Comparison of Two Place-Based Mapping Procedures on Masked Sentence Recognition as a Function of Electrode Array Angular Insertion Depth and Presence of Acoustic Low-Frequency Information: A Simulation Study.

INTRODUCTION: Cochlear implant (CI) and electric-acoustic stimulation (EAS) users may experience better performance with maps that align the electric filter frequencies to the cochlear place frequencies, known as place-based maps, than with maps that present spectrally shifted information. Individual place-based mapping procedures differ in the frequency content that is aligned to cochlear tonotopicity versus discarded or spectrally shifted. The performance benefit with different place-based maps may vary due to individual differences in angular insertion depth (AID) of the electrode array and whether functional acoustic low-frequency information is available in the implanted ear. The present study compared masked speech recognition with two types of place-based maps as a function of AID and presence of acoustic low-frequency information. METHODS: Sixty adults with normal hearing listened acutely to CI or EAS simulations of two types of place-based maps for one of three cases of electrode arrays at shallow AIDs. The strict place-based (Strict-PB) map aligned the low- and mid-frequency information to cochlear tonotopicity and discarded information below the frequency associated with the most apical electrode contact. The alternative place-based map (LFshift-PB) aligned the mid-frequency information to cochlear tonotopicity and provided more of the speech spectrum by compressing low-frequency information on the apical electrode contacts (i.e., <1 kHz). Three actual cases of a 12-channel, 24-mm electrode array were simulated by assigning the carrier frequency for an individual channel as the cochlear place frequency of the associated electrode contact. The AID and cochlear place frequency for the most apical electrode contact were 460° and 498 Hz for case 1, 389° and 728 Hz for case 2, and 335° and 987 Hz for case 3, respectively. RESULTS: Generally, better performance was observed with the Strict-PB maps for cases 1 and 2, where mismatches were 2-4 octaves for the most apical channel with the LFshift-PB map. Similar performance was observed between maps for case 3. For the CI simulations, performance with the Strict-PB map declined with decreases in AID, while performance with the LFshift-PB map remained stable across cases. For the EAS simulations, performance with the Strict-PB map remained stable across cases, while performance with the LFshift-PB map improved with decreases in AID. CONCLUSIONS: Listeners demonstrated differences with the Strict-PB versus LFshift-PB maps as a function of AID and whether acoustic low-frequency information was available (CI vs. EAS). These data support the use of the Strict-PB mapping procedure for AIDs ≥335°, though further study including time for acclimatization in CI and EAS users is warranted.

Influence of Postponed Follow-Up after Cochlear Implant Activation during the COVID-19 Pandemic on Aided Sound Field Detection and Speech Recognition.

INTRODUCTION: The objective of this study was to assess the influence of postponing the first post-activation follow-up due to the COVID-19 pandemic on the aided sound field detection thresholds and speech recognition of cochlear implant (CI) users. METHODS: A retrospective review was performed at a tertiary referral center. Two groups of adult CI recipients were evaluated: (1) patients whose first post-activation follow-up was postponed due to COVID-19 closures (postponed group; n = 10) and (2) a control group that attended recommended post-activation follow-ups prior to the COVID-19 pandemic (control group; n = 18). For both groups, electric thresholds were estimated at initial activation based on comfort levels and were measured behaviorally at subsequent post-activation follow-ups. For the control group, behavioral thresholds were measured at the 1-month follow-up. For the postponed group, behavioral thresholds were not measured until 3 months post-activation since the 1-month follow-up was postponed. The aided pure-tone average (PTA) and word recognition results were compared between groups at the 3-month follow-up and at an interim visit 2-9 weeks later. RESULTS: At the 3-month follow-up, the postponed group had significantly poorer word recognition (23 vs. 42%, p = 0.027) and aided PTA (42 vs. 37 dB HL, p = 0.041) than the control group. No significant differences were observed between 3-month data from the control group and interim data from the postponed group. CONCLUSIONS: The postponed follow-up after CI activation was associated with poorer outcomes, both in terms of speech recognition and aided audibility. However, these detrimental effects were reversed following provision of an individualized map, with behaviorally measured electric threshold and comfort levels. While adult CI recipients demonstrate an improvement in speech recognition with estimated electric thresholds, the present results suggest that behavioral mapping within the initial weeks of device use may support optimal outcomes.

Relationship Between Electrocochleography, Angular Insertion Depth, and Cochlear Implant Speech Perception Outcomes.

OBJECTIVES: Electrocochleography (ECochG), obtained before the insertion of a cochlear implant (CI) array, provides a measure of residual cochlear function that accounts for a substantial portion of variability in postoperative speech perception outcomes in adults. It is postulated that subsequent surgical factors represent independent sources of variance in outcomes. Prior work has demonstrated a positive correlation between angular insertion depth (AID) of straight arrays and speech perception under the CI-alone condition, with an inverse relationship observed for precurved arrays. The purpose of the present study was to determine the combined effects of ECochG, AID, and array design on speech perception outcomes. DESIGN: Participants were 50 postlingually deafened adult CI recipients who received one of three straight arrays (MED-EL Flex24, MED-EL Flex28, and MED-EL Standard) and two precurved arrays (Cochlear Contour Advance and Advanced Bionics HiFocus Mid-Scala). Residual cochlear function was determined by the intraoperative ECochG total response (TR) measured before array insertion, which is the sum of magnitudes of spectral components in response to tones of different stimulus frequencies across the speech spectrum. The AID was then determined with postoperative imaging. Multiple linear regression was used to predict consonant-nucleus-consonant (CNC) word recognition in the CI-alone condition at 6 months postactivation based on AID, TR, and array design. RESULTS: Forty-one participants received a straight array and nine received a precurved array. The AID of the most apical electrode contact ranged from 341° to 696°. The TR measured by ECochG accounted for 43% of variance in speech perception outcomes (p < 0.001). A regression model predicting CNC word scores with the TR tended to underestimate the performance for precurved arrays and deeply inserted straight arrays, and to overestimate the performance for straight arrays with shallower insertions. When combined in a multivariate linear regression, the TR, AID, and array design accounted for 72% of variability in speech perception outcomes (p < 0.001). CONCLUSIONS: A model of speech perception outcomes that incorporates TR, AID, and array design represents an improvement over a model based on TR alone. The success of this model shows that peripheral factors including cochlear health and electrode placement may play a predominant role in speech perception with CIs.

Frequency-to-Place Mismatch: Characterizing Variability and the Influence on Speech Perception Outcomes in Cochlear Implant Recipients.

OBJECTIVES: The spatial position of a cochlear implant (CI) electrode array affects the spectral cues provided to the recipient. Differences in cochlear size and array length lead to substantial variability in angular insertion depth (AID) across and within array types. For CI-alone users, the variability in AID results in varying degrees of frequency-to-place mismatch between the default electric frequency filters and cochlear place of stimulation. For electric-acoustic stimulation (EAS) users, default electric frequency filters also vary as a function of residual acoustic hearing in the implanted ear. The present study aimed to (1) investigate variability in AID associated with lateral wall arrays, (2) determine the subsequent frequency-to-place mismatch for CI-alone and EAS users mapped with default frequency filters, and (3) examine the relationship between early speech perception for CI-alone users and two aspects of electrode position: frequency-to-place mismatch and angular separation between neighboring contacts, a metric associated with spectral selectivity at the periphery. DESIGN: One hundred one adult CI recipients (111 ears) with MED-EL Flex24 (24 mm), Flex28 (28 mm), and FlexSOFT/Standard (31.5 mm) arrays underwent postoperative computed tomography to determine AID. A subsequent comparison was made between AID, predicted spiral ganglion place frequencies, and the default frequency filters for CI-alone (n = 84) and EAS users (n = 27). For CI-alone users with complete insertions who listened with maps fit with the default frequency filters (n = 48), frequency-to-place mismatch was quantified at 1500 Hz and angular separation between neighboring contacts was determined for electrodes in the 1 to 2 kHz region. Multiple linear regression was used to examine how frequency-to-place mismatch and angular separation of contacts influence consonant-nucleus-consonant (CNC) scores through 6 months postactivation. RESULTS: For CI recipients with complete insertions (n = 106, 95.5%), the AID (mean ± standard deviation) of the most apical contact was 428° ± 34.3° for Flex24 (n = 11), 558° ± 65.4° for Flex28 (n = 48), and 636° ± 42.9° for FlexSOFT/Standard (n = 47) arrays. For CI-alone users, default frequency filters aligned closely with the spiral ganglion map for deeply inserted lateral wall arrays. For EAS users, default frequency filters produced a range of mismatches; absolute deviations of ≤ 6 semitones occurred in only 37% of cases. Participants with shallow insertions and minimal or no residual hearing experienced the greatest mismatch. For CI-alone users, both smaller frequency-to-place mismatch and greater angular separation between contacts were associated with better CNC scores during the initial 6 months of device use. CONCLUSIONS: There is significant variability in frequency-to-place mismatch among CI-alone and EAS users with default frequency filters, even between individuals implanted with the same array. When using default frequency filters, mismatch can be minimized with longer lateral wall arrays and insertion depths that meet the edge frequency associated with residual hearing for CI-alone and EAS users, respectively. Smaller degrees of frequency-to-place mismatch and decreased peripheral masking due to more widely spaced contacts may independently support better speech perception with longer lateral wall arrays in CI-alone users.

Cochleostomy and facial recess packing alter cochlear implant electrode location in a human cochlea model.

PURPOSE: Determine the effect of cochleostomy and facial recess packing on cochlear implant electrode distance from the modiolus. MATERIALS AND METHODS: Two otolaryngology residents (PGY5 and PGY6) and one attending ear surgeon performed electrode insertions on a human cochlea model using perimodiolar (Cochlear® Slim Modiolar 532™, CI532) and lateral wall electrodes (Cochlear® Slim Straight 522™, CI522) via a cochleostomy. Packing material was simulated using cotton and placed in the cochleostomy and facial recess under the following conditions: 1) inferior to the electrode, 2) superior, 3) both inferior and superior, and 4) no packing. Distance of the electrode from the modiolus at the proximal, middle, and distal basal turn of the cochlea were measured by photomicrograph analysis. RESULTS: Packing superior to the CI532 resulted in a significant decrease in distance from the modiolus at the middle and distal basal turn compared to the inferior condition, with the largest effect in the middle basal turn (0.25 mm vs. 1.92 mm, respectively, p < 0.001). For the CI522, packing superior similarly resulted in decreased distance to the modiolus when compared to the inferior packing condition at the middle and distal basal turn regions, with the largest effect in the middle basal turn (1.25 mm vs. 1.75 mm, respectively, p = 0.002). CONCLUSIONS: Packing of the cochleostomy site and facial recess has a significant effect on electrode distance from the modiolus in the middle and distal basal turn using a model of a human cochlea. Effects were more pronounced when using the perimodiolar (CI532) electrode.

Improving resident familiarity with the translabyrinthine approach to the internal auditory canal.

OBJECTIVE: To increase otolaryngology resident experience with drilling and dissection of the internal auditory canal (IAC) via a translabyrinthine approach. STUDY DESIGN: Pilot study involving temporal bone education and drilling with completion of pre- and post-drilling surveys. METHODS: Participants observed an educational presentation on IAC anatomy and drilling, followed by manipulation of IAC nerves using a prosected cadaveric temporal bone. Participants then drilled the IAC and identified nerves using temporal bones with previously drilled mastoidectomies and labyrinthectomies. Pre- and post-drilling 5-point Likert-based surveys were completed. RESULTS: 7 participants were included in this study ranging in experience from PGY1 through PGY 5. The median number of times the IAC had been drilled previously was 0. Participants reported statistically significantly improved familiarity with the translabyrinthine approach after the session with median scores increasing from 2 to 3 (p=0.02), and a near-significant increase in familiarity with IAC anatomy with median scores increasing from 3 to 4 (p=0.06). Prior to the session, 71% of participants either disagreed or strongly disagreed that they had an idea of what the procedure would be like in a real operating room, whereas after the session 0% reported disagreement. 100% of participants were very satisfied with the overall experience. CONCLUSIONS: An educational session and temporal bone drilling experience using prosected bones significantly increased the reported familiarity with the translabyrinthine approach. Experiences such as this may enhance resident exposure to advanced lateral skull base approaches in a safe environment, and increase comprehension of the complex anatomic relationships of the IAC.

The Relation between Obesity and Hospital Length of Stay after Elective Lateral Skull Base Surgery: An Analysis of the American College of Surgeons National Surgical Quality Improvement Program.

PURPOSE: Length of stay is a marker of quality and efficiency of health care delivery. The objective of this study was to identify preoperative, intraoperative, and postoperative variables that impact length of stay after lateral skull base surgery. Methods/Procedures: The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) databases from 2009-2012 were analyzed, and patients undergoing elective lateral skull base surgery for benign lesions of cranial nerves were identified. The primary outcome measure of interest was length of hospital stay. Protracted length of stay was defined as ≥75th percentile of length of stay for all patients. The impact of demographic factors, intraoperative variables, and postoperative complications on length of stay was assessed. RESULTS: In total, 252 patients were included. Almost half of the patients (41.2%) were classified as obese (body mass index ≥30). Patients who were obese had significantly longer lengths of stay (5.6 ± 3.9 days) when compared to patients who were not obese (4.6 ± 3.4 days, p = 0.006). Multivariate regression analysis demonstrated that operative time, reoperation within 30 days of initial surgery, and obesity were independent predictors for protracted length of stay. CONCLUSION: National multi-institutional data from the ACS-NSQIP suggest that operative time, reoperation, and obesity are predictors of longer hospital stays after lateral skull base approaches for benign cranial nerve neoplasms.

Calcium Hydroxylapatite Injection for Persistent Velopharyngeal Insufficiency after Sphincter Pharyngoplasty.

BACKGROUND: The role of calcium hydroxylapatite injection pharyngoplasty after failed sphincter pharyngoplasty surgery has not previously been described. We report our technique of injecting calcium hydroxylapatite into the pharyngoplasty site to add bulk to specific areas of the velopharyngeal port. METHODS: A retrospective review of children undergoing calcium hydroxylapatite injection pharyngoplasty for persistent velopharyngeal insufficiency after sphincter pharyngoplasty was performed. Our surgical technique is described. Outcome measures included postoperative perceptual assessment of resonance, improvement in phoneme-specific nasometry scores, and rate of revision surgery. RESULTS: Fourteen patients were included in the study. Improvement in hypernasality on perceptual assessment was noted in the majority of children (85.7%). The rate of achievement of normal resonance on perceptual analysis was 35.7%. A significant decrease in nasometry scores was noted for the following phonemes: /pa/, /sa/, /sha/, and /pi/. There were no intraoperative complications or immediate postoperative complications associated with calcium hydroxylapatite injection. CONCLUSIONS: Our early experience suggests that calcium hydroxylapatite injection after failed sphincter pharyngoplasty is a safe, minimally invasive technique with favorable short-term results.

Cigarette smoke exposure is associated with vitamin D3 deficiencies in patients with chronic rhinosinusitis.

BACKGROUND: Cigarette smoke (CS) plays a role in the exacerbation of chronic rhinosinusitis (CRS); however, the mechanism for this is unknown. We hypothesize that CS impairs human sinonasal epithelial cell (HSNEC) conversion of 25(OH)D3 (25VD3) to 1,25-dihydroxyvitamin D3 (1,25VD3) and, furthermore, that supplementation with 1,25VD3 will reverse smoke-induced inflammatory responses by HSNECs. OBJECTIVE: We sought to determine the effect of CS on vitamin D3 (VD3) levels, conversion, and regulation of CS-induced inflammation in control subjects and patients with CRS. METHODS: Blood and sinus tissue explants were collected at the time of surgery from control subjects, patients with chronic rhinosinusitis without nasal polyps, and patients with chronic sinusitis with nasal polyps (CRSwNP). Expression of VD3 metabolizing enzymes were measured by using RT-PCR. Primary HSNECs were cultured from tissue explants. 25VD3 with and without cigarette smoke extract (CSE) was used to examine conversion of 25VD3 to 1,25VD3, as well as HSNEC production of proinflammatory cytokines. RESULTS: CS exposure was associated with reduced circulating and sinonasal 25VD3 levels in all groups compared with those seen in CS-naive, disease-matched counterparts. CS exposure decreased expression of CYP27B1 and was especially pronounced in patients with CRSwNP. CSE impairs control HSNEC conversion of 25VD3. HSNECs from patients with CRSwNP also demonstrate an intrinsic reduction in conversion of 25VD3 to 1,25VD3. Exogenous 1,25VD3 reduces CSE-induced cytokine production by HSNECs. CONCLUSIONS: Exposure to CS is associated with reduced 25VD3 levels and an impaired ability of HSNECs to convert 25VD3 to 1,25VD3. Addition of 1,25VD3 reduces the proinflammatory effects of CS on HSNECs. Impaired VD3 conversion by CS exposure represents a novel mechanism through which CS induces its proinflammatory effects.

Factors that influence performance in pediatric cochlear implant recipients with cochlear nerve deficiency.

OBJECTIVES: Children with cochlear nerve deficiency (CND) have wide variability in outcomes with cochlear implant (CI) use. The current study aims to report a large cohort of pediatric CI recipients with CND and to evaluate for factors that may predict improved performance. METHODS: The current study is a retrospective review of pediatric CI recipients with CND at a tertiary academic hospital. Variables including cochlear nerve status (hypoplasia vs aplasia), age at implantation, cochleovestibular malformation, bony cochlear nerve aperture, internal auditory canal aperture, and cognitive delay were evaluated for predictors of postoperative performance. A stepwise multinomial regression analysis was performed. RESULTS: Forty-seven CI recipients (54 ears) were included in the analysis. A majority (59%) showed auditory capabilities with their CI. Twenty percent of recipients achieved some level of open-set speech perception with their CI. The regression analysis identified cochlear nerve status and cognitive delay as predictors of performance. CI recipients with cochlear nerve hypoplasia had significantly improved performance compared to those with aplasia (p = 0.003). Recipients with cognitive delay had more limited benefit than those without cognitive delay (p = 0.033). CONCLUSIONS: Children with CND can benefit from CI use, with outcomes spanning from non-use to development of spoken language. Predictive factors for improved performance include a lack of cognitive delay and cochlear hypoplasia rather than aplasia. These can be important considerations for parent counseling and decision making.

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.

Effect of Place-Based Versus Default Mapping Procedures on Masked Speech Recognition: Simulations of Cochlear Implant Alone and Electric-Acoustic Stimulation.

PURPOSE: Cochlear implant (CI) recipients demonstrate variable speech recognition when listening with a CI-alone or electric-acoustic stimulation (EAS) device, which may be due in part to electric frequency-to-place mismatches created by the default mapping procedures. Performance may be improved if the filter frequencies are aligned with the cochlear place frequencies, known as place-based mapping. Performance with default maps versus an experimental place-based map was compared for participants with normal hearing when listening to CI-alone or EAS simulations to observe potential outcomes prior to initiating an investigation with CI recipients. METHOD: A noise vocoder simulated CI-alone and EAS devices, mapped with default or place-based procedures. The simulations were based on an actual 24-mm electrode array recipient, whose insertion angles for each electrode contact were used to estimate the respective cochlear place frequency. The default maps used the filter frequencies assigned by the clinical software. The filter frequencies for the place-based maps aligned with the cochlear place frequencies for individual contacts in the low- to mid-frequency cochlear region. For the EAS simulations, low-frequency acoustic information was filtered to simulate aided low-frequency audibility. Performance was evaluated for the AzBio sentences presented in a 10-talker masker at +5 dB signal-to-noise ratio (SNR), +10 dB SNR, and asymptote. RESULTS: Performance was better with the place-based maps as compared with the default maps for both CI-alone and EAS simulations. For instance, median performance at +10 dB SNR for the CI-alone simulation was 57% correct for the place-based map and 20% for the default map. For the EAS simulation, those values were 59% and 37% correct. Adding acoustic low-frequency information resulted in a similar benefit for both maps. CONCLUSIONS: Reducing frequency-to-place mismatches, such as with the experimental place-based mapping procedure, produces a greater benefit in speech recognition than maximizing bandwidth for CI-alone and EAS simulations. Ongoing work is evaluating the initial and long-term performance benefits in CI-alone and EAS users. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.19529053.

Insertion Depth and Cochlear Implant Speech Recognition Outcomes: A Comparative Study of 28- and 31.5-mm Lateral Wall Arrays.

OBJECTIVES: 1) To compare speech recognition outcomes between cochlear implant (CI) recipients of 28- and 31.5-mm lateral wall electrode arrays, and 2) to characterize the relationship between angular insertion depth (AID) and speech recognition. STUDY DESIGN: Retrospective review. SETTING: Tertiary academic referral center. PATIENTS: Seventy-five adult CI recipients of fully inserted 28-mm (n = 28) or 31.5-mm (n = 47) lateral wall arrays listening with a CI-alone device. INTERVENTIONS: Cochlear implantation with postoperative computed tomography. MAIN OUTCOME MEASURES: Consonant-nucleus-consonant (CNC) word recognition assessed with the CI-alone at 12 months postactivation. RESULTS: The mean AID of the most apical electrode contact for the 31.5-mm array recipients was significantly deeper than the 28-mm array recipients (628° vs 571°, p < 0.001). Following 12 months of listening experience, mean CNC word scores were significantly better for recipients of 31.5-mm arrays compared with those implanted with 28-mm arrays (59.5% vs 48.3%, p = 0.004; Cohen's d = 0.70; 95% CI [0.22, 1.18]). There was a significant positive correlation between AID and CNC word scores (r = 0.372, p = 0.001), with a plateau in performance observed around 600°. CONCLUSIONS: Cochlear implant recipients implanted with a 31.5-mm array experienced better speech recognition than those with a 28-mm array at 12 months postactivation. Deeper insertion of a lateral wall array appears to confer speech recognition benefit up to ∼600°, with a plateau in performance observed thereafter. These data provide preliminary evidence of the insertion depth necessary to optimize speech recognition outcomes for lateral wall electrode arrays among CI-alone users.

Comparison of Speech Recognition With an Organ of Corti Versus Spiral Ganglion Frequency-to-Place Function in Place-Based Mapping of Cochlear Implant and Electric-Acoustic Stimulation Devices.

OBJECTIVE: To compare acute speech recognition with a cochlear implant (CI) alone or electric-acoustic stimulation (EAS) device for place-based maps calculated with an organ of Corti (OC) versus a spiral ganglion (SG) frequency-to-place function. PATIENTS: Eleven adult CI recipients of a lateral wall electrode array. INTERVENTION: Postoperative imaging was used to derive place-based maps calculated with an OC versus SG function. MAIN OUTCOME MEASURE: Phoneme recognition was evaluated at initial activation with consonant-nucleus-consonant (CNC) words presented using an OC versus a SG place-based map. RESULTS: For the 9 CI-alone users, there was a nonsignificant trend for better acute phoneme recognition with the SG map (mean 18 RAUs) than the OC map (mean 9 RAUs; p = 0.071, 95% CI [≤-1.2]). When including the 2 EAS users in the analysis, performance was significantly better with the SG map (mean 21 RAUs) than the OC map (mean 7 RAUs; p = 0.019, 95% CI [≤-6.2]). CONCLUSIONS: Better phoneme recognition with the SG frequency-to-place function could indicate more natural tonotopic alignment of information compared with the OC place-based map.A prospective, randomized investigation is currently underway to assess longitudinal outcomes with place-based mapping in CI-alone and EAS devices using the SG frequency-to-place function.

Spatial Release From Masking in Pediatric Cochlear Implant Recipients With Single-Sided Deafness.

Purpose Children with single-sided deafness (SSD) experience difficulty understanding speech in multisource listening situations. Case reports and retrospective studies have indicated that a cochlear implant (CI) may improve masked speech recognition in children with SSD. This prospective study was conducted to determine whether providing a CI to children with SSD supports spatial release from masking (SRM), an improvement in speech recognition associated with separating the target and masker sources. Method Twenty children with at least a moderate-to-profound hearing loss in one ear and normal hearing in the contralateral ear underwent cochlear implantation. The average age of implantation was 5.5 years (range: 3.5-12.7). After 12 months of CI use, subjects completed a sentence recognition task in multitalker masker with and without the CI. The target was presented from the front, and the masker was either colocated with the target (0°) or from the side (+90° or -90°). A two-way repeated-measures analysis of variance was completed to investigate SRM with and without the CI. Results Pediatric CI recipients experienced significant SRM when the masker was directed to the normal-hearing ear or to the affected ear. Conclusions The results indicate that cochlear implantation in children with SSD supports binaural skills required for speech recognition in noise. These results are consistent with improved functional communication in multisource environments, like classrooms.

Effectiveness of Place-based Mapping in Electric-Acoustic Stimulation Devices.

BACKGROUND: The default mapping procedure for electric-acoustic stimulation (EAS) devices uses the cochlear implant recipient's unaided detection thresholds in the implanted ear to derive the acoustic settings and assign the lowest frequency filter of electric stimulation. Individual differences for speech recognition with EAS may be due to discrepancies between the electric frequency filters of individual electrode contacts and the cochlear place of stimulation, known as a frequency-to-place mismatch. Frequency-to-place mismatch of greater than 1/2 octave has been demonstrated in up to 60% of EAS users. Aligning the electric frequency filters via a place-based mapping procedure using postoperative imaging may improve speech recognition with EAS. METHODS: Masked sentence recognition was evaluated for normal-hearing subjects (n = 17) listening with vocoder simulations of EAS, using a place-based map and a default map. Simulation parameters were based on audiometric and imaging data from a representative 24-mm electrode array recipient and EAS user. The place-based map aligned electric frequency filters with the cochlear place frequency, which introduced a gap between the simulated acoustic and electric output. The default map settings were derived from the clinical programming software and provided the full speech frequency range. RESULTS: Masked sentence recognition was significantly better for simulated EAS with the place-based map as compared with the default map. CONCLUSION: The simulated EAS place-based map supported better performance than the simulated EAS default map. This indicates that individualizing maps may improve performance in EAS users by helping them achieve better asymptotic performance earlier and mitigate the need for acclimatization.

Spatial Release From Masking in Bimodal and Bilateral Pediatric Cochlear Implant Recipients.

Purpose Traditional clinical measures of cochlear implant (CI) recipient performance may not fully evaluate the benefit of bimodal listening (hearing aid contralateral to a CI). The clinical assessment of spatial release from masking (SRM) may be a sensitive measure of the benefit of listening with bimodal stimulation. This study compared the SRM of pediatric bimodal and bilateral CI listeners using a clinically feasible method, and investigated variables that may contribute to speech recognition performance with spatially separated maskers. Method Forty pediatric bimodal (N = 20) and bilateral CI (N = 20) participants were assessed in their best aided listening condition on sentence recognition in a four-talker masker. Testing was completed with target and masker colocated at 0° azimuth, and with the masker directed at 90° to either ear. SRM was calculated as the difference in performance between the colocated and each 90° condition. A two-way mixed-methods analysis of variance was used to compare performance between groups in the three masker conditions. Multiple regression analyses were conducted to investigate potential predictors for SRM asymmetry including hearing history, unaided thresholds, word recognition, duration of device use, and acoustic bandwidth. Results Both groups demonstrated SRM, with significantly better recognition in each 90° condition as compared to the colocated condition. The groups did not differ significantly in SRM. The multiple regression analyses did not reveal any significant predictors of SRM asymmetry. Conclusions Bimodal and bilateral CI listeners demonstrated similar amounts of SRM. While no specific variables predicted SRM asymmetry in bimodal listeners, pediatric bimodal and bilateral CI recipients should expect similar amounts of SRM regardless of the side of the masker. SRM asymmetry in pediatric bimodal listeners may signal a need for consideration of a second CI.

Incidence of Complete Insertion in Cochlear Implant Recipients of Long Lateral Wall Arrays.

OBJECTIVE: High rates of partial insertion have been reported for cochlear implant (CI) recipients of long lateral wall electrode arrays, presumably caused by resistance encountered during insertion due to cochlear morphology. With recent advances in long-electrode array design, we sought to investigate (1) the incidence of complete insertions among patients implanted with 31.5-mm flexible arrays and (2) whether complete insertion is limited by cochlear duct length (CDL). STUDY DESIGN: Retrospective review. SETTING: Tertiary referral center. METHODS: Fifty-one adult CI recipients implanted with 31.5-mm flexible lateral wall arrays underwent postoperative computed tomography to determine the rate of complete insertion, defined as all contacts being intracochlear. CDL and angular insertion depth (AID) were compared between complete and partial insertion cohorts. RESULTS: Most cases had a complete insertion (96.1%, n = 49). Among the complete insertion cohort, the median CDL was 33.6 mm (range, 30.3-37.9 mm), and median AID was 641° (range, 533-751°). Two cases of partial insertion had relatively short CDL (31.8 mm and 32.3 mm) and shallow AID (542° and 575°). Relatively shallow AID for the 2 cases of partial insertion fails to support the idea that CDL alone prevents a complete insertion. CONCLUSION: Complete insertion of a 31.5-mm flexible array is feasible in most cases and does not appear to be limited by the range of CDL observed in this cohort. Future studies are needed to estimate other variations in cochlear morphology that could predict resistance and failure to achieve complete insertion with long arrays.

Influence of Cochlear Implant Use on Perceived Listening Effort in Adult and Pediatric Cases of Unilateral and Asymmetric Hearing Loss.

OBJECTIVE: Assess the influence of cochlear implant (CI) use on the perceived listening effort of adult and pediatric subjects with unilateral hearing loss (UHL) or asymmetric hearing loss (AHL). STUDY DESIGN: Prospective cohort. SETTING: Tertiary referral center. PATIENTS: Adults and children with UHL or AHL. INTERVENTION: Cochlear implantation. Subjects received their CI as part of a clinical trial assessing the effectiveness of cochlear implantation in cases of UHL and AHL. MAIN OUTCOME MEASURES: Responses to the Listening Effort pragmatic subscale on the Speech, Spatial, and Qualities of Hearing Scale (SSQ) or SSQ for Children with Impaired Hearing (SSQ-C) were compared over the study period. Subjects or their parents completed the questionnaires preoperatively and at predetermined postactivation intervals. For the adult subjects, responses were compared to word recognition in quiet and sentence recognition in noise. RESULTS: Forty adult subjects (n = 20 UHL, n = 20 AHL) and 16 pediatric subjects with UHL enrolled and underwent cochlear implantation. Subjects in all three groups reported a significant reduction in perceived listening effort within the initial months of CI use (p < 0.001; η2 ≥ 0.351). The perceived benefit was significantly correlated with speech recognition in noise for the adult subjects with UHL at the 12-month interval (r(20) = .59, p = 0.006). CONCLUSIONS: Adult and pediatric CI recipients with UHL or AHL report a reduction in listening effort with CI use as compared to their preoperative experiences. Use of the SSQ and SSQ-C Listening Effort pragmatic subscale may provide additional information about a CI recipient's experience beyond the abilities measured in the sound booth.

Long-Term Influence of Electrode Array Length on Speech Recognition in Cochlear Implant Users.

OBJECTIVES/HYPOTHESIS: Results from a prospective trial demonstrated better speech recognition for cochlear implant (CI) recipients implanted with a long lateral wall electrode array compared to subjects with a short array after 1 year of listening experience. As short array recipients may require an extended adaptation period, this study investigated whether differences in speech recognition continued through 4 years of CI use. STUDY DESIGN: Long-term follow-up of a prospective randomized trial. METHODS: Subjects were randomized to receive a MED-EL medium (24 mm) or standard (31.5 mm) array. Linear mixed models compared speech recognition between cohorts with word recognition in quiet and sentence recognition in noise at 1, 3, 6, 12, 24, and 48 months postactivation. Postoperative imaging and electric frequency filters were reviewed to assess the influence of frequency-to-place mismatch and angular separation between neighboring contacts, a metric associated with peripheral spectral selectivity. RESULTS: Long (31.5 mm) array recipients demonstrated superior speech recognition out to 4 years postactivation. There was a significant effect of angular separation between contacts, with more closely spaced contacts associated with poorer speech recognition. There was no significant effect of mismatch, yet this may have been obscured by changes in frequency filters over time. CONCLUSIONS: Conventional MED-EL CI recipients implanted with 31.5-mm arrays experience better speech recognition than 24-mm array recipients, initially and with long-term listening experience. The benefit conferred by longer arrays in the present cohort can be partially attributed to more widely spaced electrode contacts, presumably a result of reduced channel interaction. LEVEL OF EVIDENCE: 2 Laryngoscope, 131:892-897, 2021.