Adult Cochlear Implant Recipients Research Articles

Interactive Evaluation of a Music Preprocessing Scheme for Cochlear Implants Based on Spectral Complexity Reduction.

Music is difficult to access for the majority of CI users as the reduced dynamic range and poor spectral resolution in cochlear implants (CI), amongst others constraints, severely impair their auditory perception. The reduction of spectral complexity is therefore a promising means to facilitate music enjoyment for CI listeners. We evaluate a spectral complexity reduction method for music signals based on principal component analysis that enforces spectral sparsity, emphasizes the melody contour and attenuates interfering accompanying voices. To cover a wide range of spectral complexity reduction levels a new experimental design for listening experiments was introduced. It allows CI users to select the preferred level of spectral complexity reduction interactively and in real-time. Ten adult CI recipients with post-lingual bilateral profound sensorineural hearing loss and CI experience of at least 6 months were enrolled in the study. In eight consecutive sessions over a period of 4 weeks they were asked to choose their preferred version out of 10 different complexity settings for a total number of 16 recordings of classical western chamber music. As the experiments were performed in consecutive sessions we also studied a potential long term effect. Therefore, we investigated the hypothesis that repeated engagement with music signals of reduced spectral complexity leads to a habituation effect which allows CI users to deal with music signals of increasing complexity. Questionnaires and tests about music listening habits and musical abilities complemented these experiments. The participants significantly preferred signals with high spectral complexity reduction levels over the unprocessed versions. While the results of earlier studies comprising only two preselected complexity levels were generally confirmed, this study revealed a tendency toward a selection of even higher spectral complexity reduction levels. Therefore, spectral complexity reduction for music signals is a useful strategy to enhance music enjoyment for CI users. Although there is evidence for a habituation effect in some subjects, such an effect has not been significant in general.

The Assessment and Aural Rehabilitation Tool for Cochlear Implant Recipients With Unilateral Hearing Loss

Purpose Cochlear implantation may be a viable treatment option for patients with moderate-to-profound hearing loss in 1 ear and normal to near-normal hearing in the contralateral ear. There is a need for modified aural rehabilitation assessment and intervention tools for this unique patient population to support improvements with the cochlear implant (CI). The present report describes the development and implementation of the Assessment and Aural Rehabilitation Tool (AART) created for adult CI recipients with unilateral hearing loss (UHL). Conclusion The tool was used as an early assessment measure for CI in subjects with UHL and as a method to determine individualized auditory training plans. The AART was modified considering the initial abilities of this unique subject group. Ongoing studies are assessing the effectiveness of CI use in pediatric subjects with UHL and developing the pediatric version of the AART.

Musical Sound Quality as a Function of the Number of Channels in Modern Cochlear Implant Recipients.

ObjectivesThis study examined musical sound quality (SQ) in adult cochlear implant (CI) recipients. The study goals were to determine: the number of channels needed for high levels of musical SQ overall and by musical genre; the impact of device and patient factors on musical SQ ratings; and the relationship between musical SQ, speech recognition, and speech SQ to relate these findings to measures frequently used in clinical protocols.MethodsTwenty-one post-lingually deafened adult CI recipients participated in this study. Electrode placement, including scalar location, average electrode-to-modiolus distance (), and angular insertion depth were determined by CT imaging using validated CI position analysis algorithms (e.g., Noble et al., 2013; Zhao et al., 2018, 2019). CI programs were created using 4–22 electrodes with equal spatial distribution of active electrodes across the array. Speech recognition, speech SQ, music perception via a frequency discrimination task, and musical SQ were acutely assessed for all electrode conditions. Musical SQ was assessed using pre-selected musical excerpts from a variety of musical genres.ResultsCI recipients demonstrated continuous improvement in qualitative judgments of musical SQ with up to 10 active electrodes. Participants with straight electrodes placed in scala tympani (ST) and pre-curved electrodes with higher variance reported higher levels of musical SQ; however, this relationship is believed to be driven by levels of musical experience as well as the potential for preoperative bias in device selection. Participants reported significant increases in musical SQ beyond four channels for all musical genres examined in the current study except for Hip Hop/Rap. After musical experience outliers were removed, there was no relationship between musical experience or frequency discrimination ability and musical SQ ratings. There was a weak, but significant correlation between qualitative ratings for speech stimuli presented in quiet and in noise and musical SQ.ConclusionModern CI recipients may need more channels for musical SQ than even required for asymptotic speech recognition or speech SQ. These findings may be used to provide clinical guidance for personalized expectations management of music appreciation depending on individual device and patient factors.

Auditory Performances in Older and Younger Adult Cochlear Implant Recipients: Use of the HEARRING Registry.

To evaluate the hearing outcomes of cochlear implantation in different age groups by using data collected in the HEARRING registry. A multicenter study. Data of 146 patients were collected in a HEARRING registry. Patients were divided into three different age groups; ≤ 55 years old (age group 1, n = 66), 56 to 69 years old (age group 2, n = 45), and ≥ 70 years old (age group 3, n = 35). Speech in quiet (SPIQ), speech in noise (SPIN), and hearing implant sound quality index (HISQUI19) scores were evaluated for the different age groups at different test moments (preoperatively, 3, 6, 12, and 24 mo after first fitting). A statistically significant difference (p < 0.01) was found between preoperative scores and the scores on all the follow-up moments across all age groups. For SPIQ and SPIN, none of the time points showed a statistically significant age effect (p = 0.88 and p = 0.89). For HISQUI19 scores, a statistically significant age effect was found at 12 months after first fitting. The oldest age group scored significantly lower on the HISQUI19 compared with the youngest age group. Hearing outcomes of adult cochlear implant users of different age groups were evaluated. The SPIQ and SPIN tests showed no significant differences between the different age groups. Nevertheless, the youngest group scored significantly better on self -perceived benefit (HISQUI19) with a cochlear implant compared with the oldest age group.Further research is needed to receive more insight into cochlear implantation in the elderly and its implications on rehabilitating and supporting this expanding older population.

ForwardFocus with cochlear implant recipients in spatially separated and fluctuating competing signals – introduction of a reference metric

Objective: To clinically evaluate ForwardFocus in noise with experienced Nucleus® cochlear implant (CI) recipients.Design: Listening performance with ForwardFocus was compared against the best in class directional microphone program (BEAM®). Speech comprehension was tested with the Oldenburg sentence test with competing signals (stationary, three, six and 18-talker babble) in both co-located and spatially-separated listening environments. Additionally, normal hearing participants were tested monaurally in the same listening environments as a reference and to promote cross-study comparisons between CI clinical study outcomes.Study sample: Post-lingually deaf adult CI recipients (n = 20) who were experienced users of the Nucleus sound processor (Cochlear Limited).Results: Improved speech comprehension was found with the ForwardFocus program compared to the BEAM program in a co-located frontal listening environment for both stationary and fluctuating competing signals. In spatially-separated environments ForwardFocus provided significant speech reception threshold (SRT) improvements of 5.8 dB for three-talker competing signals, respectively.Conclusions: ForwardFocus was shown to significantly improve speech comprehension in a wide range of listening environments. This technology is likely to provide significant improvements in real-world listening for CI recipients, given the clinically relevant performance outcomes in challenging dynamic noise environments, bringing their performance closer to their normal hearing peers.

Datalogging Statistics and Speech Recognition During the First Year of Use in Adult Cochlear Implant Recipients.

To examine device datalogging characteristics and postoperative speech recognition performance in adult cochlear implant (CI) recipients. Retrospective study examining datalogging characteristics throughout the first year of device use and postoperative speech recognition outcomes measured at 1 year. One hundred seventy-seven adults who received a Cochlear CI. Average values for environmental scene classification (hours of device use per day, and percent of hours per day in quiet, noise, and speech) as reported by Cochlear datalogging over the first year of device use. Speech recognition was assessed at 1 year postactivation. During the first year of devices use, CI listeners >80 years of age used their device significantly less (average = 10.97 h/d) than the youngest adult listeners (18-30 yrs), who used their device an average of 13.29 hours/d. There was no consistent effect of age on the number of hours a CI user listened to speech in noise each day. Correlational and regression analyses suggest that the number of average hours of device use is the primary factor that accounts for variance observed in postoperative consonant-nucleus-consonant word scores. Results suggest that the average number of hours listening to speech in noise is not related to postoperative performance, but the average number of hours of device use per day is correlated with postoperative performance. Further research is needed to determine if these findings are merely correlational or causal in nature.

Speech Perception Outcomes for Adult Cochlear Implant Recipients Using a Lateral Wall or Perimodiolar Array.

To assess the speech perception outcomes of adult CI recipients with significant preimplant low frequency hearing, examining differences between perimodiolar and lateral wall electrode placement in order to provide clinical guidance for clinicians and surgeons. A prospective cohort study was undertaken identifying all adults who received a thin straight electrode array (TSEA) at the Royal Victorian Eye & Ear Hospital (RVEEH) from 2010 to 2015 and who had a preimplant low frequency pure tone median ≤70 dB HL (n = 63). A retrospective review was completed of the RVEEH database to identify a comparison group who had been implanted with a perimodiolar electrode array, comprising adults implanted between 2004 and 2011 (PM Group) with preimplant hearing equivalent to the TSEA group (n = 70). The TSEA Group were further divided into subgroups in which n = 19 used EAS (TSEA-EAS) and n = 44 who used electric-only hearing (TSEA-Standard). There was no significant difference in median speech perception outcomes between the TSEA and PM Groups (TSEA 61.7%, PM 67.3%, p = 0.954). A significant difference was found between the TSEA-EAS and TSEA-Standard subgroups for median speech perception outcome (TSEA-EAS median 73.5%, TSEA-Standard median 58.3%, p = 0.043). Significant speech perception benefit following cochlear implantation was achieved with both the perimodiolar and lateral wall electrode arrays and no significant difference was found between outcomes with those array types in this population of adults with functional low frequency hearing pre-implant. Those that received a TSEA, had preserved hearing, and utilised an EAS sound processor performed better than their peers with a TSEA and electric-only hearing.

Bimodal Hearing or Bilateral Cochlear Implants? Ask the Patient.

The objectives of this study were to assess the effectiveness of various measures of speech understanding in distinguishing performance differences between adult bimodal and bilateral cochlear implant (CI) recipients and to provide a preliminary evidence-based tool guiding clinical decisions regarding bilateral CI candidacy. This study used a multiple-baseline, cross-sectional design investigating speech recognition performance for 85 experienced adult CI recipients (49 bimodal, 36 bilateral). Speech recognition was assessed in a standard clinical test environment with a single loudspeaker using the minimum speech test battery for adult CI recipients as well as with an R-SPACE 8-loudspeaker, sound-simulation system. All participants were tested in three listening conditions for each measure including each ear alone as well as in the bilateral/bimodal condition. In addition, we asked each bimodal listener to provide a yes/no answer to the question, "Do you think you need a second CI?" This study yielded three primary findings: (1) there were no significant differences between bimodal and bilateral CI performance or binaural summation on clinical measures of speech recognition, (2) an adaptive speech recognition task in the R-SPACE system revealed significant differences in performance and binaural summation between bimodal and bilateral CI users, with bilateral CI users achieving significantly better performance and greater summation, and (3) the patient's answer to the question, "Do you think you need a second CI?" held high sensitivity (100% hit rate) for identifying likely bilateral CI candidates and moderately high specificity (77% correct rejection rate) for correctly identifying listeners best suited with a bimodal hearing configuration. Clinics cannot rely on current clinical measures of speech understanding, with a single loudspeaker, to determine bilateral CI candidacy for adult bimodal listeners nor to accurately document bilateral benefit relative to a previous bimodal hearing configuration. Speech recognition in a complex listening environment, such as R-SPACE, is a sensitive and appropriate measure for determining bilateral CI candidacy and also likely for documenting bilateral benefit relative to a previous bimodal configuration. In the absence of an available R-SPACE system, asking the patient whether or not s/he thinks s/he needs a second CI is a highly sensitive measure, which may prove clinically useful.

Is Hard Failure Still a Common Indication for Revision Surgery in Adult Cochlear Implant Recipients?

STUDY DESIGN:: Retrospective chart review. Single tertiary care center, 2001 to 2016. Adult CI recipients were assessed. Inclusion required ≥1 revision surgeries, operative note(s), and postrevision follow-up of 6 months. Therapeutic/rehabilitative. Indications for revision (HF, SF, WC, and MM) were tabulated. The incidence of each was compared between cohorts implanted before/after 2011. Additional outcomes included implant usage, explantation rates, and postrevision speech scores. Four hundred thirty-two patients received 512 CIs. Of these, 30 patients required 38 revisions. Median time to revision was 24.5 months. Frequency by indication was HF (n = 14), SF (n = 12), WC (n = 8), and MM (n = 4). The overall revision rate was 7.4%. There was a significant decline in overall revisions for patients implanted before/after 2011 (10.4 versus3.5%; p = 0.009). No patients implanted after 2011 experienced a HF (p = 0.002). Patients with WC/MM had significantly shorter time to revision compared with patients with HF/SF (p = 0.04). The overall median follow-up was 24 months. Twenty-three of 30 patients are still using their revised CI. Patients revised for HF and MM achieved the best outcomes. 7.4% of adult CI recipients required revision surgery. Explantation/immediate reimplantation was an effective management strategy. While HF was the most common indication overall, no patients implanted after 2011 have suffered this complication. The overall revision rate has significantly declined since 2011.

Monitoring of the Inner Ear Function During and After Cochlear Implant Insertion Using Electrocochleography.

To preserve residual hearing during cochlear implant (CI) surgery, it is desirable to use intraoperative monitoring of inner ear function (cochlear monitoring), especially during electrode insertion. A promising method is electrocochleography (ECochG). Within this project, the relations between ongoing responses (ORs), recorded extra- and intracochlearly (EC and IC), and preservation of residual hearing were investigated. Before, during, and after insertion of hearing preservation electrodes, intraoperative ECochG recordings were performed EC using a cotton wick electrode and after insertion also IC using the CI electrode (MED-EL) and a research software tool. The stimulation was delivered acoustically using low frequency tone bursts. The recordings were conducted in 10 adult CI recipients. The amplitudes of IC ORs were detected to be larger than EC ORs. Intraoperative EC thresholds correlated highly to preoperative audiometric thresholds at 1000 Hz, IC thresholds highly at 250 Hz and 500 Hz. The correlations of both intraoperative ECochG recordings to postoperative pure tone thresholds were low. When measured postoperatively at the same appointments, IC OR thresholds correlated highly to audiometric pure tone thresholds. For all patients, it was possible to record ORs during or directly after electrode insertion. Consequently, we conclude that we did not observe any cases with severe IC trauma. Delayed hearing loss could not be predicted with our method. Nevertheless, intraoperative ECochG recordings are a promising tool to gain further insight into mechanisms impacting residual hearing. Postoperatively recorded IC OR thresholds seem to be a reliable tool for frequency specific hearing threshold estimation.

Assessing auditory nerve condition by tone decay in deaf subjects with a cochlear implant

The condition of the auditory nerve is a factor determining hearing performance of cochlear implant (CI) recipients. Abnormal loudness adaptation is associated with poor auditory nerve survival. We examined which stimulus conditions are suitable for tone decay measurements to differentiate between CI recipients with respect to their speech perception. Tone decay was defined here as occurring when the percept disappears before the stimulus stops. We measured the duration of the percept of a 60-s pulse train. Current levels ranged from below threshold up to maximum acceptable loudness, pulse rates from 250 to 5000 pulses/s, and duty cycles (percentages of time the burst of pulses is on) from 10% to 100%. Ten adult CI recipients were included: seven with good and three with poor speech perception. Largest differences among the subjects were found at 5000 pulses/s and 100% duty cycle. The well performing subjects had a continuous percept of the 60-s stimulus within 3 dB above threshold. Two poorly performing subjects showed abnormal loudness adaptation, that is, no continuous percept even at levels greater than 6 dB above threshold. We conclude that abnormal loudness adaptation can be detected via an electric tone decay test using a high pulse rate and 100% duty cycle.

Results in Adult Cochlear Implant Recipients With Varied Asymmetric Hearing: A Prospective Longitudinal Study of Speech Recognition, Localization, and Participant Report.

Asymmetric hearing with severe to profound hearing loss (SPHL) in one ear and better hearing in the other requires increased listening effort and is detrimental for understanding speech in noise and sound localization. Although a cochlear implant (CI) is the only treatment that can restore hearing to an ear with SPHL, current candidacy criteria often disallows this option for patients with asymmetric hearing. The present study aimed to evaluate longitudinal performance outcomes in a relatively large group of adults with asymmetric hearing who received a CI in the poor ear. Forty-seven adults with postlingual hearing loss participated. Test materials included objective and subjective measures meant to elucidate communication challenges encountered by those with asymmetric hearing. Test intervals included preimplant and 6 and 12 months postimplant. Preimplant testing was completed in participants' everyday listening condition: bilateral hearing aids (HAs) n = 9, better ear HA n = 29, and no HA n = 9; postimplant, each ear was tested separately and in the bimodal condition. Group mean longitudinal results in the bimodal condition postimplant compared with the preimplant everyday listening condition indicated significantly improved sentence scores at soft levels and in noise, improved localization, and higher ratings of communication function by 6 months postimplant. Group mean, 6-month postimplant results were significantly better in the bimodal condition compared with either ear alone. Audibility and speech recognition for the poor ear alone improved significantly with a CI compared with preimplant. Most participants had clinically meaningful benefit on most measures. Contributory factors reported for traditional CI candidates also impacted results for this population. In general, older participants had poorer bimodal speech recognition in noise and localization abilities than younger participants. Participants with early SPHL onset had better bimodal localization than those with later SPHL onset, and participants with longer SPHL duration had poorer CI alone speech understanding in noise but not in quiet. Better ear pure-tone average (PTA) correlated with all speech recognition measures in the bimodal condition. To understand the impact of better ear hearing on bimodal performance, participants were grouped by better ear PTA: group 1 PTA ≤40 dB HL (n = 19), group 2 PTA = 41 to 55 dB HL (n = 14), and group 3 PTA = 56 to 70 dB HL (n = 14). All groups showed bimodal benefit on speech recognition measures in quiet and in noise; however, only group 3 obtained benefit when noise was toward the CI ear. All groups showed improved localization and ratings of perceived communication. Receiving a CI for the poor ear was an effective treatment for this population. Improved audibility and speech recognition were evident by 6 months postimplant. Improvements in sound localization and self-reports of communication benefit were significant and not related to better ear hearing. Participants with more hearing in the better ear (group 1) showed less bimodal benefit but greater bimodal performance for speech recognition than groups 2 and 3. Test batteries for this population should include quality of life measures, sound localization, and adaptive speech recognition measures with spatially separated noise to capture the hearing loss deficits and treatment benefits reported by this patient population.

Temporal Fine Structure Processing, Pitch, and Speech Perception in Adult Cochlear Implant Recipients.

The aim of the study was to investigate the link between temporal fine structure (TFS) processing, pitch, and speech perception performance in adult cochlear implant (CI) recipients, including bimodal listeners who may benefit better low-frequency (LF) temporal coding in the contralateral ear. The study participants were 43 adult CI recipients (23 unilateral, 6 bilateral, and 14 bimodal listeners). Two new LF pitch perception tests-harmonic intonation (HI) and disharmonic intonation (DI)-were used to evaluate TFS sensitivity. HI and DI were designed to estimate a difference limen for discrimination of tone changes based on harmonic or inharmonic pitch glides. Speech perception was assessed using the newly developed Italian Sentence Test with Adaptive Randomized Roving level (STARR) test where sentences relevant to everyday contexts were presented at low, medium, and high levels in a fluctuating background noise to estimate a speech reception threshold (SRT). Although TFS and STARR performances in the majority of CI recipients were much poorer than those of hearing people reported in the literature, a considerable intersubject variability was observed. For CI listeners, median just noticeable differences were 27.0 and 147.0 Hz for HI and DI, respectively. HI outcomes were significantly better than those for DI. Median STARR score was 14.8 dB. Better performers with speech reception thresholds less than 20 dB had a median score of 8.6 dB. A significant effect of age was observed for both HI/DI tests, suggesting that TFS sensitivity tended to worsen with increasing age. CI pure-tone thresholds and duration of profound deafness were significantly correlated with STARR performance. Bimodal users showed significantly better TFS and STARR performance for bimodal listening than for their CI-only condition. Median bimodal gains were 33.0 Hz for the HI test and 95.0 Hz for the DI test. DI outcomes in bimodal users revealed a significant correlation with unaided hearing thresholds for octave frequencies lower than 1000 Hz. Median STARR scores were 17.3 versus 8.1 dB for CI only and bimodal listening, respectively. STARR performance was significantly correlated with HI findings for CI listeners and with those of DI for bimodal listeners. LF pitch perception was found to be abnormal in the majority of adult CI recipients, confirming poor TFS processing of CIs. Similarly, the STARR findings reflected a common performance deterioration with the HI/DI tests, suggesting the cause probably being a lack of access to TFS information. Contralateral hearing aid users obtained a remarkable bimodal benefit for all tests. Such results highlighted the importance of TFS cues for challenging speech perception and the relevance to everyday listening conditions. HI/DI and STARR tests show promise for gaining insights into how TFS and speech perception are being limited and may guide the customization of CI program parameters and support the fine tuning of bimodal listening.

The Relationship Between Spectral Modulation Detection and Speech Recognition: Adult Versus Pediatric Cochlear Implant Recipients.

Adult cochlear implant (CI) recipients demonstrate a reliable relationship between spectral modulation detection and speech understanding. Prior studies documenting this relationship have focused on postlingually deafened adult CI recipients—leaving an open question regarding the relationship between spectral resolution and speech understanding for adults and children with prelingual onset of deafness. Here, we report CI performance on the measures of speech recognition and spectral modulation detection for 578 CI recipients including 477 postlingual adults, 65 prelingual adults, and 36 prelingual pediatric CI users. The results demonstrated a significant correlation between spectral modulation detection and various measures of speech understanding for 542 adult CI recipients. For 36 pediatric CI recipients, however, there was no significant correlation between spectral modulation detection and speech understanding in quiet or in noise nor was spectral modulation detection significantly correlated with listener age or age at implantation. These findings suggest that pediatric CI recipients might not depend upon spectral resolution for speech understanding in the same manner as adult CI recipients. It is possible that pediatric CI users are making use of different cues, such as those contained within the temporal envelope, to achieve high levels of speech understanding. Further investigation is warranted to investigate the relationship between spectral and temporal resolution and speech recognition to describe the underlying mechanisms driving peripheral auditory processing in pediatric CI users.

Contralateral Routing of Signal Yields Significant Speech in Noise Benefit for Unilateral Cochlear Implant Recipients.

Bilateral cochlear implantation is the standard of care for individuals with moderate sloping-to-profound sensorineural hearing loss who do not receive benefit from appropriately fit hearing aids. Because of financial, insurance, or medical reasons, some unilateral cochlear implant (CI) recipients are unable to obtain a second CI. Here, we evaluated the first clinically available solution for individuals who have been unilaterally implanted and who do not or cannot use technology (e.g., hearing aid or CI) on the non-implanted ear. We aimed to investigate how the addition of a contralateral routing of signal (CROS) device could provide objective and/or subjective benefit to adult CI recipients with moderate-to-profound hearing loss in the non-implanted ear. Single-center prospective study using a within-subjects repeated-measures design. Participants included ten experienced unilateral CI recipients with severe-to-profound (n = 9) or moderate-to-profound (n = 1) sensorineural hearing loss in the non-implanted ear. At the time of study enrollment, participants did not use any technology on the non-implanted ear. No other exclusion criteria were used. Individuals were tested with and without a CROS device worn on the non-implanted ear. We obtained measures of speech understanding in quiet (50 and 65 dBA) and in noise (+5-dB signal-to-noise ratio with a 65-dBA speech signal) both with and without the CROS device in an acute listening condition. Subjective benefit was assessed via the Speech, Spatial and Qualities 12-item questionnaire before CROS fitting and after two weeks of continuous use. A mixed-model, repeated-measures analysis of variance was completed with three talker locations and three presentation levels included as within-subjects factors and the presence or absence of a CROS device as a between-subjects factor. There was an 11% improvement in speech understanding in noise with the addition of the CROS device when speech was located at 0° azimuth. Subjective benefit in the speech domain of the SSQ was also observed. Use of CROS provided both subjective and objective speech recognition benefit for unilateral CI recipients who do not have access to bilateral cochlear implantation.

The Benefits of Bimodal Aiding on Extended Dimensions of Speech Perception: Intelligibility, Listening Effort, and Sound Quality.

The benefits of combining a cochlear implant (CI) and a hearing aid (HA) in opposite ears on speech perception were examined in 15 adult unilateral CI recipients who regularly use a contralateral HA. A within-subjects design was carried out to assess speech intelligibility testing, listening effort ratings, and a sound quality questionnaire for the conditions CI alone, CIHA together, and HA alone when applicable. The primary outcome of bimodal benefit, defined as the difference between CIHA and CI, was statistically significant for speech intelligibility in quiet as well as for intelligibility in noise across tested spatial conditions. A reduction in effort on top of intelligibility at the highest tested signal-to-noise ratio was found. Moreover, the bimodal listening situation was rated to sound more voluminous, less tinny, and less unpleasant than CI alone. Listening effort and sound quality emerged as feasible and relevant measures to demonstrate bimodal benefit across a clinically representative range of bimodal users. These extended dimensions of speech perception can shed more light on the array of benefits provided by complementing a CI with a contralateral HA.

The Effect of Soft Tissue Infections on Device Performance in Adult Cochlear Implant Recipients.

The aim of this study was to examine the effect of cochlear implant (CI) site infection and its subsequent management on CI mapping and CI performance. Risk factors for CI infections and pathogens causing infections were reviewed. Treatment options for CI infections were examined. Retrospective case review. Tertiary referral center. Adult patients with a significant CI soft tissue infection from the Northern Cochlear Implant Programme, New Zealand over a 10-year period (August 2004 until August 2014). Patients were treated with intravenous antibiotics, washout and debridement or ex-plantation and reimplantation of CI. CI mapping results and implant performance before and after management of CI infections were compared. There were nine CI infections. Most patients (7/9) were treated with washout and debridement. One patient required removal of the CI and one patient was deemed medically unfit for a general anaesthetic and was managed conservatively with antibiotics alone. Seven patients received long-term antibiotics. Four patients were able to maintain CI performance after salvage treatment of the CI infection. Three patients had poorer CI performance after salvage treatment. One patient had reimplantation and became a nonuser due to only partial reinsertion. The pathophysiology of CI infections is complex. Infections can occur many years after CI surgery. The most common bacteria identified were Staphylococcus aureus, Pseudomonas aeruginosa, and skin commensals. Biofilms are present around implants that are removed from patients and biofilms may play a role in CI infections, but the mechanism of infection is not clear.

Performance Plateau in Prelingually and Postlingually Deafened Adult Cochlear Implant Recipients.

To characterize the performance plateau after unilateral cochlear implantation (CI) in prelingually and postlingually deafened adults and to compare their relative progress. Retrospective chart review. Tertiary referral center. Prelingually and postlingually deaf adults who received a unilateral CI and completed a minimum of 2 years of follow-up at our center. Unilateral CI. Standard speech perception testing (consonant-nucleus-consonant [CNC] monosyllabic word test and hearing in noise test [HINT] or AzBio sentence test) were performed preoperatively and 3 and 12 months postoperatively, and annually thereafter. In postlingually deaf patients (n = 102), there was a significant improvement in word scores for 3 years postimplantation (p < 0.01). Beyond the 3 years postoperative time point, word scores continued to improve, albeit at a flatter rate. In prelingually deaf patients (n = 16) word scores improved significantly for 5 years postimplantation (p = 0.03). Adults with postlingual deafness undergoing unilateral CI show significant improvement in speech perception for 3 years postimplantation, at which point their performance continues to improve, albeit at a flatter rate. The performance of adults with prelingual deafness improves significantly as late as 5 years postimplantation. These time intervals reflect a change to the currently reported 6 to 12 months period and should impact on counseling, especially in the prelingual CI candidate.

Predictors of health-related quality of life in adult cochlear implant recipients in South Africa

Objective: To identify and describe predictors of health-related quality of life (HRQoL) outcomes for adult cochlear implant (CI) recipients in South Africa. Design: A retrospective study of adult CI recipients was conducted and cross-sectional HRQoL outcome data were added at the time of data collection, using the Nijmegen Cochlear Implant Questionnaire (NCIQ). Twenty-two potential predictive factors were identified from the retrospective dataset, including demographic, hearing loss, CI and risk-related factors. Multiple regression analyses were performed to identify predictor variables that influence HRQoL outcomes. Study sample: The study sample included 100 adult CI recipients from four CI programs, implanted for at least 12 months. Results: History of no tinnitus prior to CI, bilateral implantation and mainstream schooling were strongly predictive of better overall HRQoL outcomes. Factors such as age, age at implant, gender, onset of hearing loss, duration of CI use and presence of risk factors did not predict HRQoL scores. Conclusion: A range of significant prognostic indicators were identified for HRQoL outcomes in adult CI recipients. These predictors of HRQoL outcomes can guide intervention services’ informational counselling.

Results using the OPAL strategy in Mandarin speaking cochlear implant recipients

Objective: To evaluate the effectiveness of an experimental pitch-coding strategy for improving recognition of Mandarin lexical tone in cochlear implant (CI) recipients. Design: Adult CI recipients were tested on recognition of Mandarin tones in quiet and speech-shaped noise at a signal-to-noise ratio of +10 dB; Mandarin sentence speech-reception threshold (SRT) in speech-shaped noise; and pitch discrimination of synthetic complex-harmonic tones in quiet. Two versions of the experimental strategy were examined: (OPAL) linear (1:1) mapping of fundamental frequency (F0) to the coded modulation rate; and (OPAL+) transposed mapping of high F0s to a lower coded rate. Outcomes were compared to results using the clinical ACE™ strategy. Study sample: Five Mandarin speaking users of Nucleus® cochlear implants. Results: A small but significant benefit in recognition of lexical tones was observed using OPAL compared to ACE in noise, but not in quiet, and not for OPAL+ compared to ACE or OPAL in quiet or noise. Sentence SRTs were significantly better using OPAL+ and comparable using OPAL to those using ACE. No differences in pitch discrimination thresholds were observed across strategies. Conclusions: OPAL can provide benefits to Mandarin lexical tone recognition in moderately noisy conditions and preserve perception of Mandarin sentences in challenging noise conditions.