Postlingual Hearing Loss Research Articles

Identification of a novel EYA4 likely pathogenic variant in a Chinese family with postlingual non-syndromic hearing loss and analysis of molecular epidemiology of EYA4 variants

BackgroundEYA4 variants are responsible for DFNA10 deafness. Due to its insidious onset and slow progression, hearing loss in autosomal dominant non-syndromic hearing loss (ADNSHL) is usually challenging to detect early in clinical settings, with limited intervention options. Genetic testing can aid in early detection of hearing loss, enabling timely intervention to reduce disability rates and improve the quality of life.MethodsIn this study, we report the case of a Chinese family with postlingual and progressive hearing loss that was passed down for four generations. Whole-exome sequencing (WES) was performed on DNA samples from the proband. Candidate variants identified in the proband and family members were confirmed via Sanger sequencing. In silico prediction tools and co-segregation analyses were used to assess the pathogenicity of identified variants. A literature review of known EYA4 variants was performed, analysing variant frequency, distribution characteristics across different populations, and genotype-phenotype correlations.ResultsWe identified a novel EYA4 variant, c.1745_1748del (p.Glu582ValfsTer6), in a Chinese family with ADNSHL, and co-segregation with the family’s phenotype was confirmed. The audiometry showed mid-to-high frequency downsloping hearing loss. To date, 52 pathogenic variants of EYA4 have been reported, with majority identified in Asian populations. Most observed are the missense and frameshift variants.ConclusionsA novel variant of EYA4 was identified in a Chinese family with postlingual hearing loss, contributing to the expanding spectrum of EYA4 variants. The audiological features of EYA4 variants are highly heterogeneous and often challenging to detect early in clinical settings. Our findings highlight the significance of genetic testing in patients presenting with postlingual hearing loss.

Investigating the Relationship between Non-verbal Intelligence and Adaptive Behavior in Hearing Impaired Children

The present study intended to find out the relationship between nonverbal intelligence and adaptive behaviors in children with pre-lingual and post-lingual hearing loss. A total of 200 hearing impaired children were purposively selected from Government Special Education institute in district Khanewal who aged between 6 to 11 years. The Vineland Adaptive Behavior Scale, and Raven’s Colored Progressive Matrices were used to collect the data from participating hearing impaired children. Results showed that intelligence has significant positive relationship with daily living and motor skills, and significant negative relationship with communication and socialization skills. The independent samples t test revealed a significant difference in prelingual and post lingual children in intelligence levels with little effect size. Further, the prelingual children showed more motor behavior as compared to children in post lingual group. It is important to gather a wide range of data on adaptive behavior and intelligence, including information on performance in various contexts, from various sources, and using varied techniques.

Anatomy-based fitting improves speech perception in noise for cochlear implant recipients with single-sided deafness

Abstract Objective To evaluate objective and subjective hearing outcomes in experienced cochlear implant users with single sided deafness (SSD CI) who used fitting maps created via anatomy-based fitting (ABF) and clinically-based fitting (CBF). Participants Twelve SSD CI users with postlingual hearing loss. Intervention OTOPLAN (Version 3. (MED-EL) was used to determine intracochlear electrode contact positions using post-operative high-resolution flat panel volume computed tomography. From these positions, the corresponding center frequencies and bandwidths were derived for each channel. These were implemented in the clinical fitting software MAESTRO to yield an ABF map individualized to each user. Main Outcome Measures ABF and CBF maps were compared. Objective speech perception in quiet and in noise, binaural effects, and self-perceived sound quality were evaluated. Results Significantly higher speech perception in noise scores were observed with the ABF map compared to the CBF map (mean SRT50: -6.49 vs. -4.8 dB SNR for the S0NCI configuration and − 3.85 vs. -2.75 dB SNR for the S0N0 configuration). Summation and squelch effects were significantly increased with the ABF map (0.86 vs. 0.21 dB SNR for summation and 0.85 vs. -0.09 dB SNR for squelch). No improvement in speech perception in quiet or spatial release from masking were observed with the ABF map. A similar level of self-perceived sound quality was reported for each map. Upon the end of the study, all users opted to keep the ABF map. This preference was independent of the angular insertion depth of the electrode array. Conclusions Experienced SSD CI users preferred using the ABF map, which gave them significant improvements in binaural hearing and some aspects of speech perception.

Gain-of-function variants in GSDME cause pyroptosis and apoptosis associated with post-lingual hearing loss

Gasdermin E (GSDME), a member of the gasdermin protein family, is associated with post-lingual hearing loss. All GSDME pathogenic mutations lead to skipping exon 8; however, the molecular mechanisms underlying hearing loss caused by GSDME mutants remain unclear. GSDME was recently identified as one of the mediators of programmed cell death, including apoptosis and pyroptosis. Therefore, in this study, we injected mice with GSDME mutant (MT) and examined the expression levels to assess its effect on hearing impairment. We observed loss of hair cells in the organ of Corti and spiral ganglion neurons. Further, the N-terminal release from the GSDME mutant in HEI-OC1 cells caused pyroptosis, characterized by cell swelling and rupture of the plasma membrane, releasing lactate dehydrogenase and cytokines such as interleukin-1β. We also observed that the N-terminal release from GSDME mutants could permeabilize the mitochondrial membrane, releasing cytochromes and activating the mitochondrial apoptotic pathway, thereby generating possible positive feedback on the cleavage of GSDME. Furthermore, we found that treatment with disulfiram or dimethyl fumarate might inhibit pyroptosis and apoptosis by inhibiting the release of GSDME-N from GSDME mutants. In conclusion, this study elucidated the molecular mechanism associated with hearing loss caused by GSDME gene mutations, offering novel insights for potential treatment strategies.

Single-Sided Deafness (SSD) - With the "Second" You Hear Better

Single-sided deafness (SSD) is characterised by deafness in one ear while the other ear has normal hearing. The most common cause in congenital SSD is aplasia of the auditory nerve, and in post-lingual SSD idiopathic hearing loss. Patients with SSD mainly suffer from impaired sound localisation and difficulties in speech perception in noise. There are various therapy options, but binaural hearing is only possible with a cochlear implant (CI).

Targeted Next-Generation Sequencing Analysis Reveals a Novel Genetic Variant in MYO6 Gene in an Indian Family with Postlingual Nonsyndromic Hearing Loss.

Background: Hereditary nonsyndromic hearing loss (NSHL) is an extremely heterogeneous disorder, both genetically and clinically. Myosin VI (MYO6) pathogenic variations have been reported to cause both prelingual and postlingual forms of NSHL. Postlingual autosomal dominant cases are often overlooked for genetic etiology in clinical setups. In this study, we used next-generation sequencing (NGS)-based targeted deafness gene panel assay to identify the cause of postlingual hearing loss in an Indian family. Methods: The proband and his father from a multigenerational Indian family affected by postlingual hearing loss were examined via targeted capture of 129 deafness genes, after excluding gap junction protein beta 2 (GJB2) pathogenic variants by Sanger sequencing. NGS data analysis and co-segregation of the candidate variants in the family were carried out. The variant effect was predicted by in silico tools and interpreted following American College of Medical Genetics and Genomics-Association for Molecular Pathology guidelines. Results: A novel heterozygous transversion c.3225T>G, p.(Tyr1075*) in MYO6 gene was identified as the disease-causing variant in this family. This stop-gained variant is predicted to form a truncated myosin VI protein, which is devoid of crucial cargo-binding domain. PCR-RFLP screening in 200 NSHL cases and 200 normal-hearing controls showed the absence of this variant indicating its de novo nature in the population. Furthermore, we reviewed MYO6 variants reported from various populations to date. Conclusions: To the best of our knowledge, this is the first family with MYO6-associated hearing loss from an Indian population. The study also highlights the importance of deafness gene panels in molecular diagnosis of GJB2-negative pedigrees, contributing to genetic counseling in the affected families.

Dizziness after cochlear implantation: Is the age an independent risk factor?

Abstract Background: Hearing loss and imbalance are the prevalent chronic conditions in the elderly, significantly impacting their quality of life (QoL). The relationship between otologic surgery, particularly cochlear implant (CI) procedures, and postoperative dizziness remains a critical area of investigation. Understanding this relationship is essential, especially given the rising number of older adults undergoing CI surgery. Materials and Methods: This retrospective, observational study, conducted between January 2016 and August 2021, assessed the influence of age on chronic dizziness following CI surgery. Sixty adults with postlingual sensorineural hearing loss who underwent unilateral CI surgery were evaluated. Comprehensive preoperative and postoperative assessments included the Dizziness Handicap Inventory (DHI) and QoL measures. Results: The study found a significant improvement in speech perception postimplantation, regardless of the age at surgery. However, postoperative dizziness, as measured by the DHI, increased significantly compared to preoperative levels. This increase in dizziness was not correlated with the age at implantation but was strongly associated with preexisting dizziness. Conclusions: These findings emphasize the need for thorough preoperative evaluations and patient counseling, particularly for those with preexisting balance disturbances, to optimize the outcomes and manage expectations regarding postoperative dizziness. This study contributes to the understanding of dizziness post-CI in older adults, highlighting the importance of considering individual patient conditions in the management of CI recipients.

Uses of Linguistic Context in Speech Listening: Does Acquired Hearing Loss Lead to Reduced Engagement of Prediction?

Research investigating the complex interplay of cognitive mechanisms involved in speech listening for people with hearing loss has been gaining prominence. In particular, linguistic context allows the use of several cognitive mechanisms that are not well distinguished in hearing science, namely those relating to "postdiction", "integration", and "prediction". We offer the perspective that an unacknowledged impact of hearing loss is the differential use of predictive mechanisms relative to age-matched individuals with normal hearing. As evidence, we first review how degraded auditory input leads to reduced prediction in people with normal hearing, then consider the literature exploring context use in people with acquired postlingual hearing loss. We argue that no research on hearing loss has directly assessed prediction. Because current interventions for hearing do not fully alleviate difficulty in conversation, and avoidance of spoken social interaction may be a mediator between hearing loss and cognitive decline, this perspective could lead to greater understanding of cognitive effects of hearing loss and provide insight regarding new targets for intervention.

Clinical characteristics and hearing loss etiology of cochlear implantees undergoing surgery in their teens, 20s, and 30s

PurposeThis study aimed to investigate the etiology of hearing loss, including genetic variants, in individuals who underwent cochlear implantation (CI) in their teens to thirties. It also sought to analyze post-CI speech performance and identify prognostic factors affecting CI outcomes in this age group.MethodsWe conducted a retrospective review of 421 cochlear implant patients at Seoul National University Bundang Hospital, focusing on 63 subjects aged 10–39 years who underwent their first CI by a single surgeon between July 2018 and June 2022. The study included audiologic evaluation, molecular genetic testing, and analysis of speech performance post-CI. Statistical analyses were performed using SPSS 25 and GraphPad Prism 7.ResultsAmong 63 participants (M:F, 24:39), nine underwent CI in their teens, 24 in their 20 s, and 30 in their 30 s. Most of them (40, 63.5%) had postlingual deafness. The study found that 65.2% (40/63) of subjects received a genetic diagnosis, with DFNB4 being the most common etiology (37.5%, 15/40). Post-CI speech evaluation showed an average sentence score of 80% across all subjects. Factors such as the onset of hearing loss, duration of deafness (DoD), and preoperative Speech Intelligibility Rating (SIR) significantly influenced CI outcomes. Notably, longer DoD was associated with poorer CI outcomes, but this did not affect individuals with postlingual hearing loss as much.ConclusionThe study concludes that in individuals aged 10–39 undergoing CI, the onset of hearing loss and preoperative SIR are critical predictors of postoperative outcomes. CI is recommended for those with postlingual hearing loss in this age group, irrespective of the DoD. The study highlights the importance of genetic factors especially DFNB4 in hearing loss etiology and underscores the value of the relatively easy-to-evaluate factor, preoperative SIR in predicting CI outcomes.

Functional Outcomes from Cochlear Implants in Children with Acquired Hearing Loss: Case Studies

Purpose: Early identification of postlingual hearing loss (HL) and knowing its probable cause is of great significance. Causes that result in irreversible profound HL require immediate radiological investigation and intervention to decide the best listening device.Methods: Case reports of three children with acquired HL using cochlear implant (CI) are being presented to understand the functional outcomes in domains of audition and language skills after 12 months of CI use. The age of onset of deafness and implantation were not identical. Etiology of deafness was meningitis in two cases and viral infection in the other. Consent was obtained from the parents for participating in the study. Case history review was conducted to collect demographic and audiological details of the participants. Functional benefits from CI in those children were assessed in the domains of auditory and language skills using standardized assessment tools respectively.Results: Improvements in all domains of auditory and language skills were observed. However, the degree of benefits depended on the duration of deafness, etiology of deafness, age at onset of deafness, age at implantation and effectiveness of intervention.Conclusions: The results of the study can be used during pre-implant CI counselling to facilitate development of real expectations about the functional benefits of CI in children with acquired HL due to various reasons and showed the importance of early cochlear implantation following the diagnosis. These case presentations give an understanding of the various factors that can affect the functional outcome from CI in children with post-lingual HL.

Comparison the Voice Onset Time (VOT) of Postlingual Cochlear Implant Users and Normal Peers in the CAPE_V Sentences as Continues Speech Task

BackgroundAuditory perception plays a crucial role in speech and language development, emphasizing concerns about hearing loss. While cochlear implantation nearly tackles challenges associated with post-lingual hearing loss in adults, the importance of "auditory feedback" and acoustic assessment becomes crucial for evaluating speech disorders and devising effective treatments. This study aims to address the gap in assessing Voice Onset Time (VOT) as an indicator of nuanced variations in the speech of cochlear implant users during a continuous speech task. MethodRecordings of Persian CAPE-V sentences were obtained from 25 cochlear implant (CI) users and 25 healthy speakers, with a mean age of 33.2 years (SD=11.5, range=18-55 years). Ten words, incorporating both voiced and voiceless consonants, were selected from the CAPE-V sentences. VOT measurements for the specified stop consonants at the initial syllables of these chosen words were computed using PRAAT. A comparative analysis between the two age- and gender-matched groups was conducted using an independent sample t-test. Subsequently, ANCOVA was employed to examine the influence of demographic factors on VOT values among CI participants. ResultsUnvoiced consonant /p/ in /po/, /pɑ/, /pe/, and /pa/ syllables had higher VOT values in the healthy group, while the voiced consonant /d/ in /da/ and /di/ syllables demonstrated higher VOT values in the CI group. (P<0.05) Apart from /po/ and /di/ syllables, no significant impacts of demographic factors on VOT values were observed (P≥0.8). ConclusionDespite the improvement in speech quality after cochlear implantation, subtle differences persist. The motor theory, which underscores the impact of auditory inputs on temporal coordination, highlights the role of VOT in speech discrimination. Various linguistic factors affect VOT, including articulation position, vowel context, and raised vowels. While CI enhances syllable distinction, challenges in articulation for adults suggest a need for targeted training in rehabilitation programs, ultimately enhancing the quality of life for CI users.

The cost evaluation of day-case compared to inpatient cochlear implantation in adults: subanalysis of a randomized controlled trial

ObjectiveTo investigate the assumption that day-case cochlear implantation is associated with lower costs, compared to inpatient cochlear implantation, while maintaining equal quality of life (QoL) and hearing outcomes, for the Dutch healthcare setting.Study designA single-center, non-blinded, randomized controlled trial in a tertiary referral center.MethodsThirty adult patients with post-lingual bilateral sensorineural hearing loss eligible for unilateral cochlear implantation surgery were randomly assigned to either the day-case or inpatient treatment group (i.e., one night admission). We performed an intention-to-treat evaluation of the difference of the total health care-related costs, hospital and out of hospital costs, between day-case and inpatient cochlear implantation, from a hospital and patient perspective over the course of one year. Audiometric outcomes, assessed using CVC scores, and QoL, assessed using the EQ-5D and HUI3 questionnaires, were taken into account.ResultsThere were two drop-outs. The total health care-related costs were €41,828 in the inpatient group (n = 14) and €42,710 in the day-case group (n = 14). The mean postoperative hospital stay was 1.2 days (mean costs of €1,069) in the inpatient group and 0.7 days (mean costs of €701) for the day-case group. There were no statistically significant differences in postoperative hospital and out of hospital costs. The QoL at 2 months and 1 year postoperative, measured by the EQ-5D index value and HUI3 showed no statistically significant difference. The EQ-5D VAS score measured at 1 year postoperatively was statistically significantly higher in the inpatient group (84/100) than in the day-case group (65/100). There were no differences in postoperative complications, objective hearing outcomes, and number of postoperative hospital and out of hospital visits.ConclusionA day-case approach to cochlear implant surgery does not result in a statistically significant reduction of health care-related costs compared to an inpatient approach and does not affect the surgical outcome (complications and objective hearing measurements), QoL, and postoperative course (number of postoperative hospital and out of hospital visits).Level of evidence1.

A 10-year in-depth follow-up of post-lingual hearing loss patients with Chinese domestic cochlear implants

Background Follow-up of cochlear implant effectiveness is mainly focused on 3 years postoperatively, and studies with more than 5 years of observation are rare, especially for local Chinese brands. Objectives Nurotron (Chinese domestic cochlear implant brand) CI recipients who participated in the clinical trial in 2009 were followed-up for 10 years prospectively, providing data to guide doctors and patients. Material and Methods From December 2009 to April 2010, 57 subjects underwent Nurotron Venus CI surgery at multiple-centers, and were continued to be followed up and assessed at 1, 2, 3, 4, 5, and 10 years after switch on. Results All recipients were successfully implanted with CIs with no difficulty in subsequent use with one reported case of re-implantation at 9 years after implantation. The aided hearing thresholds were significantly improved at one month after switch on (p < 0.0001) and remained stable afterwards for 10 years. Speech recognition scores were significantly higher than pre-operative results (p < 0.05) and continued to improve till 3 years after switch on. At 10 years post-operation, most subjects had improved QOL scores in most sub-items. Conclusions and Significance Nurotron Venus CI System provides long-term, stable results in hearing speech assistance capabilities and can improve the quality of life of CI recipients.

Investigation of a novel TBC1D24 variation causing autosomal dominant non-syndromic hearing loss.

Hearing loss is considered one of the most common sensory neurological defects, with approximately 60% of cases attributed to genetic factors. Human pathogenic variants in the TBC1D24 gene are associated with various clinical phenotypes, including dominant nonsyndromic hearing loss DFNA65, characterized by progressive hearing loss after the development of language. This study provides an in-depth analysis of the causative gene and mutations in a family with hereditary deafness. We recruited a three-generation family with autosomal dominant nonsyndromic hearing loss (ADNSHL) and conducted detailed medical histories and relevant examinations. Next-generation sequencing (NGS) was used to identify genetic variants in the proband, which were then validated using Sanger sequencing. Multiple computational software tools were employed to predict the impact of the variant on the function and structure of the TBC1D24 protein. A series of bioinformatics tools were applied to determine the conservation characteristics of the sequence, establish a three-dimensional structural model, and investigate changes in molecular dynamics. A detailed genotype and phenotype analysis were carried out. The family exhibited autosomal dominant, progressive, postlingual, and nonsyndromic sensorineural hearing loss. A novel heterozygous variant, c.1459C>T (p.His487Tyr), in the TBC1D24 gene was identified and confirmed to be associated with the hearing loss phenotype in this family. Conservation analysis revealed high conservation of the amino acid affected by this variant across different species. The mutant protein showed alterations in thermodynamic stability, elasticity, and conformational dynamics. Molecular dynamics simulations indicated changes in RMSD, RMSF, Rg, and SASA of the mutant structure. We computed the onset age of non-syndromic hearing loss associated with mutations in the TBC1D24 gene and identified variations in the hearing progression time and annual threshold deterioration across different frequencies. The identification of a new variant associated with rare autosomal dominant nonsyndromic hereditary hearing loss in this family broadens the range of mutations in the TBC1D24 gene. This variant has the potential to influence the interaction between the TLDc domain and TBC domain, thereby affecting the protein's biological function.

Retrospective Analysis of the Outcomes of Genetic Testing in Patients Suspected to Have Hereditary Hearing Loss or Deafness.

Uncorrected hearing loss can result in detrimental sequelae. Research addressing clinical presentation and genetic testing would inform clinical decision making. A retrospective chart review of 96 patients aged 1 month to 46 years (median age = 6 years) diagnosed with hearing loss or deafness and who underwent genetic testing at University of Rochester Medical Center from 2011 to 2021. Chi-square and Fisher's exact tests examined the relationship between a diagnostic positive genetic test result and various characteristics of hearing loss, including congenital (n = 52), noncongenital (n = 34), prelingual (n = 53), postlingual (n = 33), progressive (n = 13), not progressive (n = 47), bilateral (n = 67), unilateral (n = 26), sensorineural (n = 68), conductive (n = 14), mixed (n = 5), syndromic (n = 10), and nonsyndromic (n = 87) hearing loss. We also examined the number of patients with presence of developmental disabilities (n = 35), having a first-degree relative with hearing loss (n = 19), having hearing aids or cochlear implants (n = 45), and having a multisystem presentation prior to diagnosis (n = 45). Patients with sensorineural hearing loss (44.1%) had significantly more diagnostic positive results than those with mixed (0%) or conductive hearing loss (21.4%), p = .004. However, significantly fewer patients with disabilities (19.4%) had diagnostic positive tests than those without disabilities (43.3%), p < .05. More patients with a multisystem presentation were also found to have syndromic causes of hearing loss (23.3%) than patients who did not have a multisystem presentation, p < .05. Our study suggests a significant association between sensorineural type of hearing loss and a diagnostic positive genetic test result, while the presence of disabilities was significantly associated with a nondiagnostic genetic test result. Knowledge of these findings is critical for understanding the cause of the hearing loss, identifying other associated symptoms, and determining risk to family members.

Quality of life, hearing results, patient satisfaction and postoperative complications of day-case versus inpatient unilateral cochlear implantation in adults: a randomized controlled, equivalence trial

ObjectiveTo investigate the hypothesis that day-case cochlear implantation is associated with equal quality of life, hearing benefits and complications rates, compared to inpatient cochlear implantation.Study designA single-center, non-blinded, randomized controlled, equivalence trial in a tertiary referral center.MethodsThirty adult patients with post-lingual bilateral sensorineural hearing loss eligible for unilateral cochlear implantation surgery were randomly assigned to either the day-case or inpatient treatment group. The effect on general quality of life, patient satisfaction, (subjective) hearing improvement, postoperative complications and causes of crossover and/or readmission were assessed using questionnaires, auditory evaluations and patients’ charts over a follow-up period of 1 year.ResultsOverall quality of life measured by the HUI3 was equal between the day-case (n = 14) and inpatient group (n = 14). The overall patients’ satisfaction showed a slight favor towards an inpatient approach. There was no significant difference in the subjective and objective hearing improvement between both treatment groups. During the 1-year follow-up period no major complications occurred. Minor complications occurred intraoperatively in three day-case patients resulting in three out of nine admissions of day-case patients. Other causes of admission of day-case patients were nausea and vomiting (n = 1), drowsiness (n = 1), late scheduled surgery (n = 2), social reasons (n = 1), or due to an unclear reason (n = 1). No patients required readmission.ConclusionWe found equal outcomes of QoL, patient satisfaction, objective, and subjective hearing outcomes between day-case and inpatient unilateral cochlear implantation. Nine out of 14 day-case patients were admitted for at least one night postoperatively (crossover). No major complications occurred in both groups. A day-case approach seems feasible when using specific patient selection, surgical planning and the preoperative provision of patient information into account. Besides this, the familiarity with a day-case approach of both patient and the surgical team can increase the feasibility of day-case surgery.Level of evidence1.

Effect of Cochlear Implant Electrode Insertion Depth on Speech Perception Outcomes: A Systematic Review.

The suitable electrode array choice is broadly discussed in cochlear implantation surgery. Whether to use a shorter electrode length under the aim of structure preservation versus choosing a longer array to achieve a greater cochlear coverage is a matter of debate. The aim of this review is to identify the impact of the insertion depth of a cochlear implant (CI) electrode array on CI users' speech perception outcomes. PubMed was searched for English-language articles that were published in a peer-reviewed journal from 1997 to 2022. A systematic electronic search of the literature was carried out using PubMed to find relevant literature on the impact of insertion depth on speech perception. The review was conducted according to the preferred reporting items for systematic reviews and meta-analyses guidelines of reporting. Studies in both, children and adults with pre- or postlingual hearing loss, implanted with a CI were included in this study. Articles written in languages other than English, literature reviews, meta-analyses, animal studies, histopathological studies, or studies pertaining exclusively to imaging modalities without reporting correlations between insertion depth and speech outcomes were excluded. The risk of bias was determined using the "Risk of Bias in Nonrandomized Studies of Interventions" tool. Articles were extracted by 2 authors independently using predefined search terms. The titles and abstracts were screened manually to identify studies that potentially meet the inclusion criteria. The extracted information included: the study population, type of hearing loss, outcomes reported, devices used, speech perception outcomes, insertion depth (linear insertion depth and/or the angular insertion depth), and correlation between insertion depth and the speech perception outcomes. A total of 215 relevant studies were assessed for eligibility. Twenty-three studies met the inclusion criteria and were analyzed further. Seven studies found no significant correlation between insertion depth and speech perception outcomes. Fifteen found either a significant positive correlation or a positive effect between insertion depth and speech perception. Only 1 study found a significant negative correlation between insertion depth and speech perception outcomes. Although most studies reported a positive effect of insertion depth on speech perception outcomes, one-third of the identified studies reported no correlation. Thus, the insertion depth must be considered as a contributing factor to speech perception rather than as a major decisive criterion. This review has been registered in PROSPERO, the international prospective register of systematic reviews (CRD42021257547), available at https://www.crd.york.ac.uk/PROSPERO/.

Cochlear Implantation in the Poorer-Hearing Ear Is a Reasonable Choice.

Choosing the optimal side for cochlear implantation (CI) remains a major challenge because of the lack of evidence. We investigated the choice of the surgery side for CI (i.e., the better- or poorer-hearing ear) in patients with asymmetric hearing. Audiological records of 74 adults with a unilateral hearing aid who had undergone surgery at Okayama University Hospital were reviewed. The definition of 'better-hearing ear' was the aided ear, and the unaided ear was considered the poorer-hearing ear. We performed a multiple regression analysis to identify potential predictors of speech recognition performance after unilateral CI in the patients. Fifty-two patients underwent CI in the poorer-hearing ear. The post-Ci bimodal hearing rate was far higher in the poorer-ear group (77.8% vs. 22.2%). A multivariate analysis revealed that prelingual hearing loss and the patient's age at CI significantly affected the speech recognition outcome (beta coefficients: 24.6 and -0.33, 95% confidence intervals [11.75-37.45] and [-0.58 to -0.09], respectively), but the CI surgery side did not (-6.76, [-14.92-1.39]). Unilateral CI in the poorer-hearing ear may therefore be a reasonable choice for adult patients with postlingual severe hearing loss, providing a greater opportunity for postoperative bimodal hearing.

Electrically evoked compound action potentials in cochlear implant users with preoperative residual hearing.

Residual hearing in cochlear implant (CI) candidates requires the functional integrity of the nerve in particular regions of the cochlea. Nerve activity can be elicited as electrically evoked compound action potentials (ECAP) after cochlear implantation. We hypothesize that ECAP thresholds depend on preoperative residual hearing ability. In a retrospective study, we analyzed 84 adult cochlear implant users who had received a Nucleus® CI632 Slim Modiolar Electrode and who preoperatively had had residual hearing. Inclusion criteria were severe to profound hearing loss with preoperative measurable hearing in the ear to receive the implant, postlingual hearing loss, German as native language and correct placement of the electrode, inserted completely into the scala tympani. Electrically evoked compound action potential (ECAP) was recorded intraoperatively. The angular insertion was measured for each electrode contact from postoperative computed tomography to estimate the corresponding spiral ganglion frequency. Pure-tone audiometry and allocated ECAP thresholds were tested to investigate possible correlation. The average of hearing thresholds, tested at 0.5, 1, 2, and 4 kHz (4FPTA) was 82 ± 18 (range 47-129) dB HL. The success rate for recording ECAP thresholds was 96.9%. For all comparable pure-tone frequencies (1, 2, 4, and 8 kHz), there was significant correlation between preoperative hearing levels and intraoperative ECAP thresholds (p < 0.001). Higher hearing thresholds are associated with increased ECAP thresholds. In CI candidates with adequate residual hearing, intraoperative electrophysiological measurement records lower thresholds. This outcome may be explained by the neural survival density of the peripheral system, with less neural degeneration.

Long-term cognition and speech recognition outcomes after cochlear implantation in the elderly

ObjectiveThe purpose of this study is to investigate how cognition, as measured using the Self-Administered Gerocognitive Examination Test (SAGE), and age affect speech recognition scores in older adults (age > 65) at one year and two years after cochlear implantation. Study designThis is a prospective study. SettingThis study was conducted at a single institution. MethodsUnilateral cochlear implantation was performed by two surgeons on adult patients (>65 years) with postlingual bilateral sensorineural hearing loss. There were 230 patients who underwent cochlear implantation from January 2016 to June 2023. Fifty-five of these patients completed the SAGE questionnaire before implantation, one year after implantation, and 2 years after implantation. Paired t-test analysis was used to evaluate pre- and post-operative speech recognition scores (CNC, AzBio in Quiet). ResultsPatients who had normal preoperative cognition on SAGE showed greater improvement in postoperative speech recognition tests at 1 year and 2 years after implantation compared with patients who showed preoperative cognitive impairment. There were no significant differences in postoperative speech outcome between age group 1 (between 65 and 80 years old) and age group 2 (over 80 years old) cochlear implant recipients. There were no changes in cognitive SAGE scores after 2 years implantation. ConclusionCognitive function, as measured by SAGE, is a more reliable predictor than age in determining speech recognition improvement after cochlear implantation. Cochlear implantation did not improve postoperative cognition.