Speech perception in cochlear implant users with the HiRes 120 strategy: a systematic review

Despite technological advances employed in signal processing strategies, one of the remaining obstacles are spectral gap details on the information transmitted. Considering its importance in speech perception, researchers have investigated mechanisms to optimize spectral details through virtual spectral channels. The clinical application of this technique resulted in a new approach to signal processing - the HiRes 120.ObjectiveTo assess the auditory performance of cochlear implant users with the HiRes 120 strategy.MethodologyThe literature review was conducted in an electronic database, with standard bibliographic search in the year 2011, using specific keywords. In order to select and evaluate the scientific studies found in the search, we setup search containing the following aspects: type of study, subjects, intervention used and evaluation of the results.ConclusionScientific evidence points to an improvement in hearing performance in noisy environments with the HiRes 120 strategy, but this does not occur in quiet situations. The optimization of speech perception with this strategy is closely related to the cochlear implant user's age, to the time of sensory deprivation and the acclimatization time required to use the strategy's spectral information.     

Development of auditory and language skills in children using cochlear implants with two signal processing strategies

IntroductionThe increase in the spectral information offered by the sound processing strategy HiRes 120 has led to great expectations for the pediatric population. Due to a shorter duration of auditory deprivation and higher neural plasticity, children could benefit more substantially from the spectral information of this sound processing strategy.ObjectiveTo compare auditory and language skills in Brazilian children with cochlear implants using the HiRes and HiRes 120 sound processing strategies.MethodsThirty children, aged 1–3 years, with congenital hearing loss, were divided into two groups, according to the signal processing strategy adjusted at the time of the cochlear implant activation. The assessed children were matched according to chronological age and the time of the cochlear implant use. The auditory and language skills were evaluated longitudinally through the Infant-Toddler Meaningful Auditory Integration Scale and Production Infant Scale Evaluation, carried out before surgery, and 3, 6 and 12 months after device implantation. The Mann–Whitney test was applied for the comparison between the two groups with a 5% significance level.ResultsThe findings indicated development of hearing and language skills in the first year of cochlear implant use; however, there was no statistically significant difference in the evolution of such skills due to the adjusted processing strategy in the activation of the cochlear implant electrodes.ConclusionThe development of auditory and language skills in the assessed children was similar during the entire study period, regardless of which signal processing strategy was used.     

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.     

Short-term study of the effect of speech coding strategy on the auditory performance of pre- and post-lingually deafened adults implanted with the Clarion CII®

Objective The auditory performance of cochlear implantees is linked to numerous variables, such as audiological characteristics, age and type of speech coding strategy. In recent years, many different ways of processing sounds have been developed, with possible implications for auditory performance. The purpose of this study was to evaluate the intra-individual differences of patients for speech perception tasks in quiet and in noise as a result of switching from a standard strategy [Continuous Interleaved Sampling (CIS)/Simultaneous Analog Strategy (SAS)] to Hi-Resolution (HiRes).

Material and Methods A total of 14 post-lingual adults implanted with the Clarion CII® were selected for trials. At switch-on, six patients chose a CIS strategy and eight an SAS strategy. After an average period of 9.3 months, all patients were switched over to HiRes. All patients were tested (open-set mode) with bisyllabic words and sentences, in both quiet and noise [speech/noise ratio (SNR)=+10]. Testing was carried out after an initial period with the CIS/SAS strategy and 3 months after switching over to HiRes.

Results After switch-over a significant improvement was seen for both speech in quiet (words +25.2%, sentences +10.8%) and speech in noise (words 44.8%, sentences 45.4%).

Conclusion Despite individual differences, all patients improved their performance with HiRes use, the greatest improvements being seen under unfavourable listening conditions (SNR=+10). Subjective improvements in speech discrimination and overall sound quality perception were reported even after the first week of HiRes use.     

Short-term study of the effect of speech coding strategy on the auditory performance of pre- and post-lingually deafened adults implanted with the Clarion CII

OBJECTIVE: The auditory performance of cochlear implantees is linked to numerous variables, such as audiological characteristics, age and type of speech coding strategy. In recent years, many different ways of processing sounds have been developed, with possible implications for auditory performance. The purpose of this study was to evaluate the intra-individual differences of patients for speech perception tasks in quiet and in noise as a result of switching from a standard strategy [Continuous Interleaved Sampling (CIS)/Simultaneous Analog Strategy (SAS)] to Hi-Resolution (HiRes). MATERIAL AND METHODS:A total of 14 post-lingual adults implanted with the Clarion CII were selected for trials. At switch-on, six patients chose a CIS strategy and eight an SAS strategy. After an average period of 9.3 months, all patients were switched over to HiRes. All patients were tested (open-set mode) with bisyllabic words and sentences, in both quiet and noise [speech/noise ratio (SNR) = +10]. Testing was carried out after an initial period with the CIS/SAS strategy and 3 months after switching over to HiRes. RESULTS: After switch-over a significant improvement was seen for both speech in quiet (words +25.2%, sentences +10.8%) and speech in noise (words 44.8%, sentences 45.4%). CONCLUSION: Despite individual differences, all patients improved their performance with HiRes use, the greatest improvements being seen under unfavourable listening conditions (SNR = +10). Subjective improvements in speech discrimination and overall sound quality perception were reported even after the first week of HiRes use.     

Language evaluation in children with pre-lingual hearing loss and cochlear implant

IntroductionThe cochlear implant is an effective device for children with severe and/or profound prelingual hearing loss, since it provides considerable improvement in oral language acquisition through the auditory pathway. The use of a cochlear implant contributes to the development of auditory perception, favoring the acquisition of the linguistic processes related to communication skills, which might have a positive effect on other areas of development.ObjectiveThe aim of this study was to verify the performance of children using cochlear implants for expressive and receptive oral language.MethodsThis was a prospective cross-sectional study that used the following tests: Child language test in the phonology, vocabulary, fluency and pragmatics areas, and the Peabody picture vocabulary test. Thirty children participated in this study, of both genders, aged between 36 and 72 months, with severe and/or profound bilateral sensorineural hearing loss, without other impairments and users of unilateral cochlear implant with full electrode insertion for a minimum of 12 months.ResultsThe longer duration of the cochlear implant use, the younger age at surgery and the better performance in the auditory perception of speech influenced the performance in expressive and receptive oral language. Even though when compared to the normative language acquisition process, the results showed that these children had patterns of linguistic skills that are below their chronological age; the results indicate that these children are developing expressive and receptive oral language skills, and this is the outcome that should be taken into account in this study.ConclusionThe longer duration of the cochlear implant use, the younger age at surgery and the better performance in the auditory perception of speech influenced the performance in expressive and receptive oral language skills, but not in all the studied semantic categories.     

Phrases in noise test (PINT) Brazil: effectiveness of the test in children with hearing loss

IntroductionOne of the main implications of hearing impairment is the difficulty in perceiving speech sounds, especially in noisy environments. Thus, the frequency-modulated system is considered an important educational tool for children with hearing impairment because it improves speech perception in acoustically-unfavorable environments, such as in the classroom. The assessment of speech perception in noise is included in the verification protocol of this device.ObjectivesTo verify the effectiveness of the phrases in noise test Brazil in children with hearing impairment using an frequency-modulated system.MethodsThis was a cross-sectional cohort study. The sample included 40 children, aged 4 years to 11 years and 11 months old, divided into 4 groups: (1) 10 normal hearing children; (2) 13 children with hearing aids and frequency-modulated system; (3) 12 children using cochlear implant and fitted with the frequency-modulated system; and (4) 5 children diagnosed with auditory neuropathy spectrum disorder, fitted with hearing aids and/or cochlear implant and with the frequency-modulated system. The phrases in noise test Brazil was used to evaluate speech perception in noise under the conditions with and without the frequency-modulated system. For the statistical analysis of the data, a significance level of 5% (p < 0.05) was adopted.ResultsThere was a significant difference between the groups when they were evaluated with the frequency-modulated system. The test was also validated through concurrent and convergent validation measures. Phrases in noise test Brazil is a viable option for monitoring auditory performance in noise in different groups of children with hearing impairmen.ConclusionPhrases in noise test Brazil was effective in assessing speech perception in noise and may contribute to the improvement of the indication, fitting and follow-up protocols for the frequency-modulated system use.     

HiResolution and conventional sound processing in the HiResolution bionic ear: using appropriate outcome measures to assess speech recognition ability

OBJECTIVE: This study compared speech perception benefits in adults implanted with the HiResolution (HiRes) Bionic Ear who used both conventional and HiRes sound processing. A battery of speech tests was used to determine which formats were most appropriate for documenting the wide range of benefit experienced by cochlear-implant users. STUDY DESIGN: A repeated-measures design was used to assess postimplantation speech perception in adults who received the HiResolution Bionic Ear in a recent clinical trial. Patients were fit first with conventional strategies and assessed after 3 months of use. Patients were then switched to HiRes sound processing and assessed again after 3 months of use. To assess the immediate effect of HiRes sound processing on speech perception performance, consonant recognition testing was performed in a subset of patients after 3 days of HiRes use and compared with their 3-month performance with conventional processing. SETTING: Subjects were implanted and evaluated at 19 cochlear implant programs in the USA and Canada affiliated primarily with tertiary medical centers. PATIENTS: Patients were 51 postlinguistically deafened adults. MAIN OUTCOME MEASURES: Speech perception was assessed using CNC monosyllabic words, CID sentences and HINT sentences in quiet and noise. Consonant recognition testing was also administered to a subset of patients (n = 30) using the Iowa Consonant Test presented in quiet and noise. All patients completed a strategy preference questionnaire after 6 months of device use. RESULTS: Consonant identification in quiet and noise improved significantly after only 3 days of HiRes use. The mean improvement from conventional to HiRes processing was significant on all speech perception tests. The largest differences occurred for the HINT sentences in noise. Ninety-six percent of the patients preferred HiRes to conventional sound processing. Ceiling effects occurred for both sentence tests in quiet. CONCLUSIONS: Although most patients improved after switching to HiRes sound processing, the greatest differences were seen in the 'poor' performers because 'good' performers often reached ceiling performance, especially on tests in quiet. Future evaluations of cochlear-implant benefit should make use of more difficult measures, especially for 'good' users. Nonetheless, a range of difficulty must remain in test materials to document benefit in the entire population of implant recipients.     

Benefit and predictive factors for speech perception outcomes in pediatric bilateral cochlear implant recipients

IntroductionDespite recent advancement in the prediction of cochlear implant outcome, the benefit of bilateral procedures compared to bimodal stimulation and how we predict speech perception outcomes of sequential bilateral cochlear implant based on bimodal auditory performance in children remain unclear.ObjectivesThis investigation was performed: (1) to determine the benefit of sequential bilateral cochlear implant and (2) to identify the associated factors for the outcome of sequential bilateral cochlear implant.MethodsObservational and retrospective study. We retrospectively analyzed 29 patients with sequential cochlear implant following bimodal-fitting condition. Audiological evaluations were performed; the categories of auditory performance scores, speech perception with monosyllable and disyllables words, and the Korean version of Ling. Audiological evaluations were performed before sequential cochlear implant with the bimodal fitting condition (CI1 + HA) and one year after the sequential cochlear implant with bilateral cochlear implant condition (CI1 + CI2). The good performance group (GP) was defined as follows; 90% or higher in monosyllable and bisyllable tests with auditory-only condition or 20% or higher improvement of the scores with CI1 + CI2. Age at first implantation, inter-implant interval, categories of auditory performance score, and various comorbidities were analyzed by logistic regression analysis.ResultsCompared to the CI1 + HA, CI1 + CI2 provided significant benefit in categories of auditory performance, speech perception, and Korean version of Ling results. Preoperative categories of auditory performance scores were the only associated factor for being GP (odds ratio = 4.38, 95% confidence interval – 95% = 1.07–17.93, p = 0.04).ConclusionsThe children with limited language development in bimodal condition should be considered as the sequential bilateral cochlear implant and preoperative categories of auditory performance score could be used as the predictor in speech perception after sequential cochlear implant.     

Effect of signal processing strategy and stimulation type on speech and auditory perception in adult cochlear implant users

Objective: The objective of this study was to investigate the effects of signal processing strategy on speech understanding and auditory function for adult cochlear implant (CI) users with a focus on the effects of sequential versus paired stimulation.

Design: Within-subjects, repeated measures design was utilised to compare performance between processing strategies and stimulation type on various measures of auditory function and subjective sound quality. Testing with subsequent strategies was completed after a total familiarisation time of two weeks.

Study Sample: Ten post-lingually deafened adult CI users were recruited from a clinical population. Participants had a minimum of 13?months CI experience. Ages ranged from 25–78?years. All participants had long-term experience with the optima strategy; eight with sequential stimulation and two with paired stimulation.

Results: We found no statistically significant effect of processing strategy. We observed an effect of stimulation type with sequential stimulation yielding significantly higher performance than paired stimulation for speech understanding in quiet and in noise, and subjective estimates of sound quality. No significant differences were noted across strategy or stimulation for music perception, spectral resolution or temporal resolution.

Conclusions: Many patients utilise paired stimulation – the default stimulation type in the clinical software; however, sequential stimulation yielded significantly higher outcomes on multiple measures.     

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.     

Maximizing cochlear implant patients' performance with advanced speech training procedures

Advances in implant technology and speech processing have provided great benefit to many cochlear implant patients. However, some patients receive little benefit from the latest technology, even after many years' experience with the device. Moreover, even the best cochlear implant performers have great difficulty understanding speech in background noise, and music perception and appreciation remain major challenges. Recent studies have shown that targeted auditory training can significantly improve cochlear implant patients' speech recognition performance. Such benefits are not only observed in poorly performing patients, but also in good performers under difficult listening conditions (e.g., speech noise, telephone speech, music, etc.). Targeted auditory training has also been shown to enhance performance gains provided by new implant devices and/or speech processing strategies. These studies suggest that cochlear implantation alone may not fully meet the needs of many patients, and that additional auditory rehabilitation may be needed to maximize the benefits of the implant device. Continuing research will aid in the development of efficient and effective training protocols and materials, thereby minimizing the costs (in terms of time, effort and resources) associated with auditory rehabilitation while maximizing the benefits of cochlear implantation for all recipients.     

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.     

Cochlear implantation in recipients with single-sided deafness: Audiological performance

Objective: To examine the auditory benefit of cochlear implants (CI) in patients with single-sided deafness (SSD).

Material and methods: Twenty patients with a normal pure tone audiogram (n?=?8) or moderate hearing loss (n?=?12) in one ear and a CI system MED-EL SONATA/CONCERTO?+?OPUS2 (n?=?12), COCHLEAR CI24RE(ST)?+?CP810 (n?=?7) and Advanced Bionics HiRes90?K?+?Harmony (n?=?1) in the contralateral ear and with at least 6 months of CI experience were tested with respect to directional hearing, speech perception in noise, binaural loudness matching, and binaural pitch matching. Twenty-six normal hearing controls were included for normative reference.

Results: Addition of the CI significantly improves directional hearing (percentage of correct source identifications improved from 14.9 to 15.6%, root mean square error decreased from 125 to 93°) and improves speech perception in noise (speech perception threshold median improved from ?2.3 to ?6.0?dB signal to noise ratio, equivalent to a binaural intelligibility level difference?=?3.7?dB). Alternate binaural loudness balancing showed that matching takes place at levels between 48 and 55?dB HL (group averages). In the pitch matching experiment, the standard deviation of the relative interaural frequency difference at 500, 1000, and 2000?Hz was 24.5, 22.8, and 24.0%, respectively (compared to 11.7, 14.4, and 12.3% in the control group).

Conclusions: In SSD, cochlear implantation considerably improves audiological performance in terms of directional hearing, binaural signal equivalence, and speech perception.     

A multicentre clinical evaluation of paediatric cochlear implant users upgrading to the Nucleus® 6 system

ObjectivesThe aim of this study was to investigate whether experienced paediatric cochlear implant users could show benefits to speech perception outcomes from the introduction of noise reduction and automated scene classification technologies as implemented in the Nucleus^® 6 sound processor. Previous research with adult cochlear implant users had shown significant improvements in speech intelligibility for listening in noisy conditions and good user acceptance for upgrading to the Nucleus 6 processor. In adults, these improvements for listening in noise were primarily attributed to the use of a range of new input processing technologies including noise reduction, as well as introduction of automatic scene classification technology.MethodsExperienced paediatric cochlear implant users (n = 25) were recruited from four clinics located in three countries. Research participants were evaluated on three occasions, an initial session using their Nucleus 5 sound processor; a second session in which participants used the Nucleus 6 processor programmed with the same technologies as were used in their Nucleus 5 sound processor; and a final session in which participants used the Nucleus 6 processor programmed with the default technologies including automatic scene classification (SCAN) which automatically selects the microphone directionality, noise reduction (SNR-NR), and wind noise reduction (WNR) technologies. Prior to both the second and third evaluations, research participants had approximately two weeks take-home experience with the new system. Speech perception performances on monosyllabic word tests presented in quiet and in noise, and a sentence test presented in noise, were compared across the three processor conditions. Acceptance of the Nucleus 6 default settings was assessed in a final session.ResultsNo group mean difference in performance was found for monosyllabic words in quiet. A significant improvement in speech perception was found for both monosyllabic words and sentences in noise with the default Nucleus 6 program condition as compared with the Nucleus 5 condition. No acceptance issues were noted for any of the children.ConclusionsExperienced paediatric cochlear implant users showed a significant improvement in speech perception in listening in noise when upgraded to the Nucleus 6 sound processor primarily due to the introduction of a noise reduction technology, and all children accepted the default program. These findings suggest that school-aged children may benefit from upgrading to the Nucleus 6 sound processor using the default program.     

Speech perception results in children implanted with Clarion® devices: Hi-resolution™ and standard resolution modes

Conclusions Formal testing showed that HiRes users seem to make significant use of acoustic information. Furthermore, from observations reported by experienced care-givers, for example, family, teachers and speech therapists, these children learn a lot from their surrounding environment. Incidental learning, which takes place when acquiring skills or knowledge through naturally occurring events, is a key become available to these deaf paediatric cochlear implant recipients.

Objective To compare speech perception skills in children with a Clarion® cochlear implant using different speech coding strategies, such as continuous interleaved sampling (CIS), simultaneous analogue stimulation (SAS) and Hi-Resolution (HiRes)?.

Material and methods The study population comprised 40 children, 17 implanted with a Clarion Hi-Focus 1.2 and 23 with a Clarion CII. All children were pre-lingually deaf and differed in terms of age and cause of deafness. All children had undergone a trial (minimum 6 months) with hearing aids before implantation. Children implanted with a Clarion 1.2 were either CIS or SAS users [Standard Resolution mode (SRM) group]; children implanted with a Clarion CII were Hi-Resolution users [Hi-Resolution mode (HRM) group]. Findings were assessed according to Erber's hierarchical model (detection, discrimination, identification, recognition and comprehension), making use of a battery of speech perception tests calibrated to the age of the child. Further information concerning use of the implant in everyday situations was obtained by means of the Meaningful Auditory Integration Scale (MAIS) questionnaire, which was administered to the parents. Tests were carried out prior to each fitting session, at switch-on and then at 3, 6, 9 and 12 months. Findings at pre-implantation and at 12 months follow-up were collected for both the SRM and HRM groups. Speech perception results were analysed for the SRM and HRM groups, independent of age at implantation, for five subgroups of children according to the paediatric test battery in use and for two subgroups of children, one<?and one?>5 years of age.

Results Clarion-implanted children using the Hi-Resolution strategy can develop better speech perception skills at 12 months post-implantation compared to children fitted with the SAS or CIS strategy. SAS or CIS users implanted before the age of 5 years tend to achieve better results at 1 year follow-up than children implanted later. In contrast, in Hi-Resolution users, a trend towards better results for recognition and comprehension tasks was observed in children implanted after 5 years of age.     

Evaluation of a non-linear spectral subtraction noise suppression scheme in cochlear implant users

Abstract

The aim of the study was to determine benefit to speech recognition in noise by adult cochlear implant users with the non-linear spectral subtraction (NSS) noise suppression strategy. Users of the Nucleus 22 or Nucleus 24 cochlear implant systems were tested with sentence materials combined with stationary noise at +5 and +10 dB signal to noise ratio (SNR), with and without NSS processing applied offline. Sentence scores were significantly higher with NSS processing, for both SNRs. The effect was greater at +5 dB SNR (12% improvement with NSS) than at +10 dB SNR (5% improvement with NSS). These results are promising and suggest that online implementation of NSS as part of cochlear implant processors has the potential to yield benefits for speech recognition in noise. Copyright © 2006 John Wiley & Sons, Ltd.     

Spectral-Ripple Resolution Correlates with Speech Reception in Noise in Cochlear Implant Users

Speech perception ability in noise is one of the most practical measures of success with a cochlear implant; however, with experience, this ability can change dramatically over time, making it a less than ideal tool for comparing performance among different processing strategies. This study examined performance on a spectral discrimination task and compared it to speech perception in noise. An adaptive procedure was used to determine the spectral-ripple density that subjects could discriminate. A closed-set, forced-choice adaptive procedure was used to determine speech reception thresholds for words in two-talker babble and in speech-shaped, steady-state noise. Spectral-ripple thresholds (ripples/octave) were significantly correlated with speech reception thresholds (dB SNR) in noise for 29 cochlear implant users (r = −0.55, p = 0.002 in two-talker babble; r = −0.62, p = 0.0004 in steady-state noise), demonstrating that better spectral resolution was associated with better speech perception in noise. A significant correlation was also found between the spectral-ripple discrimination ability and word recognition in quiet (r = 0.50, p = 0.009). In addition, test–retest reliability for spectral-ripple discrimination was good, and no learning was observed. The present study demonstrates that the spectral-ripple discrimination test, which is time efficient and nonlinguistic, would be a useful tool to evaluate cochlear implant performance with different signal processing strategies.     

Evaluation of the Harmony soundprocessor in combination with the speech coding strategy HiRes 120

OBJECTIVE: The Advanced Bionics Harmony BTE processor was developed to support the new speech coding strategy HiRes 120 with a resolution of 120 channels based on "current steering." Compared with the previous Auria, the front end has been re-designed and power consumption reduced. STUDY DESIGN: HiRes 120 as well as the impact of the improved Harmony processing concerning a better speech understanding were evaluated. Subject's performance was evaluated using a test battery of the Hochmair-Schulz-Moser (HSM) sentence test and questionnaires regarding general sound quality, music perception, battery life time and processor handling. PATIENTS: In the first study group, 11 postlingually deafened adult subjects participated with a minimum of 9 months experience. The second study group consisted of 14 postlingually deafened adult subjects with a minimum of 2 years experience. INTERVENTIONS: Tested were the 2 speech coding strategies HiRes and HiRes 120 on the Harmony and the clinical system, respectively. MAIN OUTCOME MEASURES: Speech perception tests in quiet, in CCITT noise, as well as with a competing talker, questionnaires regarding sound quality and handling and perceptual channel tests. RESULTS: A total of 84% showed a clear preference for the Harmony processor compared with their previous processor with HiRes. The speech test results showed a 7.7% average increase in the HSM sentence test with 5 dB SNR competing talker. CONCLUSION: The majority of the subjects wanted to change to the new Harmony processor because of a better understanding in everyday life, handling, and improved battery-life time.     

Language and speech perception of young children with bimodal fitting or bilateral cochlear implants

Abstract

Objectives

This paper compares language development and speech perception of children with bimodal fitting (a cochlear implant in one ear and a hearing aid in the opposite ear) or bilateral cochlear implantation.

Methods

Participants were children enrolled in the Longitudinal Outcomes of Children with Hearing Impairment study. Language development was assessed at 3 years of age using standardized tests. Speech perception was evaluated at 5 years of age. Speech was presented from a frontal loudspeaker, and babble noise was presented either from the front or from both sides.

Results

On average, there was no significant difference in language outcomes between 44 children with bimodal fitting and 49 children with bilateral cochlear implants; after controlling for a range of demographic variables. Earlier age at cochlear implant activation was associated with better outcomes. Speech perception in noise was not significantly different between children with bimodal fitting and those with bilateral cochlear implants. Compared to normal-hearing children, children with cochlear implants required a better signal-to-noise ratio to perform at the same level, but demonstrated spatial release from masking of a similar magnitude.

Conclusions

This population-based study found that language scores for children with bilateral implants were higher than those with bimodal fitting or those with unilateral implants, but neither reached significance level.