Cochlear Implantation For Single-sided Deafness Research Articles

Cochlear Implantation for Single-Sided Deafness in Pediatric Patients: A Critical Assessment of Usage Rate.

To assess the usage rate of pediatric patients undergoing cochlear implantation (CI) for single-sided deafness (SSD). Retrospective cohort study. Tertiary care pediatric referral center. Pediatric patients who underwent CI for SSD. CI with requisite audiometric follow-up. Device use and audiometric testing. Sixty-six patients were implanted for SSD between 8/2015 and 7/2023 at a median age of 4.7 years (interquartile range, 1.7-7.7 yr). The cause of hearing loss was unknown in the majority of cases (28 patients, 42%), with cytomegalovirus being the most common known cause (17 patients, 26%). Hearing loss was prelingual in 38 patients (58%). Post-implantation, 12 patients (18%) were identified as lost to follow-up. For the remaining 54 patients, the median length of audiometric follow-up was 1.4 years (interquartile range, 0.9-2.2 yr). At last evaluation, only 10 of these 54 patients (19%) were designated as users (≥6 h per day), and 13 patients (24%) were designated as limited users (>2 but <6 h per day). Of patients capable of performing speech-in-noise testing (n = 13), 11 patients (85%) showed improvement on BKB-SIN SNR-50 testing with their implant on versus off with a mean improvement of 3 dB. Notably, 4 of these 11 patients (36%) were categorized as nonusers despite this benefit. Despite audiometric benefit from CI in the pediatric SSD population, usage rates over time remain markedly lower than anticipated at a high-volume, well-resourced tertiary care pediatric center. No influencing factors were identified, warranting critical assessment to ensure appropriate resource allocation.

Auditory Localization Performance in Cochlear Implant Recipients With Single-Sided Deafness: The Challenges and Limitations of Current Outcome Metrics.

Acoustic localization accuracy metrics currently employed in clinical literature both overestimate and underestimate performance benefit of cochlear implantation (CI) for single-sided deafness (SSD). Although localization in SSD with CI has been investigated, performance characterization has relied heavily on average error. Although attractively concise, this measure may misrepresent performance. Here, we characterize frequency-specific localization on a granular level in subjects with CI for SSD as a critical analysis of localization outcome metrics. Eight CI recipients with SSD were recruited. Stimuli of broadband (BBN) and narrowband noise (NBN) at low (500 Hz), mid (1000 Hz), and high (4000 Hz) frequencies were presented in a semianechoic chamber. Localization accuracy was quantified in mean angular error (MAE) and linear regression slope. Use of a CI for SSD subjects improved localization performance by slope for all stimuli ( p ≤ 0.0033) to a level that was equal to normal-hearing controls at 1 and 4 kHz ( p ≥ 0.2281). MAE was also significantly improved for SSD subjects using CI for BBN stimuli ( p ≪ 0.0001); however, no statistically significant improvement in MAE was seen for NBN ( p ≥ 0.5773) with CI use. Descriptive analysis of individual subject performance highlights the reasons for contradictory results. There is inherent challenge in characterizing localization benefit for individuals with CI for SSD. Our data demonstrate the limitations of utilization of average error as the sole metric for outcome benefit. We emphasize the importance of continued research investigating alternative outcome measures as we work toward a more refined understanding of the potential benefits and limitations of cochlear implantation for SSD.

Speech Quality Perception in Unilateral Cochlear Implant Users With Single-Sided Deafness.

Cochlear implant (CI) users frequently complain about speech quality perception (SQP). In patients undergoing cochlear implantation for single-sided deafness, there is concern that poor SQP from the implanted ear will negatively impact binaural (CI + normal hearing [NH]) SQP. In this study, we investigate if binaural SQP is measurably different than unimplanted NH alone. Cross-sectional study. Tertiary care center. Fifteen unilateral CI users with NH in the contralateral ear completed the validated Columbia Speech Quality Instrument. This instrument consists of 9 audio clips rated across 14 specific speech qualities using a 10-point visual analog scale. SQP was assessed in 3 conditions: CI only, NH only, and CI + NH. Median speech quality scores were worse in the CI only condition compared to the NH only (50.0 vs 72.6, P = .0003) and binaural (50.0 vs 71.0, P = .007) conditions. Median speech quality scores were not significantly different between the NH only and binaural conditions (72.6 vs 71, P = .8). Compared to NH, CI speech quality sounded less clear, less natural, and more mechanical. Compared to NH, SQP is poorer with a CI alone. However, in contrast to expectation, there is no significant difference between NH and binaural SQP. This suggests poorer CI speech perception does not negatively impact binaural SQP in patients undergoing cochlear implantation for single-sided deafness.

Cochlear Implantation in Single-Sided Deafness and Asymmetric Hearing Loss: 12 Months Follow-up Results of a European Multicenter Evaluation.

People with single-sided deafness (SSD) or asymmetric hearing loss (AHL) have particular difficulty understanding speech in noisy listening situations and in sound localization. The objective of this multicenter study is to evaluate the effect of a cochlear implant (CI) in adults with single-sided deafness (SSD) or asymmetric hearing loss (AHL), particularly regarding sound localization and speech intelligibility with additional interest in electric-acoustic pitch matching. A prospective longitudinal study at 7 European tertiary referral centers was conducted including 19 SSD and 16 AHL subjects undergoing cochlear implantation. Sound localization accuracy was investigated in terms of root mean square error and signed bias before and after implantation. Speech recognition in quiet and speech reception thresholds in noise for several spatial configurations were assessed preoperatively and at several post-activation time points. Pitch perception with CI was tracked using pitch matching. Data up to 12 months post activation were collected. In both SSD and AHL subjects, CI significantly improved sound localization for sound sources on the implant side, and thus overall sound localization. Speech recognition in quiet with the implant ear improved significantly. In noise, a significant head shadow effect was found for SSD subjects only. However, the evaluation of AHL subjects was limited by the small sample size. No uniform development of pitch perception with the implant ear was observed. The benefits shown in this study confirm and expand the existing body of evidence for the effectiveness of CI in SSD and AHL. Particularly, improved localization was shown to result from increased localization accuracy on the implant side.

Changing Management of Intravestibular Schwannomas in the Era of Cochlear Implantation for Single-Sided Deafness.

Intralabyrinthine schwannomas (ILSs) are a rare cause of deafness. Patients with ILS confined to the semicircular canals and the vestibule (intravestibular schwannomas) are potential candidates for cochlear implantation for hearing rehabilitation, a new option for patients with unilateral hearing loss since the 2019 FDA approval of cochlear implant (CI) for single-sided deafness. In this report, we describe an evolving management approach for ILSs causing hearing loss. Adults (≥18 years) who underwent simultaneous ILS resection and CI between January 2019 and June 2023 (n = 3). Transmastoid labyrinthectomy with simultaneous cochlear implantation. Hearing performance with cochlear implantation measured as CNC Word Recognition scores and AzBio Sentence scores. Three patients with ILS confined to the semicircular canals and vestibule underwent simultaneous tumor resection via labyrinthectomy with CI placement. In all cases, complete tumor resection and full CI insertion were achieved. No patients experienced postoperative complications. Patients 1 and 2 underwent 6- and 9-month postactivation testing, respectively, with CNC scores 64% to 80% and AzBio 81% to 99% in the implanted ears. Patient 3 scored 0% on CNC and AzBio testing at 3 months and deferred her 6-month audiometry. Patients with ILS confined to the vestibule and semicircular canals can be considered for simultaneous tumor resection and CI placement.

Comparison of independent, participant-led, high-resolution studies of pitch-matching in post-lingual single-sided cochlear implant recipients

Understanding “what the world sounds like to someone else“ is fundamental to developing technologies and therapies to improve auditory perception for people with hearing impairment. Post-lingual single-sided deaf (SSD) cochlear implant (CI) recipients can play a special role here through their ability to compare perceptions of sounds heard acoustically and “electrically.” Pitch is, ostensibly, a sonic attribute that can be quantitatively compared, and pitch perception has been studied by asking SSD CI recipients to rank or discriminate limited sets of pitches, mindful of the burden on experimental participants. Through unusual circumstances, we have independently conceived and conducted two sets of participant-driven pitch-matching experiments on authors WM and DL gaining more data and richer insights than reported elsewhere. While our findings are consistent with existing lower-resolution studies (e.g., sounds perceived via CI are at higher pitch than via normal hearing), we have gained much more detailed quantitative and qualitative descriptions of those perceptual differences. Results can be meaningfully compared after accounting for individual differences and suggest that the CI transformation of pitch information for these two recipients could be individually adjusted to improve music appreciation, particularly with respect to restoring perception of musical intervals between successive notes.

Health Insurance Coverage of Cochlear Implantation in Single-Sided Deafness and Asymmetric Hearing Loss.

There is increasing interest in providing cochlear implants (CIs) in single-sided deafness (SSD) or asymmetric hearing loss (AHL). CI clinics have experienced a range of outcomes when seeking insurance coverage for patients. The study explored the extent to which CI clinics were able to secure insurance coverage and whether there were differences in successfully gaining such coverage. A SurveyMonkey questionnaire was used to collect data from US CI clinicians. Respondents were from all regions of the United States and represented a diversity of clinic types including hospitals, university-based clinics, private clinics, and schools. Data were collected during August-October 2021 from 105 respondents regarding their clinic's experience in gaining health insurance coverage for pediatric and adult patients who had SSD or AHL. Strategies that had been used for gaining coverage after an initial denial were explored. Interviews were conducted with some respondents to gain additional insights beyond the survey. There was a substantial increase in the number of SSD operations conducted after 2019, the year when the Food and Drug Administration (FDA) manufacturer criteria expanded to include CI in SSD and AHL. Respondents were grouped into four categories based on volume of SSD operations before 2019 (≤10, 11-29, 30-49, and ≥50). The number of SSD operations after 2019 went up in all categories except for the 10 or less category, which declined by 43%. A minority of respondents indicated that they were able to obtain SSD insurance coverage infrequently (5%) or almost never (8%). Peer-to-peer review was the most successful approach to overturning an initial denial. Many clinics note that they are nearly always declined for SSD coverage on the first submission and must appeal. There is variability in CI coverage for SSD and AHL. Some health insurance coverage is available for patients of all ages, although some clinics note more difficulty gaining coverage for children younger than 5 years because of the FDA criteria. Clinicians are most successful at gaining coverage after an initial denial with peer-to-peer review, although the process is time-consuming and delays surgery. Efforts to expand access to CIs in SSD for children and adults who may benefit might best be addressed by reflecting on what was done to expand insurance coverage in bilateral deafness-a process that depended on relevant clinical research; research presented to the FDA for guidelines change; information sharing with the general public and constituencies in the hearing loss field including professionals, parent, and consumer organizations; and ongoing advocacy for change with insurers. To date, outcomes research in young children with CI in SSD is limited. Until such research is conducted and published, insurers will continue to argue that other rehabilitative options are approved and available.

Cochlear Implantation in Very Young Children With Single-Sided Deafness.

Cochlear implants (CIs) for single-sided deafness (SSD) have only been approved for patients 5 years and older despite data supporting that younger children can also benefit from implantation. This study describes our institution's experience with CI for SSD in children 5 years and younger. Case series with chart review. Tertiary referral center. A case series with chart review identified 19 patients up to age 5 years who underwent CI for SSD between 2014 and 2022. Baseline characteristics, perioperative complications, device usage, and speech outcomes were collected. The median age at CI was 2.8 (range, 1.0-5.4) years, with 15 (79%) patients being below age 5 at implantation. Etiologies of hearing loss were idiopathic (n = 8), cytomegalovirus (n = 4), enlarged vestibular aqueduct (n = 3), hypoplastic cochlear nerve (n = 3), and meningitis (n = 1). The median preoperative pure-tone average was 90 (range, 75-120) and 20 (range, 5-35) dB eHL in the poorand better hearing ears, respectively. No patients had postoperative complications. Twelve patients achieved consistent device use (average, 9 h/d). Three of the seven who were not consistent users had hypoplastic cochlear nerves and/or developmental delays. The three patients with available preoperative and postoperative speech testing showed significant benefits, and five patients with available postoperative testing demonstrated speech recognition in the implanted ear when isolated from the better ear. CI can safely be performed in younger children with SSD. Patients and families accept early implantation, as evidenced by consistent device use, and derive notable benefits in speech recognition. Candidacy can be broadened to include SSD patients under age five years, particularly individuals without hypoplastic cochlear nerves or developmental delay.

Cochlear implantation in single-sided deafness: a single-center experience of 138 cases.

Assess the outcomes in patients who underwent cochlear implant (CI) for single-sided deafness (SSD). All patients affected by SSD who underwent CI at Gruppo Otologico, Piacenza, from October 2012 to May 2022 with at least 6months of follow-up were selected in the study group. The analysis included subjective and objective measures performed pre-operative and up to 24months after surgery. Hearing threshold on both sides was evaluated with a weighted four-frequency average (PTA [0.5kHz + 1kHz + 2kHz + 4kHz]/4) on pure tone audiometry and speech audiometry (Speech Discrimination Score, SDS). The Speech Spatial and Qualities of Hearing scale (SSQ Questionnaire) for binaural hearing benefits and sound localization, the Tinnitus Handicap Inventory Questionnaire (THI) and Dizziness Handicap Inventory Questionnaire (DHI) were used for subjective assessment. Data from 138 patients, 69 males and 69 females, (mean age 49years, range 17-77years) underwent CI for SSD were examined. Single-sided hearing deprivation average before undergoing CI surgery was 2.5years (range 3months-35years). There was a significant reduction of THI and DHI scores compared to pre-operative scores alongside a referred improvement in social, physical, and emotional well-being through the SSQ questionnaire. To the best of our knowledge, this paper descried the largest cohort of SSD who underwent CI in a single institution. According to our findings CI in patients affected by SSD represents a valuable tool for an overall improvement of tinnitus and dizziness but also quality of life, after at least 6months of follow-up. Further studies are desirable to improve rehabilitation pathways and possibly set new standards of care of this condition.

Event-Related Potentials of Single-Sided Deaf Cochlear Implant Users: Using a Semantic Oddball Paradigm in Noise

Introduction: In individuals with single-sided deafness (SSD), who are characterised by profound hearing loss in one ear and normal hearing in the contralateral ear, binaural input is no longer present. A cochlear implant (CI) can restore functional hearing in the profoundly deaf ear, with previous literature demonstrating improvements in speech-in-noise intelligibility with the CI. However, we currently have limited understanding of the neural processes involved (e.g., how the brain integrates the electrical signal produced by the CI with the acoustic signal produced by the normal hearing ear) and how modulation of these processes with a CI contributes to improved speech-in-noise intelligibility. Using a semantic oddball paradigm presented in the presence of background noise, this study aims to investigate how the provision of CI impacts speech-in-noise perception of SSD-CI users. Method: Task performance (reaction time, reaction time variability, target accuracy, subjective listening effort) and high density electroencephalography from twelve SSD-CI participants were recorded, while they completed a semantic acoustic oddball task. Reaction time was defined as the time taken for a participant to press the response button after stimulus onset. All participants completed the oddball task in three different free-field conditions with the speech and noise coming from different speakers. The three tasks were: (1) CI-On in background noise, (2) CI-Off in background noise, and (3) CI-On without background noise (Control). Task performance and electroencephalography data (N2N4 and P3b) were recorded for each condition. Speech in noise and sound localisation ability were also measured. Results: Reaction time was significantly different between all tasks with CI-On (M [SE] = 809 [39.9] ms) having faster RTs than CI-Off (M [SE] = 845 [39.9] ms) and Control (M [SE] = 785 [39.9] ms) being the fastest condition. The Control condition exhibited significantly shorter N2N4 and P3b area latency compared to the other two conditions. However, despite these differences noticed in RTs and area latency, we observed similar results between all three conditions for N2N4 and P3b difference area. Conclusion: The inconsistency between the behavioural and neural results suggests that EEG may not be a reliable measure of cognitive effort. This rationale is further supported by different explanations used in past studies to explain N2N4 and P3b effects. Future studies should look to alternative measures of auditory processing (e.g., pupillometry) to gain a deeper understanding of the underlying auditory processes that facilitate speech-in-noise intelligibility.

A Study of Event-Related Potentials During Monaural and Bilateral Hearing in Single-Sided Deaf Cochlear Implant Users.

Single-sided deafness (SSD) is characterized by a profoundly deaf ear and normal hearing in the contralateral ear. A cochlear implant (CI) is the only method to restore functional hearing in a profoundly deaf ear. In a previous study, we identified that the cortical processing of a CI signal differs from the normal-hearing ear (NHE) when directly compared using an auditory oddball paradigm consisting of pure tones. However, exactly how the brain integrates the electrical and acoustic signal is not well investigated. This study aims to understand how the provision of the CI in combination with the NHE may improve SSD CI users' ability to discriminate and evaluate auditory stimuli. Electroencephalography from 10 SSD-CI participants (4 participated in the previous pure-tone study) were recorded during a semantic acoustic oddball task, where they were required to discriminate between odd and even numbers. Stimuli were presented in four hearing conditions: directly through the CI, directly to the NHE, or in free field with the CI switched on and off. We examined task-performance (response time and accuracy) and measured N1, P2, N2N4, and P3b event-related brain potentials (ERPs) linked to the detection, discrimination, and evaluation of task relevant stimuli. Sound localization and speech in noise comprehension was also examined. In direct presentation, task performance was superior during NHE compared with CI (shorter and less varied reaction times [~720 versus ~842 msec], higher target accuracy [~93 versus ~70%]) and early neural responses (N1 and P2) were enhanced for NHE suggesting greater signal saliency. However, the size of N2N4 and P3b target-standard effects did not differ significantly between NHE and CI. In free field, target accuracy was similarly high with the CI (FF-On) and without the CI (FF-Off) (~95%), with some evidence of CI interference during FF-On (more variable and slightly but significantly delayed reaction times [~737 versus ~709 msec]). Early neural responses and late effects were also greater during FF-On. Performance on sound localization and speech in noise comprehension (S CI N NHE configuration only) was significantly greater during FF-On. Both behavioral and neural responses in the semantic oddball task were sensitive to CI in both direct and free-field presentations. Direct conditions revealed that participants could perform the task with the CI alone, although performance was suboptimal and early neural responses were reduced when compared with the NHE. For free-field, the addition of the CI was associated with enhanced early and late neural responses, but this did not result in improved task performance. Enhanced neural responses show that the additional input from the CI is modulating relevant perceptual and cognitive processes, but the benefit of binaural hearing on behavior may not be realized in simple oddball tasks which can be adequately performed with the NHE. Future studies interested in binaural hearing should examine performance under noisy conditions and/or use spatial cues to allow headroom for the measurement of binaural benefit.

Quality of Life Impact of Cochlear Implantation for Single-Sided Deafness: Assessing the Interrelationship of Objective and Subjective Measures.

To determine the effect on quality of life (QOL) of cochlear implantation (CI) for single-sided deafness (SSD) and asymmetric hearing loss (AHL) using the first psychometrically developed CI-specific QOL tool for English-speaking patients and to assess its relationship to objective perceptual measures. Retrospective cohort study. Tertiary-care medical center. English-speaking adults with SSD or AHL. Unilateral CI. Cochlear Implant Quality of Life (CIQOL) score, CI-alone speech-in-quiet (SIQ) score (CNC and AzBio), binaural speech-in-noise (SIN) threshold, binaural azimuthal sound localization (SL) error. At the most recent postoperative evaluation (median, 9.3 months postimplantation), 25 of 28 subjects (89%) had a CIQOL improvement, with the improvement considered clinically beneficial (>3 points) for 18 of 28 subjects (64%). Group-mean CIQOL improvement was observed at the first postoperative visit and did not change significantly thereafter. Objective perceptual measures (SL, SIQ, SIN) continued to improve over 12 months after implantation. Linear mixed-model regression analyses showed a moderate positive correlation between SIN and SIQ improvements (r = 0.50 to 0.59, p < 0.0001) and a strong positive correlation between the improvement in the two SIQ measures (r = 0.89, p < 0.0001). No significant relationships were observed ( p > 0.05) among QOL or the objective perceptual measures. QOL improved for the majority of subjects implanted for SSD and AHL. Different time courses for improvement in QOL and audiologic tests, combined with the lack of significant relationships among them, suggest that QOL outcomes reflect different aspects of the CI experience than those captured by speech-understanding and localization measures. SIQ may substitute for SIN when clinical constraints exist.

Cochlear Implants for Single-Sided Deafness: Quality of Life, Daily Usage, and Duration of Deafness.

To report our experience for adults undergoing cochlear implantation (CI) for single-sided deafness (SSD). This is a retrospective case series for adults with SSD who underwent CI between January 2013 and May 2021 at our institution. CNC and AzBio speech recognition scores, Tinnitus Handicap Inventory (THI), Speech, Spatial, and Qualities of Hearing Scale (SSQ12), datalogging, and the Cochlear Implant Quality of Life (CIQOL)-10 Global measure were utilized. Sixty-six adults underwent CI for SSD (median 51.3 years, range 20.0-74.3 years), and 57 (86.4%) remained device users at last follow-up. Compared to pre-operative performance, device users demonstrated significant improvement in speech recognition scores and achieved peak performance at six months post-activation for CNC (8.0% increased to 45.6%, p < 0.0001) and AzBio in quiet (12.2% increased to 59.5%, p < 0.0001). THI was decreased at 6 months post-implantation (58.1-14.6, p < 0.0001), with 77% of patients reporting improved or resolved tinnitus. Patients demonstrated improved SSQ12 scores as well as the disease-specific CIQOL-10 Global questionnaire. Duration of deafness was not associated with significant differences in speech recognition performance. Average daily wear time was positively associated with CNC and AzBio scores as well as post-operative CIQOL-10 scores. Herein we present the largest cohort of adult CI recipients with SSD with data on speech recognition scores, tinnitus measures, and SSQ12. Novel insights regarding the correlation of datalogging, duration of deafness, and CI-specific quality of life (CIQOL-10) metrics are discussed. Data continue to support CI as an efficacious treatment option for SSD. 4 Laryngoscope, 133:2362-2370, 2023.

(Even Off-Label) Cochlear Implantation in Single-Sided Deafness and Asymmetric Hearing Loss Results in Measurable Objective and Subjective Benefit.

To quantify objective and subjective outcomes in cochlear implant (CI) recipients with asymmetric hearing loss, including single-sided deafness (SSD) whose candidacy was determined on an ear-specific basis when word recognition was 50% or less. Retrospective case review. Tertiary referral center. The effectiveness of CI in cases of SSD and asymmetric hearing loss (AHL) has been described in terms of tinnitus suppression, improved speech recognition in quiet and noise, enhanced localization ability, and improved quality of life. However, CI is not yet routinely offered as a top option or standard of care for these individuals. Recent Food and Drug Administration (FDA) labeling limits aided word recognition in the ear to be implanted to only 5% in cases of AHL/SSD, which is significantly poorer than 40 to 50%, which is often referenced in cases of bilateral hearing loss. Anecdotal experience suggests that patients with much better preoperative word recognition than 5% can benefit from CI. We conducted a retrospective chart review of all adult CI candidates, with one ear exhibiting consonant-nucleus-consonant (CNC) word recognition scores at least 50% and one ear not meeting CI candidacy (i.e., CNC word recognition >50%). Outcome variables of interest included word and sentence recognition and subjective handicap questionnaires (hearing, tinnitus, dizziness) and the Speech Spatial Qualities questionnaire. Statistically and clinically significant improvement in speech understanding (word, sentence, sentence in noise) was noted for both the SSD and AHL groups in the implanted ear. There were statistically and clinically significant subjective improvements noted for both groups on the Hearing Handicap Inventory, the Tinnitus Handicap Inventory, and the Speech Spatial Qualities questionnaire by 1 month after activation. There were no significant differences between the AHL and SSD groups on either objective or subjective measures of the implanted ear. Individual word understanding improved for the majority of recipients across both groups and is not dependent on meeting the FDA criteria of less than 5%. Cochlear implantation is a viable option with measurable objective and perceived benefits for recipients with preoperative aided CNC word scores exceeding current FDA labeling. There is no significant difference between the AHL and SSD groups, suggesting that candidacy and outcome expectations should be set based on the ear to be implanted alone, without regard for the ability of the better hearing ear.

Hearing rehabilitation for unilateral deafness using a cochlear implant: the influence of the subjective duration of deafness on speech intelligibility

BackgroundFor patients with single sided deafness (SSD) or severe asymmetric sensorineural hearing loss (ASHL), cochlear implantation remains the only solution to restore bilateral hearing capacity. Prognostically, the duration of hearing loss in terms of audiological outcome is not yet clear. Therefore, the aim of this study was to retrospectively investigate the influence of subjective deafness duration on postoperative speech perception after cochlear implantation for SSD as well as its impact on quality of life.Materials and methodsThe present study included a total of 36 adults aged 50.2 ± 15.5 years who underwent CI for SSD/ASHL at our clinic between 2010 and 2015. Patients were audiometrically assessed at 3 and 12–36 months postoperatively. Test results were correlated with self-reported duration of deafness. Quality of life was assessed by questionnaire.ResultsMean duration of deafness was 193.9 ± 185.7 months. The side-separated hearing threshold showed an averaged target range between 30 and 40 dB HL. Freiburg monosyllable test increased from 0% pre-operatively to 20% after 3 months (p = 0.001) and to 50% after 12–36 months (p = 0.002). There was a significant correlation between audiometric outcome and subjective deafness duration at 12–36 months postoperatively (r = − 0.564; p = 0.02) with a cutoff for open-set monosyllable recognition at a duration of deafness of greater than 408 months. Quality of life was significantly improved by CI.ConclusionsCI implantation in unilaterally deafened patients provides objective and subjective benefits. Duration of deafness is unlikely to be an independent negative predictive factor and thus should not generally be considered as contraindication.

Audiologic and patient perceived benefit in cochlear implantation for single-sided deafness

Background CI in SSD strives to restore binaural hearing. With normal acoustic hearing on one ear, the benefits of rehabilitating the deaf ear with an implant are not well established. Objectives We investigate audiologic and quality-of-life measures, and long-term usage patterns of cochlear implantation (CI) in patients with single-sided deafness (SSD) Methods Eight patients with idiopathic sudden sensorineural hearing loss of less than 5-year duration were recruited. Pure tone average (PTA), speech discrimination score (SDS), hearing-in-noise test (HINT), tinnitus handicap inventory (THI), quality-of-life speech spatial qualities (SSQ) scale tests were performed before, and one-year after CI. Long-term usage of CI four-years post-operatively was determined. Results The median PTA of the deaf ear was 96 dBHL (IQR = 90–120) before, and 30 dBHL (IQR = 27–33) after CI ( p = 0.0156). SDS improved from median of 0% (IQR = 0–3) to 33% (IQR = 24–58) ( p = 0.0360). Median signal-to-noise ratio (SNR), particularly of the S0Nbetter setting of HINT showed improvement from 6.4 dB (IQR = 5.7–7) to 0.9 dB (IQR = −2.25–6.2) ( p = 0.1094). Despite median THI improving from 24 (IQR = 6–47) to 4 (IQR = 2–7) ( p = 0.1563), two patients experienced worsening of tinnitus. SSQ scores in all subscales showed modest improvement not approaching significance. 5 of 8 (62%) patients stopped using their implant four years after surgery. Conclusion Despite improved audiologic and tinnitus outcome measures, our patients’ SDS remained in non-serviceable range, while quality-of-life measures showed only modest improvement. Majority of our patients stopped using their implant four years post-surgery. Our study suggests that objective measurable benefits of CI in SSD may not translate to actual patient perceived benefits.

Sound localisation of low- and high-frequency sounds in cochlear implant users with single-sided deafness

Objective Localisation of low- and high-frequency sounds in single-sided deaf cochlear implant users was investigated using noise stimuli designed to mitigate monaural localisation cues. Design Within subject design. Sound source localisation was tested in the horizontal plane using an array of seven loudspeakers along the azimuthal angle span from −90° to +90°. Stimuli were broadband noise and high- and low-frequency noise. Study sample Twelve adult subjects with single-sided deafness participated in the study. All had normal hearing in the healthy ear and were supplied with a cochlear implant (CI) in their deaf ear. Results With broadband noise, the mean angular localisation error was 39° in aided condition as compared to a median angular error of 83.6° when the speech processor was not worn. For high-frequency noise, the median angular error was 30° and for low-frequency noise, it was 46° in the CI-aided condition. Conclusions Single-sided deaf CI users show the best sound localisation for high-frequency sounds. This supports the view that interaural level differences are dominant for sound localisation in these listeners. Nonetheless, a limited ability to localise low-frequency sounds was observed, which may be based on the supportive perception of interaural time differences.

Speech Perception Performance Growth and Benchmark Score Achievement After Cochlear Implantation for Single-Sided Deafness.

Compare speech perception performance growth and benchmark score achievement among adult cochlear implant (CI) recipients with single-sided deafness (SSD) versus bilateral moderate to profound hearing loss. Retrospective matched cohort analysis. Tertiary referral center. Adults with SSD or bilateral moderate to profound hearing sensorineural hearing loss who underwent cochlear implantation from 2014 to 2019. Cochlear implantation. Time-to-benchmark speech perception score (CNC, AzBio in quiet) and speech performance within first postoperative year. Thirty-three SSD patients were matched to 66 bilateral hearing loss patients (referent cohort) for duration of deafness and preoperative ipsilateral CNC scores. Although SSD patients were more likely to achieve benchmark CNC scores more quickly compared with matched referents, this difference did not reach statistical significance (HR 1.72; 95% CI 0.78-3.82; p = 0.18). AzBio scores showed similar trends (HR 1.40; 95% CI 0.66-2.98; p = 0.38). At last follow-up, the SSD cohort had lower CNC (median 54% vs. 62%; p = 0.019) and AzBio scores (median 72% vs. 84%; p = 0.029) compared to the referent cohort. No significant difference in speech perception performance growth (i.e., time-to-benchmark speech perception score) was identified between SSD and bilateral hearing loss CI recipients, although patients with bilateral hearing loss achieved higher scores in the implanted ear within the first year of follow-up.

Valid Acoustic Models of Cochlear Implants: One Size Does Not Fit All.

This study tests the hypothesis that it is possible to find tone or noise vocoders that sound similar and result in similar speech perception scores to a cochlear implant (CI). This would validate the use of such vocoders as acoustic models of CIs. We further hypothesize that those valid acoustic models will require a personalized amount of frequency mismatch between input filters and output tones or noise bands. Noise or tone vocoders have been used as acoustic models of CIs in hundreds of publications but have never been convincingly validated. Acoustic models were evaluated by single-sided deaf CI users who compared what they heard with the CI in one ear to what they heard with the acoustic model in the other ear. We evaluated frequency-matched models (both all-channel and 6-channel models, both tone and noise vocoders) as well as self-selected models that included an individualized level of frequency mismatch. Self-selected acoustic models resulted in similar levels of speech perception and similar perceptual quality as the CI. These models also matched the CI in terms of perceived intelligibility, harshness, and pleasantness. Valid acoustic models of CIs exist, but they are different from the models most widely used in the literature. Individual amounts of frequency mismatch may be required to optimize the validity of the model. This may be related to the basalward frequency mismatch experienced by postlingually deaf patients after cochlear implantation.

Quality standards for adult cochlear implantation in single-sided deafness and asymmetric hearing loss

Quality standards for adult cochlear implantation in single-sided deafness and asymmetric hearing loss