Multiple processes of vocal sensory-motor interaction in primate auditory cortex.

Sensory-motor interactions in the auditory system play an important role in vocal self-monitoring and control. These result from top-down corollary discharges, relaying predictions about vocal timing and acoustics. Recent evidence suggests such signals may be two distinct processes, one suppressing neural activity during vocalization and another enhancing sensitivity to sensory feedback, rather than a single mechanism. Single-neuron recordings have been unable to disambiguate due to overlap of motor signals with sensory inputs. Here, we sought to disentangle these processes in marmoset auditory cortex during production of multi-phrased 'twitter' vocalizations. Temporal responses revealed two timescales of vocal suppression: temporally-precise phasic suppression during phrases and sustained tonic suppression. Both components were present within individual neurons, however, phasic suppression presented broadly regardless of frequency tuning (gating), while tonic was selective for vocal frequencies and feedback (prediction). This suggests that auditory cortex is modulated by concurrent corollary discharges during vocalization, with different computational mechanisms.

Reassessing the Utility of Surgical Intervention for Skull Base Osteomyelitis: A 16-Year Experience.

OBJECTIVE: The role of surgery in lateral skull base osteomyelitis (SBO) is controversial. Surgical intervention is often requested by consulting services in the interest of additional culture data to inform medical management. However, whether surgery alters subsequent antibiotic treatment or modifies disease outcome remains unknown. The aim of this study was to investigate the role of surgical intervention in the treatment of SBO by (1) comparing nonsurgical and surgical culture data and (2) assessing clinical outcomes and treatment course following surgical intervention. STUDY DESIGN: Retrospective. SETTING: Tertiary care center. METHODS: The electronic record was queried for all patients with SBO who presented to a single institution over a 16-year period (2007-2023). Information recorded included history and exam, bedside and intraoperative culture data, antibiotic course, and disease outcomes. Primary outcome measures included change in medical management based on intraoperative cultures, recurrence rates, and mortality rates. RESULTS: Forty patients (41 ears, average age 73 ± 13 years) met inclusion criteria. Out of 13 (32%) patients who underwent surgical intervention, one intraoperative culture changed the antibiotic course due to identification of resistance to the original antibiotic used. Surgery did not demonstrate a benefit in overall mortality (23% vs 18%, P = 0.36) or facial nerve function (33% vs 50%, P = 0.56) compared to medical management, and was associated with increased recurrence rates (54% vs 11%, P = 0.05). CONCLUSION: Surgical cultures rarely changed antibiotic selection. Surgical debridement in treatment-refractory SBO was also not associated with improvement in recurrence or mortality rates, though this may reflect underlying differences in disease severity.

Frontal-Auditory Cortical Interactions and Sensory Prediction During Vocal Production in Marmoset Monkeys.

The control of speech and vocal production involves the calculation of error between the intended vocal output and the resulting auditory feedback. Consistent with this model, recent evidence has demonstrated that the auditory cortex is suppressed immediately before and during vocal production, yet is still sensitive to differences between vocal output and altered auditory feedback. This suppression has been suggested to be the result of top-down signals containing information about the intended vocal output, potentially originating from motor or other frontal cortical areas. However, whether such frontal areas are the source of suppressive and predictive signaling to the auditory cortex during vocalization is unknown. Here, we simultaneously recorded neural activity from both the auditory and frontal cortices of marmoset monkeys while they produced self-initiated vocalizations. We found increases in neural activity in both brain areas preceding the onset of vocal production, notably changes in both multi-unit activity and local field potential theta-band power. Connectivity analysis using Granger causality demonstrated that frontal cortex sends directed signaling to the auditory cortex during this pre-vocal period. Importantly, this pre-vocal activity predicted both vocalization-induced suppression of the auditory cortex as well as the acoustics of subsequent vocalizations. These results suggest that frontal cortical areas communicate with the auditory cortex preceding vocal production, with frontal-auditory signals that may reflect the transmission of sensory prediction information. This interaction between frontal and auditory cortices may contribute to mechanisms that calculate errors between intended and actual vocal outputs during vocal communication.

Meningitis Risk and Role of Prophylactic Antibiotics in Spontaneous Lateral Skull Base CSF Leaks.

OBJECTIVE: To review the literature and our institutional experience regarding the risk of meningitis in patients with spontaneous lateral skull base cerebrospinal fluid (sCSF) leaks awaiting surgical repair, and the roles of antibiotic prophylaxis and pneumococcal vaccination, if known. METHODS: A retrospective chart review and systematic review of the literature was undertaken to identify the incidence of meningitis in patients with sCSF leaks awaiting surgical repair. Adults managed surgically for sCSF leaks at an academic tertiary care center over a 10-year period were included. Data was collected on receipt of prophylactic antibiotics and/or pneumococcal vaccines during the timeframe between diagnosis and surgical repair. RESULTS: Institutional review identified 87 patients who underwent surgical repair of spontaneous leaks, with a 0% incidence of meningitis over a median duration of 2 months while awaiting surgery (mean 5.5 months, range 0.5-118 months). Eighty-eight percent of patients did not receive prophylactic antibiotics. No studies in the published literature demonstrated the impact of prophylactic antibiotics or pneumococcal vaccine on meningitis risk. CONCLUSIONS: There appears to be a low risk of meningitis among patients with lateral skull base sCSF leaks awaiting surgery for short durations (≤2 months), even in the absence of prophylactic antibiotics. There is a substantial gap in the published literature assessing the risk of meningitis and roles of antibiotics and vaccination in this patient population, indicating the need for large-scale study to conclusively elucidate the nature of this risk.

Impact of Anticholinergic Medications on Speech Perception Performance after Cochlear Implantation.

OBJECTIVE: To identify and characterize the impact of anticholinergic medications, which have known adverse effects on cognition in older adults, on speech perception after cochlear implantation. STUDY DESIGN: Retrospective cohort. SETTING: Tertiary referral center. SUBJECT POPULATION: Adult patients who underwent cochlear implantation between January 2010 and September 2020 with speech perception scores at 3, 6, and 12 months. INTERVENTIONS: Anticholinergic burden of patients' prescribed medications. MAIN OUTCOME MEASURES: AzBio speech perception scores after implantation. RESULTS: One hundred twenty-six patients had documented AzBio in quiet speech perception score at all three postactivation time points. Patients were divided into three groups by anticholinergic burden (ACB) score, including ACB = 0 (90 patients), 1 (23 patients), and ≥2 (13 patients). There was no statistically significant difference between ACB groups in audiologic performance at candidacy testing ( p = 0.77) or at 3 months after implantation ( p = 0.13). Beginning at 6 months, a lower mean AzBio was seen in patients with higher ACB scores (68% ACB = 0; 62% ACB = 1; 48.1% ACB ≥ 2; p = 0.03). At 12 months, there were further differences between the groups (71.0% ACB = 0, 69.5% ACB = 1, 48.0% ACB ≥2, p < 0.01). Controlling for the effects of age using multivariate linear regression showed persistent effects of ACB score on learning-related AzBio improvements. Comparatively, the negative impact of a single ACB score point was equivalent to nearly 10 years of aging ( p = 0.03). CONCLUSIONS: Increased ACB is associated with worse speech perception scores after cochlear implantation, an effect that persists even when accounting for patient age, suggesting that these medications may have cognitive and learning effects that reduce cochlear implant performance.

Effects of Cortical Stimulation on Feedback-Dependent Vocal Control in Non-Human Primates.

OBJECTIVES: Hearing plays an important role in our ability to control voice, and perturbations in auditory feedback result in compensatory changes in vocal production. The auditory cortex (AC) has been proposed as an important mediator of this behavior, but causal evidence is lacking. We tested this in an animal model, hypothesizing that AC is necessary for vocal self-monitoring and feedback-dependent control, and that altering activity in AC during vocalization will interfere with vocal control. METHODS: We implanted two marmoset monkeys (Callithrix jacchus) with bilateral AC electrode arrays. Acoustic signals were recorded from vocalizing marmosets while altering vocal feedback or electrically stimulating AC during random subsets of vocalizations. Feedback was altered by real-time frequency shifts and presented through headphones and electrical stimulation delivered to individual electrodes. We analyzed recordings to measure changes in vocal acoustics during shifted feedback and stimulation, and to determine their interaction. Results were correlated with the location and frequency tuning of stimulation sites. RESULTS: Consistent with previous results, we found electrical stimulation alone evoked changes in vocal production. Results were stronger in the right hemisphere, but decreased with lower currents or repeated stimulation. Simultaneous stimulation and shifted feedback significantly altered vocal control for a subset of sites, decreasing feedback compensation at some and increasing it at others. Inhibited compensation was more likely at sites closer to vocal frequencies. CONCLUSIONS: Results provide causal evidence that the AC is involved in feedback-dependent vocal control, and that it is sufficient and may also be necessary to drive changes in vocal production. LEVEL OF EVIDENCE: N/A Laryngoscope, 133:1-10, 2023.

Diagnostic Yield and Utility of Radiographic Imaging in the Evaluation of Pulsatile Tinnitus: A Systematic Review.

Objective: The objective of this study is to assess diagnostic yield of imaging modalities used to evaluate patients presenting with pulsatile tinnitus (PT). Databases Reviewed: PubMed, Embase, and Scopus were queried using the search terms "pulsatile tinnitus," "pulse-synchronous tinnitus," and "pulse synchronous tinnitus" with no date limitations. Methods: Studies that reported diagnostic imaging for patients presenting with PT were included. Data were reviewed for sample size, gender, age, imaging study, indications, and diagnoses. The primary outcome measure from aggregated data was the yield of positive diagnoses made with each imaging modality. The quality of evidence was assessed for risk of bias. Results: From an initial search of 1145 articles, 17 manuscripts met inclusion criteria, of which 12 studies evaluated individual imaging modalities. The number of unique patients included was 1232. The diagnostic yield varied between modalities: carotid ultrasound (21%, 95% confidence interval [CI]: 12%-35%), CT temporal bone (65%, CI: 20%-93%), computed tomographic angiography (86%, CI: 80%-90%), and MRI/magnetic resonance angiography (58%, CI: 43%-72%). Conclusion: Studies on the diagnostic approach to PT are limited by heterogeneity in both inclusion criteria and reporting standards. A wide range of imaging modalities are used in practice during the initial evaluation of PT, and the diagnostic yield for imaging can be improved by utilizing more specific clinical indications.

Audiometric and Surgical Outcomes of a Novel Bone-Conduction Hearing Aid.

OBJECTIVE: To report the audiometric and surgical outcomes of a series of patients having undergone implantation of a novel transcutaneous bone conduction implant (t-BCI). STUDY DESIGN: Retrospective case series. SETTING: Single academic tertiary referral center. PATIENTS: Adults (≥18 yr) implanted between December 1, 2019, and August 1, 2021, with audiometric data available before and after device implantation and a minimum of 4 weeks follow-up. INTERVENTIONS: Surgical t-BCI. MAIN OUTCOME MEASURES: Change in aided pure tone average (PTA) after implantation. Secondary outcomes include average operative time, and adverse events. RESULTS: Twenty-three patients underwent implantation of the t-BCI via either a conventional or minimally invasive surgical approach. The most common indication for implantation was unilateral conductive hearing loss with a history of chronic otitis media. The mean operative time was 59 minutes. The mean preimplantation unaided air conduction PTA was 65 dB, and mean postimplantation was 27.2 dB. The mean change in PTA was 37.8 dB, which was significant ( p < 0.0001). There were 30.4% of the patients that suffered from adverse events, the most common of which were pain (8.7%) and device-related complications (13%). One major adverse event occurred, involving magnet displacement that impaired device activation and required reoperation for replacement. CONCLUSION: Forming the largest series of patients implanted with this t-BCI in the published literature, our data demonstrate that implantation of the device is feasible via either a traditional or minimally invasive surgical approach, with good audiometric benefit and a favorable safety profile.

Pure tone audiometry as assessed by a commercially-available mobile phone application compared to formal audiometry.

PURPOSE: Comparison of audiometric measurements of commercially available smartphone audiogram application thresholds as compared to gold standard audiometric evaluation. MATERIALS AND METHODS: A single-institution, original contribution. Ninety consecutive adult patients presenting to a tertiary care auditory clinic with auditory complaints were evaluated using standard audiometric testing and an application-based hearing test. Correlation between app results and standard audiogram for air conduction pure tone thresholds was evaluated. RESULTS: Mimi™ (Berlin, Germany) results for audiometric thresholds were moderately correlated with standard audiogram (r = 0.51-0.68) depending on severity. The percentage of patients whose hearing loss severity on formal audiometry results were accurately reflected in the Mimi™ (app-based hearing test: ABHT)1 results ranged from 18.2 to 80 %. Among patients whose results were at the extremes of hearing performance, app and standard audiogram results were similar. ABHT yielded an overall sensitivity of 35.5 % and specificity of 97.1 % for normal hearing, and an overall sensitivity of 80 % and specificity of 96 % for severe hearing loss. CONCLUSIONS: Results from an audiometric smart phone application showed accurate categorization of hearing loss at the high and extremes as compared to standard audiometry. However, correlation of pure tone values was more variable and dependent on hearing level.

Comparison of Outcomes of Surgical Repair of Spontaneous Temporal Bone CSF Leaks and Encephaloceles Using Bone Cement and Autologous Material.

OBJECTIVE: To compare outcomes transmastoid repair of spontaneous middle fossa cerebrospinal fluid (CSF) leak using only bone cement (BC) versus only autologous material (AM) or combined materials (CM) with both bone cement and autologous material. STUDY DESIGN: Retrospective Chart Review. SETTING: Tertiary Care Hospital. PATIENTS: Forty-three adult patients undergoing transmastoid repair of spontaneous middle fossa CSF leak between 2014 and 2020 (BC:12, AM:15, CR:16). INTERVENTIONS: Cortical mastoidectomy, identification of defect, and repair with BC (Cranios® hydroxyapatite), AM (local bone, fascia, fat, and/or cartilage), or CM (Cranios® combined with autologous materials). MAIN OUTCOME MEASURES: Successful repair without recurrent CSF leak or encephalocele throughout follow up. RESULTS: Fifty-one percent of subjects were female. Mean age at repair was 58.6 years (SD 10.9). Mean BMI was 35.4 (SD 7.6; BC:36.3, AM:36.5, CM:33.6). Forty (93%) patients had successful repair without known recurrent CSF leak or encephalocele since surgery (BC:11, 91.6%; AM:14, 93.3%; CM:15, 93.8%; p = 0.49) over a mean length of follow up of 49.6 months (BC: 37.9, AM: 59.2, CR: 49.5). The difference in mean operative time amongst the groups was faster for patients using bone cement (BC: 100.2 min, AM: 182.8, CM: 133.2; p < 0.00001). CONCLUSIONS: BC, AM, and CM techniques each demonstrate effective and sustained means of repair for middle fossa CSF leak and encephalocele, even in the presence of multiple defects. Use of isolated BC offers a significant decrease in operative time with a noninferior outcome. Active CSF leak at the time of surgery is associated with increased risk of recurrence.

Rates of Sensorineural Hearing Loss and Revision Surgery After Stapedotomy: A Single-institution Experience Using the Nitinol Prosthesis.

Background: Historically, stapedectomy complication rates are quoted as 1% profound postoperative sensorineural hearing loss (SNHL), 5%-10% nonprofound SNHL, and 5%-10% revision surgery. Objective: We sought to reassess rates of post-stapedotomy complications based on our experience using contemporary surgical technique. Methods: A retrospective case series was carried out at an academic tertiary referral center. Adult patients undergoing stapedotomy from 2013 to 2020 were included. Primary outcomes were rates of hearing loss and revision surgery. Rates of dizziness, tinnitus, dysgeusia, and proportions of patients who achieved air-bone gap (ABG) closure at 8-12 weeks postoperatively were also assessed. Results: Four hundred sixty-eight stapedotomies in 399 patients with a median follow-up duration of 99 days (range, 11-5134) were reviewed. One patient (0.21%) suffered profound SHNL and 15 (3.20%) patients suffered nonprofound SNHL. The revision rate for stapedotomies from our institution was 4.49% (21 total revision surgeries). In 277 operations (59.19%), the patient had closure of the ABG within 10 dB. A further 132 (28.21%) had closure of the ABG between 10 and 20 dB. Air pure-tone audiometry scores improved by an average of 25.03 dB. Eighty-three (17.74%) patients complained of postoperative dizziness, which resolved by the time of the first follow-up appointment in all but 26 (5.56%). Seventeen patients (3.63%) complained of tinnitus, and 22 (4.70%) complained of dysgeusia. Conclusions: SNHL, complications, and revision rates for stapedotomy in the modern era may be substantially lower than those currently presented to patients based on classic techniques and historical data.

Age-related Patterns of Vestibular Dysfunction in Dizziness and Imbalance: A Review of Vestibular Testing Results Among 1,116 Patients.

OBJECTIVE: To characterize differences in vestibular testing results among patients presenting with balance-related complaints; to stratify patterns of testing abnormalities by age. STUDY DESIGN: Retrospective chart review. SETTING: Academic Balance Center at a Tertiary Referral Center. PATIENT POPULATION: All patients who underwent vestibular testing in a 1-year period from 2017 to 2018. MAIN OUTCOME MEASURE: Balance function test results. RESULTS: We reviewed 1,116 patients with age ranging from 11 to 94 years, including 521 patients ≥60 years. Most patients had at least 1 abnormal result, with only 21% of patients ≥60 years and 43% of patients <60 years yielding no test abnormalities (p < 0.001). Among 754 individuals with abnormal testing results, caloric testing did not show any significant difference between age groups. Patients ≥60 years of age were more likely to demonstrate abnormalities on saccadic and horizontal tracking eye movements (p < 0.01; sacc 20.8% vs 6.3%; HT 9.2% vs 4.7%), as well as positional and Dix-Hallpike testing with videonystagmography (p < 0.001; pos 52.3% vs 37.5%, DH 14.4% vs 6.8%). On computerized dynamic posturography, there were significantly more abnormal composite scores in the older group for both sensory organization and motor control testing (p < 0.001; SOT 31.8% vs 8.8%, MCT 7.6% vs 1.8%). CONCLUSION: Among patients presenting balance-related complaints, a majority demonstrate at least one abnormality on vestibular testing. While caloric abnormalities occur across the life span, patients ≥60 years of age are more likely to have abnormal results in random saccades, positional, Dix-Hallpike testing, and posturography, with greater effect sizes in tests of central function. While the causes of imbalance and vertigo remain multifactorial, vestibular dysfunction can be considered a major contributor to balance dysfunction in the elderly population and should be thoroughly evaluated.

Current practices in nutrition management and disease incidence of common marmosets (Callithrix jacchus).

BACKGROUND: A survey was developed to characterize disease incidence, common pathology lesions, environmental characteristics, and nutrition programs within captive research marmoset colonies. METHODS: Seventeen research facilities completed the electronic survey. RESULTS: Nutritional management programs varied amongst research institutions housing marmosets; eight primary base diets were reported. The most common clinical syndromes reported were gastrointestinal disease (i.e. inflammatory bowel disease like disease, chronic lymphocytic enteritis, chronic malabsorption, chronic diarrhea), metabolic bone disease or fracture, infectious diarrhea, and oral disease (tooth root abscesses, gingivitis, tooth root resorption). The five most common pathology morphologic diagnoses were colitis, nephropathy/nephritis, enteritis, chronic lymphoplasmacytic enteritis, and cholecystitis. Obesity was more common (average 20% of a reporting institution's population) than thin body condition (average 5%). CONCLUSIONS: Through review of current practices, we aim to inspire development of evidence-based practices to standardize husbandry and nutrition practices for marmoset research colonies.

Predictors of Postoperative Electrode Deactivation Among Adult Cochlear Implantees.

OBJECTIVE: To characterize postoperative electrode functionality after adult cochlear implantation; to identify rationale and risk factors for electrode deactivation. STUDY DESIGN: Retrospective Chart Review. SETTING: Academic Cochlear Implant Center. SUBJECT POPULATION: Five hundred nineteen cochlear implants in 433 adult patients over 5 years. INTERVENTIONS: Unilateral or bilateral cochlear implantation. MAIN OUTCOME MEASURES: Rate of electrode deactivation after adult cochlear implantation. RESULTS: One hundred twenty (27.7%) patients experienced electrode deactivation postoperatively, involving a total of 447 electrodes. The most common reasons for deactivation were bothersome nonauditory symptoms (n = 170, 38.0%), perceived benefit by patients (n = 64, 14.3%), and bothersome auditory symptoms (n = 60, 13.4%). Four hundred nineteen (93.7%) of involved electrodes remained deactivated at most recent follow-up, whereas 28 (6.3%) were able to be reactivated. Deactivation was most likely to occur within the first 4 weeks after activation (n = 90 patients,75.0%; p < 0.01). Among affected patients, the average number of electrodes deactivated was 3.44 (range 1-13; SD 2.50). Age was not associated with electrode deactivation. CONCLUSIONS: While 98% of cochlear implants had full insertions, more than a quarter of implantees may experience electrode deactivation postoperatively for a multitude of reasons, with bothersome nonauditory symptoms most prevalent. Deactivation of five or more electrodes and simultaneous deactivation of two or three electrodes seems to increase the odds of subsequent device failure. However, deactivation encompasses a wide range of issues that likely include patient factors, surgical technique, and device-specific issues. Prognosis varies greatly at the individual level and further evaluation is required to better identify the issues underlying deactivation and identify true predictors of failure.

Streamlining the Cochlear Implant Evaluation: Utility of Community Audiometry in Cochlear Implant Candidacy Assessment.

OBJECTIVE: To identify redundancy in the cochlear implant candidacy evaluation and assess its financial impact. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary care academic cochlear implant center. PATIENTS: One hundred thirty-five patients referred for cochlear implant candidacy evaluation from 2004 through 2019. INTERVENTION: Community and academic audiometry were compared in a matched-pair analysis. MAIN OUTCOME MEASURES: Pure-tone audiometry and word recognition scores (WRS) were compared using the Wilcoxon signed-rank test. Cost of repeated audiometry was estimated using the Medicare Provider Utilization and Payment data. RESULTS: The majority of pure-tone thresholds (PTT) and pure-tone averages (PTA) had no statistically significant differences between community and academic centers. Only air PTT at 2000 Hz on the right and air PTA on the right demonstrated differences with α = 0.05 after Bonferroni correction. Despite statistical differences, mean differences in PTT and PTA were all under 3.5 dB. WRS were on average lower at the academic center, by 14.7% on the right (p < 0.001) and 10.6% on the left (p = 0.003). Repeating initial audiometry costs patients up to $60.58 and costs the healthcare system up to $42.94 per patient. CONCLUSIONS: Pure-tone audiometry between community and academic centers did not demonstrate clinically significant differences. Lower academic WRS implies that patients identified as potential cochlear implant candidates based on community WRS are likely suitable to proceed to sentence testing without repeating audiometry, saving patients and the healthcare system time and resources.

Bitter Taste Receptors and Chronic Otitis Media.

OBJECTIVE: To evaluate the presence of bitter taste receptors (T2Rs) in the middle ear and to examine their relationship with chronic ear infections. STUDY DESIGN: Cross-sectional study. SETTING: Tertiary care hospital. METHODS: This study enrolled 84 patients being evaluated for otologic surgery: 40 for chronic otitis media (COM) and 44 for other surgical procedures (controls). We collected a small piece of mucosa from 14 patients for mRNA analysis and from 23 patients for immunohistochemistry. A total of 55 patients underwent a double-blind taste test to gauge sensitivity to phenylthiocarbamide, denatonium, quinine, sucrose, and sodium chloride; 47 patients gave a salivary sample for single-nucleotide polymorphism analysis of rs1376251 (TAS2R50) and rs1726866 (TAS2R38). RESULTS: Bitter taste receptors were found in all samples, but the repertoire varied among patients. T2R50 was the most consistently identified receptor by mRNA analysis. Its rs1376251 allele was related to susceptibility to COM but not the expression pattern of T2R50. Ratings of bitterness intensity of phenylthiocarbamide, a ligand for T2R38, differed significantly between the COM and control groups. CONCLUSION: T2Rs were found within the middle ear of every patient sampled; the rs1376251 allele of TAS2R50 appears to be related to chronic ear infections. These receptors are an intriguing target for future research and possible drug targeting.

A Rare Case of Temporal Bone Pneumocephalus Tracking through the Internal Auditory Canal.

A 39-year-old male with chronic hydrocephalus requiring biventricular shunts presented with progressive pneumocephalus over several years. He showed no improvement following ventriculoperitoneal (VP) shunt revision and anterior skull base repair for a sphenoid dehiscence. Imaging continued to show worsening pneumocephalus with air tracking along the right facial nerve from the geniculate ganglion to the internal auditory canal (IAC). The patient then underwent tympanomastoidectomy and skull base reconstruction. Based on a search of published literature, this appears to be the first reported case of temporal bone pneumocephalus coursing through the IAC, unlike most cases associated with tegmen defects and middle fossa pneumocephalus.

Failure and Revision Surgery After Cochlear Implantation in the Adult Population: A 10-year Single-institution Retrospective and Systematic Review of the Literature.

OBJECTIVE: To characterize failure rate and etiology after cochlear implantation; to identify predictors and describe outcomes after implant failure. STUDY DESIGN: Retrospective chart review and systematic review of the literature using PubMed and Embase. SETTING: Academic Cochlear Implant Center. SUBJECT POPULATION: Four hundred ninety-eight devices in 439 distinct adult patients. INTERVENTIONS: Unilateral or bilateral cochlear implantation. MAIN OUTCOME MEASURES: Implant failure rate and etiology. RESULTS: A total of 32 devices (5.9%) failed in 31 patients encompassing the following failure types in accordance with the European Consensus Statement of Cochlear Implants: 17 device failures (53.1%), 11 failures due to performance decrement/adverse reactions (34.4%), and 4 medical reasons (12.9%). There was no significant difference in age, sex, or manufacturer between patients with and without failures. Twenty-five percent of patients with failure leading to explantation had childhood onset of deafness compared to 12.1% of patients with adult-onset hearing loss (OR = 2.42; p = 0.04). Performance decrement/adverse reaction patients had an older average age at implantation compared to device failure patients (mean 68.5 yr 95% CI: 59.9-77.1 vs mean 47.6 yr, CI: 39.9-55.3, p < 0.01). There was no significant difference in time to failure, sex, or device manufacturer between the different types of failures. Twenty-nine patients who experienced CI failure underwent a revision surgery, while the remaining two opted for explantation without reimplantation. One patient who underwent revision surgery subsequently presented with a second failure and underwent a second revision, which was successful.In our systematic review, 815 citations were reviewed, and 9 studies were selected for inclusion. Overall failure rate across all studies was 5.5%. Device failure was the leading cause of failure in the majority (6/9) of studies, accounting for 40.8% of all failures. Medical reasons were the second leading cause at 33.6%, followed by performance decrement/adverse reaction (20.9%) and other (4.8%). CONCLUSIONS: Cochlear implant failure is a rare phenomenon. Childhood-onset of hearing loss appears to be associated with an increased risk of overall failure. Older patients are at increased risk for performance decrement/adverse reaction. Revision surgery success rates remain very high and patients with failure of any cause should be offered explantation with concurrent reimplantation.

Auditory Feedback Control of Vocal Pitch in Spasmodic Dysphonia.

OBJECTIVES/HYPOTHESIS: Hearing plays an important role in the maintenance of vocal control in normal individuals. In patients with spasmodic dysphonia (SD), however, the ability to maintain sustained control of phonation is impaired. The origins of SD are unknown, and it is unclear whether auditory feedback-dependent vocal control is compromised in these patients. STUDY DESIGN: Prospective case-control study. METHODS: We tested 15 SD patients and 11 age-matched controls. Voice recordings were performed while subjects repeated the vowel /e/ and auditory feedback of their vocal sounds was altered in real-time to introduce a pitch-shift (±2 semitones), presented back to subjects using headphones. Recordings were analyzed to determine voice changes following the pitch-shifted feedback. Results were further compared with patient demographics and subjective measures of dysphonia, including the Voice Handicap Index (VHI). RESULTS: Despite considerable pitch variability and vocal breaks, SD patients exhibited significantly higher average vocal pitch compensation than control subjects. SD patients also exhibited greater variability than controls. However, there were no significant correlations between vocal compensation and patient demographics, although there was a significant inverse correlation with VHI. CONCLUSIONS: In this pilot study, patients with SD exhibited increased sensitivity to altered auditory feedback during sustained phonation. These results are consistent with recent theories of SD as a disorder of sensory-motor feedback processing, and suggest possible avenues for future investigation. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:2070-2075, 2021.