The Effect of Bimodal Hearing on Postoperative Quality of Life.

INTRODUCTION: The aim of this study was to examine how bimodal stimulation affects quality of life (QOL) during the postoperative period following cochlear implantation (CI). These data could potentially provide evidence to encourage more bimodal candidates to continue hearing aid (HA) use after CI. METHODS: In this prospective study, patients completed preoperative and 1-, 3-, and 6-month post-activation QOL surveys on listening effort, speech perception, sound quality/localization, and hearing handicap. Fifteen HA users who were candidates for contralateral CI completed the study (mean age 65.6 years). RESULTS: Patients used both devices at a median rate of 97%, 97%, and 98% of the time at 1, 3, and 6 months, respectively. On average, patients' hearing handicap scores decreased by 16% at 1 month, 36% at 3 months, and 30% at 6 months. Patients' listening effort scores decreased by a mean of 10.8% at 1 month, 12.6% at 3 months, and 18.7% at 6 months. Localization significantly improved by 24.3% at 1 month and remained steady. There was no significant improvement in sound quality scores. CONCLUSION: Bimodal listeners should expect QOL to improve, and listening effort and localization are generally optimized using CI and HA compared to CI alone. Some scores improved at earlier time points than others, suggesting bimodal auditory skills may develop at different rates.

The Benefit of Bimodal Hearing and Beamforming for Cochlear Implant Users.

INTRODUCTION: Cochlear implantation is the standard treatment for severe to profound hearing loss. While cochlear implant (CI) users can communicate effectively in quiet environments, speech understanding in noise remains challenging. Bimodal hearing, combining a CI in one ear and a hearing aid (HA) in the other, has shown advantages over unilateral electrical hearing, especially for speech understanding in noisy conditions. Beamforming is a technique used to improve speech understanding in noise by detecting sound direction and enhancing frontal (speech) sounds while attenuating background noise. One specific beamformer, Stereozoom, combines signals from microphones in both ears to create a focused beam toward the front resulting in a binaural beamformer (BB), in order to improve speech intelligibility in noise for bilateral and bimodal CI users. METHODS: A prospective crossover study involving 17 bimodal CI users was conducted, and participants were tested with various device configurations (CI, HA, CI + HA) with and without BB. Speech recognition testing with the Dutch/Flemish matrix test was performed in a sound-attenuated booth with diffuse noise to simulate realistic listening conditions. RESULTS: The results showed a statistically significant benefit of bimodal hearing over the CI configuration and showed a statistical significant benefit of BB for the CI and CI + HA configuration. The benefit of BB in the HA configuration was not statistically significant probably due to the higher variance. The benefit of BB in the three configurations did not differ statistically significant. CONCLUSION: In conclusion, bimodal hearing offers advantages for speech understanding in noise for CI users. BB provides a benefit in various device configurations, leading to improved speech intelligibility when speech comes from the front in challenging listening environments.

[Audiological outcome of bimodal CI users over time and depending on different influencing factors]. / Audiologisches Ergebnis bimodal versorgter CI-Träger:innen im zeitlichen Verlauf und in Abhängigkeit unterschiedlicher Einflussfaktoren.

BACKGROUND: Hearing-impaired persons with asymmetric hearing loss and a unilateral indication for a cochlear implant (CI) generally benefit from a bimodal hearing solution. The influence of bimodal fitting on speech comprehension (SC) over time has not yet been sufficiently investigated. The present study examines the influence of bimodal fitting on SC in bimodally fitted CI users with postlingual deafness at least 36 months after implantation and analyzes possible influencing factors. METHODS: Included in this retrospective longitudinal study were 54 bimodally fitted speech-competent CI users with at least 36 months of CI experience. Audiometric data of these CI users at predefined timepoints were compared. RESULTS: The change in the results of the Freiburg monosyllabic test (FT) over 36 months was significant (p < 5%) for the deafness group at <10 years for both the 65 dB sound pressure level (SPL) and at 80 dB SPL and also significant for the deafness group ≥10 years for 65 dB SPL. In the Oldenburg sentence test (OlSa) there was a highly significant change (p < 0.1%) for S0, S0N0, and S0NCI configurations and a very significant change (p < 1%) for S0NHA (HA: hearing aid). Age at implantation as a possible influencing factor could not be confirmed in the FT. In contrast, the duration of deafness was a negative influencing factor for SC with CI in the FT, whereas a longer duration of deafness was associated with worse results in the FT. The degree of hearing loss in the ear fitted with an HA did not influence SC. The median bimodal benefit (here: difference in SC with bimodal fitting compared to unilateral HA fitting for FT at 65 dB SPL) was 10% over the total study period. For a median of 79% of the test subjects, the bimodal benefit was found over the entire period of 36 months. CONCLUSION: Over time, SC improves significantly with a CI for the bimodal test subjects. The investigated influencing factors (age, duration of deafness, and degree of hearing loss in the contralateral ear) support the indication for bimodal provision in accordance with the guideline in Germany for cochlear implantation-regardless of age, duration of deafness, and hearing ability of the contralateral ear.

Production of Tone 2 in disyllabic words in Mandarin Chinese speaking children aged 3-5 with a cochlear implant and a contralateral hearing aid.

To investigate Mandarin Tone 2 production of disyllabic words of prelingually deafened children with a cochlear implant (CI) and a contralateral hearing aid (HA) and to evaluate the relationship between their demographic variables and tone-production ability. Thirty prelingually Mandarin-speaking preschoolers with CI+HA and 30 age-matched normal-hearing (NH) children participated in the study. Fourteen disyllabic words were recorded from each child. A total of 840 tokens (14 × 60) were then used in tone-perception tests in which four speech therapists participated. The production of T2-related disyllabic words of the bimodal group was significantly worse than that of the NH group, as reflected in the overall accuracy (88.57% ± 16.31% vs 99.29% ± 21.79%, p < 0.05), the accuracy of T1+T2 (93.33% vs 100%), the accuracy of T2+T1 (66.67 ± 37.91% vs 98.33 ± 9.13%), and the accuracy of T2+T4 (78.33 ± 33.95% vs 100%). In addition, the bimodal group showed significantly inferior production accuracy of T2+T1 than T2+T2 and T3+T2, p < 0.05. Both bimodal age and implantation age were significantly negatively correlated with the overall production accuracy, p < 0.05. For the error patterns, bimodal participants experienced more errors when T2 was in the first position of the tone combination, and T2 was most likely to be mispronounced as T1 and T3. Bimodal patients aged 3-5 have T2-related disyllabic lexical tone production defects, and their performances are related to tone combination, implantation age, and bimodal age.

Bimodal cochlear implantation in elderly patients.

OBJECTIVE: Bimodal stimulation is a standard option for asymmetric hearing loss in adults. Questions have been raised whether receiving two stimulations may conflict in elderly listeners where the central integration of an acoustic/electrical signal may be very important to obtain benefit in terms of speech perception. DESIGN: Clinical retrospective study. STUDY SAMPLE: The outcomes from 17 bimodal cochlear implant (CI) users were analysed. The test material consisted of speech audiometry in quiet and in noise (STARR and Matrix). RESULTS: Bimodal PTA and speech perception both in quiet and in noise were significantly better than CI or HA alone. Age showed a significant effect on bimodal STARR outcomes. Similarly, bimodal STARR scores improved significantly in comparison to Better Ear. CONCLUSION: Both Matrix and STARR tests were very difficult for many elderly CI listeners from the present study group, especially in unilateral listening condition. The performance improved significantly, emphasising a good integration of acoustic and electric hearing in this group of elderly bimodal listeners. Overall results highlighted how a specific study, based on speech perception in noise in the elderly listeners, might shed light on the effect of speech test modality on bimodal outcomes.

The P300 auditory event-related potential as a method to assess the benefit of contralateral hearing aid use in bimodal listeners: a proof-of-concept.

Objective: Bimodal listeners vary in the amount of benefit they receive from wearing the contralateral hearing aid. This may partially depend on the listener's auditory processing capacities. The current study explores whether the P300 event-related potential can provide insight into the mechanisms underlying the benefits of wearing a contralateral hearing aid.Design: P300s were recorded using an oddball paradigm with 500 and 250 Hz tone-bursts as standard and deviant stimuli, respectively. Subjects counted the number of deviants - a measure of performance. N2b latencies, P300 latencies, N2b-P300 amplitudes, and performance were assessed during CI-only and bimodal listening.Study sample: Five bimodal listeners.Results: P300s were present in four subjects. Amplitudes were larger during bimodal listening (bimodal: 22.3 ± 4.83 µV, CI-only: 13.1 ± 3.86 µV). Both N2b and P300 latencies were shorter during bimodal (N2b: 265 ± 20.0 ms, P300: 551 ± 129.4 ms) than CI-only listening (N2b: 326 ± 42.2 ms, P300: 402 ± 38.4 ms). While performance often reached ceiling level, the difference between the standard and deviant was generally more salient during bimodal listening.Conclusions: This study provides a proof-of-concept, suggesting that P300s may provide insight into benefits that are not always measurable with behavioural tasks.

The Effect of Binaural Beamforming Technology on Speech Intelligibility in Bimodal Cochlear Implant Recipients.

Although the benefit of bimodal listening in cochlear implant users has been agreed on, speech comprehension remains a challenge in acoustically complex real-life environments due to reverberation and disturbing background noises. One way to additionally improve bimodal auditory performance is the use of directional microphones. The objective of this study was to investigate the effect of a binaural beamformer for bimodal cochlear implant (CI) users. This prospective study measured speech reception thresholds (SRT) in noise in a repeated-measures design that varied in listening modality for static and dynamic listening conditions. A significant improvement in SRT of 4.7 dB was found with the binaural beamformer switched on in the bimodal static listening condition. No significant improvement was found in the dynamic listening condition. We conclude that there is a clear additional advantage of the binaural beamformer in bimodal CI users for predictable/static listening conditions with frontal target speech and spatially separated noise sources.

A directional remote-microphone for bimodal cochlear implant recipients.

To evaluate whether speech recognition in noise differs according to whether a wireless remote microphone is connected to just the cochlear implant (CI) or to both the CI and to the hearing aid (HA) in bimodal CI users. The second aim was to evaluate the additional benefit of the directional microphone mode compared with the omnidirectional microphone mode of the wireless microphone. This prospective study measured Speech Recognition Thresholds (SRT) in babble noise in a 'within-subjects repeated measures design' for different listening conditions. Eighteen postlingually deafened adult bimodal CI users. No difference in speech recognition in noise in the bimodal listening condition was found between the wireless microphone connected to the CI only and to both the CI and the HA. An improvement of 4.1 dB was found for switching from the omnidirectional microphone mode to the directional mode in the CI only condition. The use of a wireless microphone improved speech recognition in noise for bimodal CI users. The use of the directional microphone mode led to a substantial additional improvement of speech perception in noise for situations with one target signal.

Evaluation of a wireless remote microphone in bimodal cochlear implant recipients.

OBJECTIVE: To evaluate the benefit of a wireless remote microphone (MM) for speech recognition in noise in bimodal adult cochlear implant (CI) users both in a test setting and in daily life. DESIGN: This prospective study measured speech reception thresholds in noise in a repeated measures design with factors including bimodal hearing and MM use. The participants also had a 3-week trial period at home with the MM. STUDY SAMPLE: Thirteen post-lingually deafened adult bimodal CI users. RESULTS: A significant improvement in SRT of 5.4 dB was found between the use of the CI with the MM and the use of the CI without the MM. By also pairing the MM to the hearing aid (HA) another improvement in SRT of 2.2 dB was found compared to the situation with the MM paired to the CI alone. In daily life, participants reported better speech perception for various challenging listening situations, when using the MM in the bimodal condition. CONCLUSION: There is a clear advantage of bimodal listening (CI and HA) compared to CI alone when applying advanced wireless remote microphone techniques to improve speech understanding in adult bimodal CI users.

International survey of bimodal hearing and bilateral cochlear implant service provision for adults.

OBJECTIVES: As cochlear implant (CI) criteria widen, more candidates with usable residual hearing are being considered for a CI. Unlike children, adults mostly receive only one implant. The aim of this survey was to determine bimodal-hearing and bilateral CI service provision for adults around the world. This survey offers the backdrop against which future clinical practice and service delivery can be considered. METHODS: CI professionals from across the world were invited to participate in an international multicentre survey. The online questionnaire was circulated to CI professionals in 75 countries. There were 64 respondents, representing 25 countries across five world regions. RESULTS: In this sample, adult CI users most had unilateral CI (74.5%) and only 25.5% were bilateral CI users. Some 54% of unilateral CI users used a hearing aid (HA) in the non-implanted ear. Funding for a second implant or HA was not well supported for adult unilateral CI users, and there was no clear practice guidance for fitting and maintaining the contralateral HA in most regions. CONCLUSIONS: CI professionals recognised the value of fitting contralateral HAs at CI services, with audiology departments and private HA dispensers playing an ongoing role in general maintenance and support.

Evaluating Listening Effort in Unilateral, Bimodal, and Bilateral Cochlear Implant Users.

OBJECTIVE: Evaluate listening effort (LE) in unilateral, bilateral, and bimodal cochlear implant (CI) users. Establish an easy-to-implement task of LE that could be useful for clinical decision making. STUDY DESIGN: Prospective cohort study. SETTING: Tertiary neurotology center. METHODS: The Sentence Final Word Identification and Recall Task, an established measure of LE, was modified to include challenging listening conditions (multitalker babble, gender, and emotional variation; test), in addition to single-talker sentences (control). Participants listened to lists of sentences in each condition and recalled the last word of each sentence. LE was quantified by percentage of words correctly recalled and was compared across conditions, across CI groups, and within subjects (best aided vs monaural). RESULTS: A total of 24 adults between the ages of 37 and 82 years enrolled, including 4 unilateral CI users (CI), 10 bilateral CI users (CICI), and 10 bimodal CI users (CIHA). Task condition impacted LE (P < .001), but hearing configuration and listener group did not (P = .90). Working memory capacity and contralateral hearing contributed to individual performance. CONCLUSION: This study adds to the growing body of literature on LE in challenging listening conditions for CI users and demonstrates feasibility of a simple behavioral task that could be implemented clinically to assess LE. This study also highlights the potential benefits of bimodal hearing and individual hearing and cognitive factors in understanding individual differences in performance, which will be evaluated through further research.

Lexical tone recognition in multi-talker babbles and steady-state noise by Mandarin-speaking children with unilateral cochlear implants or bimodal hearing.

BACKGROUND AND OBJECTIVES: Lexical tone presents challenges to cochlear implant (CI) users especially in noise conditions. Bimodal hearing utilizes residual acoustic hearing in the contralateral side and may offer benefits for tone recognition in noise. The purpose of the present study was to evaluate tone recognition in both steady-state noise and multi-talker babbles by the prelingually-deafened, Mandarin-speaking children with unilateral CIs or bimodal hearing. METHODS: Fifty-three prelingually-deafened, Mandarin-speaking children who received CIs participated in this study. Twenty-two of them were unilateral CI users and 31 wore a hearing aid (HA) in the contralateral ear (i.e., bimodal hearing). All subjects were tested for Mandarin tone recognition in quiet and in two types of maskers: speech-spectrum-shaped noise (SSN) and two-talker babbles (TTB) at four signal-to-noise ratios (-6, 0, +6, and +12 dB). RESULTS: While no differences existed in tone recognition in quiet between the two groups, the Bimodal group outperformed the Unilateral CI group under noise conditions. The differences between the two groups were significant at SNRs of 0, +6, and +12 dB in the SSN conditions (all p < 0.05), and at SNRs of +6 and +12 dB of TTB conditions (both p < 0.01), but not significant at other conditions (p > 0.05). The TTB exerted a greater masking effect than the SSN for tone recognition in the Unilateral CI group as well as in the Bimodal group at all SNRs tested (all p < 0.05). Among demographic or audiometric variables, only age at implantation showed a weak but significant correlation with the mean tone recognition performance under the SSN conditions (r = -0.276, p = 0.045). However, when Bonferroni correction was applied to the correlation analysis results, the weak correlation became not significant. CONCLUSION: Prelingually-deafened children with CIs face challenges in tone perception in noisy environments, especially when the noise is fluctuating in amplitude such as the multi-talker babbles. Wearing a HA on the contralateral side when residual hearing permits is beneficial for tone recognition in noise.

Clinical Feasibility and Familiarization Effects of Device Delay Mismatch Compensation in Bimodal CI/HA Users.

Subjects utilizing a cochlear implant (CI) in one ear and a hearing aid (HA) on the contralateral ear suffer from mismatches in stimulation timing due to different processing latencies of both devices. This device delay mismatch leads to a temporal mismatch in auditory nerve stimulation. Compensating for this auditory nerve stimulation mismatch by compensating for the device delay mismatch can significantly improve sound source localization accuracy. One CI manufacturer has already implemented the possibility of mismatch compensation in its current fitting software. This study investigated if this fitting parameter can be readily used in clinical settings and determined the effects of familiarization to a compensated device delay mismatch over a period of 3-4 weeks. Sound localization accuracy and speech understanding in noise were measured in eleven bimodal CI/HA users, with and without a compensation of the device delay mismatch. The results showed that sound localization bias improved to 0°, implying that the localization bias towards the CI was eliminated when the device delay mismatch was compensated. The RMS error was improved by 18% with this improvement not reaching statistical significance. The effects were acute and did not further improve after 3 weeks of familiarization. For the speech tests, spatial release from masking did not improve with a compensated mismatch. The results show that this fitting parameter can be readily used by clinicians to improve sound localization ability in bimodal users. Further, our findings suggest that subjects with poor sound localization ability benefit the most from the device delay mismatch compensation.

An overview of factors affecting bimodal and electric-acoustic stimulation (EAS) speech understanding outcomes.

Improvements in device technology, surgical technique, and patient outcomes have resulted in a broadening of cochlear implantation criteria to consider those with increasing levels of useful low-to-mid frequency residual acoustic hearing. Residual acoustic hearing allows for the addition of a hearing aid (HA) to complement the cochlear implant (CI) and has demonstrated enhanced listening outcomes. However, wide inter-subject outcome variability exists and thus identification of contributing factors would be of clinical interest and may aid with pre-operative patient counselling. The optimal fitting procedure and frequency assignments for the two hearing devices used in combination to enhance listening outcomes also remains unclear. The understanding of how acoustic and electric speech information is fundamentally combined and utilised by the listener may allow for the optimisation of device fittings and frequency allocations to provide best bimodal and electric-acoustic stimulation (EAS) patient outcomes. This article will provide an overview of contributing factors to bimodal and EAS listening outcomes, explore areas of contention, and discuss common study limitations.

Effects of noise and noise reduction on audiovisual speech perception in cochlear implant users: An ERP study.

OBJECTIVE: Hearing with a cochlear implant (CI) is difficult in noisy environments, but the use of noise reduction algorithms, specifically ForwardFocus, can improve speech intelligibility. The current event-related potentials (ERP) study examined the electrophysiological correlates of this perceptual improvement. METHODS: Ten bimodal CI users performed a syllable-identification task in auditory and audiovisual conditions, with syllables presented from the front and stationary noise presented from the sides. Brainstorm was used for spatio-temporal evaluation of ERPs. RESULTS: CI users revealed an audiovisual benefit as reflected by shorter response times and greater activation in temporal and occipital regions at P2 latency. However, in auditory and audiovisual conditions, background noise hampered speech processing, leading to longer response times and delayed auditory-cortex-activation at N1 latency. Nevertheless, activating ForwardFocus resulted in shorter response times, reduced listening effort and enhanced superior-frontal-cortex-activation at P2 latency, particularly in audiovisual conditions. CONCLUSIONS: ForwardFocus enhances speech intelligibility in audiovisual speech conditions by potentially allowing the reallocation of attentional resources to relevant auditory speech cues. SIGNIFICANCE: This study shows for CI users that background noise and ForwardFocus differentially affect spatio-temporal cortical response patterns, both in auditory and audiovisual speech conditions.

Corrigendum: Selective attention decoding in bimodal cochlear implant users.

[This corrects the article DOI: 10.3389/fnins.2022.1057605.].

Selective attention decoding in bimodal cochlear implant users.

The growing group of cochlear implant (CI) users includes subjects with preserved acoustic hearing on the opposite side to the CI. The use of both listening sides results in improved speech perception in comparison to listening with one side alone. However, large variability in the measured benefit is observed. It is possible that this variability is associated with the integration of speech across electric and acoustic stimulation modalities. However, there is a lack of established methods to assess speech integration between electric and acoustic stimulation and consequently to adequately program the devices. Moreover, existing methods do not provide information about the underlying physiological mechanisms of this integration or are based on simple stimuli that are difficult to relate to speech integration. Electroencephalography (EEG) to continuous speech is promising as an objective measure of speech perception, however, its application in CIs is challenging because it is influenced by the electrical artifact introduced by these devices. For this reason, the main goal of this work is to investigate a possible electrophysiological measure of speech integration between electric and acoustic stimulation in bimodal CI users. For this purpose, a selective attention decoding paradigm has been designed and validated in bimodal CI users. The current study included behavioral and electrophysiological measures. The behavioral measure consisted of a speech understanding test, where subjects repeated words to a target speaker in the presence of a competing voice listening with the CI side (CIS) only, with the acoustic side (AS) only or with both listening sides (CIS+AS). Electrophysiological measures included cortical auditory evoked potentials (CAEPs) and selective attention decoding through EEG. CAEPs were recorded to broadband stimuli to confirm the feasibility to record cortical responses with CIS only, AS only, and CIS+AS listening modes. In the selective attention decoding paradigm a co-located target and a competing speech stream were presented to the subjects using the three listening modes (CIS only, AS only, and CIS+AS). The main hypothesis of the current study is that selective attention can be decoded in CI users despite the presence of CI electrical artifact. If selective attention decoding improves combining electric and acoustic stimulation with respect to electric stimulation alone, the hypothesis can be confirmed. No significant difference in behavioral speech understanding performance when listening with CIS+AS and AS only was found, mainly due to the ceiling effect observed with these two listening modes. The main finding of the current study is the possibility to decode selective attention in CI users even if continuous artifact is present. Moreover, an amplitude reduction of the forward transfer response function (TRF) of selective attention decoding was observed when listening with CIS+AS compared to AS only. Further studies to validate selective attention decoding as an electrophysiological measure of electric acoustic speech integration are required.

Sound Localization Bias and Error in Bimodal Listeners Improve Instantaneously When the Device Delay Mismatch Is Reduced.

Users of a cochlear implant (CI) in one ear, who are provided with a hearing aid (HA) in the contralateral ear, so-called bimodal listeners, are typically affected by a constant and relatively large interaural time delay offset due to differences in signal processing and differences in stimulation. For HA stimulation, the cochlear travelling wave delay is added to the processing delay, while for CI stimulation, the auditory nerve fibers are stimulated directly. In case of MED-EL CI systems in combination with different HA types, the CI stimulation precedes the acoustic HA stimulation by 3 to 10 ms. A self-designed, battery-powered, portable, and programmable delay line was applied to the CI to reduce the device delay mismatch in nine bimodal listeners. We used an A-B-B-A test design and determined if sound source localization improves when the device delay mismatch is reduced by delaying the CI stimulation by the HA processing delay (τHA). Results revealed that every subject in our group of nine bimodal listeners benefited from the approach. The root-mean-square error of sound localization improved significantly from 52.6° to 37.9°. The signed bias also improved significantly from 25.2° to 10.5°, with positive values indicating a bias toward the CI. Furthermore, two other delay values (τHA -1 ms and τHA +1 ms) were applied, and with the latter value, the signed bias was further reduced in some test subjects. We conclude that sound source localization accuracy in bimodal listeners improves instantaneously and sustainably when the device delay mismatch is reduced.

Participation of Acoustic and Electric Hearing in Perceiving Musical Sounds.

Introduction: The objective of our study was to evaluate musical perception and its relation to the quality of life in patients with bimodal binaural auditory stimulation. Materials and Methods: Nineteen adult patients with a cochlear implant (CI) for minimum 6 months, and moderate to severe contralateral hearing loss with a hearing aid (HA), and 21 normal hearing adults were included in this prospective, cross-sectional study. Pure-tone and speech audiometry, musical test evaluating sound perception characteristics and musical listening abilities, Munich questionnaire for musical habits, and the APHAB questionnaire were recoded. Performance in musical perception test with HA, CI, and HA + CI, and potential correlations between music test, audiometry and questionnaires were investigated. Results: Bimodal stimulation improved musical perception in several features (sound brightness, roughness, and clarity) in comparison to unimodal hearing, but CI did not add to HA performances in texture, polyphony or musical emotion and even appeared to interfere negatively in pitch perception with HA. Musical perception performances (sound clarity, instrument recognition) appeared to be correlated to hearing-related quality of life (APHAB RV and EC subdomains) but not with speech performances suggesting that the exploration of musical perception complements speech understanding evaluation to better describe every-day life hearing handicap. Conclusion: Testing musical sound perception provides important information on hearing performances as a complement to speech audiometry and appears to be related to hearing-related quality of life.

The Importance of Access to Bilateral Hearing through Cochlear Implants in Children.

Children with hearing loss require early access to sound in both ears to support their development. In this article, we describe barriers to providing bilateral hearing and developmental consequences of delays during early sensitive periods. Barriers include late identification of hearing loss in one or both ears and delayed access to intervention with hearing devices such as cochlear implants. Effects of delayed bilateral input on the auditory pathways and brain are discussed as well as behavioral effects on speech perception and other developmental outcomes including language and academics. Evidence for these effects has supported an evolution in cochlear implant candidacy in children that was started with unilateral implantation in children with profound deafness bilaterally to bilateral implantation to implantation of children with asymmetric hearing loss including children with single-side deafness. Opportunities to enhance the developmental benefits of bilateral hearing in children with hearing loss are also discussed including efforts to improve binaural/spatial hearing and consideration of concurrent vestibular deficits which are common in children with hearing loss.