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

Zirn, Stefan; Angermeier, Julian; Arndt, Susan; Aschendorff, Antje; Wesarg, Thomas

doi:10.1177/2331216519843876

Cited by 35 publications

(41 citation statements)

References 27 publications

(45 reference statements)

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“…Simulations of bimodal hearing suggest that disruptive effects of mismatched compression across ears may also occur for CI users ( Wess & Bernstein, 2019 ). Further, envelope distortion and differences in processing times of the CI and HA devices can also degrade performance in bimodal listeners ( Wess & Bernstein, 2019 ; Zirn et al., 2019 ). Investigations of device setting manipulations are needed to support the clinical decision making to optimize outcomes in CI recipients with AHL and UHL.…”

Section: Discussionmentioning

confidence: 99%

Cochlear Implantation in Cases of Asymmetric Hearing Loss: Subjective Benefit, Word Recognition, and Spatial Hearing

et al. 2020

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A prospective clinical trial evaluated the effectiveness of cochlear implantation in adults with asymmetric hearing loss (AHL). Twenty subjects with mild-to-moderate hearing loss in the better ear and moderate-to-profound hearing loss in the poorer ear underwent cochlear implantation of the poorer hearing ear. Subjects were evaluated preoperatively and at 1, 3, 6, 9, and 12 months post-activation. Preoperative performance was evaluated unaided, with traditional hearing aids (HAs) or with a bone-conduction HA. Post-activation performance was evaluated with the cochlear implant (CI) alone or in combination with a contralateral HA (bimodal). Test measures included subjective benefit, word recognition, and spatial hearing (i.e., localization and masked sentence recognition). Significant subjective benefit was reported as early as the 1-month interval, indicating better performance with the CI compared with the preferred preoperative condition. Aided word recognition with the CI alone was significantly improved at the 1-month interval compared with preoperative performance with an HA and continued to improve through the 12-month interval. Subjects demonstrated early, significant improvements in the bimodal condition on the spatial hearing tasks compared with baseline preoperative performance tested unaided. The magnitude of the benefit was reduced for subjects with AHL when compared with published data on CI users with normal hearing in the contralateral ear; this finding may reflect significant differences in age at implantation and hearing sensitivity across cohorts.

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Section: Discussionmentioning

confidence: 99%

Cochlear Implantation in Cases of Asymmetric Hearing Loss: Subjective Benefit, Word Recognition, and Spatial Hearing

et al. 2020

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“…This heterogeneity might disguise potential correlations between accuracy of localization and JND-ITDs, since accuracy was measured with different modes of amplification, while JND-ITD was determined with headphone presentation of stimuli. The delay introduced by signal processing in the hearing aid (on average between 3 ms and 11 ms [ 11 ]) potentially distorts the transfer of temporal binaural timing cues [ 40 ].…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2020

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In this study, localization accuracy and sensitivity to acoustic interaural time differences (ITDs) in subjects using cochlear implants with combined electric-acoustic stimulation (EAS) were assessed and compared with the results of a normal hearing control group. Methods Eight CI users with EAS (2 bilaterally implanted, 6 unilaterally implanted) and symmetric binaural acoustic hearing and 24 normal hearing subjects participated in the study. The first experiment determined mean localization error (MLE) for different angles of sound incidence between ± 60˚(frontal and dorsal presentation). The stimuli were either low-pass, high-pass or broadband noise bursts. In a second experiment, just noticeable differences (JND) of ITDs were measured for pure tones of 125 Hz, 250 Hz and 500 Hz (headphone presentation). Results Experiment 1: MLE of EAS subjects was 8.5˚, 14.3˚and 14.7˚, (low-, high-pass and broadband stimuli respectively). In the control group, MLE was 1.8˚(broadband stimuli). In the differentiation between sound incidence from front and back, EAS subjects performed on chance level. Experiment 2: The JND-ITDs were 88.7 μs for 125 Hz, 48.8 μs for 250 Hz and 52.9 μs for 500 Hz (EAS subjects). Compared to the control group, JND-ITD for 125 Hz was on the same level of performance. No statistically significant correlation was found between MLE and JND-ITD in the EAS cohort. Conclusions Near to normal ITD sensitivity in the lower frequency acoustic hearing was demonstrated in a cohort of EAS users. However, in an acoustic localization task, the majority of the subjects did not reached the level of accuracy of normal hearing. Presumably, signal processing time

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“…2016). Since the comparison of interaural signals is essential to accurate sound localization (Seebacher et al, 2019;Zirn et al, 2019), a delicate calibration between the signals received from the two ears must be maintained. Moreover, the efferent architecture has been shown to have a significant function in the "cocktail party effect," which refers to the ability to parse one particular auditory stream from a complex acoustic environment (Giraud et al, 1997;Kumar and Vanaja, 2004;Kim et al, 2006;Andéol et al, 2011;Smith and Keil, 2015;Lopez-Poveda et al, 2016).…”

Section: Significance Statementmentioning

confidence: 99%

Effects of Efferent Activity on Hair Bundle Mechanics

Lin

Bozovic

2020

J. Neurosci.

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Hair cells in both the auditory and vestibular systems receive efferent innervation. A number of prior studies have indicated that efferent regulation serves to diminish the overall sensitivity of the auditory system. The efferent pathway is believed to affect the sensitivity and frequency selectivity of the hair cell by modulating its membrane potential. However, its effect on the mechanical response of the hair cell has not been established. We explored how stimulation of the efferent neurons affects the mechanical responsiveness of an individual hair bundle. We tested this effect on in vitro preparations of hair cells in the sacculi of American bullfrogs of both genders. Efferent stimulation routinely resulted in an immediate increase of the frequency of hair bundle spontaneous oscillations for the duration of the stimulus. Enlarging the stimulus amplitude and pulse length, or conversely, decreasing the interpulse interval led to oscillation suppression. Additionally, we tested the effects of efference on the hair bundle response to mechanical stimulation. The receptive field maps of hair cells undergoing efferent actuation demonstrated an overall desensitization with respect to those of unstimulated cells.

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

Cited by 35 publications

References 27 publications

Cochlear Implantation in Cases of Asymmetric Hearing Loss: Subjective Benefit, Word Recognition, and Spatial Hearing

Cochlear Implantation in Cases of Asymmetric Hearing Loss: Subjective Benefit, Word Recognition, and Spatial Hearing

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

Effects of Efferent Activity on Hair Bundle Mechanics

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