of speechreading for sentences is related to phrase familiarity. (e) Users of bimodal CIs benefit from low-frequency acoustic hearing even when V cues are available, and a second CI adds to the benefit of a single CI when V cues are available. (f) V information facilitates lexical segmentation by improving the recognition of the number of syllables produced and the relative strength of these syllables. Conclusions Our data are consistent with the view that V information improves CI users' ability to identify syllables in the acoustic stream and to recognize their relative juxtaposed strengths. Enhanced syllable resolution allows better identification of word onsets, which, when combined with place-of-articulation information from visible consonants, improves lexical access.

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Speech Understanding in Noise by Patients With Cochlear Implants Using a Monaural Adaptive Beamformer

Journal of Speech Language and Hearing Research ◽

10.1044/2017_jslhr-h-16-0312 ◽

2017 ◽

Vol 60 (8) ◽

pp. 2360-2363 ◽

Cited By ~ 1

Author(s):

Michael F. Dorman ◽

Sarah Natale ◽

Anthony Spahr ◽

Erin Castioni

Keyword(s):

Cochlear Implants ◽

Hearing Preservation ◽

Speech Understanding ◽

Cocktail Party ◽

Test Protocol ◽

Noise Environment ◽

Adaptive Beamformer ◽

Speech Understanding In Noise

Purpose The aim of this experiment was to compare, for patients with cochlear implants (CIs), the improvement for speech understanding in noise provided by a monaural adaptive beamformer and for two interventions that produced bilateral input (i.e., bilateral CIs and hearing preservation [HP] surgery). Method Speech understanding scores for sentences were obtained for 10 listeners fit with a single CI. The listeners were tested with and without beamformer activated in a “cocktail party” environment with spatially separated target and maskers. Data for 10 listeners with bilateral CIs and 8 listeners with HP CIs were taken from Loiselle, Dorman, Yost, Cook, and Gifford (2016), who used the same test protocol. Results The use of the beamformer resulted in a 31 percentage point improvement in performance; in bilateral CIs, an 18 percentage point improvement; and in HP CIs, a 20 percentage point improvement. Conclusion A monaural adaptive beamformer can produce an improvement in speech understanding in a complex noise environment that is equal to, or greater than, the improvement produced by bilateral CIs and HP surgery.

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Bilateral Cochlear Implants Allow Listeners to Benefit from Visual Information When Talker Location is Varied

Journal of the American Academy of Audiology ◽

10.1055/s-0040-1709444 ◽

2020 ◽

Vol 31 (07) ◽

pp. 547-550

Author(s):

Michael F. Dorman ◽

Sarah Natale ◽

Alissa Knickerbocker

Keyword(s):

Cochlear Implants ◽

Visual Information ◽

Target Sentence ◽

Test Material ◽

Speech Understanding ◽

Improve Performance ◽

Test Environment ◽

Bilateral Cochlear Implants ◽

Test Conditions ◽

Different Response

Abstract Background Previous research has found that when the location of a talker was varied and an auditory prompt indicated the location of the talker, the addition of visual information produced a significant and large improvement in speech understanding for listeners with bilateral cochlear implants (CIs) but not with a unilateral CI. Presumably, the sound-source localization ability of the bilateral CI listeners allowed them to orient to the auditory prompt and benefit from visual information for the subsequent target sentence. Purpose The goal of this project was to assess the robustness of previous research by using a different test environment, a different CI, different test material, and a different response measure. Research Design Nine listeners fit with bilateral CIs were tested in a simulation of a crowded restaurant. Auditory–visual (AV) sentence material was presented from loudspeakers and video monitors at 0, +90, and −90 degrees. Each trial started with the presentation of an auditory alerting phrase from one of the three target loudspeakers followed by an AV target sentence from that loudspeaker/monitor. On each trial, the two nontarget monitors showed the speaker mouthing a different sentence. Sentences were presented in noise in four test conditions: one CI, one CI plus vision, bilateral CIs, and bilateral CIs plus vision. Results Mean percent words correct for the four test conditions were: one CI, 43%; bilateral CI, 60%; one CI plus vision, 52%; and bilateral CI plus vision, 84%. Visual information did not significantly improve performance in the single CI conditions but did improve performance in the bilateral CI conditions. The magnitude of improvement for two CIs versus one CI in the AV condition was approximately twice that for two CIs versus one CI in the auditory condition. Conclusions Our results are consistent with previous data showing the large value of bilateral implants in a complex AV listening environment. The results indicate that the value of bilateral CIs for speech understanding is significantly underestimated in standard, auditory-only, single-speaker, test environments.

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Spatial Release From Masking in Adults With Bilateral Cochlear Implants: Effects of Distracter Azimuth and Microphone Location

Journal of Speech Language and Hearing Research ◽

10.1044/2017_jslhr-h-16-0441 ◽

2018 ◽

Vol 61 (3) ◽

pp. 752-761 ◽

Cited By ~ 1

Author(s):

Timothy J. Davis ◽

René H. Gifford

Keyword(s):

Cochlear Implants ◽

Spatial Configuration ◽

Block Design ◽

Speech Understanding ◽

Traditional Assessment ◽

Bilateral Cochlear Implants ◽

Secondary Purpose ◽

Spatial Release ◽

Bilateral Cochlear Implant ◽

Release From Masking

PurposeThe primary purpose of this study was to derive spatial release from masking (SRM) performance-azimuth functions for bilateral cochlear implant (CI) users to provide a thorough description of SRM as a function of target/distracter spatial configuration. The secondary purpose of this study was to investigate the effect of the microphone location for SRM in a within-subject study design.MethodSpeech recognition was measured in 12 adults with bilateral CIs for 11 spatial separations ranging from −90° to +90° in 20° steps using an adaptive block design. Five of the 12 participants were tested with both the behind-the-ear microphones and a T-mic configuration to further investigate the effect of mic location on SRM.ResultsSRM can be significantly affected by the hemifield origin of the distracter stimulus—particularly for listeners with interaural asymmetry in speech understanding. The greatest SRM was observed with a distracter positioned 50° away from the target. There was no effect of mic location on SRM for the current experimental design.ConclusionOur results demonstrate that the traditional assessment of SRM with a distracter positioned at 90° azimuth may underestimate maximum performance for individuals with bilateral CIs.

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Using ILD or ITD Cues for Sound Source Localization and Speech Understanding in a Complex Listening Environment by Listeners With Bilateral and With Hearing-Preservation Cochlear Implants

Journal of Speech Language and Hearing Research ◽

10.1044/2015_jslhr-h-14-0355 ◽

2016 ◽

Vol 59 (4) ◽

pp. 810-818 ◽

Cited By ~ 23

Author(s):

Louise H. Loiselle ◽

Michael F. Dorman ◽

William A. Yost ◽

Sarah J. Cook ◽

Rene H. Gifford

Keyword(s):

Cochlear Implants ◽

Source Localization ◽

Sound Source ◽

Hearing Preservation ◽

Sound Source Localization ◽

Speech Understanding ◽

Cocktail Party ◽

Localization Accuracy ◽

Low Pass ◽

High Pass

PurposeTo assess the role of interaural time differences and interaural level differences in (a) sound-source localization, and (b) speech understanding in a cocktail party listening environment for listeners with bilateral cochlear implants (CIs) and for listeners with hearing-preservation CIs.MethodsEleven bilateral listeners with MED-EL (Durham, NC) CIs and 8 listeners with hearing-preservation CIs with symmetrical low frequency, acoustic hearing using the MED-EL or Cochlear device were evaluated using 2 tests designed to task binaural hearing, localization, and a simulated cocktail party. Access to interaural cues for localization was constrained by the use of low-pass, high-pass, and wideband noise stimuli.ResultsSound-source localization accuracy for listeners with bilateral CIs in response to the high-pass noise stimulus and sound-source localization accuracy for the listeners with hearing-preservation CIs in response to the low-pass noise stimulus did not differ significantly. Speech understanding in a cocktail party listening environment improved for all listeners when interaural cues, either interaural time difference or interaural level difference, were available.ConclusionsThe findings of the current study indicate that similar degrees of benefit to sound-source localization and speech understanding in complex listening environments are possible with 2 very different rehabilitation strategies: the provision of bilateral CIs and the preservation of hearing.

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