Asymmetric hearing loss: rule 3,000 for screening vestibular schwannoma

Practice Patterns in Asymmetric Sensorineural Hearing Loss: Survey Data

OBJECTIVE

Although screening protocols for patients who present with asymmetric sensorineural hearing loss (ASNHL) exist, there are no clear guidelines to direct practitioners. In particular, various thresholds have been proposed for the degree of hearing loss that should prompt MRI studies, but the topic remains understudied. This project aims to compare protocols followed by practitioners to guide their imaging practices.

STUDY DESIGN

Web-based survey.

SETTING

Otolaryngology faculty at academic medical centers.

METHODS

A list of 530 otolaryngologists (276 otology/neurotology specialists, 254 general otolaryngologists) was compiled. A survey consisting of three parts: demographics, general practice patterns, and simulated patient cases was distributed.

RESULTS

A total of 468 surveys were successfully distributed, resulting in 88 (18.8%) responses. The majority of respondents (63.8%) self-reported their definition of ASNHL as ">30 dB hearing asymmetry at one frequency OR >20 dB hearing asymmetry at two continuous frequencies OR >10 dB hearing asymmetry at three contiguous frequencies." Overall, general otolaryngologists were more likely to observe asymmetric findings with serial audiogram alone, whereas otology/neurotology specialists were more likely to obtain imaging.

CONCLUSION

There is significant variability between providers with regard to managing patients with ASNHL and evidence-based guidelines would be useful in guiding imaging practices.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:4745-4753, 2024.

Predictors of Abnormal MRI Findings in Patients with Asymmetrical Sensorineural Hearing Loss

OBJECTIVE

This study aimed to determine the predictive factors of abnormal MRI findings in patients with asymmetrical sensorineural hearing loss (ASNHL).

STUDY DESIGN

A retrospective review of medical records.

SETTING

A tertiary care hospital.

METHODS

Patients with asymmetries of ≥10 dB in at least 1 frequency, who underwent an MRI study of the temporal bone or brain during 2019-2021, were included. Age, sex, clinical symptoms, past medical history, and audiometric parameters, including pure tone thresholds, speech reception thresholds, and speech discrimination scores, were retrieved from the electronic database. The MRI findings reported by radiologists were reviewed and extracted.

RESULTS

Of 390 patients, 50 (12.8%) patients had relevant abnormal MRI findings that could explain ASNHL. The most prevalent abnormal MRI finding was an internal acoustic canal (IAC) or cerebellopontine angle (CPA) tumor (n = 38; 76.0%), with other notable abnormalities including labyrinthitis, stroke, mucocele, and epidermoid. Multiple logistic regression analysis highlighted that hearing asymmetry of 15 dB at 1000 Hz (OR = 4.8; 95% CI 2.2-10.5) was a significant variable. The proposed predictor demonstrated 84% sensitivity and 48% specificity in detecting abnormal MRI findings.

CONCLUSION

A hearing asymmetry of 15 dB at 1000 Hz was an important clinical predictor of abnormal MRI findings in patients with ASNHL. This finding has the potential to serve as a referral guide for further MRI investigations.

LEVEL OF EVIDENCE

Level 3 Laryngoscope, 2024.

Clinical Practice Guideline: Age-Related Hearing Loss

OBJECTIVE

Age-related hearing loss (ARHL) is a prevalent but often underdiagnosed and undertreated condition among individuals aged 50 and above. It is associated with various sociodemographic factors and health risks including dementia, depression, cardiovascular disease, and falls. While the causes of ARHL and its downstream effects are well defined, there is a lack of priority placed by clinicians as well as guidance regarding the identification, education, and management of this condition.

PURPOSE

The purpose of this clinical practice guideline is to identify quality improvement opportunities and provide clinicians trustworthy, evidence-based recommendations regarding the identification and management of ARHL. These opportunities are communicated through clear actionable statements with explanation of the support in the literature, evaluation of the quality of the evidence, and recommendations on implementation. The target patients for the guideline are any individuals aged 50 years and older. The target audience is all clinicians in all care settings. This guideline is intended to focus on evidence-based quality improvement opportunities judged most important by the guideline development group (GDG). It is not intended to be a comprehensive, general guide regarding the management of ARHL. The statements in this guideline are not intended to limit or restrict care provided by clinicians based on their experience and assessment of individual patients.

ACTION STATEMENTS

The GDG made strong recommendations for the following key action statements (KASs): (KAS 4) If screening suggests hearing loss, clinicians should obtain or refer to a clinician who can obtain an audiogram. (KAS 8) Clinicians should offer, or refer to a clinician who can offer, appropriately fit amplification to patients with ARHL. (KAS 9) Clinicians should refer patients for an evaluation of cochlear implantation candidacy when patients have appropriately fit amplification and persistent hearing difficulty with poor speech understanding. The GDG made recommendations for the following KASs: (KAS 1) Clinicians should screen patients aged 50 years and older for hearing loss at the time of a health care encounter. (KAS 2) If screening suggests hearing loss, clinicians should examine the ear canal and tympanic membrane with otoscopy or refer to a clinician who can examine the ears for cerumen impaction, infection, or other abnormalities. (KAS 3) If screening suggests hearing loss, clinicians should identify sociodemographic factors and patient preferences that influence access to and utilization of hearing health care. (KAS 5) Clinicians should evaluate and treat or refer to a clinician who can evaluate and treat patients with significant asymmetric hearing loss, conductive or mixed hearing loss, or poor word recognition on diagnostic testing. (KAS 6) Clinicians should educate and counsel patients with hearing loss and their family/care partner(s) about the impact of hearing loss on their communication, safety, function, cognition, and quality of life (QOL). (KAS 7) Clinicians should counsel patients with hearing loss on communication strategies and assistive listening devices. (KAS 10) For patients with hearing loss, clinicians should assess if communication goals have been met and if there has been improvement in hearing-related QOL at a subsequent health care encounter or within 1 year. The GDG offered the following KAS as an option: (KAS 11) Clinicians should assess hearing at least every 3 years in patients with known hearing loss or with reported concern for changes in hearing.

Clinical practice guideline on the management of vestibular schwannoma

INTRODUCTION

Vestibular schwannoma (VS) is the most common tumour of the cerebellopontine angle. The greater accessibility to radiological tests has increased its diagnosis. Taking into account the characteristics of the tumour, the symptoms and the age of the patient, three therapeutic strategies have been proposed: observation, surgery or radiotherapy. Choosing the most appropriate for each patient is a frequent source of controversy.

MATERIAL AND METHODS

This paper includes an exhaustive literature review of issues related to VS that can serve as a clinical guide in the management of patients with these lesions. The presentation has been oriented in the form of questions that the clinician usually asks himself and the answers have been written and/or reviewed by a panel of national and international experts consulted by the Otology Commission of the SEORL-CCC.

RESULTS

A list has been compiled containing the 13 most controversial thematic blocks on the management of VS in the form of 50 questions, and answers to all of them have been sought through a systematic literature review (articles published on PubMed and Cochrane Library between 1992 and 2023 related to each thematic area). Thirty-three experts, led by the Otology Committee of SEORL-CCC, have analyzed and discussed all the answers. In Annex 1, 14 additional questions divided into 4 thematic areas can be found.

CONCLUSIONS

This clinical practice guideline on the management of VS offers agreed answers to the most common questions that are asked about this tumour. The absence of sufficient prospective studies means that the levels of evidence on the subject are generally medium or low. This fact increases the interest of this type of clinical practice guidelines prepared by experts.

Could the Audiometric Criteria for Sudden Sensorineural Hearing Loss Miss Vestibular Schwannomas?

OBJECTIVE

To investigate the likelihood of missing a vestibular schwannoma (VS) diagnosis in patients who present with a sudden hearing loss (SHL) that does not meet the most accepted audiometric criteria for sudden sensorineural hearing loss (SSNHL) (a decrease of ≥30 dB at three consecutive frequencies).

METHODS

All adult patients (>18 years) diagnosed with SHL of any severity in a tertiary care referral medical center between 2015 and 2020 and who underwent an MRI scan to rule out VS were included. Statistical analyses were conducted to evaluate the difference between the rate of VS among patients with an initial audiogram, which met the abovementioned criteria, and those who did not. Other audiometric criteria for SNHL were also evaluated (≥10 dB at ≥2 frequencies and ≥ 15 dB at one frequency).

RESULTS

Of the 332 patients included in the study, 152 met the audiometric criteria for SSNHL, and 180 did not. Both groups had a similar VS rate (8.6% vs. 8.9%, p = 0.914). Similar results were found when other audiometric criteria for asymmetric SNHL were analyzed. In a subgroup analysis of patients with VS-associated SSNHL, neither the tumor size nor the Koos classification was associated with any of the audiometric criteria systems.

CONCLUSION

There should be a high index of suspicion for the presence of VS in patients with an SHL of any severity.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:670-675, 2023.

MRI Screening in Vestibular Schwannoma: A Deep Learning-based Analysis of Clinical and Audiometric Data

Objective

To find a more objective method of assessing which patients should be screened for a vestibular schwannoma (VS) with magnetic resonance imaging (MRI) using a deep-learning algorithm to assess clinical and audiometric data.

Materials and Methods

Clinical and audiometric data were collected for 592 patients who received an audiogram between January 2015 and 2020 at Duke University Health Center with and without VS confirmed by MRI. These data were analyzed using a deep learning-based analysis to determine if the need for MRI screening could be assessed more objectively with adequate sensitivity and specificity.

Results

Patients with VS showed slightly elevated, but not statistically significant, mean thresholds compared to those without. Tinnitus, gradual hearing loss, and aural fullness were more common in patients with VS. Of these, only the presence of tinnitus was statistically significant. Several machine learning algorithms were used to incorporate and model the collected clinical and audiometric data, but none were able to distinguish ears with and without confirmed VS. When tumor size was taken into account the analysis was still unable to distinguish a difference.

Conclusions

Using audiometric and clinical data, deep learning-based analyses failed to produce an adequately sensitive and specific model for the detection of patients with VS. This suggests that a specific pattern of audiometric asymmetry and clinical symptoms may not necessarily be predictive of the presence/absence of VS to a level that clinicians would be comfortable forgoing an MRI.

Machine Learning for Vestibular Schwannoma Diagnosis Using Audiometrie Data Alone

OBJECTIVE

The aim of this study is to compare machine learning algorithms and established rule-based evaluations in screening audiograms for the purpose of diagnosing vestibular schwannomas. A secondary aim is to assess the performance of rule-based evaluations for predicting vestibular schwannomas using the largest dataset in the literature.

STUDY DESIGN

Retrospective case-control study.

SETTING

Tertiary referral center.

PATIENTS

Seven hundred sixty seven adult patients with confirmed vestibular schwannoma and a pretreatment audiogram on file and 2000 randomly selected adult controls with audiograms.

INTERVENTIONS

Audiometric data were analyzed using machine learning algorithms and standard rule-based criteria for defining asymmetric hearing loss.

MAIN OUTCOME MEASURES

The primary outcome is the ability to identify patients with vestibular schwannomas based on audiometric data alone, using machine learning algorithms and rule-based formulas. The secondary outcome is the application of conventional rule-based formulas to a larger dataset using advanced computational techniques.

RESULTS

The machine learning algorithms had mildly improved specificity in some fields compared with rule-based evaluations and had similar sensitivity to previous rule-based evaluations in diagnosis of vestibular schwannomas.

CONCLUSIONS

Machine learning algorithms perform similarly to rule-based evaluations in identifying patients with vestibular schwannomas based on audiometric data alone. Performance of established rule-based formulas was consistent with earlier performance metrics, when analyzed using a large dataset.

Human vestibular schwannoma reduces density of auditory nerve fibers in the osseous spiral lamina

Hearing loss in patients with vestibular schwannoma (VS) is commonly attributed to mechanical compression of the auditory nerve, though recent studies suggest that this retrocochlear pathology may be augmented by cochlear damage. Although VS-associated loss of inner hair cells, outer hair cells, and spiral ganglion cells has been reported, it is unclear to what extent auditory-nerve peripheral axons are damaged in VS patients. Understanding the degree of damage VSs cause to auditory nerve fibers (ANFs) is important for accurately modeling clinical outcomes of cochlear implantation, which is a therapeutic option to rehabilitate hearing in VS-affected ears. A retrospective analysis of human temporal-bone histopathology was performed on archival specimens from the Massachusetts Eye and Ear collection. Seven patients met our inclusion criteria based on the presence of sporadic, unilateral, untreated VS. Tangential sections of five cochlear regions were stained with hematoxylin and eosin, and adjacent sections were stained to visualize myelinated ANFs and efferent fibers. Following confocal microscopy, peripheral axons of ANFs within the osseous spiral lamina were quantified manually, where feasible, and with a "pixel counting" method, applicable to all sections. ANF density was substantially reduced on the VS side compared to the unaffected contralateral side. In the upper basal turn, a significant difference between the VS side and unaffected contralateral side was found using both counting methods, corresponding to the region tuned to 2000 Hz. Even spiral ganglion cells (SGCs) contralateral to VS were affected by the tumor as the majority of contralateral SGC counts were below average for age. This observation provides histological insight into the clinical observation that unilateral vestibular schwannomas pose a long-term risk of progression of hearing loss in the contralateral ear as well. Our pixel counting method for ANF quantification in the osseous spiral lamina is applicable to other pathologies involving sensorineural hearing loss. Future research is needed to classify ANFs into morphological categories, accurately predict their electrical properties, and use this knowledge to inform optimal cochlear implant programming strategies.

Multiple Audiometric Analysis in the Screening of Vestibular Schwannoma

Introduction

Asymmetric sensorineural hearing loss is the main early symptom of retrocochlear lesions, hence its importance in screening for vestibular schwannomas. Currently, there is no consensus regarding its definition. The objective was to identify the audiometric pattern that would serve as a predictor for vestibular schwannoma in patients with asymmetric hearing loss.

Materials and methods

A cross-sectional study was conducted that included patients with asymmetric hearing loss attending a secondary care center and a tertiary care center. Clinical, audiometric and imaging (MRI with gadolinium) variables were collected. Asymmetric hearing loss was defined as a difference of 15 dB in one or more frequencies between both ears. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of different audiometric patterns were analyzed.

Results

A total of 107 patients were studied and divided into two groups: group 1 without vestibular schwannoma (n=98); and group 2 with vestibular schwannoma (n=9). No significant difference in demographic characteristics or audiometric patterns was found in patients with and without vestibular schwannoma. The audiometric pattern with the best sensitivity as a screening test was a difference >20 dB in the 4,000 Hz frequency, with a sensitivity of 77.78%, specificity of 30.61%, PPV of 8.33%, NPV of 93.75% and accuracy of 34.50%.

Conclusion

The audiometric pattern with the best results was a difference >20 dB in the 4,000 Hz frequency range; however, patients with asymmetric hearing loss could not be differentiated from patients with retrocochlear lesions based only on audiometry. Asymmetrical hearing loss must be studied with MRI.

Assessing a Sensory-Motor-Cognition Triad in Amnestic Mild Cognitive Impairment With Dichotic Listening While Walking: A Dual-Task Paradigm

A contemporary topic in aging research relates to the significance of cognitive changes proper to mild cognitive impairment (MCI) to higher risk of falls and gait deteriorations. The present study addresses this question in the amnestic type of MCI (aMCI) by examining a triad of interrelated comorbidities occurring in the MCI condition: attentional impairments, hearing loss and gait disturbances. To this end, we applied a dichotic listening (DL) test during over-ground walking. DL assesses spontaneous and lateralized auditory attention in three conditions (i.e., free report or Non-forced (NF), Forced-Right (FR) ear and Forced-Left (FL) ear). Earlier reports suggest that this dual-task paradigm evoke asymmetric gait effects on healthy controls, which are moderated by degree of hearing loss. Therefore, the aim of the present study was to evaluate the effects of DL on bilateral (data from both limbs) and lateralized (each limb separately) gait outcomes in a group of forty-three aMCI participants (mean = 71.19) and fifty-two healthy older controls (mean = 70.90) by using hearing loss as a covariate in all analyses. Results showed the aMCI group presented overall compromised gait parameters, especially higher gait variability in all DL conditions during lateralized attentional control. These findings were observed bilaterally, and no lateralized effects on gait were observed. Only after controlling for hearing acuity, gait asymmetries on step length variability emerged almost exclusively in healthy controls. It was concluded that hearing loss in the aMCI group together with higher attentional impairments preclude aMCI individuals to properly execute DL and therefore, they do not display gait asymmetries. The present data demonstrate that varied demands on attentional control dependent on hearing acuity affects gait negatively in healthy older adults and aMCI individuals in very different ways. The appearance of asymmetric effects seems to be a perturbation related to normal aging, while the lack of asymmetries but exaggerated gait variability characterizes aMCI. The present findings show the intricate interplay of sensory, cognitive, and motor deteriorations in different group of older adults, which stresses the need of addressing co-occurring comorbidities behind gait perturbations in individuals prone to develop a dementia state.

Calculated versus measured pure tone bone conduction 3 kHz thresholds in sudden sensorineural hearing loss

OBJECTIVE

To compare the measured bone conduction threshold at 3 kHz with the calculated threshold in newly diagnosed sudden sensorineural hearing loss.

METHODS

A retrospective chart review was conducted of pure tone audiograms in confirmed sudden sensorineural hearing loss cases.

RESULTS

Of 157 patients with sudden sensorineural hearing loss, 144 had idiopathic hearing loss, 8 had vestibular schwannoma and 5 had Ménière's disease. The r value for the correlation between the two methods of 3 kHz assessment for all patients was 0.887 (p < 0.001). The mean difference between the measured and calculated 3 kHz thresholds was 0.76 ± 7.96 dB, 0.4 ± 8.08 dB and 1.5 ± 1.8 dB in the sudden sensorineural hearing loss, idiopathic and Ménière's disease groups, respectively. The mean difference between the measured and calculated 3 kHz thresholds was significantly greater in the vestibular schwannoma group (6.86 ± 4.38 dB) than in the idiopathic group (p = 0.013).

CONCLUSION

The 3 kHz frequency may encompass important audiometric information. A discrepancy between the measured and calculated bone conduction 3 kHz thresholds raises suspicion of an underlying vestibular schwannoma as an aetiology for sudden sensorineural hearing loss, and these thresholds should therefore be measured independently and routinely.

Modeling Hearing Loss Progression and Asymmetry in the Older Old: A National Population-Based Study

OBJECTIVE

The progression and asymmetry of age-related hearing loss has not been well characterized in those 80 years of age and older because public datasets mask upper extremes of age to protect anonymity. We aim to characterize the progression, severity, and asymmetry of hearing loss in those 80 years of age and older using a representative, national database.

METHODS

Cross-sectional, multicentered U.S. epidemiologic analysis using the National Health and Nutrition Examination Survey (NHANES) 2005 to 2006, 2009 to 2010, and 2011 to 2012 cycles. Subjects included noninstitutionalized, civilian adults aged 80 years and older (n = 621). Federal security clearance was granted to access publicly restricted age data. Outcome measures included pure-tone average (PTA) air conduction thresholds and the 4-frequency PTA.

RESULTS

Six hundred and twenty-one subjects were 80 years old or older (mean = 84.2 years, range = 80-104 years), representing 10,600,197 Americans. The average PTA was 38.9 dB (95% confidence interval [CI] = 37.8, 40.0). Hearing loss exhibited constant acceleration across the adult lifespan at a rate of 0.0052 dB/year2 (95% CI = 0.0049, 0.0055). This model predicted mean PTA within 2 dB of accuracy for most ages between 20 and 100 years. From age 80 years to approximately 100 years, the average PTA difference between the better and worse ear was 6.75 dB (95% CI = 5.8, 7.1). This asymmetry was relatively constant (i.e., nonsignificant linear regression coefficient of asymmetry over age = 0.07 [95% CI = -0.01, 0.2]).

CONCLUSION

Hearing loss steadily and predictably accelerates across the adult lifespan to at least age 100 years, becoming near universal. These population-level statistics will guide treatment and policy recommendations for hearing health in the older old.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:879-884, 2021.

Evaluation of pure-tone audiometric protocols in vestibular schwannoma screening

The objective was to evaluate the pure-tone audiogram-based screening protocols in VS diagnostics. We retrospectively analyzed presenting symptoms, pure tone audiometry and MRI finding from 246 VS patients and 442 controls were collected to test screening protocols (AAO-HNS, AMCLASS-A/B, Charing Cross, Cueva, DOH, Nashville, Oxford, Rule3000, Schlauch, Seattle, Sunderland) for sensitivity and specificity. Results were pooled with data from five other studies, and analysis of sensitivity, specificity and positive likelihood ratio (LR+) for each protocol was performed. Our results show that protocols with significantly higher sensitivity (AMCLASS-A/B, Nashville) show also significantly lowest specificity, and tend to have low association (positive likelihood ratio, LR+) to the VS. The highest LR+ was found for protocols AAO-HNS, Rule3000 and Seattle. In conclusions, knowing their properties, screening protocols are simple decision-making tools in VS diagnostic. To use the advantage of the highest sensitivity, protocols AMCLASS-A + B or Nashville can be of choice. For more reasonable approach, applying the protocols with high LR+ (AAO-HNS, Rule3000, Seattle) may reduce the overall number of MRI scans at expense of only few primarily undiagnosed VS.

Ear Preference and Interaural Threshold Asymmetry

OBJECTIVE

To define the relationships among ear preference strength, audiometric interaural asymmetry magnitude, and hearing impairment.

STUDY DESIGN

Prospective, cross-sectional.

SETTING

Academic audiology clinic.

PATIENTS

Adults.

INTERVENTIONS

Diagnostic.

MAIN OUTCOME MEASURES

Patient-reported ear preference strength using a seven-category preference (no preference; left or right somewhat, strongly, or completely) scheme, hearing disability level on the Speech, Spatial, and Qualities of Hearing scale, and audiometric interaural threshold asymmetry were analyzed in three study cohorts: 1) normal hearing (thresholds ≤ 25 dB, n = 66), 2) symmetric hearing loss (any single threshold > 25 dB, n = 81), and 3) asymmetric hearing loss (maximum average interaural threshold difference at any two adjacent frequencies (IThrDmax2)≥ 15 dB, n = 112).

RESULTS

Receiver operating characteristic curves for somewhat, strongly, and completely ear preference levels using IThrDmax2 cutoff values at 15, 30, and 45 dB showed good to excellent classifier performance (all curve areas ≥ 0.84). The mapping of ear preference strength to the most likely IThrDmax2 range by odds ratio analysis demonstrated: no preference (< 15 dB), somewhat (15-29 dB), strongly (30-44 dB), and completely (≥ 45 dB). Complete dependence on one ear was associated with the most severe degradation in spatial hearing function.

CONCLUSION

Categorical ratings of ear preference strength may be mapped to ranges of audiometric threshold asymmetry magnitude and spatial hearing disability level. Querying ear preference strength in routine clinical practice would enable practitioners to identify patients with asymmetric hearing more expeditiously and promote timely evaluation and treatment.

Inner ear MRI: is it always useful to manage intravenous contrast?

OBJECTIVE

To evaluate the added value of administering intravenous contrast (IVC) routinely to the MRI of patients with audiovestibular symptoms in the assessment of a neuroradiologist and a resident.

MATERIALS AND METHODS

Retrospective study including patients who had an inner ear MRI for two months. Two radiologists reviewed independently and blinded the images. A first assessment was made analyzing just the sequences acquired without contrast and then a second evaluation of all the sequences, including post-contrast T1 sequences. The interobserver correlation and the correlation between MRI findings and the reason for requesting the study were calculated.

RESULTS

40 patients were included. The range age was 36-80 years. The most frequent reason for request the MRI was hearing loss (52.5%). Neuroradiologist without IVC found 82.5% of extraotic pathology and 17.5% of otic pathology, highlighting the neurinoma of the VIII pair (7.5%); ossifying labyrinthitis, retrofenestrated otosclerosis and cholesteatoma. After IVC administration, findings were similar. The resident identified otic pathology in 5% in baseline sequences and 20% using CIV. The interobserver correlation using IVC was excellent (0.97), but weak without IVC (0.52). There was a correlation between the reasons for request the MRI and the findings in the ears, both in protocols without IVC (p = 0.004) and in protocols with IVC (p = 0.002).

CONCLUSION

Inner ear MRI without contrast gives relevant information to assess audiovestibular symptoms. The use of IVC increases the degree of confidence in a novel radiologist, while in the expert its use is less relevant. A protocol should be proposed in which gadolinium is used in selected patients.

The impact of age-related hearing loss and lateralized auditory attention on spatiotemporal parameters of gait during dual-tasking among community dwelling older adults

This investigation assessed the impact of hearing loss and lateralized auditory attention on spatiotemporal parameters of gait during overground dual-tasking by the use of the dichotic listening task. Seventy-eight right-handed, healthy older adults between 60 and 88 years were assigned to a Young-Old (<70 years) or an Old-Old (>71 years) group. Cognitive assessment and pure tone audiometry were conducted. Spatiotemporal parameters of gait quantified by mean (M), and coefficient of variations (CoV) were evaluated with the OptoGait system during 3 dichotic listening conditions: Non-Forced, Forced-Right and Forced-Left. Factorial analyses of variance and covariance were used to assess group differences and the moderating effects of hearing status, respectively. Results demonstrated that three of the gait parameters assessed were affected asymmetrically by the dual-task paradigm after controlling for hearing status. Asymmetries existed on step width, gait speed and variability of stride length. Finally, correlations between gait outcomes and dichotic listening results showed that M and CoVs in gait parameters during right-ear responses were longer compared with left-ear. Left-ear responses were related to increased variability on stride length, which indicates higher difficulty level. Hearing status varying from normal to mild levels of hearing loss modulates spatiotemporal gait outcomes measured during dichotic listening execution. Findings suggest that attending to left side stimuli relates to increased gait variability, while focusing on right-side assures a safe walk. Results demonstrated that attending to right-ear stimuli is an adaptive strategy for older adults that compensates for limited sensorimotor and cognitive resources during walking.

Asymmetric Hearing Loss Prompting MRI Referral in a Military Population: Redefining Audiometric Criteria

Objective

To reevaluate asymmetric sensorineural hearing loss (ASNHL) criteria used to justify magnetic resonance imaging (MRI) in the evaluation of retrocochlear tumors in a military population.

Study Design

Retrospective case-control study.

Setting

Tertiary care military medical center.

Subjects and Methods

Patients with military service and a history of ASNHL prompting referral for MRI, with or without retrocochlear tumors, were compared between 2005 and 2016. Predictor variables included pure tone ASNHL, speech audiometry, and a history of noise exposure. Logistic regression models for hearing asymmetries were performed, and receiver operator curves were used to calculate sensitivity and specificity.

Results

Thirty-eight retrocochlear tumors were identified. The MRI diagnosis rate for patients with ASHNL was 0.85%. Patients with tumors were slightly older (42 vs 37 years, P = .021) and had less noise exposure (47% vs 85%, P < .001). A sensitivity of 0.83 and a specificity of 0.58 were calculated for asymmetries ≥10 dB at 2000 Hz without adjusting for noise exposure. Instituting this imaging threshold would have reduced the number of MRI scans by half while missing 16% of tumors.

Conclusion

The tumor diagnosis rate among those undergoing MRI for ASNHL is low in the military population, likely because service-related noise exposure commonly causes ASNHL. Optimal MRI referral criteria should conserve resources while balancing the risks of over- and underdiagnosis. For those with a history of military service, an asymmetry ≥10 dB at 2000 Hz among patients meeting current ANSHL referral criteria is most predictive of a retrocochlear tumor.

[Asymmetric sensorineural hearing impairment in the adult population]

The relevance of the problem of a sensorineural hearing loss (ASNL) arises from the necessity of the special approaches to the diagnostics of this condition, the complications accompanying this pathology, and the difficulties encountered in the implementation of the methods designed for hearing rehabilitation of such patients. The objective of the present study was to estimate the prevalence of ASHL among the adult population. The sensorineural impairment of hearing was diagnosed in a total of 2456 (72%) examined patients presenting with hearing loss. To determine the presence of asymmetry of sensorineural hearing loss, we employed three counting techniques allowing (1) to calculate the difference between the average hearing thresholds at four frequencies within the range from 0.5 to 4 kHz (the difference was found to be 15 dB or more in 17% of the patients), (2) to calculate the difference between the degrees of hearing loss in the right and left ears (the difference was documented in 47% of the patients), (3) to calculate the difference between the hearing thresholds at least at a single frequency within the range from 0.125 to 8 kHz (he difference was found to be 15 dB or more in 71% of the patients). When using the third method to characterize asymmetry of hearing impairment, it was identified in most patients (53%) at one or two frequencies. Moreover, there was a large number of the patients (13%) with asymmetry apparent over the entire frequency range. A high degree of threshold asymmetry (in excess of 40 dB) was more often noted in the mid-frequency range. In the majority of the patients, the asymmetry manifested itself as the different degree of bilateral sensorineural hearing impairment (51%) or unilateral sensorineural hearing loss with the normal hearing ability preserved in the contralateral ear (35%). The results of the present study give evidence of the necessity of developing a reliable method for the identification of clinically significant ACNL.

Typewriter tinnitus revisited: The typical symptoms and the initial response to carbamazepine are the most reliable diagnostic clues

Although neurovascular compression of the cochlear nerve (NVC-C) presenting as typewriter tinnitus is a discrete disease category, verified diagnostic criteria are lacking. We sought to refine the diagnostic criteria for NVC-C by reference to a relatively large case series. The medical records of 22 NVC-C patients were retrospectively reviewed. Psychoacoustic characteristics, the results of diagnostic work-up (including audiovestibular neurophysiological tests and radiological evaluations), and the initial treatment response to carbamazepine were investigated. All subjects described their tinnitus as a typical “typewriter” or “staccato” sound. Of the 22 subjects, 11 (50%) had histories of vertiginous spells, but none had ipsilesional hearing loss. Vestibular function tests in 11 subjects tested revealed only 2 (18.2%) isolated cervical vestibular evoked myogenic potential abnormalities. Radiological comparisons of the symptomatic and asymptomatic sides, regarding the type of the vascular loop and neurovascular contact, revealed no significant differences. However, all 22 subjects exhibited immediate and marked responses to short-term carbamazepine treatment. Meticulous history-taking in terms of the psychoacoustic characteristics and the response to initial carbamazepine, are more reliable diagnostic clues than are radiological or neurophysiological data in NVC-C subjects. Therefore, the typical psychoacoustic characteristics and the response to initial carbamazepine should be included in the diagnostic criteria.

Cost analysis of vestibular schwannoma screening with contrast-enhanced magnetic resonance imaging in patients with asymmetrical hearing loss

BACKGROUND

Vestibular schwannomas are a rare cause of asymmetrical hearing loss, and routine screening with magnetic resonance imaging can be costly. This paper reports results on vestibular schwannoma screening at our institution and compares the cost of screening to a utility of hearing benefit.

METHOD

All screening examinations with magnetic resonance imaging performed for asymmetrical hearing loss between 2006 and 2011 were retrospectively reviewed. The cost per new vestibular schwannoma diagnosis was calculated. The cost per patient for those who benefitted from intervention was estimated based on rates of hearing preservation reported in the literature.

RESULTS

Forty-five (4.3 per cent) of 1050 screening examinations with magnetic resonance imaging performed for asymmetrical hearing loss were positive for vestibular schwannoma, and the cost per new diagnosis was $11,436. The estimated screening cost per patient for those who benefitted from surgery or radiation was $147,030, while US federal compensation for unilateral hearing loss was $44,888.

CONCLUSION

Although we achieved a lower screening cost per new diagnosis than reported in the current literature, there remains disparity between the screening cost per benefitted patient and the 'benefit' of hearing.

Clinical Practice Guideline

Objective

Tinnitus is the perception of sound without an external source. More than 50 million people in the United States have reported experiencing tinnitus, resulting in an estimated prevalence of 10% to 15% in adults. Despite the high prevalence of tinnitus and its potential significant effect on quality of life, there are no evidence-based, multidisciplinary clinical practice guidelines to assist clinicians with management. The focus of this guideline is on tinnitus that is both bothersome and persistent (lasting 6 months or longer), which often negatively affects the patient’s quality of life. The target audience for the guideline is any clinician, including nonphysicians, involved in managing patients with tinnitus. The target patient population is limited to adults (18 years and older) with primary tinnitus that is persistent and bothersome.

Purpose

The purpose of this guideline is to provide evidence-based recommendations for clinicians managing patients with tinnitus. This guideline provides clinicians with a logical framework to improve patient care and mitigate the personal and social effects of persistent, bothersome tinnitus. It will discuss the evaluation of patients with tinnitus, including selection and timing of diagnostic testing and specialty referral to identify potential underlying treatable pathology. It will then focus on the evaluation and treatment of patients with persistent primary tinnitus, with recommendations to guide the evaluation and measurement of the effect of tinnitus and to determine the most appropriate interventions to improve symptoms and quality of life for tinnitus sufferers.

Action Statements

The development group made a strong recommendation that clinicians distinguish patients with bothersome tinnitus from patients with nonbothersome tinnitus. The development group made a strong recommendation against obtaining imaging studies of the head and neck in patients with tinnitus, specifically to evaluate tinnitus that does not localize to 1 ear, is nonpulsatile, and is not associated with focal neurologic abnormalities or an asymmetric hearing loss. The panel made the following recommendations: Clinicians should (a) perform a targeted history and physical examination at the initial evaluation of a patient with presumed primary tinnitus to identify conditions that if promptly identified and managed may relieve tinnitus; (b) obtain a prompt, comprehensive audiologic examination in patients with tinnitus that is unilateral, persistent (≥ 6 months), or associated with hearing difficulties; (c) distinguish patients with bothersome tinnitus of recent onset from those with persistent symptoms (≥ 6 months) to prioritize intervention and facilitate discussions about natural history and follow-up care; (d) educate patients with persistent, bothersome tinnitus about management strategies; (e) recommend a hearing aid evaluation for patients who have persistent, bothersome tinnitus associated with documented hearing loss; and (f) recommend cognitive behavioral therapy to patients with persistent, bothersome tinnitus. The panel recommended against (a) antidepressants, anticonvulsants, anxiolytics, or intratympanic medications for the routine treatment of patients with persistent, bothersome tinnitus; (b) Ginkgo biloba, melatonin, zinc, or other dietary supplements for treating patients with persistent, bothersome tinnitus; and (c) transcranial magnetic stimulation for the routine treatment of patients with persistent, bothersome tinnitus. The development group provided the following options: Clinicians may (a) obtain an initial comprehensive audiologic examination in patients who present with tinnitus (regardless of laterality, duration, or perceived hearing status); and (b) recommend sound therapy to patients with persistent, bothersome tinnitus. The development group provided no recommendation regarding the effect of acupuncture in patients with persistent, bothersome tinnitus.

The limitations of computed tomography in adult cochlear implant evaluation

OBJECTIVE

To demonstrate the added value of magnetic resonance imaging (MRI) over computed tomography (CT) during adult cochlear implant evaluation.

PATIENTS

Two adult patients are discussed in whom MRI studies diagnosed bilateral vestibular schwannomas during cochlear implant candidacy evaluation.

INTERVENTIONS

Temporal bone CT and MRI.

MAIN OUTCOME MEASURE

Diagnosis of NF2.

RESULTS

Two adult patients, ages 67 and 68 years, were evaluated for cochlear implant candidacy. Both patients experienced slowly progressive, bilateral hearing loss without complaints of vertigo, and neither patient had a family history of hearing loss or neurogenic tumors. Both patients had near-symmetric pure tone thresholds on audiometric testing. An MRI and a CT scan were performed on both patients, and bilateral vestibular schwannomas were identified on MRI.

CONCLUSIONS

Though MRI is not routinely utilized in adult cochlear implant evaluation, it may be of greater clinical value than CT in the setting of adult-onset hearing loss. MRI allows for sensitive evaluation of cochlear patency and architecture, and cochlear nerve status. As demonstrated in the two index cases, MRI also provides the added benefit of evaluating for causes of retrocochlear hearing loss. These two patients would have likely experienced a significant delay in diagnosis of NF2 without preoperative MRI, particularly given the limitations of scanning following CI magnet placement.

Dysfunction of the cochlea contributing to hearing loss in acoustic neuromas: an underappreciated entity

OBJECTIVE

Hearing loss is a common symptom in patients with cochleovestibular schwannoma. Clinical and histologic observations have suggested that the hearing loss may be caused by both retrocochlear and cochlear mechanisms. Our goal was to perform a detailed assessment of cochlear pathology in patients with vestibular schwannoma (VS).

STUDY DESIGN

Retrospective analysis of temporal bone histopathology.

SETTING

Multi-center study.

MATERIAL

Temporal bones from 32 patients with unilateral, sporadic VS within the internal auditory canal.

MAIN OUTCOME MEASURES

Sections through the cochleae on the VS side and opposite (control) ear were evaluated for loss of inner and outer hair cells, atrophy of the stria vascularis, loss of cochlear neurons, and presence of endolymphatic hydrops and precipitate within the endolymph or perilymph. Observed pathologies were correlated to nerve of origin, VS volume, and distance of VS from the cochlea. Hearing thresholds also were assessed.

RESULTS

VS caused significantly more inner and outer hair cell loss, cochlear neuronal loss, precipitate in endolymph and perilymph, and decreased pure tone average, when compared with the opposite ear. Tumor size, distance from the cochlea, and nerve of origin did not correlate with structural changes in the cochlea or the hearing threshold.

CONCLUSION

There is significant degeneration of cochlear structures in ears with VS. Cochlear dysfunction may be an important contributor to the hearing loss caused by VS and can explain certain clinically observed phenomena in patients with VS.

Incidence of vestibular schwannoma and incidental findings on the magnetic resonance imaging and computed tomography scans of patients from a direct referral audiology clinic

OBJECTIVE

To identify the incidence of vestibular schwannoma amongst patients referred from a direct referral audiology clinic, and also the number of incidental findings, as seen on magnetic resonance imaging or computed tomography scans.

METHOD

Prospective data collection for patients referred from a direct referral audiology clinic due to audiological evidence of asymmetrical hearing loss. The audiograms, magnetic resonance imaging and computed tomography scans of patients with diagnosed vestibular schwannoma were subsequently reviewed.

RESULTS

A total of 4100 patients were seen during the study period, with 396 scans performed. Six (1.5 per cent) patients had vestibular schwannoma, while 12 (3 per cent) had significant incidental findings.

CONCLUSION

Patients referred from the direct referral audiology clinic had a low incidence of vestibular schwannoma detection. Their detection rate for significant incidental findings was similar to previous reports. If the current protocol had not been in place, over 300 patients would have been needlessly added to the ENT clinic list. Thus, general practitioner referral to direct referral audiology clinics provides a cost-effective way of managing asymmetrical sensorineural hearing loss in older patients. The number of such clinics could be expanded.

Three-Year Ear, Nose, and Throat Cross-sectional Analysis of Audiometric Protocols for Magnetic Resonance Imaging Screening of Acoustic Tumors

Objectives. (1) Evaluate audiometric protocols and recommend protocols with best sensitivity and specificity for magnetic resonance imaging (MRI) screening of acoustic tumors; (2) determine clinical risks (false negative) of missing acoustic tumors and potential wastes in screening (false positive) nonacoustic tumors or radiologically “normal” cases; and (3) identify the decibel difference and range of frequencies compared by the best-performing protocols.

Study Design. Cross-sectional study with chart review.

Setting. Ear, nose, and throat (ENT); audiology; and radiology departments in a tertiary-care hospital.

Subjects and Methods. Three-year cohort (2006-2009) of 1751 ENT patients underwent MRI screening and pure-tone audiometry indicating sensorineural hearing loss. Audiometric protocols were ranked by highest sensitivity to acoustic tumors, specificity A to nonacoustic tumors, and specificity B to “radiologically normal” cases.

Results. No audiometric protocols achieved 100% sensitivity or specificity rates. Only 2 protocols achieved ≥90% sensitivity: the AMCLASS-A-Urben protocol (93.16%) and the Mangham protocol (91.58%). Eleven of 15 protocols for specificity A and 12 of 15 protocols for specificity B achieved ≥50%. Clinical risks ranged from 6.84% to 18.95%, whereas potential wastes ranged from 33.56% to 68.37% for specificity A and 31.76% to 66.86% for specificity B. Interaural difference parameters indicating highest mean sensitivity were on the order of ≥10 dB, ≥15 dB, and ≥20 dB. For frequency comparison parameters, “2 or more adjacent frequency” and “single-frequency” comparison indicated higher mean sensitivity than the “averaged multifrequency” comparison. Mean specificity showed an opposite pattern.

Conclusions. For optimum sensitivity, the Mangham protocol is preferred (sensitivity, 91.58%; specificity A, 44.23%; specificity B, 44.91%), which proposes a ≥10-dB interaural difference, averaging 1 to 8 kHz. For optimum specificity, the American Academy of Otolaryngology–Head and Neck Surgery protocol is preferred (sensitivity, 87.37%; specificity A, 65.38%; specificity B, 66.04%), which proposes ≥15 dB between ears, averaging 0.5 to 3 kHz.

Intracochlear schwannoma presenting as diffuse cochlear enhancement: diagnostic challenges of a rare cause of deafness

Intracochlear schwannoma is a rare, treatable, cause of unilateral hearing loss. Due to the small size, position, and variable clinical and imaging features, diagnosis presents a significant challenge and is often delayed. We present a case of a patient with an intracochlear schwannoma presenting as a diffuse enhancement of the cochlea, mimicking an infectious or inflammatory process. The absence of focal nodularity in this lesion on multiple high-resolution MRI examinations led to a delay of over 3 years from the patient's initial presentation to surgical diagnosis. Clinical history and examination, imaging features, pathologic findings, and surgical management options are described.