1-year postactivation results for sequentially implanted bilateral cochlear implant users.

OBJECTIVE: Evaluate speech recognition in quiet and in noise for a group of 12 children, all of whom underwent sequential bilateral cochlear implantation at various ages (range, 1 yr, 8 mo to 9 yr, 6 mo at time of second implant). STUDY DESIGN: Retrospective. SETTING: Outpatient cochlear implant clinic. PATIENTS: Children who underwent sequential bilateral cochlear implantation. INTERVENTION: Rehabilitative. MAIN OUTCOME MEASURES: Speech recognition in quiet was evaluated for each ear separately using single-word speech recognition assessments (Multisyllabic Lexical Neighborhood Test and Early Speech Perception Test) via recorded presentation. Speech recognition in noise was assessed for each ear separately and in the bilateral condition by obtaining a spondee recognition threshold in the presence of speech-weighted noise presented at 45 dB hearing level. The primary outcome measure for speech recognition in noise assessment was the signal-to-noise ratio for 50% performance, which was calculated by determining the difference between the presentation level of the noise and the presentation level at which the speech recognition threshold was obtained. The results of these assessments were contrasted between children receiving their second cochlear implant before 4 years of age and children receiving their second cochlear implant after 4 years of age. RESULTS: A statistically significant difference for speech recognition scores in quiet was obtained between the early-implanted ear and the late-implanted ears for children receiving their second cochlear implant after 4 years of age. There was not a statistically significant difference in speech recognition scores in quiet between the early-implanted and late-implanted ears of children receiving their second cochlear before 4 years of age. Both groups of children possessed better speech recognition scores in noise (statistically significant at an alpha = 0.05) in the bilateral condition relative to either unilateral condition. However, there was not a statistically significant relationship between speech recognition performance in noise and the duration of deafness of the later implanted ear. CONCLUSION: Bilateral cochlear implantation allowed for better speech recognition in noise relative to unilateral performance for a group of 12 children who underwent sequential bilateral cochlear implantation at various ages. There was not a statistically significant relationship between speech recognition in noise benefit, which was defined as the difference in performance between the first implanted ear and the bilateral condition and the age at which the second implant was received. Children receiving bilateral cochlear implants younger than 4 years of age achieved better speech recognition in quiet performance for the later implanted ear as compared with children receiving their second cochlear implant after 4 year of age.     

A practical guide to cochlear implantation in adults with long durations of monaural sound deprivation

Abstract

Objective: This paper aims to summarize published findings by the authors and integrate these within current literature to support clinical guidelines when choosing an ear for cochlear implantation in adults with long-term monaural sound deprivation. Study sample: Four retrospective cohort studies based on data collected in five cochlear implantation centres with adults with bilateral hearing loss who used a single hearing aid for at least 15 years prior to unilateral or bilateral cochlear implantation. Design: Review, integration and interpretation of retrospective cohort studies to support clinical recommendations. Results: In this population, the prelingual nature of the hearing loss and the duration of bilateral significant hearing loss were the most reliable predictors of cochlear implantation outcomes. Importantly, the duration of sound deprivation in the ear to be implanted was not a significant predictor of speech recognition scores after cochlear implantation and should carry less weight in making recommendations. Conclusions: In most adults with postlingual hearing loss and long-term monaural sound deprivation, the sound-deprived sound deprivation ear should be preferred for implantation. For adults with prelingual deafness and monaural sound deprivation, the decision should weigh the risks of obtaining poorer results with the cochlear implant compared to the benefits of accessing binaural hearing.     

Comparison of bilateral and unilateral cochlear implants in children with sequential surgery

Objective

The objective of this study was to evaluate the effect of bilateral versus unilateral cochlear implants and the importance of the inter-implant interval.

Methods

Seventy-three prelingually deaf children received sequential bilateral cochlear implants. Speech recognition in quiet with the first, second and with both implants simultaneously was evaluated at the time of the second implantation and after 12 and 24 months.

Results

Mean bilateral speech recognition 12 and 24 months after the second implantation was significantly higher than that obtained with either the first or the second implant. The addition of a second implant was demonstrated to have a beneficial effect after both 12 and 24 months. Speech recognition with the second implant increased significantly during the first year. A small, non-significant improvement was observed during the second year. The inter-implant interval significantly influenced speech recognition with the second cochlear implant both at 12 and 24 months, and bilateral speech recognition at 12 months, but not at 24 months.

Conclusions

A small, but statistically significant improvement in speech recognition was found with bilateral cochlear implants compared with a unilateral implant. A major increase in speech recognition occurred with the second cochlear implant during the first year. A shorter time interval between the two implantations resulted in better speech recognition with the second implant. However, no definitive time-point was found for when the second implant could no longer add a positive effect.     

Aplicación de la tecnología de enrutamiento inalámbrico contralateral de la señal (CROS) en usuarios de implante coclear unilateral

IntroductionSingle cochlear implantation usually provides substantial speech intelligibility benefits but bilaterally deaf, unilaterally implanted subjects will continue to experience limitations due to the head shadow effect, like single-sided deaf individuals. In the treatment of individuals with single-sided deafness one option is contralateral routing of signal (CROS) devices, which constitute a non-surgical intervention of the second ear in unilaterally implanted individuals.MethodTwelve experienced adult cochlear implant users with Naída Q70 processor and the CROS device used in combination participated in the study. For the study 3 conditions were provided: cochlear implant only, omnidirectional microphone mode (CROS deactivated); cochlear implant plus CROS activated, omnidirectional microphone mode and cochlear implant plus CROS activated, UltraZoom mode. Speech reception thresholds were determined in quiet and noise. Subjective feedback regarding the practical usability of the CROS device and the perceived benefit were collected.ResultsThere was a 27.6% improvement in speech understanding in quiet and 32.5% improvement in noise when CROS device was activated. Using advanced directional microphones, a statistically significant benefit of 35% was obtained. The responses to the questionnaires revealed that the subjects perceived benefit in their everyday lives when using the CROS device with their cochlear implants.ConclusionThe investigated CROS device used by unilateral CI recipients in cases where bilateral implantation is not an option provides both subjective and objective speech recognition benefit when the signal is directed to the CROS device. Unfavourable conditions where speech is presented from the cochlear implant side and noise from the CROS side or diffusely were not included in this evaluation since the CROS device adds additional noise and performance is expected to decrease as has previously been shown.     

Speech understanding in quiet and noise in bilateral users of the MED-EL COMBI 40/40+ cochlear implant system

OBJECTIVE: The purpose of the study was to investigate speech understanding in quiet and noise in subjects bilaterally implanted with multi-channel cochlear implants. DESIGN: Nine adults bilaterally implanted with MED-EL implants were included in the study. The subjects were tested in three conditions: with both implants, with the right implant only, and with the left implant only. Speech tests included monosyllables in quiet and sentences in noise (10 dB signal to noise ratio). Speech was presented from the front, and noise was presented from either 90 degrees or 270 degrees azimuth. RESULTS: All subjects reported benefit from bilateral stimulation. Speech scores for all subjects were higher with bilateral than with unilateral stimulation. The average score across subjects for sentence understanding was 31.1 percentage points higher with both cochlear implants compared with the cochlear implant ipsilateral to the noise, and 10.7 percentage points higher with both cochlear implants compared with the cochlear implant contralateral to the noise. The average score for recognition of monosyllabic words was 18.7 percentage points higher with both cochlear implants than with one cochlear implant. All of these differences in average scores were significant at the 5% level. CONCLUSIONS: Bilateral cochlear implantation provides a significant benefit in speech understanding in both quiet and noise.     

Bilateral versus unilateral cochlear implants in children: Speech recognition,sound localization,and parental reports

Abstract

Objective: To compare bilateral and unilateral speech recognition in quiet and in multi-source noise, and horizontal sound localization of low and high frequency sounds in children with bilateral cochlear implants. Design: Bilateral performance was compared to performance of the implanted side with the best monaural speech recognition in quiet result. Parental reports were collected in a questionnaire. Results from the CI children were compared to binaural and monaural performance of normal-hearing peers. Study sample: Sixty-four children aged 5.1–11.9 years who were daily users of bilateral cochlear implants. Thirty normal-hearing children aged 4.8–9.0 years were recruited as controls. Results and Conclusions: Group data showed a statistically significant bilateral speech recognition and sound localization benefit, both behaviorally and in parental reports. The bilateral speech recognition benefit was smaller in quiet than in noise. The majority of subjects localized high and low frequency sounds significantly better than chance using bilateral implants, while localization accuracy was close to chance using unilateral implants. Binaural normal-hearing performance was better than bilateral performance in implanted children across tests, while bilaterally implanted children showed better localization than normal-hearing children under acute monaural conditions.     

A longitudinal study of the bilateral benefit in children with bilateral cochlear implants

Objective: To study the development of the bilateral benefit in children using bilateral cochlear implants by measurements of speech recognition and sound localization. Design: Bilateral and unilateral speech recognition in quiet, in multi-source noise, and horizontal sound localization was measured at three occasions during a two-year period, without controlling for age or implant experience. Longitudinal and cross-sectional analyses were performed. Results were compared to cross-sectional data from children with normal hearing. Study sample: Seventy-eight children aged 5.1–11.9 years, with a mean bilateral cochlear implant experience of 3.3 years and a mean age of 7.8 years, at inclusion in the study. Thirty children with normal hearing aged 4.8–9.0 years provided normative data. Results: For children with cochlear implants, bilateral and unilateral speech recognition in quiet was comparable whereas a bilateral benefit for speech recognition in noise and sound localization was found at all three test occasions. Absolute performance was lower than in children with normal hearing. Early bilateral implantation facilitated sound localization. Conclusions: A bilateral benefit for speech recognition in noise and sound localization continues to exist over time for children with bilateral cochlear implants, but no relative improvement is found after three years of bilateral cochlear implant experience.     

Sequential bilateral cochlear implantation in a patient with bilateral Ménière's disease

This case study describes a 45-yr-old female with bilateral, profound sensorineural hearing loss due to Ménière's disease. She received her first cochlear implant in the right ear in 2008 and the second cochlear implant in the left ear in 2010. The case study examines the enhancement to speech recognition, particularly in noise, provided by bilateral cochlear implants. Speech recognition tests were administered prior to obtaining the second implant and at a number of test intervals following activation of the second device. Speech recognition in quiet and noise as well as localization abilities were assessed in several conditions to determine bilateral benefit and performance differences between ears. The results of the speech recognition testing indicated a substantial improvement in the patient's ability to understand speech in noise and her ability to localize sound when using bilateral cochlear implants compared to using a unilateral implant or an implant and a hearing aid. In addition, the patient reported considerable improvement in her ability to communicate in daily life when using bilateral implants versus a unilateral implant. This case suggests that cochlear implantation is a viable option for patients who have lost their hearing to Ménière's disease even when a number of medical treatments and surgical interventions have been performed to control vertigo. In the case presented, bilateral cochlear implantation was necessary for this patient to communicate successfully at home and at work.     

Utility of bilateral acoustic hearing in combination with electrical stimulation provided by the cochlear implant

Abstract

Objective: The aim of the study was to quantify the benefit provided by having access to amplified acoustic hearing in the implanted ear for use in combination with contralateral acoustic hearing and the electrical stimulation provided by the cochlear implant. Design: Measures of spatial and non-spatial hearing abilities were obtained to compare performance obtained with different configurations of acoustic hearing in combination with electrical stimulation. In the combined listening condition participants had access to bilateral acoustic hearing whereas the bimodal condition used acoustic hearing contralateral to the implanted ear only. Experience was provided with each of the listening conditions using a repeated-measures A-B-B-A experimental design. Study sample: Sixteen post-linguistically hearing-impaired adults participated in the study. Results: Group mean benefit was obtained with use of the combined mode on measures of speech recognition in coincident speech in noise, localization ability, subjective ratings of real-world benefit, and musical sound quality ratings. Conclusions: Access to bilateral acoustic hearing after cochlear implantation provides significant benefit on a range of functional measures.     

A systematic review of the effectiveness and cost‐effectiveness of bilateral multichannel cochlear implants in adults with severe‐to‐profound hearing loss

Clin. Otolaryngol. 2012, 37 , 342–354 Background: In the UK, approximately 10 000 people have cochlear implants, more than 99% with a unilateral implant. Evidence shows that adults implanted bilaterally may benefit from binaural advantages; however, systematic review evidence is limited. Objectives of the review: To conduct a systematic review to discover the evidence for effectiveness and cost‐effectiveness of using bilateral cochlear implants in adults with severe‐to‐profound hearing loss by comparing their effectiveness with unilateral cochlear implantation or unilateral cochlear implantation and acoustic hearing aid in the contralateral ear. Type of review: Systematic review. Search strategy: This examined 16 electronic databases, plus bibliographies and references for published and unpublished studies. Evaluation method: Abstracts were independently assessed against inclusion criteria by two researchers, and disagreements were resolved. Selected papers were then retrieved and further independently assessed in a similar way. Included studies had their data extracted by one reviewer and checked by another. Results: Searches yielded 2892 abstracts producing 19 includable studies. Heterogeneity between studies precluded meta‐analysis. However, all studies reported that bilateral cochlear implants improved hearing and speech perception: one randomised controlled trial found a significant binaural benefit over the first ear alone for speech and noise from the front (12.6 ± 5.4%, P < 0.001) and when noise was ipsilateral to the first ear (21 ± 6%, P < 0.001); and another found a significant benefit for spatial hearing at 3 and 9 months post‐implantation compared with pre‐implantation [mean difference (sd ) scores: 3 months = 1.46 (0.83–2.09), P < 0.01].Quality of life results varied, showing bilateral implantation may improve quality of life in the absence of worsening tinnitus. Limited cost‐effectiveness evidence showed that bilateral implantation is probably only cost‐effective at a willingness‐to‐pay threshold above £62 000 per quality adjusted life year. Conclusions: Despite inconsistency in the quality of available evidence, the robustness of systematic review methods gives weight to the positive findings of included studies demonstrating that bilateral implantation is clinically effective in adults but unlikely to be cost‐effective.     

United Kingdom national paediatric bilateral project: Demographics and results of localization and speech perception testing

Objectives: To assess longitudinal outcomes in a large and varied population of children receiving bilateral cochlear implants both simultaneously and sequentially.

Methods: This observational non-randomized service evaluation collected localization and speech recognition in noise data from simultaneously and sequentially implanted children at four time points: before bilateral cochlear implants or before the sequential implant, 1 year, 2 years, and 3 years after bilateral implants. No inclusion criteria were applied, so children with additional difficulties, cochleovestibular anomalies, varying educational placements, 23 different home languages, a full range of outcomes and varying device use were included.

Results: 1001 children were included: 465 implanted simultaneously and 536 sequentially, representing just over 50% of children receiving bilateral implants in the UK in this period. In simultaneously implanted children the median age at implant was 2.1 years; 7% were implanted at less than 1 year of age. In sequentially implanted children the interval between implants ranged from 0.1 to 14.5 years. Children with simultaneous bilateral implants localized better than those with one implant. On average children receiving a second (sequential) cochlear implant showed improvement in localization and listening in background noise after 1 year of bilateral listening. The interval between sequential implants had no effect on localization improvement although a smaller interval gave more improvement in speech recognition in noise. Children with sequential implants on average were able to use their second device to obtain spatial release from masking after 2 years of bilateral listening. Although ranges were large, bilateral cochlear implants on average offered an improvement in localization and speech perception in noise over unilateral implants.

Conclusion: These data represent the diverse population of children with bilateral cochlear implants in the UK from 2010 to 2012. Predictions of outcomes for individual patients are not possible from these data. However, there are no indications to preclude children with long inter-implant interval having the chance of a second cochlear implant.     

The hearing benefit of cochlear implantation for individuals with unilateral hearing loss,but no tinnitus

Conclusion: Cochlear implants improve the hearing abilities of individuals with unilateral hearing loss and no tinnitus. The benefit is no different from that seen in patients with unilateral hearing loss and incapacitating tinnitus.

Objective: To evaluate hearing outcomes after cochlear implantation in individuals with unilateral hearing loss and no tinnitus and compare them to those obtained in a similar group who had incapacitating tinnitus.

Methods: Six cases who did not experience tinnitus before operation and 15 subjects with pre-operative tinnitus were evaluated with a structured interview, a monosyllabic word test under difficult listening situations, a sound localization test, and an APHAB (abbreviated profile of hearing aid benefit) questionnaire.

Results: All subjects used their cochlear implant more than 8?hours a day, 7 days a week. In ‘no tinnitus’ patients, mean benefit of cochlear implantation was 19% for quiet speech, 15% for speech in noise (with the same signal-to-noise ratio in the implanted and non-implanted ear), and 16% for a more favourable signal-to-noise ratio at the implanted ear. Sound localization error improved by an average of 19°. The global score of APHAB improved by 16%. The benefits across all evaluations did not differ significantly between the ‘no tinnitus’ and ‘tinnitus’ groups.     

Impact of auditory cortical asymmetry in cochlear implantation

Abstract

Objective

Is there a cochlear implant ear advantage for speech perception?

Patients

A total number of 68 cochlear implant recipients were evaluated retrospectively. They were 20 adults implanted in right ear, 20 matched adults implanted in left ear while 14 children implanted in right ear and 14 matched children implanted in left ear.

Methods

Behavioral responses & age based speech perception tests were evaluated at 6 months and 1 year post implantation.

Results

Adult showed no statistical difference in all tests at 6 months evaluation while 1 year evaluation showed significant better performance for right implanted group in monosyllabic discrimination test. Children showed statistical significant performance in monosyllabic identification and minimal pairs testes at 6 months evaluation; and in monosyllabic identification only at 1 year evaluation.

Conclusion

The present data support that right ear implantation would fasten the development of auditory skills especially in young children, an issue to be considered in unilateral implantation.     

Evidence-based guidelines for recommending cochlear implantation for postlingually deafened adults

Abstract

Objective: Adult selection criteria for cochlear implantation have been developed based on analysis of the post-operative performance of a large group of postlingually deafened adults. Original criteria published in 2004 were reviewed and amended to reflect outcomes currently being achieved by implant recipients. Design: Retrospective review of 12-month post-operative speech perception performance of adults implanted at the Eye and Ear Hospital, Melbourne, Australia. Study sample: A total of 382 postlingually deafened adults, using a Freedom, Nucleus 5, or CI422 Slim Straight cochlear implant were used to create a comparative set of data. Results: Revised guidelines suggest that adults with postlingual hearing loss can now be considered cochlear implant candidates if they obtain scores of up to 55% for open-set phonemes in quiet in the ear to be implanted. Functional benefit may vary depending on the recipients’ contralateral hearing. Conclusions: This study supports the provision of cochlear implants to candidates with significant residual hearing when at least one ear meets the criterion outlined above. Patient-specific counseling is required to ensure the potential to benefit predicted by the current model is acceptable to the individual patient and their family. Counseling regarding functional benefit must take into consideration hearing in the contralateral ear.     

Speech perception benefits of sequential bilateral cochlear implantation in children and adults: a retrospective analysis.

Objective: To examine speech perception outcomes and determine the impact of length of deafness and time between implants on performance in the sequentially bilateral implanted population. STUDY DESIGN: Retrospective review. SETTING: Tertiary academic referral center. PATIENTS: Forty-three children (age, <18 yr) and 22 adults underwent sequential bilateral implantation with at least 6 months between surgeries. The mean age at the time of the second implant in children was 7.83 years, and mean time between implants was 5.16 years. Five children received the first side implant (C1) below 12 months of age; 16, at 12 to 23 months; 9, between the ages of 24 and 35 months; and 11, at 36 to 59 months; 2 were implanted above the age of 5 years. In adults, mean age at second implant was 46.6 years, and mean time between implants was 5.6 years. INTERVENTION: Sequential implantation with 6 months or more between implantations. MAIN OUTCOME MEASURES: Speech perception tests were performed preoperatively before the second implantation and at 3 months postoperatively. RESULTS: Results revealed significant improvement in the second implanted ear and in the bilateral condition, despite time between implantations or length of deafness; however, age of first-side implantation was a contributing factor to second ear outcome in the pediatric population. CONCLUSION: Sequential bilateral implantation leads to significantly better speech understanding. On average, patients improved, despite length of deafness, time between implants, or age at implantation.     

Importance of age and postimplantation experience on speech perception measures in children with sequential bilateral cochlear implants.

OBJECTIVES: Clinical trials in which children received bilateral cochlear implants in sequential operations were conducted to analyze the extent to which bilateral implantation offers benefits on a number of measures. The present investigation was particularly focused on measuring the effects of age at implantation and experience after activation of the second implant on speech perception performance. STUDY DESIGN: Thirty children aged 3 to 13 years were recipients of 2 cochlear implants, received in sequential operations, a minimum of 6 months apart. All children received their first implant before 5 years of age and had acquired speech perception capabilities with the first device. They were divided into 3 age groups on the basis of age at time of second ear implantation: Group I, 3 to 5 years; Group II, 5.1 to 8 years; and Group III, 8.1 to 13 years. Speech perception measures in quiet included the Multisyllabic Lexical Neighborhood Test (MLNT) for Group I, the Lexical Neighborhood Test (LNT) for Groups II and III, and the Hearing In Noise Test for Children (HINT-C) sentences in quiet for Group III. Speech perception in noise was assessed using the Children's Realistic Intelligibility and Speech Perception (CRISP) test. Testing was performed preoperatively and again postactivation of the second implant at 3, 6, and 12 months (CRISP at 3 and 9 mo) in both the unilateral and bilateral conditions in a repeated-measures study design. Two-way repeated-measures analysis of variance was used to analyze statistical significance among device configurations and performance over time. SETTING: US Multicenter. RESULTS: Results for speech perception in quiet show that children implanted sequentially acquire open-set speech perception in the second ear relatively quickly (within 6 mo). However, children younger than 8 years do so more rapidly and to a higher level of speech perception ability at 12 months than older children (mean second ear MLNT/LNT scores at 12 months: Group I, 83.9%; range, 71-96%; Group II, 59.5%; range, 40-88%; Group III, 32%; range, 12-56%). The second-ear mean HINT-C score for Group III children remained far less than that of the first ear even after 12 months of device use (44 versus 89%; t, 6.48; p<0.001; critical value, 0.025). Speech intelligibility for spondees in noise was significantly better under bilateral conditions than with either ear alone when all children were analyzed as a single group and for Group III children. At the 9-month test interval, performance in the bilateral configuration was significantly better for all noise conditions (13.2% better for noise at first cochlear implant, 6.8% better for the noise front and noise at second cochlear implant conditions, t=2.32, p=0.024, critical level=0.05 for noise front; t=3.75, p<0.0001, critical level=0.05 for noise at first implant; t=2.73, p = 0.008, critical level=0.05 for noise at second implant side). The bilateral benefit in noise increased with time from 3 to 9 months after activation of the second implant. This bilateral advantage is greatest when noise is directed toward the first implanted ear, indicating that the head shadow effect is the most effective binaural mechanism. The bilateral condition produced small improvements in speech perception in quiet and for individual Group I and Group II patient results in noise that, in view of the relatively small number of subjects tested, do not reach statistical significance. CONCLUSION: Sequential bilateral cochlear implantation in children of diverse ages has the potential to improve speech perception abilities in the second implanted ear and to provide access to the use of binaural mechanisms such as the head shadow effect. The improvement unfolds over time and continues to grow during the 6 to 12 months after activation of the second implant. Younger children in this study achieved higher open-set speech perception scores in the second ear, but older children still demonstrate bilateral benefit in noise. Determining the long-term impact and cost-effectiveness that results from such potential capabilities in bilaterally implanted children requires additional study with larger groups of subjects and more prolonged monitoring.     

Simultaneous bilateral cochlear implantation in adults: a multicenter clinical study

OBJECTIVE: To determine the efficacy of "simultaneous" bilateral cochlear implantation (both implants placed during a single surgical procedure) by comparing bilateral and unilateral implant use in a large number of adult subjects tested at multiple sites. DESIGN: Prospective study of 37 adults with postlinguistic onset of bilateral, severe to profound sensorineural hearing loss. Performance with the bilateral cochlear implants, using the same speech processor type and speech processing strategy, was compared with performance using the left implant alone and the right implant alone. Speech understanding in quiet (CNCs and HINT sentences) and in noise (BKB-SIN Test) were evaluated at several postactivation time intervals, with speech presented at 0 degrees azimuth, and noise at either 0 degrees , 90 degrees right, or 90 degrees left in the horizontal plane. APHAB questionnaire data were collected after each subject underwent a 3-wk "bilateral deprivation" period, during which they wore only the speech processor that produced the best score during unilateral testing, and also after a period of listening again with the bilateral implants. RESULTS: By 6-mo postactivation, a significant advantage for speech understanding in quiet was found in the bilateral listening mode compared with either unilateral listening modes. For speech understanding in noise, the largest and most robust bilateral benefit was when the subject was able to take advantage of the head shadow effect; i.e., results were significantly better for bilateral listening compared with the unilateral condition when the ear opposite to the side of the noise was added to create the bilateral condition. This bilateral benefit was seen on at least one of the two unilateral ear comparisons for nearly all (32/34) subjects. Bilateral benefit was also found for a few subjects in spatial configurations that evaluated binaural redundancy and binaural squelch effects. A subgroup of subjects who had asymmetrical unilateral implant performances were, overall, similar in performance to subjects with symmetrical hearing. The questionnaire data indicated that bilateral users perceive their own performance to be better with bilateral cochlear implants than when using a single device. CONCLUSIONS: Findings with a large patient group are in agreement with previous reports on smaller groups, showing that, overall, bilateral implantation offers the majority of patients advantages when listening in simulated adverse conditions.     

The benefits of sequential bilateral cochlear implantation for hearing-impaired children

CONCLUSION: Sequential bilateral implantation offers listening advantages demonstrable on speech recognition in noise and for lateralization. Whilst the trend was for shorter inter-implant intervals and longer implant experience to positively impact binaural advantage, we observed no contraindications for binaural advantage. OBJECTIVE: To evaluate the benefits of sequential bilateral cochlear implantation over unilateral implantation in a multicentre study evaluating speech recognition in noise and lateralization of sound. SUBJECTS AND METHODS: Twenty children, implanted bilaterally in sequential procedures, had the following characteristics: they were native German-speaking, were3 years or older and had a minimum of 1 year inter-implant interval and had between 2 months and 4 years 7 months binaural listening experience. Binaural advantage was assessed including speech recognition in noise using the Regensburg modification of the Oldenburger Kinder-Reimtest (OLKI) and lateralization of broadband stimuli from three speakers. RESULTS: A significant binaural advantage of 37% was observed for speech recognition in noise. Binaural lateralization ability was statistically superior for the first and second implanted ear (p = 0.009, p = 0.001, respectively). Binaural experience was shown to correlate moderately with absolute binaural speech recognition scores, with binaural advantage for speech recognition and with binaural lateralization ability. The time interval between implants correlated in an inverse direction with binaural advantage for speech recognition.     

Sequential bilateral cochlear implant: results in children and adolescents

IntroductionThe use of the bilateral cochlear implants can promote the symmetrical development of the central auditory pathways, thus benefiting the development of auditory abilities and improving sound localization and the ability of auditory speech perception in situations of competitive noise.ObjectiveTo evaluate the ability of speech perception in children and adolescents using sequential bilateral cochlear implants, considering the association of these variables: age at surgery, time of device use and interval between surgeries.MethodsA total of 14 individuals between 10 and 16 years of age, who demonstrated surgical indication for the use of sequential bilateral cochlear implants as intervention in the auditory habilitation process, were assessed. The speech perception ability was assessed through sentence lists constructed in the Portuguese language, presented in two situations: in silence, with fixed intensity of 60 dB SPL, and in competitive noise, with a signal-to-noise ratio of +15 dB. The evaluation was performed under the following conditions: unilateral with the first activated cochlear implant, unilateral with the second activated cochlear implant and bilateral with both devices activated.ResultsThe results of the speech perception tests showed better performance in both silence and in noise for the bilateral cochlear implant condition when compared to the 1st cochlear implant and the 2nd cochlear implant alone. A worse result of speech perception was found using the 2nd cochlear implant alone. No statistically significant correlation was found between age at the surgical procedure, interval between surgeries and the time of use of the 2nd cochlear implant, and the auditory speech perception performance for all assessed conditions. The use of a hearing aid prior to the 2nd cochlear implant resulted in benefits for auditory speech perception with the 2nd cochlear implant, both in silence and in noise.ConclusionThe bilateral cochlear implant provided better speech perception in silence and in noise situations when compared to the unilateral cochlear implant, regardless of the interval between surgeries, age at the surgical procedure and the time of use of the 2nd cochlear implant. Speech perception with the 1st cochlear implant was significantly better than with the 2nd cochlear implant, both in silence and in noise. The use of the hearing aid prior to the 2nd cochlear implant influenced speech perception performance with the 2nd cochlear implant, both in silence and in noise.     

Simultaneous Bilateral Cochlear Implantation: Prospective Study in Adults

Normal-hearing listeners gain important everyday benefits from having two ears, particularly for determining where sounds come from and for understanding speech in noisy environments. Users of two cochlear implants may have the opportunity to experience some of these bilateral advantages. The primary aim of this study was to document bilateral versus unilateral listening benefit in 15 postlinguistically deafened adults implanted simultaneously with two Harmony^® (HiRes 90K^®) cochlear implants. Speech perception (in quiet and in noise) and localization accuracy were assessed for each ear alone and both ears together. Subjects showed improved sound localization and better speech perception in quiet and in noise when using two implants compared with using one implant alone.