A frequency peak at 3.1 kHz obtained from the spectral analysis of the cochlear implant electrocochleography noise.

INTRODUCTION: The functional evaluation of auditory-nerve activity in spontaneous conditions has remained elusive in humans. In animals, the frequency analysis of the round-window electrical noise recorded by means of electrocochleography yields a frequency peak at around 900 to 1000 Hz, which has been proposed to reflect auditory-nerve spontaneous activity. Here, we studied the spectral components of the electrical noise obtained from cochlear implant electrocochleography in humans. METHODS: We recruited adult cochlear implant recipients from the Clinical Hospital of the Universidad de Chile, between the years 2021 and 2022. We used the AIM System from Advanced Bionics® to obtain single trial electrocochleography signals from the most apical electrode in cochlear implant users. We performed a protocol to study spontaneous activity and auditory responses to 0.5 and 2 kHz tones. RESULTS: Twenty subjects including 12 females, with a mean age of 57.9 ± 12.6 years (range between 36 and 78 years) were recruited. The electrical noise of the single trial cochlear implant electrocochleography signal yielded a reliable peak at 3.1 kHz in 55% of the cases (11 out of 20 subjects), while an oscillatory pattern that masked the spectrum was observed in seven cases. In the other two cases, the single-trial noise was not classifiable. Auditory stimulation at 0.5 kHz and 2.0 kHz did not change the amplitude of the 3.1 kHz frequency peak. CONCLUSION: We found two main types of noise patterns in the frequency analysis of the single-trial noise from cochlear implant electrocochleography, including a peak at 3.1 kHz that might reflect auditory-nerve spontaneous activity, while the oscillatory pattern probably corresponds to an artifact.

A Case Report of Riboflavin Treatment and Cochlear Implants in a 4-Year-Old Girl with Progressive Hearing Loss and Delayed Speech Development: Brown-Vialetto-Van Laere Syndrome.

BACKGROUND Brown-Vialetto-Van Laere (BVVL) syndrome is a rare autosomal recessive disorder caused by mutations in intestinal riboflavin transporter genes, resulting in a motor neuron disorder of childhood, which can be associated with sensorineural deafness. This report describes a 4-year-old Polish girl with progressive hearing loss and delayed speech development diagnosed with Brown-Vialetto-Van Laere syndrome who was treated with riboflavin (vitamin B2) and cochlear implants. CASE REPORT The case report concerns a girl from Poland who, at the age of 2 years 10 months, developed progressive atypical neurological symptoms of unknown etiology: ataxia of the upper and lower limbs, gait abnormalities, generalized muscle weakness, visual and hearing problems, and regression of speech development. A karyotype study (whole-exome sequencing) revealed alterations within SLC52A2, leading to the diagnosis of Brown-Vialetto-Van Laere syndrome and initiation of high-dose riboflavin treatment. As a 4-year-old child, she presented to the Institute of Physiology and Pathology of Hearing - World Hearing Center in Poland with progressive hearing loss and speech regression. Hearing tests revealed bilateral profound sensorineural hearing loss with auditory neuropathy. Surgical treatment was applied in the form of bilateral cochlear implantation. CONCLUSIONS This report shows the importance of genetic testing in infants who present with atypical symptoms or signs. In this case, the diagnosis of Brown-Vialetto-Van Laere syndrome resulted in timely correction of the genetic riboflavin (vitamin B2) deficiency and improved hearing following the use of cochlear implants.

Emotions and Psychological Mechanisms of Listening to Music in Cochlear Implant Recipients.

OBJECTIVES: Music is a multidimensional phenomenon and is classified by its arousal properties, emotional quality, and structural characteristics. Although structural features of music (i.e., pitch, timbre, and tempo) and music emotion recognition in cochlear implant (CI) recipients are popular research topics, music-evoked emotions, and related psychological mechanisms that reflect both the individual and social context of music are largely ignored. Understanding the music-evoked emotions (the "what") and related mechanisms (the "why") can help professionals and CI recipients better comprehend the impact of music on CI recipients' daily lives. Therefore, the purpose of this study is to evaluate these aspects in CI recipients and compare their findings to those of normal hearing (NH) controls. DESIGN: This study included 50 CI recipients with diverse auditory experiences who were prelingually deafened (deafened at or before 6 years of age)-early implanted (N = 21), prelingually deafened-late implanted (implanted at or after 12 years of age-N = 13), and postlingually deafened (N = 16) as well as 50 age-matched NH controls. All participants completed the same survey, which included 28 emotions and 10 mechanisms (Brainstem reflex, Rhythmic entrainment, Evaluative Conditioning, Contagion, Visual imagery, Episodic memory, Musical expectancy, Aesthetic judgment, Cognitive appraisal, and Lyrics). Data were presented in detail for CI groups and compared between CI groups and between CI and NH groups. RESULTS: The principal component analysis showed five emotion factors that are explained by 63.4% of the total variance, including anxiety and anger, happiness and pride, sadness and pain, sympathy and tenderness, and serenity and satisfaction in the CI group. Positive emotions such as happiness, tranquility, love, joy, and trust ranked as most often experienced in all groups, whereas negative and complex emotions such as guilt, fear, anger, and anxiety ranked lowest. The CI group ranked lyrics and rhythmic entrainment highest in the emotion mechanism, and there was a statistically significant group difference in the episodic memory mechanism, in which the prelingually deafened, early implanted group scored the lowest. CONCLUSION: Our findings indicate that music can evoke similar emotions in CI recipients with diverse auditory experiences as it does in NH individuals. However, prelingually deafened and early implanted individuals lack autobiographical memories associated with music, which affects the feelings evoked by music. In addition, the preference for rhythmic entrainment and lyrics as mechanisms of music-elicited emotions suggests that rehabilitation programs should pay particular attention to these cues.

A State-of-the-Art Method for Preserving Residual Hearing During Cochlear Implant Surgery.

The developments in surgical techniques and cochlear implant (CI) electrode design have expanded the indications for CI treatment. Currently, patients with high-frequency hearing loss may benefit from CIs when low-frequency residual hearing can be preserved, as this enables combined electric-acoustic stimulation (EAS). The possible benefits of EAS include, for example, improved sound quality, music perception, and speech intelligibility in noise. The risks of inner ear trauma and a deterioration or even complete loss of residual hearing vary according to the surgical technique and the type of electrode array used. Short, lateral-wall electrodes with shallower angular insertion depths have demonstrated higher rates of hearing preservation than longer electrodes. The very slow insertion of the electrode array through the round window of the cochlea contributes to insertion atraumaticity and, thus, may lead to favorable hearing preservation results. However, residual hearing can be lost even after an atraumatic insertion. Electrocochleography (ECochG) can be used to monitor inner ear hair cell function during the insertion of the electrode. Several investigators have demonstrated that the ECochG responses during surgery may predict postoperative hearing preservation results. In a recent study, we correlated the patients' subjective hearing perception with simultaneously recorded intracochlear ECochG responses during the insertion. This is the first report evaluating the association between intraoperative ECochG responses and hearing perception in a subject undergoing cochlear implantation under local anesthesia without sedation. The combination of intraoperative ECochG responses with the patient's real-time feedback to sound stimuli has excellent sensitivity for the intraoperative monitoring of cochlear function. This paper presents a state-of-the-art method for the preservation of residual hearing during CI surgery. We describe this treatment procedure with the special consideration of performing the surgery under local anesthesia, which makes it feasible for monitoring the patient's hearing during the insertion of the electrode array.

Acceptance and Benefit of Electroacoustic Stimulation in Children.

OBJECTIVE: Children with high-frequency severe-to-profound hearing loss and low-frequency residual hearing who do not derive significant benefit from hearing aids are now being considered for cochlear implantation. Previous research shows that hearing preservation is possible and may be desirable for the use of electroacoustic stimulation (EAS) in adults, but this topic remains underexplored in children. The goal of this study was to explore factors relating to hearing preservation, acceptance, and benefits of EAS for children. STUDY DESIGN: Retrospective review. SETTING: Tertiary academic medical center. PATIENTS: Forty children (48 ears) with preoperative low-frequency pure-tone averages of 75 dB HL or less at 250 and 500 Hz (n = 48). INTERVENTION: All patients underwent cochlear implantation with a standard-length electrode. MAIN OUTCOME MEASURE: Low-frequency audiometric thresholds, speech perception, and EAS usage were measured at initial stimulation, and 3 and 12 months postoperatively. Outcomes were compared between children with and without hearing preservation, and between EAS users and nonusers. RESULTS: Hearing was preserved at similar rates as adults but worse for children with an enlarged vestibular aqueduct. Fewer than half of children who qualified to use EAS chose to do so, citing a variety of audiologic and nonaudiologic reasons. No differences were detected in speech perception scores across the groups for words, sentences, or sentences in noise tests. CONCLUSIONS: Neither hearing preservation nor EAS use resulted in superior speech perception in children with preoperative residual hearing; rather, all children performed well after implantation.

[Cochlear implantation - Adverse effects on the cochlea and the vestibular organ]. / Cochlea-Implantation.

Cochlear implantation is the treatment of choice for patients with profound hearing loss and deafness. At the same time, inserting a cochlear implant (CI) leaves damage to the inner ear. The preservation of inner ear structure and function has become a central issue in CI surgery. The reasons for this are i) electroacoustic stimulation (EAS), i.e., the option of joint stimulation by a hearing aid and a CI; ii) an improved audiologic outcome in electric-only stimulation; iii) the preservation of structures and residual hearing for potential future therapy options; and iv) the avoidance of side effects, such as vertigo. The exact mechanisms that determine the extent of damage to the inner ear and which factors contribute to preservation of residual hearing are not yet fully understood. In addition to the surgical technique, electrode selection may play a role. This article provides an overview of what is known about the direct and indirect adverse effects of cochlear implantation on the inner ear, of the methods available to monitor inner ear function during cochlear implantation, and of the focus of future research on preservation of inner ear structure and function.

Cochlear Implants in Deaf Patients with Novel TMPRSS3 Gene Mutation.

Objective: To investigate the effect of cochlear implants in deaf patients with TMPRSS3 gene pathogenic variations. Methods: Variations of deafness genes were detected in 2 patients with profound hearing loss. Both received unilateral cochlear implantation. Hearing and speech abilities were evaluated and analyzed before and 3 and 6 months after surgery. The analysis included post-surgery evaluation of auditory behavior (Categories of Performance [CAP]) and Speech Intelligibility Rating (SIR). Results: In the 2 patients, 3 pathogenic single nucleotide variations (SNVs) of TMPRSS3 gene and a large deletion in 21q22.3 were detected. The CAP and SIR grades increased with the recovery time. Conclusion: Cochlear implants have a good effect in patients with TMPRSS3 gene mutation deafness. Preoperative gene testing has a certain reference significance for the prognosis in patients with the deafness gene mutation.

Auditory evoked response to an oddball paradigm in children wearing cochlear implants.

OBJECTIVE: Although children with cochlear implants (CI) achieve remarkable success with their device, considerable variability remains in individual outcomes. Here, we explored whether auditory evoked potentials recorded during an oddball paradigm could provide useful markers of auditory processing in this pediatric population. METHODS: High-density electroencephalography (EEG) was recorded in 75 children listening to standard and odd noise stimuli: 25 had normal hearing (NH) and 50 wore a CI, divided between high language (HL) and low language (LL) abilities. Three metrics were extracted: the first negative and second positive components of the standard waveform (N1-P2 complex) close to the vertex, the mismatch negativity (MMN) around Fz and the late positive component (P3) around Pz of the difference waveform. RESULTS: While children with CIs generally exhibited a well-formed N1-P2 complex, those with language delays typically lacked reliable MMN and P3 components. But many children with CIs with age-appropriate skills showed MMN and P3 responses similar to those of NH children. Moreover, larger and earlier P3 (but not MMN) was linked to better literacy skills. CONCLUSIONS: Auditory evoked responses differentiated children with CIs based on their good or poor skills with language and literacy. SIGNIFICANCE: This short paradigm could eventually serve as a clinical tool for tracking the developmental outcomes of implanted children.

Influence of Electric Frequency-to-Place Mismatches on the Early Speech Recognition Outcomes for Electric-Acoustic Stimulation Users.

PURPOSE: Cochlear implant (CI) recipients with hearing preservation experience significant improvements in speech recognition with electric-acoustic stimulation (EAS) as compared to with a CI alone, although outcomes across EAS users vary. The individual differences in performance may be due in part to default mapping procedures, which result in electric frequency-to-place mismatches for the majority of EAS users. This study assessed the influence of electric mismatches on the early speech recognition for EAS users. METHOD: Twenty-one participants were randomized at EAS activation to listen exclusively with a default or place-based map. For both groups, the unaided thresholds determined the acoustic cutoff frequency (i.e., > 65 dB HL). For default maps, the electric filter frequencies were assigned to avoid spectral gaps in frequency information but created varying magnitudes of mismatches. For place-based maps, the electric filter frequencies were assigned to avoid frequency-to-place mismatches. Recognition of consonant-nucleus-consonant words and vowels was assessed at activation and 1, 3, and 6 months postactivation. RESULTS: For participants with default maps, electric mismatch at 1500 Hz ranged from 2 to -12.0 semitones (Mdn = -5 semitones). Poorer performance was observed for those with larger magnitudes of electric mismatch. This effect was observed through 6 months of EAS listening experience. CONCLUSIONS: The present sample of EAS users experienced better initial performance when electric mismatches were small or eliminated. These data suggest the utility of methods that reduce electric mismatches, such as place-based mapping procedures. Investigation is ongoing to determine whether these differences persist with long-term EAS use. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.22096523.

Longitudinal Electrocochleography as an Objective Measure of Serial Behavioral Audiometry in Electro-Acoustic Stimulation Patients.

OBJECTIVE: Minimally traumatic surgical techniques and advances in cochlear implant (CI) electrode array designs have allowed acoustic hearing present in a CI candidate prior to surgery to be preserved postoperatively. As a result, these patients benefit from combined electric-acoustic stimulation (EAS) postoperatively. However, 30% to 40% of EAS CI users experience a partial loss of hearing up to 30 dB after surgery. This additional hearing loss is generally not severe enough to preclude use of acoustic amplification; however, it can still impact EAS benefits. The use of electrocochleography (ECoG) measures of peripheral hair cell and neural auditory function have shed insight into the pathophysiology of postimplant loss of residual acoustic hearing. The present study aims to assess the long-term stability of ECoG measures and to establish ECoG as an objective method of monitoring residual hearing over the course of EAS CI use. We hypothesize that repeated measures of ECoG should remain stable over time for EAS CI users with stable postoperative hearing preservation. We also hypothesize that changes in behavioral audiometry for EAS CI users with loss of residual hearing should also be reflected in changes in ECoG measures. DESIGN: A pool of 40 subjects implanted under hearing preservation protocol was included in the study. Subjects were seen at postoperative visits for behavioral audiometry and ECoG recordings. Test sessions occurred 0.5, 1, 3, 6, 12 months, and annually after 12 months postoperatively. Changes in pure-tone behavioral audiometric thresholds relative to baseline were used to classify subjects into two groups: one group with stable acoustic hearing and another group with loss of acoustic hearing. At each test session, ECoG amplitude growth functions for several low-frequency stimuli were obtained. The threshold, slope, and suprathreshold amplitude at a fixed stimulation level was obtained from each growth function at each time point. Longitudinal linear mixed effects models were used to study trends in ECoG thresholds, slopes, and amplitudes for subjects with stable hearing and subjects with hearing loss. RESULTS: Preoperative, behavioral audiometry indicated that subjects had an average low-frequency pure-tone average (125 to 500 Hz) of 40.88 ± 13.12 dB HL. Postoperatively, results showed that ECoG thresholds and amplitudes were stable in EAS CI users with preserved residual hearing. ECoG thresholds increased (worsened) while ECoG amplitudes decreased (worsened) for those with delayed hearing loss. The slope did not distinguish between EAS CI users with stable hearing and subjects with delayed loss of hearing. CONCLUSIONS: These results provide a new application of postoperative ECoG as an objective tool to monitor residual hearing and understand the pathophysiology of delayed hearing loss. While our measures were conducted with custom-designed in-house equipment, CI companies are also designing and implementing hardware and software adaptations to conduct ECoG recordings. Thus, postoperative ECoG recordings can potentially be integrated into clinical practice.

Cochlear Implantation for Unilateral and Asymmetric Hearing Loss: Long-Term Subjective Benefit.

OBJECTIVES: Assess the long-term patterns of perceived tinnitus severity and subjective benefit for adult cochlear implant (CI) users with asymmetric or unilateral hearing loss (AHL or UHL). METHODS: Forty adults underwent cochlear implantation as part of a prospective clinical trial assessing the outcomes of CI use in cases of AHL (n = 20) and UHL (n = 20). Subjective measures included the Tinnitus Handicap Inventory (THI), the Speech, Spatial, & Qualities of Hearing Scale (SSQ), and the Abbreviated Profile of Hearing Aid Benefit (APHAB). Responses were obtained preoperatively and at routine intervals out to 5 years post-activation. RESULTS: For subjective benefit, participants with AHL and UHL reported a significant improvement as compared to preoperative abilities, which was maintained with long-term CI use. For perceived tinnitus severity, participants with AHL and UHL reported a significant reduction with CI use as compared to preoperative perceptions. The perceived tinnitus severity significantly differed for the AHL and UHL cohorts over time. This pattern of results is likely influenced by the worse perceived severity levels for the UHL cohort preoperatively and the fluctuating perceived severity levels for some participants in the AHL cohort post-activation. CONCLUSION: Adults with AHL and UHL report an early, significant reduction in perceived tinnitus severity and improvement in quality of life with CI use that is generally maintained with long-term device use. Questionnaires such as the THI, SSQ, and APHAB may contribute to a more holistic assessment of the benefits of cochlear implantation in this population. LEVEL OF EVIDENCE: 2 Laryngoscope, 133:2792-2797, 2023.

Common challenges in cochlear implant surgery performed under local anaesthesia and how to overcome them: the experience of UK surgeons.

BACKGROUND: Cochlear implantation performed under local anaesthesia is an increasingly accepted technique worldwide, though the literature to date includes only single-surgeon and single-centre experiences. This study explored the national experience of UK surgeons using this challenging surgical technique, with the goal of providing consensus recommendations. METHODS: A qualitative analysis was conducted of semi-structured interviews with 10 UK-based cochlear implantation surgeons, focusing on common challenges, how to overcome them and candidate selection. RESULTS: Cochlear implantation under local anaesthesia can potentially be offered to all eligible adult patients with favourable anatomy. A posterior tympanotomy and round window approach is recommended. Common challenges and recommendations are explored thematically: managing patient, surgeon and staff expectations; optimising communication; patient comfort and position; minimising pain and vertigo; and safe use of sedation. CONCLUSION: This is the first study of national experience of cochlear implantation performed under local anaesthesia. Key themes, including refinements to surgical technique and optimising patient comfort and communication, have been explored in depth.

Evaluation of auditory pathway excitability using a pre-operative trans-tympanic electrically evoked auditory brainstem response under local anesthesia in cochlear implant candidates.

OBJECTIVE: Subjective promontory stimulation is used to evaluate cochlear implant (CI) candidacy, but the test reliability is low. Electrically evoked auditory brainstem response (EABR) can verify the function of the auditory system objectively. This study's procedure uses a trans-tympanic rounded bent-tip electrode to perform pre-operative EABR under local anaesthesia (LA-TT-EABR) using MED-EL Software and Hardware. This study aimed to determine usability and effectiveness for CI candidates. DESIGN: We hypothesised that LA-TT-EABR waveforms of good quality would be related to successful hearing outcomes. We assumed that the duration of hearing loss/deafness was a confounding factor to study outcomes. STUDY SAMPLE: 19 borderline CI candidates. RESULTS: Positive LA-TT-EABR results were confirmed in 14 patients. LA-TT-EABR's mean latency was 2.05 ± 0.31 ms (eII/eIII) and 4.24 ± 0.39 ms (eIV/eV). Latencies weren't statistically different from intra-operative EABR elicited by basal CI contacts. All positive LA-TT-EABR patients benefitted from CI and speech performance improved one year after implantation. One patient with negative LA-TT-EABR was cochlear-implanted and had no hearing sensation. CONCLUSIONS: LA-TT-EABR is a tool in the frame of pre-operative objective testing the auditory pathway. It seems useful for clinical testing CI candidacy. Based on this study's outcomes, LA-TT-EABR should be recommended for uncertain CI candidates.

The Relationship Between Interaural Insertion-Depth Differences, Scalar Location, and Interaural Time-Difference Processing in Adult Bilateral Cochlear-Implant Listeners.

Sensitivity to interaural time differences (ITDs) in acoustic hearing involves comparison of interaurally frequency-matched inputs. Bilateral cochlear-implant arrays are, however, only approximately aligned in angular insertion depth and scalar location across the cochleae. Interaural place-of-stimulation mismatch therefore has the potential to impact binaural perception. ITD left-right discrimination thresholds were examined in 23 postlingually-deafened adult bilateral cochlear-implant listeners, using low-rate constant-amplitude pulse trains presented via direct stimulation to single electrodes in each ear. Angular insertion depth and scalar location measured from computed-tomography (CT) scans were used to quantify interaural mismatch, and their association with binaural performance was assessed. Number-matched electrodes displayed a median interaural insertion-depth mismatch of 18° and generally yielded best or near-best ITD discrimination thresholds. Two listeners whose discrimination thresholds did not show this pattern were confirmed via CT to have atypical array placement. Listeners with more number-matched electrode pairs located in the scala tympani displayed better thresholds than listeners with fewer such pairs. ITD tuning curves as a function of interaural electrode separation were broad; bandwidths at twice the threshold minimum averaged 10.5 electrodes (equivalent to 5.9 mm for a Cochlear-brand pre-curved array). Larger angular insertion-depth differences were associated with wider bandwidths. Wide ITD tuning curve bandwidths appear to be a product of both monopolar stimulation and angular insertion-depth mismatch. Cases of good ITD sensitivity with very wide bandwidths suggest that precise matching of insertion depth is not critical for discrimination thresholds. Further prioritizing scala tympani location at implantation should, however, benefit ITD sensitivity.

A Computational Model of a Single Auditory Nerve Fiber for Electric-Acoustic Stimulation.

Cochlear implant (CI) recipients with preserved acoustic low-frequency hearing in the implanted ear are a growing group among traditional CI users who benefit from hybrid electric-acoustic stimulation (EAS). However, combined ipsilateral electric and acoustic stimulation also introduces interactions between the two modalities that can affect the performance of EAS users. A computational model of a single auditory nerve fiber that is excited by EAS was developed to study the interaction between electric and acoustic stimulation. Two existing models of sole electric or acoustic stimulation were coupled to simulate responses to combined EAS. Different methods of combining both models were implemented. In the coupled model variant, the refractoriness of the simulated fiber leads to suppressive interaction between electrically evoked and acoustically evoked spikes as well as spontaneous activity. The second model variant is an uncoupled EAS model without electric-acoustic interaction. By comparing predictions between the coupled and the noninteracting EAS model, it was possible to infer electric-acoustic interaction at the level of the auditory nerve. The EAS model was used to simulate fiber populations with realistic inter-unit variability, where each unit was represented by the single-fiber model. Predicted thresholds and dynamic ranges, spike rates, latencies, jitter, and vector strengths were compared to empirical data. The presented EAS model provides a framework for future studies of peripheral electric-acoustic interaction.

Electrophysiological Examination of Ambient Speech Processing in Children With Cochlear Implants.

PURPOSE: This research examined the expression of cortical auditory evoked potentials in a cohort of children who received cochlear implants (CIs) for treatment of congenital deafness (n = 28) and typically hearing controls (n = 28). METHOD: We make use of a novel electroencephalography paradigm that permits the assessment of auditory responses to ambiently presented speech and evaluates the contributions of concurrent visual stimulation on this activity. RESULTS: Our findings show group differences in the expression of auditory sensory and perceptual event-related potential components occurring in 80- to 200-ms and 200- to 300-ms time windows, with reductions in amplitude and a greater latency difference for CI-using children. Relative to typically hearing children, current source density analysis showed muted responses to concurrent visual stimulation in CI-using children, suggesting less cortical specialization and/or reduced responsiveness to auditory information that limits the detection of the interaction between sensory systems. CONCLUSION: These findings indicate that even in the face of early interventions, CI-using children may exhibit disruptions in the development of auditory and multisensory processing.

Cochlear implantation for paediatric and adult cases of unilateral and asymmetric hearing loss.

PURPOSE OF REVIEW: Children and adults with unilateral or asymmetric hearing loss (UHL/AHL) have poorer spatial hearing (e.g. speech understanding in complex maskers and localization) and quality of life compared with peers with normal hearing bilaterally. Patients with UHL/AHL experience limited benefits with contralateral-routing technologies (e.g. bone conduction, CROS hearing aid systems). Cochlear implantation allows for stimulation of the auditory pathway for the poorer hearing ear. The present study reviews the recent literature on outcomes of cochlear implant use for recipients with UHL/AHL. RECENT FINDINGS: Recent research corroborates previous investigations of the significant benefits on measures of spatial hearing, tinnitus severity and quality of life for adult cochlear implant recipients. These benefits are also observed in pediatric cochlear implant recipients, with an association of better outcomes with younger ages at implantation for congenital cases and shorter durations of UHL/AHL for acquired cases. In addition, randomized trials demonstrate better outcomes with cochlear implant use versus contralateral-routing technologies. SUMMARY: Cochlear implantation supports better spatial hearing and quality of life in children and adults with UHL/AHL as compared to alternative listening conditions. Current research supports the expansion of candidacy criteria and insurance coverage for cochlear implantation for patients with UHL/AHL to improve their binaural hearing.

In an era of bilateral funding and changing criteria, when is unilateral cochlear implantation a better option?

BACKGROUND: Funding for paediatric bilateral cochlear implantation became available in Ireland in 2014. Prior to this, children eligible for cochlear implantation received a unilateral implant. OBJECTIVE: To examine the cohort of children who received a unilateral cochlear implant in the 4 year period following bilateral cochlear implantation funding becoming available. METHODS: A clinical audit of all children implanted for the first time between July 2014 and July 2018. The unilaterally implanted children (n = 105) were divided into 3 groups according to whether they met the audiometric thresholds for implantation in neither ear (Group 1), one ear (Group 2) or both ears (Group 3). One year post operative functional outcomes were examined for all 3 groups. RESULTS: All 3 groups showed significant improvements in functional outcomes at 1 year post op. To date, 20% of the unilaterally implanted children have proceeded to get a sequential CI, often where there was no change in audiological status. CONCLUSIONS: The number of children in Groups 1 and 2 highlighted how our decision making around cochlear implantation has changed in recent years. Unilateral cochlear implantation in certain circumstances is good practice, independent of the audiological profile when an experienced multi-disciplinary team (MDT) is involved in the decision making process. Decision making using a holistic model approach is key, including involving the parent/carer and, where appropriate, the child/teenager themselves. A staged bilateral cochlear implant is also a good option, where careful monitoring and support for the first implant has resulted in positive outcomes.