Toward a Diagnostic Imaging Algorithm for Undifferentiated Pulsatile Tinnitus.

OBJECTIVE: Decisions around the diagnostic evaluation for pulsatile tinnitus (PT) remain challenging. We describe the usage patterns and diagnostic accuracy of imaging modalities and propose an evidence-based diagnostic approach for undifferentiated PT. STUDY DESIGN: Retrospective. SETTING: Single otology/neurotology clinic. SUBJECTS: Patients with PT presenting between 2009 and 2020. MAIN OUTCOME MEASURES: Sensitivity, specificity, diagnostic yield, and diagnostic accuracy. RESULTS: A total of 315 subjects met inclusion criteria (74% female, mean ± SD age = 52 ± 17 years). Subjects were divided into four cohorts based on exam findings: normal (n = 229), venous cohort (n = 34), arterial cohort (n = 16), and outer/middle ear pathology cohort (n = 40). In total, 53% of patients received a nonidiopathic diagnosis for PT. The most common identifiable cause was sigmoid sinus dehiscence (78%) in the venous cohort, carotid stenosis (36%) in the arterial cohort, and glomus tumor (56%) in the outer/middle ear pathology cohort. There was a higher diagnostic rate among patients with positive exam findings compared to those with unrevealing exams ( p = 0.04). Imaging studies with the highest diagnostic yield were computed tomography (CT) venography (44%), formal angiography (42%), and magnetic resonance venography (40%); studies with the highest specificity were formal angiography (0.82), CT angiography (0.67), and CT venography (0.67). A diagnostic algorithm is proposed. CONCLUSIONS: Reaching a diagnosis in patients with PT requires a systematic approach, taking into account both clinical and radiographic information. Physical examination is a key first step for differentiating patients into venous, arterial, and other cohorts to narrow down the likely pathology and determine which radiographic studies have the highest yield and accuracy.

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.

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.

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.

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.

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.

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.