Comparison of two frequency-to-electrode maps for acoustic-electric stimulation

The fitting of a cochlear implant together with aided residual hearing was evaluated by means of matching frequency and/or perceived pitch between acoustic and electric modalities. Five cochlear implant users with the Nucleus^® Freedom? electrode array with residual acoustic hearing participated. Psychophysical procedures were used to create a map in which the implant was programmed to provide the listener with high-frequency information only above the frequency at which acoustic hearing was no longer considered useful. This was compared to a second map which provided the full frequency range. Listeners wore each map for a number of weeks before speech recognition was measured in quiet and noise. Post-operatively across subjects, average hearing thresholds worsened by 27 dB. However, cochlear implantation provided superior recognition of speech compared to pre-operative scores, with the best results found when subjects were wearing their hearing aids together with the implant. No significant differences were found between the two maps on speech tests when subjects were wearing their implant together with hearing aid/s. In conclusion, the combination of a cochlear implant together with hearing aid/s was effective at providing speech perception benefits for the listeners of the current study, regardless of the frequency-to-electrode allocation selected.     

Assessment of basal sound identification skills and communication abilities in profoundly deaf children fitted with hearing aids or a cochlear implant

Basal auditory functions and early verbal communication skills were examined in young, profoundly deaf children with hearing aids or a cochlear implant. The hearing aid users (n = 23) were subdivided on the basis of their (unaided) hearing thresholds into: group A (pure tone average (PTA) at 0.5, 1 and 2 kHz: 90–100 dB HL); group B (PTA: 100–110 dB HL); and group C (PTA > 110 dB HL). All the children with a cochlear implant (n = 20) had a profound sensorineural hearing loss with a PTA that exceeded 120 dB HL. Functional hearing was evaluated by means of basal sound identification. The child’s communication abilities with hearing aids or a cochlear implant were assessed using structured observations on the Scales of Early Communication Skills for Hearing Impaired Children. The basal auditory functions on a sound identification level improved over time in the cochlear implant users and groups A and B. Hardly any improvement was seen in group C. The performance of all the groups (either hearing aid or cochlear implant) on the Scales of Early Communication Skills for Hearing Impaired Children at 6 months after fitting the device and at later evaluations, was close to the average level for their age.     

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.     

Monosyllable speech perception of Japanese hearing aid users with prelingual hearing loss: implications for surgical indication of cochlear implant

OBJECTIVE: The monosyllable speech perception ability after years of educational intervention was compared between prelingually deafened pediatric hearing aid users and their cochlear implant counterparts. DESIGN: An open-set monosyllabic speech perception test was conducted on all subjects. The test required subjects to indicate a corresponding Japanese character to that spoken by the examiner. Fifty-two subjects with prelingual hearing impairment (47 hearing aid users and 5 cochlear implant users) were examined. RESULTS: Hearing aid users with average pure-tone thresholds less than 90 dB HL demonstrated generally better monosyllable perception than 70%, which was equivalent or better performance than that of the cochlear implant group. Widely dispersed speech perception was observed within the 90-99 dB HL hearing-aid user group with most subjects demonstrating less than 50% speech perception. In the cluster of >100 dB HL, few cases demonstrated more than 50% in speech perception. The perception ability of the vowel part of each mora within the cochlear implant group was 100% and corresponding to that of hearing aid users with moderate and severe hearing loss. CONCLUSION: Hearing ability among cochlear implant users can be comparable with that of hearing aid users with average unaided pure-tone thresholds of 90 dB HL, after monosyllabic speech perception testing was performed.     

Bimodal benefit for cochlear implant listeners with different grades of hearing loss in the opposite ear

Objective: To determine speech perception in quiet and noise of adult cochlear implant listeners retaining a hearing aid contralaterally. Second, to investigate the influence of contralateral hearing thresholds and speech perception on bimodal hearing.

Patients and methods: Sentence recognition with hearing aid alone, cochlear implant alone and bimodally at 6 months after cochlear implantation were assessed in 148 postlingually deafened adults. Data were analyzed for bimodal summation using measures of speech perception in quiet and in noise.

Results: Most of the subjects showed improved sentence recognition in quiet and in noise in the bimodal condition compared to the hearing aid-only or cochlear implant-only mode. The large variability of bimodal benefit in quiet can be partially explained by the degree of pure tone loss. Also, subjects with better hearing on the acoustic side experience significant benefit from the additional electrical input.

Conclusions: Bimodal summation shows different characteristics in quiet and noise. Bimodal benefit in quiet depends on hearing thresholds at higher frequencies as well as in the lower- and middle-frequency ranges. For the bimodal benefit in noise, no correlation with hearing threshold in any frequency range was found.     

Cochlear implant in patients with residual hearing

Objective: The postoperative speech perception abilities of severely hearing-impaired patients with multi-channel cochlear implant were compared with preoperative speech perception performance with conventional hearing aids. Methods: Cochlear implantation was performed in six severely to profoundly hearing-impaired patients. They had unaided pure-tone thresholds of 70–100-dB HL and aided thresholds of 35–90-dB HL in the better ear, but were not able to perceive speech sounds well with hearing aids. Results: Postoperatively, all the patients had significantly improved speech perception performance, exceeded the average skills of profoundly deaf cochlear implant users, and were able to communicate without writing. Conclusion: These results imply that cochlear implant may be indicated for severely to profoundly deaf subjects, if they receive little or no benefit from conventional hearing aids.     

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.     

Deficits in auditory frequency discrimination and speech recognition in cochlear implant users

Abstract

Objectives

Speech recognition varies considerably following cochlear implantation for reasons that are still poorly understood. Considering the role of frequency discrimination in normal speech recognition, the aim of this study was to investigate the association between deficits in auditory frequency discrimination and speech recognition in cochlear implant users.

Methods

Frequency discrimination thresholds and speech recognition were assessed in a group of 20 cochlear implant users and 16 normally hearing controls.

Results

Based on their results on the speech recognition task, the cochlear implant users were categorized either as proficient (n = 10) or non-proficient users (n = 10). The non-proficient cochlear implant users had poorer auditory frequency discrimination compared to the normal hearing participants and proficient cochlear implant users (both P < 0.05). No significant difference was found between the proficient cochlear implant users and the normally hearing group (P > 0.05). Furthermore, a bivariate correlation analysis revealed a relationship between speech recognition and frequency discrimination.

Conclusions

The present findings suggest an association between auditory frequency discrimination and speech recognition proficiency in cochlear implant users. Although no causal link can be drawn from these data, possible reasons for this association are discussed.     

Natural history of contralateral residual hearing in binaural-bimodal hearing

Conclusions. The range of evaluation tools used in deciding which ear to implant and which to designate for a hearing aid (HA) should be expanded to include additional aspects to those tested by audiometry and basic speech perception. Residual hearing in non-implanted ears remains stable for at least 3 years after unilateral cochlear implantation, but regular refitting and monitoring of the HA function combined with cochlear implant (CI) mapping are mandatory for maximizing benefit from binaural-bimodal hearing. Objectives. To examine whether the clinical decision-making tools currently used to assess hearing are reliable guides when choosing the preferred ear for CI, and to determine the rate of residual hearing deterioration in the non-implanted ear over 36 months post-CI as a guide to recommending subsequent continued use of a contralateral HA as opposed to CI. Patients and methods. This was a retrospective evaluation of patients’ charts. The pre-CI choice of the ear for implantation in a group of 37 binaural-bimodal users was re-evaluated. In a second group of 22 patients, residual hearing deterioration was followed for 36 months post-implantation. Results. In the group of 37 patients, subjective identification of the worse-hearing ear was in agreement with audiometric results in 28 cases, but disagreed with the unaided audiometric results in the other 9. Mean threshold values for the group of 22 patients remained stable over 36 months post-CI, except for the aided threshold at 4.0kHz, which deteriorated by 10.9dB (p=0.003).     

Effect of bimodal hearing in Korean children with profound hearing loss

Conclusion. Bimodal hearing with combined acoustic stimulation and electric stimulation could enhance speech performance in deaf patients by residual hearing even though the amount of residual hearing is not enough to be used for communication by amplification. Objectives. The cochlear implant (CI) is a well-known therapeutic option for patients with profound hearing loss. However, deaf patients with a CI still have trouble in localization of sounds and understanding speech in a noisy environment. The aim of this study was to evaluate the benefits of bimodal hearing with a CI in one ear and a hearing aid in the contralateral ear in Korean children with profound hearing loss. Subjects and methods. Fourteen deaf children with residual hearing participated in this study. There were eight male and six female patients, with an age range of 4.6–13.8 years at the time of testing. The test was conducted between 3 months and 4.2 years after cochlear implantation. Speech performance was examined in a noisy environment using Korean word lists. A speech sound and the noise were presented to the child from the front loudspeaker. Results. The results showed that speech performance in a noisy environment was significantly better with bimodal hearing than with a CI alone.     

Receptive language as a predictor of cochlear implant outcome for prelingually deaf adults

Abstract

Objective: This study investigated outcomes and predictive factors, specifically language skills, for a group of prelingually hearing-impaired adults who received a cochlear implant. Design: Speech perception data, demographic information, and other related variables such as communication mode, residual hearing, and receptive language abilities were explored. Pre- and post-implant speech perception scores were compared and multiple regression analysis was used to identify significant predictive relationships. Study sample: The study included 43 adults with a prelingual onset of hearing loss, who proceeded with cochlear implantation at the Royal Victorian Eye and Ear Hospital in Melbourne, Australia. Results: The majority of patients experienced benefit from their cochlear implants, with 88% demonstrating significant improvement in speech perception performance. Volunteers achieved better post-operative speech perception scores if they had a shorter duration of severe-to-profound hearing loss, better language skills, and used an exclusively oral communication mode. Conclusions: Although post-operative speech perception performance is significantly poorer for prelingually hearing-impaired adults compared to postlingually hearing-impaired patients, the study group demonstrated significant benefit from their cochlear implants. The variability in post-operative outcomes can be predicted to some extent from the hearing history and language abilities of the individual patient.     

Effect of Speech Degradation on Top-Down Repair: Phonemic Restoration with Simulations of Cochlear Implants and Combined Electric–Acoustic Stimulation

The brain, using expectations, linguistic knowledge, and context, can perceptually restore inaudible portions of speech. Such top-down repair is thought to enhance speech intelligibility in noisy environments. Hearing-impaired listeners with cochlear implants commonly complain about not understanding speech in noise. We hypothesized that the degradations in the bottom-up speech signals due to the implant signal processing may have a negative effect on the top-down repair mechanisms, which could partially be responsible for this complaint. To test the hypothesis, phonemic restoration of interrupted sentences was measured with young normal-hearing listeners using a noise-band vocoder simulation of implant processing. Decreasing the spectral resolution (by reducing the number of vocoder processing channels from 32 to 4) systematically degraded the speech stimuli. Supporting the hypothesis, the size of the restoration benefit varied as a function of spectral resolution. A significant benefit was observed only at the highest spectral resolution of 32 channels. With eight channels, which resembles the resolution available to most implant users, there was no significant restoration effect. Combined electric-acoustic hearing has been previously shown to provide better intelligibility of speech in adverse listening environments. In a second configuration, combined electric-acoustic hearing was simulated by adding low-pass-filtered acoustic speech to the vocoder processing. There was a slight improvement in phonemic restoration compared to the first configuration; the restoration benefit was observed at spectral resolutions of both 16 and 32 channels. However, the restoration was not observed at lower spectral resolutions (four or eight channels). Overall, the findings imply that the degradations in the bottom-up signals alone (such as occurs in cochlear implants) may reduce the top-down restoration of speech.     

Communication abilities of children with aided residual hearing: comparison with cochlear implant users

OBJECTIVE: To compare the communication outcomes between children with aided residual hearing and children with cochlear implants. DESIGN: Measures of speech recognition and language were administered to pediatric hearing aid users and cochlear implant users followed up longitudinally as part of an ongoing investigation on cochlear implant outcomes. The speech recognition measures included the Lexical Neighborhood Test, Phonetically Balanced-Kindergarten Word Lists, and the Hearing in Noise Test for Children presented in quiet and noise (+5 dB signal-to-noise ratio). Language measures included the Peabody Picture Vocabulary Test: Third Edition (PPVT-III), the Reynell Developmental Language Scales, and the Clinical Evaluation of Language Fundamentals-Revised.Subjects The experimental group was composed of 39 pediatric hearing aid users with a mean unaided pure-tone average threshold of 78.2 dB HL (hearing level). The comparison group was composed of 117 pediatric cochlear implant users with a mean unaided pure-tone average threshold of 110.2 dB HL. On average, both groups lost their hearing at younger than 1 year and were fitted with their respective sensory aids at 2 to 2.6 years of age. Not every child was administered every test for a variety of reasons. RESULTS: Between-group performance was equivalent on most speech recognition and language measures. The primary difference found between groups was on the PPVT-III, in which the hearing aid group had a significantly higher receptive vocabulary language quotient than the cochlear implant group. Notably, the cochlear implant group was substantially younger than the hearing aid group and had less experience with their sensory devices on this measure. CONCLUSION: Data obtained from children with aided residual hearing can be useful in determining cochlear implant candidacy.     

The influence of lexical-access ability and vocabulary knowledge on measures of speech recognition in noise

Objective: The main objective was to investigate the effect of linguistic abilities (lexical-access ability and vocabulary size) on different measures of speech-in-noise recognition in normal-hearing listeners with various levels of language proficiency. Design: Speech reception thresholds (SRTs) were measured for sentences in steady-state (SRT_stat) and fluctuating noise (SRT_fluc), and for digit-triplets in steady-state noise (DIN). Lexical-access ability was measured with a lexical-decision test and a word-naming test. Vocabulary size was also measured. For the SRT, keyword scoring and sentence scoring were compared. Study sample: To introduce variation in linguistic abilities, three groups of 24 young normal-hearing listeners were included: higher-educated native, lower-educated native, and higher-educated non-native listeners. Results: Lexical-access ability was most accurately measured with combined results of lexical decision and word naming. Lexical-access ability explained 60% of the variance in SRT. The effect of linguistic abilities on SRTs was up to 5.6 dB for SRT_stat and 8 dB for SRT_fluc. Using keyword scoring reduced this effect by approximately 1.5 dB. For DIN the effect of linguistic ability was less than 1 dB. Conclusions: Lexical-access ability is an important predictor of SRTs in normal-hearing listeners. These results are important to consider in the interpretation of speech-in-noise scores of hearing-impaired listeners.     

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.     

Hearing aid and cochlear implant use in children with hearing loss at three years of age: Predictors of use and predictors of changes in use

Objective: To examine usage patterns of hearing aids and cochlear implants in children up to three years of age, how usage changes longitudinally, and factors associated with device usage. Design: Parent report and Parent’s Evaluation of Aural/oral Performance of Children (PEACH) data were obtained at six and twelve months after hearing-aid fitting or cochlear implant switch-on, and again at three years of age. The effect of device use on auditory functional performance was investigated using the PEACH questionnaire. Study sample: Four hundred and thirteen participants from the Longitudinal Outcomes of Children with Hearing Impairment (LOCHI) study were included for analysis. Results: For users of hearing aids, higher usage at three years was associated with higher maternal education, and more severe hearing loss. For users of cochlear implants, higher usage was associated with higher maternal education and the absence of additional disabilities. Higher PEACH scores were associated with higher usage scores. After allowing for the effects of demographic characteristics, device use was not a significant predictor of functional performance. Conclusions: Sixty-two percent of children achieved consistent use (> 75% of waking hours) within the first year of receiving a hearing aid or a cochlear implant, and 71% by three years of age.     

The case for earlier cochlear implantation in postlingually deaf adults

Abstract

Objective: This paper aimed to estimate the difference in speech perception outcomes that may occur due to timing of cochlear implantation in relation to the progression of hearing loss. Design: Data from a large population-based sample of adults with acquired hearing loss using cochlear implants (CIs) was used to estimate the effects of duration of hearing loss, age, and pre-implant auditory skills on outcomes for a hypothetical standard patient. Study sample: A total of 310 adults with acquired severe/profound bilateral hearing loss who received a CI in Melbourne, Australia between 1994 and 2006 provided the speech perception data and demographic information to derive regression equations for estimating CI outcomes. Results: For a hypothetical CI candidate with progressive sensorineural hearing loss, the estimates of speech perception scores following cochlear implantation are significantly better if implantation occurs relatively soon after onset of severe hearing loss and before the loss of all functional auditory skills. Conclusions: Improved CI outcomes and quality of life benefit may be achieved for adults with progressive severe hearing loss if they are implanted earlier in the progression of the pathology.     

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.     

人工耳蜗植入者对侧耳佩戴助听器的效果评价

目的　探讨人工耳蜗植入者对侧耳佩戴助听器的意义和作用。方法　对 6例年龄 7～ 18岁的语前聋患者于术后开机半年时在不同助听方式下 (人工耳蜗 +助听器和单独使用人工耳蜗 )进行声场 (啭音 )测听、言语功能评估和问卷调查 ,将结果进行统计分析。结果　人工耳蜗 +助听器较单独使用人工耳蜗声场 (啭音 )测试的各频率听阈低 (P <0 .0 1)。词汇识别测试显示两者均有良好的聆听效果 (P >0 .0 5 )。问卷调查显示患者普遍接受人工耳蜗 +助听器的方式 ,感觉舒适、方向性立体感强 ,交流更佳。结论　使用人工耳蜗者对侧耳佩戴助听器有助于更好地聆听。