Faculty Bibliography

OBJECTIVES:There are many potential advantages to combined electric and acoustic stimulation (EAS) with a cochlear implant (CI), including benefits for hearing in noise, localization, frequency selectivity, and music enjoyment. However, performance on these outcome measures is variable, and the residual acoustic hearing may not be beneficial for all patients. As such, we propose a measure of spectral resolution that might be more predictive of the usefulness of the residual hearing than the audiogram alone. In the following experiments, we measured performance on spectral resolution and speech perception tasks in individuals with normal hearing (NH) using low-pass filters to simulate steeply sloping audiograms of typical EAS candidates and compared it with performance on these tasks for individuals with sensorineural hearing loss with similar audiometric configurations. Because listeners with NH had similar levels of audibility and bandwidth to listeners with hearing loss, differences between the groups could be attributed to distortions due to hearing loss. DESIGN:Listeners with NH (n = 12) and those with hearing loss (n = 23) with steeply sloping audiograms participated in this study. The group with hearing loss consisted of 7 EAS users, 14 hearing aid users, and 3 who did not use amplification in the test ear. Spectral resolution was measured with the spectral-temporal modulated ripple test (SMRT), and speech perception was measured with AzBio sentences in quiet and noise. Listeners with NH listened to stimuli through low-pass filters and at two levels (40 and 60 dBA) to simulate low and high audibility. Listeners with hearing loss listened to SMRT stimuli unaided at their most comfortable listening level and speech stimuli at 60 dBA. RESULTS:Results suggest that performance with SMRT is significantly worse for listeners with hearing loss than for listeners with NH and is not related to audibility. Performance on the speech perception task declined with decreasing frequency information for both listeners with NH and hearing loss. Significant correlations were observed between speech perception, SMRT scores, and mid-frequency audiometric thresholds for listeners with hearing loss. CONCLUSIONS:NH simulations describe a "best case scenario" for hearing loss where audibility is the only deficit. For listeners with hearing loss, the likely broadening of auditory filters, loss of cochlear nonlinearities, and possible cochlear dead regions may have contributed to distorted spectral resolution and thus deviations from the NH simulations. Measures of spectral resolution may capture an aspect of hearing loss not evident from the audiogram and be a useful tool for assessing the contributions of residual hearing post-cochlear implantation.

OBJECTIVE:To determine factors associated with infection, management, and resultant outcomes following pediatric cochlear implantation. STUDY DESIGN/METHODS:Retrospective cohort study with nested case series. SETTING/METHODS:Tertiary academic medical center. PATIENTS/METHODS:Children who underwent either unilateral or bilateral cochlear implantation between June 2011 and September 2016 and were under the age of 18 at the time of surgery. INTERVENTION(S)/METHODS:Subjects were compared based on age, cochlea malformation, revision surgery, operative time, device manufacturer, and antibiotic use. Infections were compared based on location, time, bacteria, management, and resolution. MAIN OUTCOME MEASURE(S)/METHODS:Rate of infection, rate of device explantation. RESULTS:There were 16 infections among 246 surgeries, an infection rate of 6.5%. There was a significant age difference between infected and noninfected patients overall (n = 246, 1.4 versus 4.3 years, p = 0.005), but not within the cohort of patients five or younger (n = 172, 1.4 versus 1.8 years, p = 0.363). The most common infectious complication was skin infection, followed by device infection. No cases of meningitis were seen. The most common organism was S Aureus. The implant was salvaged in 9 of 16 patients (56.3%), with higher rates in patients treated with IV versus oral antibiotics (70 versus 40%). CONCLUSIONS:Postoperative infection is positively associated with younger age overall, but not in patients below the age of 5. With modern devices and surgical practices, risk of meningitis-though a concern-may be lower than cited in the literature. Prompt and aggressive therapy with IV antibiotics and operative intervention can allow for high rates of device salvage.

BACKGROUND:Prior studies have shown an advantage for electro-acoustic stimulation (EAS) in cochlear implant (CI) patients with residual hearing, but the degree of benefit can vary. The objective was to explore which factors relate to performance with and acceptance of EAS for CI users with conventional-length electrodes. METHODS:A retrospective chart review was conducted for adults with an average threshold of 75 dB hearing loss or better across 250 and 500 Hz preoperatively (n = 83). All patients underwent cochlear implantation with a conventional-length electrode. Low-frequency audiometric thresholds were measured at initial activation as well as 3 and 12 months postoperatively to determine who met the criteria for EAS. Speech perception for CNC words and AzBio sentences in quiet and +10 dB SNR noise was evaluated 3 and 12 months after activation. RESULTS:Speech perception in quiet and noise was similar regardless of whether or not the patient was eligible for EAS. Less than half of the patients who met the EAS criteria chose to use it, citing reasons such as physical discomfort or lack of perceived benefit. EAS users performed better on CNC words but not sentence recognition than EAS nonusers. CONCLUSIONS:EAS use is dependent on audiologic and nonaudiologic issues. Hearing preservation is possible with conventional electrodes, but hearing preservation alone does not guarantee superior speech perception.

Introduction: While cochlear implants (CI) prior to 12 months of age have become common, the prevalence and impact of issues that either arise or were not evident prior to implantation is unknown. Methods: Retrospective chart review of children implanted under 12 months of age with minimum 3 years follow up. The children were divided into three groups: those with no identified additional disabilities, those with no known disabilities at time of implantation but diagnosed with additional disabilities following implantation, and those that had known anticipated additional disabilities at time of implantation. Results: 108 children under the age of 12 months were implanted at our Center between 2000 and 2013 with an average age of 9 months at time of implantation and n = 93 met inclusion criteria. In 79.6% (74/93) of children, there were no additional issues detected. In 11.8% (11/93), additional issues were known at the time of implantation while in 8.6% (8/93) of the children were diagnosed with additional issues that were not evident prior to implantation. The auditory and linguistic benefits vary commensurate with the severity of their disabilities. Those with anticipated issues preoperatively did not perform as well. Conclusions: Children implanted below one year of age but diagnosed with additional disabilities following implantation obtained substantial though varying degrees of benefit. In none of these cases would knowledge of the disability have altered the decision to offer early CI. It is important to address these potential issues when counseling families about outcomes.

Objective: To describe cochlear implantation (CI) outcomes for rehabilitation of hearing loss due to retrocochlear pathology and/or its treatment.
Method(s): Retrospective review between 1995 and 2019 from a single tertiary care center of all patients with retrocochlear pathology who underwent CI. Demographics, clinical history, and audiometric data were reviewed. Study endpoints include (1) logged device use, (2) ability to achieve auditory perception, and (3) word recognition score (WRS) in the CI-only condition.
Result(s): Thirty-two patients (63% of females) with retrocochlear pathology were implanted at our center. The average age at implantation was 46.9 years (SD: 19, range: 13-80). Mean duration of deafness was 4.5 years (SD: 5.0, range: 0.4-19.0). Etiology of hearing loss included VS in 24 (75%), CNS malignancy treated with radiation in 4 (13%), intralabyrinthine schwannoma in 2 (6%), head and neck malignancy treated with radiation in 1 (3%), and superficial siderosis in 1 (3%). The mean preoperative PTA was 95.8 dBHL (SD 24.7) and WRS was 7.2% (SD 13.1). Of the 24 VSs, 21 were NF2-associated and 3 were sporadic. The mean tumor size was 1.64 cm (SD: 0.6, range: 0.5-2.6 cm). At the time of CI, 11 patients had prior microsurgery, 6 patients had prior radiation to the ipsilateral tumor, and 7 patients had stable tumors without prior surgery or radiation. Device use was classified as regular (>7 hours/day) in 15 (47%), limited (<7 hours/day) in 12 (38%), and nonuse is 5 (16%). The audiometric outcomes of 26 patients are reported, as the other 6 patients have been implanted too recently for review. Auditory perception was achieved in 24/26 patients. The two patients who failed to achieve auditory perception underwent prior surgery. Open-set speech recognition (WRS > 20%) was achieved in 18 patients. Meaningful sound perception but without significant open-set speech (WRS < 20%) was seen in six patients. Altogether, the mean WRS at most recent follow-up (mean: 3.4 years, SD: 1.8) for the observation, microsurgery, and radiation cohorts was 51% (SD: 15), 36% (SD: 28), and 39% (SD: 26), respectively. Over long-term follow-up, two patients experienced decline in CI performance associated with tumor regrowth and necessitated additional surgery; both underwent explantation of the CI and successful auditory brainstem implantation. The remaining patients have demonstrated durable benefit. A multivariate analysis is presented to evaluate the effects of the following variables: duration of deafness, time interval between treatment and CI, diagnosis of NF2, treatment cohort, pathology, and status of hearing in the contralateral ear.
Conclusion(s): In appropriately selected patients, cochlear implantation is feasible for the rehabilitation of hearing loss due to retrocochlear pathology and/or its treatment. Given the heterogeneity inherent to this population, outcomes are variable. In most cases, auditory percept was achieved and over half of the patients obtained open-set speech perception, irrespective of prior management and treatment

BACKGROUND:Measurement of the angular depth of insertion (aDOI) of cochlear implant electrode arrays has numerous clinical and research applications. Plain-film radiographs are easily obtained intraoperatively and have been described as a means to calculate aDOI. CT imaging with 3D reformatting can also be used for this measurement, but is less conveniently obtained and requires higher radiation doses, a particular concern in pediatrics. The extent to which plain-film and 3D CT image-based measurements are representative of the true position of the electrode within the cochlea is unknown. METHODS:Cochlear implantation was performed on 10 cadaveric temporal bones. Five bones were implanted with perimodiolar electrodes (Contour Advance TM, Cochlear, Sydney, Australia) and five were implanted with lateral wall electrodes (Slim Straight, Cochlear). The insertion depths of the electrodes were varied. Each bone was imaged with a radiograph and CT. aDOI was measured for each bone in each imaging modality by a neurotologist and a neuroradiologist. To obtain a 'gold standard' estimate of aDOI, the implanted temporal bones were embedded in an epoxy resin and methodically sectioned at 100 μm intervals; histologic images were captured at each interval. A 3D stack of the images was compounded, and a MATLAB script used to calculate aDOI of the most apical electrode. Measurements in the three modalities (radiograph, CT, and histology) were then compared. RESULTS:The average aDOI across all bones was similar for all modalities: 423° for radiographs, 425° for CT scans, and 427° for histology, indicating that neither imaging modality resulted in large systematic errors. Using the histology-measured angles as a reference, the average error for CT-based measures (regardless of whether the error was in the positive or negative direction) was 12°, and that for radiograph-based measures was 15°. This small difference (12 vs 15° error) was not statistically significant. CONCLUSION/CONCLUSIONS:Based on this cadaveric temporal bone model, both radiographs and CTs can provide reasonably accurate aDOI measurements. In this small sample, and as expected, the CT-based estimates were more accurate than the radiograph-based measurements. However, the difference was small and not statistically significant. Thus, the use of plain radiographs to calculate aDOI seems judicious whenever it is desired to prevent unnecessary radiation exposure and expense.

Background/UNASSIGNED:Harmony is an important part of tonal music that conveys context, form and emotion. Two notes sounded simultaneously form a harmonic interval. In normal-hearing (NH) listeners, some harmonic intervals (e.g., minor 2nd, tritone, major 7th) typically sound more dissonant than others (e.g., octave, major 3rd, 4th). Because of the limited spectro-temporal resolution afforded by cochlear implants (CIs), music perception is generally poor. However, CI users may still be sensitive to relative dissonance across intervals. In this study, dissonance ratings for harmonic intervals were measured in 11 unilaterally deaf CI patients, in whom ratings from the CI could be compared to those from the normal ear. Methods/UNASSIGNED:Stimuli consisted of pairs of equal amplitude MIDI piano tones. Intervals spanned a range of two octaves relative to two root notes (F3 or C4). Dissonance was assessed in terms of subjective pleasantness ratings for intervals presented to the NH ear alone, the CI ear alone, and both ears together (NH + CI). Ratings were collected for both root notes for within- and across-octave intervals (1-12 and 13-24 semitones). Participants rated the pleasantness of each interval by clicking on a line anchored with "least pleasant" and "most pleasant." A follow-up experiment repeated the task with a smaller stimulus set. Results/UNASSIGNED:< 0.001). Ratings were similar between NH-only and NH + CI listening, with no significant binaural enhancement/interference. The follow-up tests showed that ratings were reliable for the least and most pleasant intervals. Discussion/UNASSIGNED:Although pleasantness ratings were less differentiated for the CI ear than the NH ear, there were similarities between the two listening modes. Given the lack of spectro-temporal detail needed for harmonicity-based distinctions, temporal envelope interactions (within and across channels) associated with a perception of roughness may contribute to dissonance perception for harmonic intervals with CI-only listening.

OBJECTIVE:Given rising scrutiny of healthcare expenditures, understanding intervention costs is increasingly important. This study aimed to compare and characterize costs for vestibular schwannoma (VS) management with microsurgery and radiosurgery to inform practice decisions and appraise cost reduction strategies. METHODS:In conjunction with medical records, internal hospital financial data were used to evaluate costs. Total cost was divided into index costs (costs from arrival through discharge for initial intervention) and follow-up costs (through 36 months) for 317 patients with unilateral VSs undergoing initial management between June 2011 and December 2015. A retrospective matched cohort based on tumor size with 176 patients (88 undergoing each intervention) was created to objectively compare costs between microsurgery and radiosurgery. The full sample of 203 patients treated with resection and 114 patients who underwent radiosurgery was used to evaluate a broad range of outcomes and identify cost contributors within each intervention group. RESULTS:Within the matched cohort, average index costs were significantly higher for microsurgery (100% by definition, because costs are presented as a percentage of the average index cost for the matched microsurgery group; 95% CI 93-107) compared to radiosurgery (38%, 95% CI 38-39). Microsurgery had higher average follow-up costs (1.6% per month, 95% CI 0.8%-2.4%) compared to radiosurgery (0.5% per month, 95% CI 0.4%-0.7%), largely due to costs incurred in the initial months after resection. A major contributor to total cost and cost variability for both resection and radiosurgery was the need for additional interventions in the follow-up period, which were necessary due to complications or persistent functional deficits. Although tumor size was not associated with increased total costs for radiosurgery, linear regression analysis demonstrated that, for patients who underwent microsurgery, each centimeter increase in tumor maximum diameter resulted in an estimated increase in total cost of 50.2% of the average index cost of microsurgery (95% CI 34.6%-65.7%) (p < 0.001, R2 = 0.17). There were no cost differences associated with the proportion of inpatient days in the ICU or with specific surgical approach for patients who underwent resection. CONCLUSIONS:This study is the largest assessment to date based on internal cost data comparing VS management with microsurgery and radiosurgery. Both index and follow-up costs are significantly higher when tumors were managed with resection compared to radiosurgery. Larger tumors were associated with increased resection costs, highlighting the incremental costs associated with observation as the initial management.

OBJECTIVE:To assess auditory brainstem implant (ABI) outcomes in children with a prospective study. METHODS:Twelve patients with cochlear nerve deficiency received an auditory brainstem implant. Patients were evaluated with age appropriate speech perception and production assessments, and health related quality of life (HRQoL) surveys for parents of subjects and for subjects if age appropriate. RESULTS:Twelve patients received an ABI without major complications. Eleven out of twelve received some auditory benefit from their ABI. Parental HRQoL ratings were positive for all domains with the exception of communication. Self reported overall HRQoL metrics from two subjects were also positive. CONCLUSIONS:ABI is a good option for patients who are not eligible for or fail CI. Our findings show that despite varying degrees of postoperative performance, HRQoL ratings were positive. The presence of additional disabilities and health problems resulted in less positive HRQoL outcomes. Our results emphasize the need to assess outcomes in these patients beyond speech perception and communication.

OBJECTIVE:To assess bimodal auditory performance in children with a cochlear implant (CI) and contralateral auditory brainstem implant (ABI). METHODS:This is a retrospective case review performed at a tertiary referral center. Four patients with cochlear nerve deficiency initially underwent cochlear implantation but were not benefiting from their devices and underwent ABI in the contralateral ear. The main outcome measures included age-appropriate speech perception and production assessments. RESULTS:Three subjects performed better on their auditory perception assessments using both of their devices than with either device alone. One subject had only preliminary outcomes, but subjectively performed best with both devices. CONCLUSIONS:We observed continued improvement in CI performance over time, even if no benefit was evident before the decision for ABI. This could suggest that ABI and CI have a synergistic effect, or it could simply be the adaptive ability of the developing brain to utilize the signals coming from these devices. There is preliminary evidence to support choosing the ear contralateral to the CI for an ABI in a pediatric patient with bilateral cochlear nerve deficiency.