Sentences In Quiet Research Articles

Initial surgical and clinical experience with the Nucleus CI532 slim modiolar electrode in the UK

ObjectiveThe goal of this work is to describe the first experience in the UK with the slim pre-curved perimodiolar electrode Nucleus CI532 in a continuous series of patients in terms of surgical and clinical reliability and early performance outcomes.MethodIn this retrospective review we describe the complication rate (including electrode array tip fold-over), NRT thresholds, hearing preservation, power efficiency and CI performance outcomes in a continuous series of 40 cochlear implants CI532 performed between October 2016 and November 2017 in 17 adults and 13 children with severe to profound hearing loss.ResultsPreliminary data from these groups reveals some low-frequency hearing preservation in the CI532 group although none of the patients were conventional hearing preservation candidates. NRT thresholds, power efficiency, and BKB sentences in quiet were measured at 3 and 6 months post activation. There were no significant differences in these results. The average BKB score in quiet increases from 22% pre-operatively to 58% at 3 months and 70% at 6 months. In addition, although hearing preservation was not an objective, low-frequency thresholds were preserved in 20% of cases at 3 and 6 months post-operatively. Complications were observed in 5 cases, one case with non-device related aerocoele and four related to the device array: two cases of tip roll over, one case of the electrode array being placed extra-cochlea, and one case with the electrode buckling into the middle ear. The last 2 cases were dealt with per-operatively.DiscussionOur preliminary results with the CI532 implant indicate that it may be reliably placed with standard surgical techniques but care is needed during the deployment of the electrode. Further initial data suggest that switch on and early electrophysiological measures are comparable to the existing CI 512 device. However whilst preliminary, our data suggest that it may be possible to use this electrode for hearing preservation. However, further studies are required to determine its definitive advantage over other electrode designs.ConclusionCI532 is a reliable device offering good initial results and could be an option for hearing preservation although further studies are required.

Assessing Cognitive Abilities in High-Performing Cochlear Implant Users

Despite being considered one of the most successful neural prostheses, cochlear implants (CIs) provide recipients with a wide range of speech perception performance. While some CI users can understand speech in the absence of visual cues, other recipients exhibit more limited speech perception. Cognitive skills have been documented as a contributor to complex auditory processing, such as language understanding; however, there are no normative data for existing standardized clinical tests assessing cognitive abilities in CI users. Here, we assess the impact of modality of presentation (i.e., auditory-visual versus visual) for the administration of working memory tests in high-performing CI users in addition to measuring processing speed, cognitive efficiency and intelligence quotient (IQ). Second, we relate performance on these cognitive measures to clinical CI speech perception outcomes.Methods: Twenty one post-lingually deafened, high-performing, adult CI users [age range: 52–88 years; 3 unilateral CI, 13 bimodal (i.e., CI with contralateral hearing aid), 5 bilateral CI] with clinical speech perception scores (i.e., AzBio sentences in quiet for the first-ear CI) of ≥60% were recruited. A cognitive test battery assessing auditory-visual working memory (AVWM), visual working memory (VWM), processing speed, cognitive efficiency and IQ was administered, in addition to clinical measures of speech perception in quiet (i.e., AzBio sentences in quiet). AzBio sentences were assessed in two conditions: first-ear CI only, and best-aided everyday wearing condition. Subjects also provided self-reported measures of performance and benefit from their CI using standardized materials, including the Glasgow Benefit Inventory (GBI) and the Nijmegen Cochlear Implant questionnaire (NCIQ).Results: High-performing CI users demonstrated greater VWM than AVWM recall. VWM was positively related to AzBio scores when measured in the first-ear CI only. AVWM, processing speed, cognitive efficiency, and IQ did not relate to either measure of speech perception (i.e., first-ear CI or best-aided conditions). Subjects’ self-reported benefit as measured by the GBI predicted best-aided CI speech perception performance.Conclusion: In high-performing CI recipients, visual presentation of working memory tests may improve our assessment of cognitive function.

Effect of age and hearing loss on sentence perception in noise using temporal envelope and temporal fine structure cues

Purpose: The perception of speech is affected by many physical, physiological and pathological factors related to the stimuli and the listener. Researchers have addressed the effect of each of these factors independently on the perception of speech. In everyday situations, these factors do not occur in isolation but they may occur simultaneously and affect the overall perception of speech. The information on the extent to which each of these factors affect the speech perception is seldom being investigated.Methods: The present study explored the role of temporal envelope and temporal fine structures in the perception of sentences in noise by normal hearing young & older adults; and young & older adults with hearing loss. The envelope and fine structures of the sentences were extracted based on Hilbert transformation using Matlab software. The effect of noise was estimated by processing the sentences in quiet and at 0 dB and -5 dB SNR. The sentences were also filtered using 4, 8, 16 and 32 frequency channels to assess the role of frequency filtering on speech perception.Results: The envelope was more important for speech perception in both quiet and noise. The perception of speech was inversely proportional to age, hearing loss and noise levels, whereas it was directly proportional to the number of frequency channels.Conclusion: These findings indicate that the temporal envelope is important for speech perception in noise. The research findings may help in designing new signal processing strategies for hearing aids and cochlear implants based on the envelope cues.

Nonverbal Reasoning as a Contributor to Sentence Recognition Outcomes in Adults With Cochlear Implants

Significant variability in speech recognition persists among postlingually deafened adults with cochlear implants (CIs). We hypothesize that scores of nonverbal reasoning predict sentence recognition in adult CI users. Cognitive functions contribute to speech recognition outcomes in adults with hearing loss. These functions may be particularly important for CI users who must interpret highly degraded speech signals through their devices. This study used a visual measure of reasoning (the ability to solve novel problems), the Raven's Progressive Matrices (RPM), to predict sentence recognition in CI users. Participants were 39 postlingually deafened adults with CIs and 43 age-matched normal-hearing (NH) controls. CI users were assessed for recognition of words in sentences in quiet, and NH controls listened to eight-channel vocoded versions to simulate the degraded signal delivered by a CI. A computerized visual task of the RPM, requiring participants to identify the correct missing piece in a 3×3 matrix of geometric designs, was also performed. Particular items from the RPM were examined for their associations with sentence recognition abilities, and a subset of items on the RPM was tested for the ability to predict degraded sentence recognition in the NH controls. The overall number of items answered correctly on the 48-item RPM significantly correlated with sentence recognition in CI users (r = 0.35-0.47) and NH controls (r = 0.36-0.57). An abbreviated 12-item version of the RPM was created and performance also correlated with sentence recognition in CI users (r = 0.40-0.48) and NH controls (r = 0.49-0.56). Nonverbal reasoning skills correlated with sentence recognition in both CI and NH subjects. Our findings provide further converging evidence that cognitive factors contribute to speech processing by adult CI users and can help explain variability in outcomes. Our abbreviated version of the RPM may serve as a clinically meaningful assessment for predicting sentence recognition outcomes in CI users.

When to replace legacy cochlear implants for technological upgrades: Indications and outcomes.

To determine indications, surgical efficacy, and audiologic outcomes of replacing Advanced Bionics Clarion C1.2 internal devices (Advanced Bionics, LLC, Valencia, CA) as a means of technology upgrade. Retrospective review, case series. Ten patients were initially implanted as a child (mean age = 3.87 years) and underwent cochlear implant reimplantation (CIR) with current Advanced Bionics internal device as a young adult (mean duration of implant use = 15.66 years). Demographic data and pre- and post-CIR speech perception scores were collected. Technology upgrade was the primary (9) or secondary (1) motivation for CIR. No surgical complications were noted, and full insertion was obtained in nine cases. Intraoperative impedance levels and neural response imaging measures were within normal limits for eight patients. At most recent post-CIR follow-up evaluation, all patients (100%) performed within or better than the 95% confidence interval of their pre-CIR word and sentence recognition scores; and 55.6%, 50.0%, and 50.0% of patients performed above the 95% confidence interval of their pre-CIR scores for the CNC words, sentences in quiet, and sentences in noise, respectively. Post-CIR audiological benefit was stable or improved compared to pre-CIR results in all categories by 3 months after reactivation. Given these results, patients who are unable to use the most current external processors due to incompatibility with a legacy internal device could consider reimplanation to optimize their overall performance with a cochlear implant. 4 Laryngoscope, 129:748-753, 2019.

CI Programming in Patients with Neurologic Impairment

CI Programming in Patients with Neurologic Impairment

Improved Speech Perception in Cochlear Implant Users With Interleaved High-Rate Pulse Trains.

Electrical stimulation with a cochlear implant (CI) elicits abnormally high neural synchrony, which poses significant challenges for speech perception. Previous investigations showed that constant-amplitude high-rate pulse trains (HRPs) desynchronize neural responses and improve stimulus encoding. The study objective was to investigate the effects of HRP on speech perception in adult CI users. Prospective, within-subject design. Tertiary CI center. Ten adult CI recipients. Sentence stimuli were created by modifying a basic continuous interleaved sampling (CIS) strategy (1,000 pulses per second; pps) with interleaved biphasic pulse trains (3,000 pps) on even electrodes. Institute of Electrical and Electronics Engineers sentences in quiet and in noise were tested without HRP, and with HRPs of various stimulation levels. Sentence perception in percent correct was calculated for all conditions. The highest speech perception score with HRP stimulation was defined as "max-HRP." Group analyses showed significantly improved sentence perception in background noise with HRPs (p < 0.001). There was no significant difference for sentence perception in quiet for the group. However, seven of 10 subjects experienced some benefit from HRP stimuli in quiet and the degree of HRP benefit showed significant relationships with baseline performance and age at implantation, indicating that HRP stimuli may be most beneficial for older patients or poorer performers. Significant improvement in speech perception in noise was observed with HRP stimuli. Some recipients may also benefit from HRP stimulation in quiet. Interleaved HRPs hold promise as a novel stimulation paradigm with clinical sound processing strategies to improve patient performance.

Effects of noise and talker intelligibility on judgments of accentedness.

The goal of this study was to determine how noise affects listeners' subjective judgments of foreign-accented speech and how those judgments relate to the intelligibility of foreign-accented talkers. Fifty native English listeners heard native Mandarin speakers and native English speakers producing English sentences in quiet and in three levels of noise. Participants judged the accent of each speaker on a scale from 1 (native-like) to 9 (foreign). The results show that foreign-accented talkers were rated as less accented in the presence of noise, and that, while lower talker intelligibility was generally associated with higher (more foreign) accent ratings, the presence of noise significantly attenuated this relationship. In contrast, noise increased accent ratings and strengthened the relationship between intelligibility and accent ratings for native talkers. These findings indicate that, by obscuring the acoustic-phonetic cues that listeners use to judge accents, noise makes listeners less confident about the foreign (or native) status of a given talker.

Restoration of spatial hearing in adult cochlear implant users with single-sided deafness

In recent years, cochlear implants (CIs) have been provided in growing numbers to people with not only bilateral deafness but also to people with unilateral hearing loss, at times in order to alleviate tinnitus. This study presents audiological data from 15 adult participants (ages 48 ± 12 years) with single sided deafness. Results are presented from 9/15 adults, who received a CI (SSD-CI) in the deaf ear and were tested in Acoustic or Acoustic + CI hearing modes, and 6/15 adults who are planning to receive a CI, and were tested in the unilateral condition only. Testing included (1) audiometric measures of threshold, (2) speech understanding for CNC words and AzBIO sentences, (3) tinnitus handicap inventory, (4) sound localization with stationary sound sources, and (5) perceived auditory motion. Results showed that when listening to sentences in quiet, performance was excellent in the Acoustic and Acoustic + CI conditions. In noise, performance was similar between Acoustic and Acoustic + CI conditions in 4/6 participants tested, and slightly worse in the Acoustic + CI in 2/6 participants. In some cases, the CI provided reduced tinnitus handicap scores. When testing sound localization ability, the Acoustic + CI condition resulted in improved sound localization RMS error of 29.2° (SD: ±6.7°) compared to 56.6° (SD: ±16.5°) in the Acoustic-only condition. Preliminary results suggest that the perception of motion direction, whereby subjects are required to process and compare directional cues across multiple locations, is impaired when compared with that of normal hearing subjects.

Development of unfamiliar accent comprehension continues through adolescence.

School-age children's understanding of unfamiliar accents is not adult-like and the age at which this ability fully matures is unknown. To address this gap, eight- to fifteen-year-old children's (n = 74) understanding of native- and non-native-accented sentences in quiet and noise was assessed. Children's performance was adult-like by eleven to twelve years for the native accent in noise and by fourteen to fifteen years for the non-native accent in quiet. However, fourteen- to fifteen-year old's performance was not adult-like for the non-native accent in noise. Thus, adult-like comprehension of unfamiliar accents may require greater exposure to linguistic variability or additional cognitive-linguistic growth.

Fluctuating Hearing Loss in the Only Hearing Ear: Cochlear Implantation in the Contralateral Deaf Side.

Objective To investigate the hearing performance of adult patients presenting unilateral deafness with contralateral fluctuating hearing loss who received a cochlear implant on the deaf side. Study Design Case series with chart review. Setting University tertiary referral center. Subjects and Methods Preoperatively and at 6 and 12 months postoperatively, 23 patients underwent pure tone audiometry and speech audiometry with disyllabic and monosyllabic words in a quiet environment and sentences in quiet and noisy (signal-to-noise ratio +10 dB SPL) environments under best-aided conditions. The Abbreviated Profile of Hearing Aid Benefit (APHAB) inventory was evaluated preoperatively and at 6 and 12 months postoperatively. Results No difference was found between pre- and postoperative tests for disyllabic and monosyllabic words. For sentences in quiet and noisy environments, a difference between pre- and postoperative performance was present at 1 year ( P = .002 and P = .02, respectively). In a noisy environment, a difference was present at 6 and 12 months postoperatively as compared with the preoperative value (mean ± SD: 6 months: 42% ± 7.1% vs 61% ± 6.5%, P = .016). A significant improvement in the APHAB score was found at 6 and 12 months postimplantation (Friedman's 2-way analysis of variance by ranks, P < .001). The number of years of hearing deprivation of the deaf ear was not correlated with performance. Conclusion When incapacitating fluctuating hearing loss occurs in patients presenting a contralateral deaf ear, a cochlear implant is indicated in the latter ear, significantly improving performance in noisy conditions and allowing a better quality of communication to be achieved.

The Impact of Age, Background Noise, Semantic Ambiguity, and Hearing Loss on Recognition Memory for Spoken Sentences.

The goal of this study was to determine how background noise, linguistic properties of spoken sentences, and listener abilities (hearing sensitivity and verbal working memory) affect cognitive demand during auditory sentence comprehension. We tested 30 young adults and 30 older adults. Participants heard lists of sentences in quiet and in 8-talker babble at signal-to-noise ratios of +15 dB and +5 dB, which increased acoustic challenge but left the speech largely intelligible. Half of the sentences contained semantically ambiguous words to additionally manipulate cognitive challenge. Following each list, participants performed a visual recognition memory task in which they viewed written sentences and indicated whether they remembered hearing the sentence previously. Recognition memory (indexed by d') was poorer for acoustically challenging sentences, poorer for sentences containing ambiguous words, and differentially poorer for noisy high-ambiguity sentences. Similar patterns were observed for Z-transformed response time data. There were no main effects of age, but age interacted with both acoustic clarity and semantic ambiguity such that older adults' recognition memory was poorer for acoustically degraded high-ambiguity sentences than the young adults'. Within the older adult group, exploratory correlation analyses suggested that poorer hearing ability was associated with poorer recognition memory for sentences in noise, and better verbal working memory was associated with better recognition memory for sentences in noise. Our results demonstrate listeners' reliance on domain-general cognitive processes when listening to acoustically challenging speech, even when speech is highly intelligible. Acoustic challenge and semantic ambiguity both reduce the accuracy of listeners' recognition memory for spoken sentences. https://doi.org/10.23641/asha.5848059.

The Benefits of Residual Hair Cell Function for Speech and Music Perception in Pediatric Bimodal Cochlear Implant Listeners.

Objective The aim of this study was to investigate the benefits of residual hair cell function for speech and music perception in bimodal pediatric Mandarin-speaking cochlear implant (CI) listeners. Design Speech and music performance was measured in 35 Mandarin-speaking pediatric CI users for unilateral (CI-only) and bimodal listening. Mandarin speech perception was measured for vowels, consonants, lexical tones, and sentences in quiet. Music perception was measured for melodic contour identification (MCI). Results Combined electric and acoustic hearing significantly improved MCI and Mandarin tone recognition performance, relative to CI-only performance. For MCI, performance was significantly better with bimodal listening for all semitone spacing conditions (p < 0.05 in all cases). For tone recognition, bimodal performance was significantly better only for tone 2 (rising; p < 0.05). There were no significant differences between CI-only and CI + HA for vowel, consonant, or sentence recognition. Conclusions The results suggest that combined electric and acoustic hearing can significantly improve perception of music and Mandarin tones in pediatric Mandarin-speaking CI patients. Music and lexical tone perception depends strongly on pitch perception, and the contralateral acoustic hearing coming from residual hair cell function provided pitch cues that are generally not well preserved in electric hearing.

Investigating the role of temporal lobe activation in speech perception accuracy with normal hearing adults: An event-related fNIRS study

Functional near infrared spectroscopy (fNIRS) is a safe, non-invasive, relatively quiet imaging technique that is tolerant of movement artifact making it uniquely ideal for the assessment of hearing mechanisms. Previous research demonstrates the capacity for fNIRS to detect cortical changes to varying speech intelligibility, revealing a positive relationship between cortical activation amplitude and speech perception score. In the present study, we use an event-related design to investigate the hemodynamic response in the temporal lobe across different listening conditions. We presented participants with a speech recognition task using sentences in quiet, sentences in noise, and vocoded sentences. Hemodynamic responses were examined across conditions and then compared when speech perception was accurate compared to when speech perception was inaccurate in the context of noisy speech. Repeated measures, two-way ANOVAs revealed that the speech in noise condition (−2.8dB signal-to-noise ratio/SNR) demonstrated significantly greater activation than the easier listening conditions on multiple channels bilaterally. Further analyses comparing correct recognition trials to incorrect recognition trials (during the presentation phase of the trial) revealed that activation was significantly greater during correct trials. Lastly, during the repetition phase of the trial, where participants correctly repeated the sentence, the hemodynamic response demonstrated significantly higher deoxyhemoglobin than oxyhemoglobin, indicating a difference between the effects of perception and production on the cortical response. Using fNIRS, the present study adds meaningful evidence to the body of knowledge that describes the brain/behavior relationship related to speech perception.

Effects of electrode deactivation on speech recognition in multichannel cochlear implant recipients

Objectives: The objective of the current study is to evaluate how speech recognition performance is affected by the number of active electrodes that are turned off in multichannel cochlear implants. Several recent studies have demonstrated positive effects of deactivating stimulation sites based on an objective measure in cochlear implant processing strategies. Previous studies using an analysis of variance have shown that, on average, cochlear implant listeners’ performance does not improve beyond eight active electrodes. We hypothesized that using a generalized linear mixed model would allow for better examination of this question.Methods: Seven peri- and post-lingual adult cochlear implant users (eight ears) were tested on speech recognition tasks using experimental MAPs which contained either 8, 12, 16 or 20 active electrodes. Speech recognition tests included CUNY sentences in speech-shaped noise, TIMIT sentences in quiet as well as vowel (CVC) and consonant (CV) stimuli presented in quiet and in signal-to-noise ratios of 0 and +10 dB.Results: The speech recognition threshold in noise (dB SNR) significantly worsened by approximately 2 dB on average as the number of active electrodes was decreased from 20 to 8. Likewise, sentence recognition scores in quiet significantly decreased by an average of approximately 12%.Discussion/conclusion: Cochlear implant recipients can utilize and benefit from using more than eight spectral channels when listening to complex sentences or sentences in background noise. The results of the current study suggest a conservative approach for turning off stimulation sites is best when using site-selection procedures.

Relating quality of life to outcomes and predictors in adult cochlear implant users: Are we measuring the right things?

Current clinical outcome measures for adults receiving cochlear implants (CIs) consist of word and sentence recognition, primarily under quiet conditions. However, these measures may not adequately reflect patients' CI-specific quality of life (QOL). This study first examined traditional auditory-only speech recognition measures and other potentially relevant auditory measures as correlates of QOL in CI users. Second, scores on nonauditory tasks of language and cognition were examined as potential predictors of QOL. Twenty-five postlingually deafened adults with CIs were assessed. Participants completed a validated CI-specific QOL measure (the Nijmegen Cochlear Implant Questionnaire) and were tested for word and sentence recognition in quiet, as well as sentence recognition in speech-shaped noise. Participants also completed assessments of audiovisual speech recognition, environmental sound identification, and a task of complex auditory verbal processing. Several nonauditory language and cognitive tasks were examined as potential predictors of QOL. Quality-of-life scores significantly correlated with scores for audiovisual speech recognition and recognition of complex sentences in quiet but not sentences in noise or isolated words. No significant correlations were obtained between QOL and environmental sound identification or complex auditory verbal processing. Quality-of-life subdomain scores were predicted by several nonauditory language and cognitive tasks as well as some patient characteristics. Postoperative measures of recognition of sentences in quiet and audiovisual sentence recognition correlate with CI-related QOL. Findings suggest that sentence recognition tasks are QOL-relevant outcomes but only explain a small fraction of the variability in QOL outcomes for this patient population. 4. Laryngoscope, 128:959-966, 2018.

Is the digit triplet test an effective and acceptable way to assess speech recognition in adults using cochlear implants in a home environment?

Objectives: To evaluate the validity of the Digit Triplet Test (DTT) in a simulated home environment for measuring speech recognition in adults with cochlear implants by comparing the result to clinic speech perception tests. To evaluate the acceptability of the DTT in adults using cochlear implants.Methods: A prospective single-centre study with the following outcomes:• DTT Speech Reception Threshold• Clinic speech perception tests (BKB sentences in quiet and noise, City University of New York sentences with lip-reading)• A satisfaction questionnaire to assess patient perception of the DTTSixteen people using cochlear implants aged from 43 to 83 years took part.Results: • Eighty-eight percent of participants were able to be tested on the DTT; there were no floor or ceiling effects.• DTT SRT was highly correlated with clinic BKB sentence scores in quiet and adaptive noise, and participants felt positive about using the DTT for home testing.Conclusion: The majority of adults using cochlear implants in this study were able and willing to use the DTT to test their speech recognition in a simulated home environment. The DTT SRT was highly correlated with traditional clinic sentence scores, supporting its validity as a home test for hearing in adults using cochlear implants. Hearing testing in the clinic is still the gold standard of clinical care for people with cochlear implants, but a home test could provide a useful addition.

A Longitudinal Study in Children With Sequential Bilateral Cochlear Implants: Time Course for the Second Implanted Ear and Bilateral Performance.

Whether, and if so when, a second-ear cochlear implant should be provided to older, unilaterally implanted children is an ongoing clinical question. This study evaluated rate of speech recognition progress for the second implanted ear and with bilateral cochlear implants in older sequentially implanted children and evaluated localization abilities. A prospective longitudinal study included 24 bilaterally implanted children (mean ear surgeries at 5.11 and 14.25 years). Test intervals were every 3-6 months through 24 months postbilateral. Test conditions were each ear and bilaterally for speech recognition and localization. Overall, the rate of progress for the second implanted ear was gradual. Improvements in quiet continued through the second year of bilateral use. Improvements in noise were more modest and leveled off during the second year. On all measures, results from the second ear were poorer than the first. Bilateral scores were better than either ear alone for all measures except sentences in quiet and localization. Older sequentially implanted children with several years between surgeries may obtain speech understanding in the second implanted ear; however, performance may be limited and rate of progress gradual. Continued contralateral ear hearing aid use and reduced time between surgeries may enhance outcomes.

Factors Affecting Outcomes in Cochlear Implant Recipients Implanted With a Perimodiolar Electrode Array Located in Scala Tympani.

To identify primary biographic and audiologic factors contributing to cochlear implant (CI) performance variability in quiet and noise by controlling electrode array type and electrode position within the cochlea. Although CI outcomes have improved over time, considerable outcome variability still exists. Biographic, audiologic, and device-related factors have been shown to influence performance. Examining CI recipients with consistent array type and electrode position may allow focused investigation into outcome variability resulting from biographic and audiologic factors. Thirty-nine adults (40 ears) implanted for at least 6 months with a perimodiolar electrode array known (via computed tomography [CT] imaging) to be in scala tympani participated. Test materials, administered CI only, included monosyllabic words, sentences in quiet and noise, and spectral ripple discrimination. In quiet, scores were high with mean word and sentence scores of 76 and 87%, respectively; however, sentence scores decreased by an average of 35 percentage points when noise was added. A principal components (PC) analysis of biographic and audiologic factors found three distinct factors, PC1 Age, PC2 Duration, and PC3 Pre-op Hearing. PC1 Age was the only factor that correlated, albeit modestly, with speech recognition in quiet and noise. Spectral ripple discrimination strongly correlated with speech measures. For these recipients with consistent electrode position, PC1 Age was related to speech recognition performance. Consistent electrode position may have contributed to high speech understanding in quiet. Inter-subject variability in noise may have been influenced by auditory/cognitive processing, known to decline with age, and mechanisms that underlie spectral resolution ability.

Feasibility of an implanted microphone for cochlear implant listening.

This study aimed at evaluating the feasibility of an implanted microphone for cochlear implants (CI) by comparison of hearing outcomes, sound quality and patient satisfaction of a subcutaneous microphone to a standard external microphone of a behind-the-ear sound processor. In this prospective feasibility study with a within-subject repeated measures design comparing the microphone modalities, ten experienced adult unilateral CI users received an implantable contralateral subcutaneous microphone attached to a percutaneous plug. The signal was pre-processed and fed into their CI sound processor. Subjects compared listening modes at home for a period of up to 4months. At the end of the study the microphone was explanted. Aided audiometric thresholds, speech understanding in quiet, and sound quality questionnaires were assessed. On average thresholds (250, 500, 750, 1k, 2k, 3k, 4k and 6kHz) with the subcutaneous microphone were 44.9dB, compared to 36.4dB for the external mode. Speech understanding on sentences in quiet was high, within approximately 90% of performance levels compared to hearing with an external microphone. Body sounds were audible but not annoying to almost all subjects. This feasibility study with a research device shows significantly better results than previous studies with implanted microphones. This is attributed to technology enhancements and careful fitting. Listening effort was somewhat increased with an implanted microphone. Under good sound conditions, speech performance is nearly similar to that of external microphones demonstrating that an implanted microphone is feasible in a range of normal listening conditions.