Benefits of Cochlear Implantation for Older Adults With Asymmetric Hearing Loss.

OBJECTIVE(S): FDA-approved indications for cochlear implantation include patients with severe-to-profound unilateral hearing loss (UHL) or asymmetric hearing loss (AHL); however, these indications are not covered for Medicare beneficiaries. We assessed the outcomes of cochlear implant (CI) use for older adults with UHL or AHL. METHODS: Eighteen older adults (≥65 years of age at surgery) with UHL/AHL participated in a prospective, longitudinal investigation evaluating outcomes of CI use. Speech recognition for the affected ear was evaluated with consonant-nucleus-consonant (CNC) words. Spatial hearing was assessed with measures of sound source localization and sentence recognition in noise. The target sentence was presented from the front and the masker was either co-located with the target (SoNo), presented toward the affected ear (SoNci) or contralateral ear (SoNcontra). Perceived benefit was assessed with the Speech, Spatial, and Qualities of Hearing scale (SSQ) and the Tinnitus Handicap Inventory (THI). RESULTS: Participants experienced significant improvements with CI use for CNC words (mean [SD]; preop: 8% [10%], 1 yr: 51% [22%], 5 yr: 50% [19%]), masked sentence recognition (SoNcontra preop: 5% [6%], 1 yr: 22% [15%], 5 yr: 41% [14%]), and localization (preop: 76° [18°], 1 yr: 40° [11°], 5 yr: 41° [14°]), and reported significant improvements in hearing abilities (SSQ Spatial Hearing preop: 3 [1], 1 yr: 6 [2], 5 yr: 6 [2]) and tinnitus severity (THI preop: 16 [18], 1 yr: 4 [14], 5 yr: 6 [12]). CONCLUSION: Older adults with UHL/AHL experience significant improvements in speech recognition, spatial hearing, and subjective perceptions (e.g., hearing abilities and tinnitus severity) with a CI as compared to pre-operative abilities. LEVEL OF EVIDENCE: IV Laryngoscope, 2024.

Management of Cochlear Implant Electrode Arrays Misplaced in the Internal Auditory Canal: A Systematic Review.

OBJECTIVE: Misplacement of electrode arrays in the internal auditory canal (IAC) presents a unique clinical challenge. Speech recognition is limited for cochlear implant (CI) users with misplaced arrays, and there are risks with revision surgery including facial and/or cochlear nerve injury. DATABASES REVIEWED: PubMed, Embase, and Scopus. METHODS: A literature search was performed from inception to September 2023. The search terms were designed to capture articles on misplaced arrays and the management options. Articles written in English that described cases of array misplacement into the IAC for children and adults were included. The level of evidence was assessed using Oxford Center for Evidence Based Medicine guidelines. Descriptive statistical analyses were performed. RESULTS: Twenty-eight cases of arrays misplaced in the IAC were identified. Thirteen (46%) were patients with incomplete partition type 3 (IP3), and 7 (25%) were patients with common cavity (CC) malformations. Most misplaced arrays were identified postoperatively (19 cases; 68%). Of these cases, 11 (58%) were managed with array removal. No facial nerve injuries were reported with revision surgery. Eight cases (42%) were left in place. Several underwent mapping procedures in an attempt improve the sound quality with the CI. CONCLUSION: Electrode array misplacement in the IAC is a rare complication that reportedly occurs predominately in cases with IP3 and CC malformations. Removal of misplaced arrays from the IAC reportedly has not been associated with facial nerve injuries. Cases identified with IAC misplacement postoperatively can potentially be managed with modified mapping techniques before proceeding with revision surgery.

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.

Frequency Mapping of a Precurved Electrode Array in the Internal Auditory Canal for a Pediatric Cochlear Implant Recipient.

OBJECTIVES: Review the effectiveness of an alternative mapping procedure of a precurved electrode array in the internal auditory canal (IAC). DESIGN: A 7-year-old bilateral cochlear implant (CI) recipient of precurved arrays transferred to the study site and demonstrated no speech recognition with the left CI. Imaging revealed bilateral incomplete partition type III malformations. For the left CI, four contacts were observed in the basal cochlear turn and 18 contacts were coiled in the IAC. The family decided against revision surgery. Pitch ranking was completed to map the contacts in the IAC that were perceptually discrete and tonotopically organized. RESULTS: For the left CI, PB-K word recognition improved from no recognition to 32% after 1 month and to 52% after 3 months. In the bilateral CI condition, performance improved from 56 to 72% after 1 month and 80% after 3 months. CONCLUSION: A precurved array in the IAC creates difficult management decisions. Direct stimulation of the auditory nerve resulted in better monaural and bilateral speech recognition, likely due to better spectral representation of the speech signal. Individualizing the map using imaging and behavioral findings may improve performance for malpositioned arrays when revision surgery is not pursued.

Assessing Cochlear Implant Insertion Angle From an Intraoperative X-ray Using a Rotating 3D Helical Scala Tympani Model.

BACKGROUND: Angular insertion depth (AID) of the electrode array provides valuable information regarding intracochlear positioning, which can be used to predict outcomes and optimize performance. While computed tomography (CT) offers high-resolution imaging, there is a need to develop technology to accurately determine AID from intraoperative x-rays acquired at unknown angles. METHODS: An algorithm was developed using a three-dimensional model of the scala tympani to estimate AID from an x-ray acquired at an unknown angle. The model is manipulated over the x-ray until the projection angle is inferred and the location of the round window and individual electrode contacts are identified. Validation of the algorithm involved 1) assessing accuracy with deviation from cochlear view by comparing AID determined with simulated x-rays to those determined with CT in a temporal bone model, and 2) assessing reproducibility in the clinical setting, by comparing intra- and inter-rater reliability with intraoperative x-ray in cochlear implant (CI) recipients, which were subsequently compared to AID determined with postoperative CT. RESULTS: Estimates of AID from x-rays were generally within 10 degrees of CT regardless of deviation from cochlear view. Excluding two outliers with poor imaging quality, the intraclass correlation coefficients for intra- and inter-rater reliability were excellent (0.991 and 0.980, respectively). CONCLUSION: With intraoperative x-rays of sufficient quality, the helical scala tympani model can be used to accurately and reliably determine AID without the need to specify a preferred image angle. The application can therefore be used in most CI recipients when a postoperative CT is not available.

Subjective Benefits of Bimodal Listening in Cochlear Implant Recipients with Asymmetric Hearing Loss.

OBJECTIVE: To investigate the influence of cochlear implant (CI) use on subjective benefits in quality of life in cases of asymmetric hearing loss (AHL). STUDY DESIGN: Prospective clinical trial. SETTING: Tertiary academic center. SUBJECTS AND METHODS: Subjects included CI recipients with AHL (n = 20), defined as moderate-to-profound hearing loss in the affected ear and mild-to-moderate hearing loss in the contralateral ear. Quality of life was assessed with the Speech, Spatial, and Qualities of Hearing Scale (SSQ) pragmatic subscales, which assess binaural benefits. Subjective benefit on the pragmatic subscales was compared to word recognition in quiet and spatial hearing abilities (ie, masked sentence recognition and localization). RESULTS: Subjects demonstrated an early, significant improvement (P < .01) in abilities with the CI as compared to preoperative abilities on the SSQ pragmatic subscales by the 1-month interval. Perceived abilities were either maintained or continued to improve over the study period. There were no significant correlations between results on the Speech in Quiet subscale and word recognition in quiet, the Speech in Speech Contexts subscale and masked sentence recognition, or the Localization subscale and sound field localization. CONCLUSIONS: CI recipients with AHL report a significant improvement in quality of life as measured by the SSQ pragmatic subscales over preoperative abilities. Reported improvements are observed as early as 1 month postactivation, which likely reflect the binaural benefits of listening with bimodal stimulation (CI and contralateral hearing aid). The SSQ pragmatic subscales may provide a more in-depth insight into CI recipient experience as compared to behavioral sound field measures alone.

Translabyrinthine Excision of Vestibular Schwannoma with Concurrent Cochlear Implantation: Systematic Review.

Objectives Hearing rehabilitation is an important management aspect of patients undergoing excision of vestibular schwannomas. Studies have shown cochlear implantation (CI) is possible at the time of tumor excision via a translabyrinthine approach. Primary objectives of this report are (1) to review prospective studies pertaining to outcomes of concurrent CI and translabyrinthine tumor removal in detail and (2) perform an aggregate analysis of outcomes for case reports and series. Design Systematic review based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Setting Review of literature using PubMed and Cochrane databases. Participants Eligibility included patients undergoing translabyrinthine excision of vestibular schwannoma with concurrent CI. Main Outcome Measures Open-set speech discrimination scores, sound localization, patient-reported outcome measures. Results Forty-one subjects were identified. Two prospective studies have been performed, which showed improvement in speech localization and patient-reported outcome measures. While the majority of patients achieved open set speech recognition, data pertaining to improvement in speech perception were variable. Approximately 85% of subjects had audibility with their CI. Of those that achieved open-set speech discrimination, 75% could be classified as either intermediate or high performers. The majority of low performers in open-set speech either endorsed subjective benefit or demonstrated improvement compared to preoperative measures. There was a high risk of selection and reporting bias. Conclusions The majority of patients undergoing translabyrinthine excision of vestibular schwannoma with concurrent CI achieve open set speech perception, with 75% of these patients meeting criteria for being intermediate to high performers. Additional benefits include improved subjective hearing measures, decreased tinnitus, and improved sound localization.

Reconstruction Outcomes Following Lateral Skull Base Resection.

OBJECTIVE: Compare reconstruction outcomes for various lateral skull base closure techniques. STUDY DESIGN: Retrospective medical records review. SETTING: University-based tertiary referral center. PATIENTS: Patients who underwent resections of tumors involving the lateral skull base requiring reconstruction beyond primary closure. INTERVENTION(S): Reconstructive techniques, from rotational flaps to free tissue transfer. MAIN OUTCOME MEASURE(S): Outcome data including wound complications, cerebrospinal fluid (CSF) leakage, and need for surgical revision were tabulated. RESULTS: Eighty-six patients underwent lateral skull base tumor resection and reconstruction. Procedures were primarily lateral temporal bone resections but also included subtotal temporal bone, total temporal bone, and infratemporal fossa resections. Cutaneous malignancy was the most common resection indication (83%) and the temporalis rotational flap was the most commonly employed reconstructive option (30%). When free tissue transfer techniques were used, the radial forearm, anterolateral thigh, and latissimus dorsi were the most frequent donor sites. Patients with T2 disease were more likely to undergo temporalis flaps, whereas patients with T4 disease were more likely to undergo free flap reconstruction. Major complications were uncommon (∼8%), the most frequent being stroke (∼3%). The postoperative wound complication rate was approximately 45%. The majority involved minor dehiscences and were managed conservatively. Patients with T4 disease were more likely to have wound complications (p < 0.05). Radial forearm free flaps were less likely to have wound complications when compared with other reconstruction techniques (p < 0.05). CONCLUSIONS: Many factors go into planning lateral skull base reconstruction. Free flaps were more often used for T4 disease. Radial forearm free flaps tended to have lower wound complication rates when compared with other techniques.