Revision Cochlear Implantation With Device Manufacturer Conversion: Surgical Outcomes and Speech Perception Performance.

OBJECTIVE: Describe the clinical profile of revision cochlear implantation (RCI) cases involving device manufacturer conversion (RCImc+), compare them to cases without manufacturer conversion (RCImc-), and classify the reasons for manufacturer conversion (MC). STUDY DESIGN: Retrospective case review. SETTING: Tertiary academic center. METHODS: Data on demographics, RCI indications, medical background, surgical details, and the reasons for MC were collected for all RCIs from 1989 to 2020. Post-RCI speech perception performance was categorized as unchanged, improved, or declined, according to clinically based criteria. RESULTS: Of 185 RCIs, 39 (21%) involved MC, mostly in pediatric patients (67%). The leading RCImc+ indications were device-related (59%) and medical (31%) failures. Initial implant manufacturers were Advanced Bionics (49%), Cochlear (25.5%), or Medel (25.5%). Most MC reasons were patient-driven (64%) versus CI team recommendations (36%). The RCImc+ group demonstrated a 3-fold higher rate of medical indications than RCImc- (31% vs 11.5%, P = .007). The time interval from symptom onset to RCI was longer in RCImc+ (43 vs 20.3 months, P = .001), and the rate of multiple revisions in the same ear was higher (25.6% vs 8.2%, P = .009). Complete reinsertion rates were high in both RCImc+ and RCImc- (94.8% vs 94.5%, P = 1) without any complications. Speech perception improved or remained unchanged in most (84%) cases, with no significant difference between the groups (P = .183). CONCLUSION: This retrospective study showed that RCI involving MC is safe and beneficial. Although RCImc+ patients exhibited distinct clinical characteristics, MC did not impact surgical or speech perception outcomes. This provides evidence-based data to support informed decision-making by CI teams and patients.

Current demographic and auditory profiles of adult cochlear implant candidates and factors affecting uptake.

OBJECTIVES: Despite growth of CI and widening of implantation criteria, penetration rates remain low and the clinical profile of adult CI candidates has not substantially changed. This study evaluated the demographic and auditory profiles of current adult CI candidates and identified factors affecting CI uptake. DESIGN: Preoperative data from patients who underwent CI candidacy evaluation between 2016-2018 were retrospectively reviewed. Data included demographics, medical reports, audiological results, and reasons for not pursuing implantation. Comparisons between candidates who pursued implantation and those who did not were performed. STUDY SAMPLE: Ninety-five candidates (54 females), average age 52 years. RESULTS: Most candidates exhibited post-lingual bilateral hearing loss with mean unaided PTA4 of 105dBHL and monosyllabic word score of 26%. Forty-nine candidates were implanted, and the main reason for not pursuing CI was candidates' reluctance. Candidates that pursued CI were mostly younger females with poorer unaided PTA4. Age was the only significant predictor of CI uptake. CONCLUSIONS: While current candidates demonstrated greater demographic diversity and better speech perception compared to previous findings, unaided thresholds are still within the profound range. Our findings indicate that eligible candidates face barriers to the utilisation of CI, some of which are modifiable by means of updated candidacy protocols.

Rates, Indications, and Speech Perception Outcomes of Revision Cochlear Implantations.

Revision cochlear implant (RCI) is a growing burden on cochlear implant programs. While reports on RCI rate are frequent, outcome measures are limited. The objectives of the current study were to: (1) evaluate RCI rate, (2) classify indications, (3) delineate the pre-RCI clinical course, and (4) measure surgical and speech perception outcomes, in a large cohort of patients implanted in a tertiary referral center between 1989-2018. Retrospective data review was performed and included patient demographics, medical records, and audiologic outcomes. Results indicated that RCI rate was 11.7% (172/1465), with a trend of increased RCI load over the years. The main indications for RCI were device-related failures (soft-45.4%, hard-23.8%), medical failure (14%), trauma (8.1%), and surgical failure (6.4%). Success rate was 98.8%. Children comprised 78% (134) of the cohort and were more likely than adults to undergo RCI. Most (70%) of the RCIs were performed within 10 years from primary implantation. Speech perception outcome analysis revealed unchanged or improved performance in 85% of the cases and declined performance in 15%. Current findings confirm that RCI is a safe with high clinical efficacy; however, the non-negligible percentage of patients that exhibited declined performance post-RCI should be considered in decision-making processes regarding RCI. Routine follow-up during their first years post-implantation is warranted.

Hearing with Two Ears: Evidence for Cortical Binaural Interaction during Auditory Processing.

BACKGROUND: Integration of information presented to the two ears has been shown to manifest in binaural interaction components (BICs) that occur along the ascending auditory pathways. In humans, BICs have been studied predominantly at the brainstem and thalamocortical levels; however, understanding of higher cortically driven mechanisms of binaural hearing is limited. PURPOSE: To explore whether BICs are evident in auditory event-related potentials (AERPs) during the advanced perceptual and postperceptual stages of cortical processing. RESEARCH DESIGN: The AERPs N1, P3, and a late negative component (LNC) were recorded from multiple site electrodes while participants performed an oddball discrimination task that consisted of natural speech syllables (/ka/ vs. /ta/) that differed by place-of-articulation. Participants were instructed to respond to the target stimulus (/ta/) while performing the task in three listening conditions: monaural right, monaural left, and binaural. STUDY SAMPLE: Fifteen (21-32 yr) young adults (6 females) with normal hearing sensitivity. DATA COLLECTION AND ANALYSIS: By subtracting the response to target stimuli elicited in the binaural condition from the sum of responses elicited in the monaural right and left conditions, the BIC waveform was derived and the latencies and amplitudes of the components were measured. The maximal interaction was calculated by dividing BIC amplitude by the summed right and left response amplitudes. In addition, the latencies and amplitudes of the AERPs to target stimuli elicited in the monaural right, monaural left, and binaural listening conditions were measured and subjected to analysis of variance with repeated measures testing the effect of listening condition and laterality. RESULTS: Three consecutive BICs were identified at a mean latency of 129, 406, and 554 msec, and were labeled N1-BIC, P3-BIC, and LNC-BIC, respectively. Maximal interaction increased significantly with progression of auditory processing from perceptual to postperceptual stages and amounted to 51%, 55%, and 75% of the sum of monaural responses for N1-BIC, P3-BIC, and LNC-BIC, respectively. Binaural interaction manifested in a decrease of the binaural response compared to the sum of monaural responses. Furthermore, listening condition affected P3 latency only, whereas laterality effects manifested in enhanced N1 amplitudes at the left (T3) vs. right (T4) scalp electrode and in a greater left-right amplitude difference in the right compared to left listening condition. CONCLUSIONS: The current AERP data provides evidence for the occurrence of cortical BICs during perceptual and postperceptual stages, presumably reflecting ongoing integration of information presented to the two ears at the final stages of auditory processing. Increasing binaural interaction with the progression of the auditory processing sequence (N1 to LNC) may support the notion that cortical BICs reflect inherited interactions from preceding stages of upstream processing together with discrete cortical neural activity involved in binaural processing. Clinically, an objective measure of cortical binaural processing has the potential of becoming an appealing neural correlate of binaural behavioral performance.

Pain in cochlear implant recipients: an uncommon, yet serious, consequence of cochlear implantation.

OBJECTIVES/HYPOTHESIS: We describe pain around the receiver/stimulator [RS] presenting months to years after implantation. STUDY DESIGN: A retrospective chart review. METHODS: We performed a retrospective review of all cochlear implant recipients complaining of pain around their RS through the years 2009 through 2013, with a follow-up of at least 6 months. Excluded from the study were patients with an identifiable cause for their pain such as trauma, local infection, or skin breakdown. The therapy regimen and outcomes were reviewed. RESULTS: Thirty patients complained of delayed pain over their RS, representing 2.8% of 1,044 implantations performed at the Sheba Medical Center, Tel Hashomer, Israel, as of 2013. The time from implantation to the presentation of pain ranged from 3 months to 12 years. The pain was perceptible even when the external magnet and processor were not used, and was usually most obvious in specific points around the RS. Seventy-seven percent of our patients responded well to conservative therapy. Fifteen (50%) responded to prolonged antibiotic treatment. Five patients (17%) responded to antiinflammatories alone. One patient (3%) responded to deactivation of two electrodes. Six patients (20%) required reimplantation, after which the pain resolved in all. At explantation, no signs of infection, foreign body reaction, or obvious device damage were found. CONCLUSION: Delayed pain around the RS that is unrelated to use is a serious consequence of cochlear implantation, and in some cases, those necessitating reimplantation, should be considered a major complication. LEVEL OF EVIDENCE: 4.

Neural correlates of auditory-cognitive processing in older adult cochlear implant recipients.

With the growing number of older adults receiving cochlear implants (CI), there is general agreement that substantial benefits can be gained. Nonetheless, variability in speech perception performance is high, and the relative contribution and interactions among peripheral, central-auditory, and cognitive factors are not fully understood. The goal of the present study was to compare auditory-cognitive processing in older-adult CI recipients with that of older normal-hearing (NH) listeners by means of behavioral and electrophysiologic manifestations of a high-load cognitive task. Auditory event-related potentials (AERPs) were recorded from 9 older postlingually deafened adults with CI (age at CI >60) and 10 age-matched listeners with NH, while performing an auditory Stroop task. Participants were required to classify the speaker's gender (male/female) that produced the words 'mother' or 'father' while ignoring the irrelevant congruent or incongruent word meaning. Older CI and NH listeners exhibited comparable reaction time, performance accuracy, and initial sensory-perceptual processing (i.e. N1 potential). Nonetheless, older CI recipients showed substantially prolonged and less efficient perceptual processing (i.e. P3 potential). Congruency effects manifested in longer reaction time (i.e. Stroop effect), execution time, and P3 latency to incongruent versus congruent stimuli in both groups in a similar fashion; however, markedly prolonged P3 and shortened execution time were evident in older CI recipients. Collectively, older adults (CI and NH) employed a combined perceptual and postperceptual conflict processing strategy; nonetheless, the relative allotment of perceptual resources was substantially enhanced to maintain adequate performance in CI recipients. In sum, the recording of AERPs together with the simultaneously obtained behavioral measures during a Stroop task exposed a differential time course of auditory-cognitive processing in older CI recipients that was not manifested in the behavioral end products of processing. These data may have implications regarding clinical evaluation and rehabilitation procedures that should be tailored specifically for this unique group of patients.

Auditory conflict processing: behavioral and electrophysiologic manifestations of the stroop effect.

BACKGROUND: One of the most extensively studied phenomena in cognitive neuroscience is the Stroop effect. In an enormous corpus of literature, the Stroop task has been used to study conflict processing in the visual modality; however, scarce data exist in the auditory modality. PURPOSE: The main goal of the present study was to investigate auditory conflict processing by means of behavioral and electrophysiologic measures elicited during standard and reversed Stroop tasks. A secondary goal was to examine practice-related effects. RESEARCH DESIGN: Event-related potentials (ERPs) were recorded from 16 adults during tasks requiring classification of word meaning or speaker's gender while ignoring the irrelevant (congruent or incongruent) speaker's gender or word meaning, respectively. The behavioral measures, reaction time and performance accuracy, were simultaneously obtained. RESULTS: Results indicated (1) a significant behavioral Stroop effect manifested by prolonged reaction time and reduced performance accuracy. In contrast, ERP latencies were unaffected by the processing of incongruent versus congruent stimuli, supporting postperceptual conflict processing associated with response selection and execution; (2) reduced N1 amplitude while processing incongruent versus congruent stimuli; (3) similar behavioral Stroop effects in both tasks together with nonsignificant task by stimulus type (incongruent, congruent) interactions for N1 and N4; (4) significantly prolonged N4 and reaction time together with reduced N1 amplitude in the speaker's gender task (to both congruent and incongruent stimuli) compared to those found in the word meaning task; and (5) practice-related improvement in processing efficacy based on enhanced N1 amplitude, as well as shorter N4 and reaction time. CONCLUSIONS: Auditory conflict processing was predominantly postperceptual and was located at the response selection and execution stages. Alterations in the N1 component, however, provided support for an auditory conflict-processing "signature" at the initial stages of the arrival of information to the auditory cortex. The current data indicate that speaker's gender and word meaning intruded on one another in a similar fashion, supporting symmetry between standard and reversed auditory Stroop effects. Nonetheless, improved processing efficacy was evident while classifying word meaning. Utilization of the present methodology may prove advantageous for studying clinical populations exhibiting auditory and/or linguistic processing deficits.