Benefits of Bilateral Hearing on the Telephone for Cochlear Implant Recipients.

BACKGROUND: Cochlear implant (CI) recipients frequently experience difficulty understanding speech over the telephone and rely on hearing assistive technology (HAT) to improve performance. Bilateral inter-processor audio streaming technology using nearfield magnetic induction is an advanced technology incorporated within a hearing aid or CI processor that can deliver telephone audio signals captured at one sound processor to the sound processor at the opposite ear. To date, limited data exist examining the efficacy of this technology in CI users to improve speech understanding on the telephone. PURPOSE: The primary objective of this study was to examine telephone speech recognition outcomes in bilateral CI recipients in a bilateral inter-processor audio streaming condition (DuoPhone) compared with a monaural condition (i.e., telephone listening with one sound processor) in quiet and in background noise. Outcomes in the monaural and bilateral conditions using either a telecoil or T-Mic2 technology were also assessed. The secondary aim was to examine how deactivating microphone input in the contralateral processor in the bilateral wireless streaming conditions, and thereby modifying the signal-to-noise ratio, affected speech recognition in noise. RESEARCH DESIGN: A repeated-measures design was used to evaluate speech recognition performance in quiet and competing noise with the telephone signal transmitted acoustically or via the telecoil to the ipsilateral sound processor microphone in monaural and bilateral wireless streaming listening conditions. STUDY SAMPLE: Nine bilateral CI users with Advanced Bionics HiRes 90K and/or CII devices were included in the study. DATA COLLECTION AND ANALYSIS: The effects of phone input (monaural [DuoPhone Off] vs. bilateral [DuoPhone on]) and processor input (T-Mic2 vs. telecoil) on word recognition in quiet and noise were assessed using separate repeated-measures analysis of variance. Effect of the contralateral device mic deactivation on speech recognition outcomes for the T-Mic2 DuoPhone conditions was assessed using paired Student's t-tests. RESULTS: Telephone speech recognition was significantly better in the bilateral inter-processor streaming conditions relative to the monaural conditions in both quiet and noise. Speech recognition outcomes were similar in quiet and noise when using the T-Mic2 and telecoil in the monaural and bilateral conditions. For the acoustic DuoPhone conditions using the T-Mic2, speech recognition in noise was significantly better when the microphone of the contralateral processor was disabled. CONCLUSION: Inter-processor audio streaming allows for bilateral listening on the telephone and produces better speech recognition in quiet and in noise compared with monaural listening conditions for adult CI recipients.

Evaluation of Speech Recognition of Cochlear Implant Recipients Using Adaptive, Digital Remote Microphone Technology and a Speech Enhancement Sound Processing Algorithm.

BACKGROUND: Cochlear implant recipients often experience difficulty with understanding speech in the presence of noise. Cochlear implant manufacturers have developed sound processing algorithms designed to improve speech recognition in noise, and research has shown these technologies to be effective. Remote microphone technology utilizing adaptive, digital wireless radio transmission has also been shown to provide significant improvement in speech recognition in noise. There are no studies examining the potential improvement in speech recognition in noise when these two technologies are used simultaneously. PURPOSE: The goal of this study was to evaluate the potential benefits and limitations associated with the simultaneous use of a sound processing algorithm designed to improve performance in noise (Advanced Bionics ClearVoice) and a remote microphone system that incorporates adaptive, digital wireless radio transmission (Phonak Roger). RESEARCH DESIGN: A two-by-two way repeated measures design was used to examine performance differences obtained without these technologies compared to the use of each technology separately as well as the simultaneous use of both technologies. STUDY SAMPLE: Eleven Advanced Bionics (AB) cochlear implant recipients, ages 11 to 68 yr. DATA COLLECTION AND ANALYSIS: AzBio sentence recognition was measured in quiet and in the presence of classroom noise ranging in level from 50 to 80 dBA in 5-dB steps. Performance was evaluated in four conditions: (1) No ClearVoice and no Roger, (2) ClearVoice enabled without the use of Roger, (3) ClearVoice disabled with Roger enabled, and (4) simultaneous use of ClearVoice and Roger. RESULTS: Speech recognition in quiet was better than speech recognition in noise for all conditions. Use of ClearVoice and Roger each provided significant improvement in speech recognition in noise. The best performance in noise was obtained with the simultaneous use of ClearVoice and Roger. CONCLUSIONS: ClearVoice and Roger technology each improves speech recognition in noise, particularly when used at the same time. Because ClearVoice does not degrade performance in quiet settings, clinicians should consider recommending ClearVoice for routine, full-time use for AB implant recipients. Roger should be used in all instances in which remote microphone technology may assist the user in understanding speech in the presence of noise.

Enhanced hearing in noise for cochlear implant recipients: clinical trial results for a commercially available speech-enhancement strategy.

OBJECTIVE: To demonstrate benefits for speech perception and everyday listening in quiet and in noise with a speech-enhancement strategy called ClearVoice, which was designed to improve listening in complex acoustic environments without compromising hearing in quiet. STUDY DESIGN: A 2-week randomized crossover design was used to evaluate ClearVoice in 46 adults unilaterally implanted with a CII/HiRes 90K cochlear implant who had at least 6 months experience with HiRes Fidelity 120 sound processing. Speech perception was assessed using the AzBio sentences presented in quiet, in speech-spectrum noise and in multitalker babble. Subjective listening benefit and strategy preference were assessed with a questionnaire. ClearVoice has 3 gain settings (low, medium, and high), each intended as a full-time listening option according to individual preference. Speech understanding after acute use of ClearVoice-low was compared with HiRes Fidelity 120 during an initial test session. Speech perception abilities were compared with HiRes Fidelity 120 after 2 weeks of exclusive use of ClearVoice-medium, and after 2 weeks of exclusive use of ClearVoice-high. During a fifth week, participants were fit with 3 programs for comparison (HiRes Fidelity 120, ClearVoice-medium, and ClearVoice-high), after which, they reported preference and everyday listening benefits via a questionnaire. RESULTS: ClearVoice significantly improved speech understanding in speech-spectrum noise and multitalker babble, did not compromise listening in quiet, was preferred for everyday listening, and provided improved hearing in real-life situations. CONCLUSION: ClearVoice improves hearing in noise for cochlear implant recipients who use HiRes Fidelity 120 sound processing.

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.

Current steering creates additional pitch percepts in adult cochlear implant recipients.

OBJECTIVE: The number of spectral channels is the number of discriminable pitches heard as current is delivered to distinct locations along the cochlea. This study aimed to determine whether cochlear implant users could hear additional spectral channels using current "steering." Current steering involves the simultaneous delivery of current to adjacent electrodes, where stimulation can be steered to sites between the contacts by varying the proportion of current delivered to each electrode in an electrode pair. Current steering may increase the number of spectral channels beyond the number of fixed electrode contacts. STUDY DESIGN: Prospective clinical study. SETTING: Twelve tertiary care centers in North America. PATIENTS: The subjects were 106 adults with postlingual onset of severe-to-profound hearing loss. INTERVENTIONS: Subjects received the Advanced Bionics CII or HiResolution 90K device (Advanced Bionics Corporation, Valencia, CA, USA). MAIN OUTCOME MEASURES: After loudness balancing and pitch ranking the 3 electrode pairs (2 and 3, 8 and 9, and 13 and 14), the subjects identified the electrode with the higher pitch while current was varied proportionally between the electrodes in each pair. The smallest change in proportion yielding a discriminable change in pitch was defined as the spectral resolution. RESULTS: The data from 115 ears indicate that the number of spectral channels averaged 3.8 for the basal pair, 6.0 for the midarray pair, and 5.3 for the apical pair. Assuming that the number of channels on these 3 electrode pairs represents the entire array, the total potential number of spectral channels was calculated and ranged from 8 to 451, with an average of 63. CONCLUSION: These results indicate that additional pitch percepts can be created using current steering.

Using current steering to increase spectral resolution in CII and HiRes 90K users.

OBJECTIVES: The HiResolution Bionic Ear has the capability of creating virtual spectral channels using current steering. Through simultaneous delivery of current to pairs of adjacent electrodes, it is hypothesized that the effective locus of stimulation can be steered to sites between the contacts by varying the proportion of current delivered to each electrode of the pair. Thus, theoretically, many intermediate regions of stimulation can be created with fine control over the proportion and amplitude of current delivered to each electrode. This study investigated the number of spectral channels-or different pitches-that could be resolved by adult users of the CII and HiRes 90K cochlear implants when current steering was applied to three pairs of electrodes along the implanted array. DESIGN: Subjects were postlinguistically deafened adults recruited from the general CII and HiRes 90K user populations at 11 participating study sites. After loudness balancing and pitch ranking electrode pairs (2 and 3, 8 and 9, 13 and 14), an adaptive paradigm was used to estimate the number of intermediate pitch percepts that could be heard for each pair when current steering was implemented. Those data were used to estimate the potential number of spectral channels for each electrode pair. RESULTS: Data from 57 implanted ears indicated that the numbers of spectral channels per electrode pair ranged from one (subjects who could not tell the electrodes apart) to 52 (an individual who had 52 different pitch percepts for the midarray pair of electrodes). The average numbers of spectral channels that could be distinguished were 5.4 for the basal electrode pair, 8.7 for the midarray electrode pair, and 7.2 for the apical electrode pair. Assuming that the average numbers of spectral channels for these three electrode pairs were representative of the entire 16-contact array, the potential total numbers of spectral channels could be estimated. For the 57 ears, the number of potential channels ranged from 8 to 466, with an average of 93. CONCLUSIONS: The HiResolution Bionic Ear has the ability to steer current through simultaneous stimulation of adjacent electrode contacts. These data show that the majority of subjects perceive additional spectral channels other than those associated with stimulation of the fixed electrodes when current steering is implemented. The results suggest that the average cochlear implant user may have significantly more place-pitch capability than is exploited presently by cochlear implant systems. Current steering will be implemented in a wearable sound-processing strategy that can deliver up to 120 spectral channels to CII and HiRes 90K recipients. The new strategy takes advantage of untapped capabilities of the CII/HiRes 90K implanted electronics and will be implemented through software, with no additional surgery required. It is anticipated that the improved spectral resolution offered by current steering will lead to better speech perception in noise and improved music appreciation.

Standard cochlear implantation of adults with residual low-frequency hearing: implications for combined electro-acoustic stimulation.

OBJECTIVE: This study compared preoperative and postoperative cochlear implant benefit in subjects with steeply sloping high-frequency hearing losses (HLs) who were implanted with standard long cochlear implant electrodes to: 1) determine the effect of etiology, 2) compare outcomes in studies exploring the use of combined electrical and acoustic stimulation, and 3) compare outcomes in patients implanted using standard criteria. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Nine adults with steeply sloping high-frequency congenital (n=2) or acquired (n=7) bilateral sensorineural HL. All pure-tone audiograms fit the criteria for trials of a short electrode aimed at preserving low-frequency acoustic hearing. INTERVENTION: Subjects received full insertion of a standard cochlear implant long electrode in the poorer ear. MAIN OUTCOME MEASURES: Preoperative versus postoperative audiograms, word and sentence recognition in quiet and noise. RESULTS: Patients with progressive acquired HLs experienced significantly improved speech understanding in quiet and in noise with the cochlear implant, especially when combined with hearing aid use in the contralateral ear. Patients with congenital HLs experienced little or no improvement in the implanted ear when tested with the implant alone, but achieved some benefit when the implant was combined with a hearing aid in the nonimplanted ear. CONCLUSION: Based on this small sample, patients with acquired steeply sloping high-frequency HLs obtain significant benefit from cochlear implantation with standard long electrodes. In progressive losses, full insertion of a long electrode would be preferable to a short electrode because acoustic hearing may diminish over time. In contrast, patients with congenital losses may not benefit from long electrodes, and might be better served by implanting a short electrode, thereby allowing use of low-frequency acoustic stimulation.

Bioengineering solutions for hearing loss and related disorders.

Advances in digital signal processing, microelectronics, and power technology have produced devices that have contributed significantly to the quality of life and communication abilities of individuals with hearing impairment and tinnitus. Future technological developments will expand the benefits of current devices and offer new treatments for otologic disorders.

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.

Effect of age at cochlear implantation on auditory skill development in infants and toddlers.

OBJECTIVES: To investigate the effect of age at cochlear implantation on the auditory development of children younger than 3 years and to compare these children's auditory development with that of peers with normal hearing. DESIGN: Using a repeated-measures paradigm, auditory skill development was evaluated before and 3, 6, and 12 months after implantation. Data were compared with previously published data from cohorts with normal hearing. PARTICIPANTS: One hundred seven hearing-impaired children (age range, 12-36 months) who received a cochlear implant during clinical trials in North America. MAIN OUTCOME MEASURE: Auditory skill development was assessed using the Infant-Toddler Meaningful Auditory Integration Scale, a tool that provides a quantitative measure in children as young as newborns. RESULTS: Infants and toddlers who receive implants show rapid improvement in auditory skills during the first year of device use regardless of age at implantation, although younger children achieve higher scores. Children who undergo implantation at a younger age acquire auditory skills nearer to those of their peers with normal hearing at a younger age. The mean rate of acquisition of auditory skills is similar to that of infants and toddlers with normal hearing regardless of age at implantation. CONCLUSION: Performing implantation in children with profound hearing loss at the youngest age possible allows the best opportunity for them to acquire communication skills that approximate those of their peers with normal hearing.

Cochlear implant candidacy and performance trends in children.

Data from Clarion cochlear implant pediatric clinical trials were examined retrospectively to uncover trends in candidacy and postimplant benefit over time. In particular, age at implantation, educational setting, and communication mode were examined with respect to speech perception performance after implantation. The results showed that 1) age at implantation is decreasing, 2) children in oral education programs obtain more benefit from a cochlear implant than children in total communication programs, 3) children who undergo implantation before 2 years of age show greater benefit than children who undergo implantation between 2 and 3 years of age, 4) more younger children are using oral communication than older children, and 5) more children with good auditory skills before implantation and more residual hearing are undergoing implantation. In sum, in the 11 years since implants have been available to children in the United States, candidacy criteria have evolved and benefit has increased as cochlear implant technology has advanced.