To image or not to image? A cost-effectiveness analysis of MRI for patients with asymmetric sensorineural hearing loss

Brazilian Society of Otology task force - Vestibular Schwannoma ‒ evaluation and treatment

OBJECTIVE

To review the literature on the diagnosis and treatment of vestibular schwannoma.

METHODS

Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on vestibular schwannoma were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 2 parts: (1) Diagnosis - audiologic, electrophysiologic tests, and imaging; (2) Treatment - wait and scan protocols, surgery, radiosurgery/radiotherapy, and systemic therapy.

CONCLUSIONS

Decision making in VS treatment has become more challenging. MRI can diagnose increasingly smaller tumors, which has disastrous consequences for the patients and their families. It is important to develop an individualized approach for each case, which highly depends on the experience of each surgical team.

Model-Projected Cost-Effectiveness of Adult Hearing Screening in the USA

BACKGROUND

While 60% of older adults have hearing loss (HL), the majority have never had their hearing tested.

OBJECTIVE

We sought to estimate long-term clinical and economic effects of alternative adult hearing screening schedules in the USA.

DESIGN

Model-based cost-effectiveness analysis simulating Current Detection (CD) and linkage of persons with HL to hearing healthcare, compared to alternative screening schedules varying by age at first screen (45 to 75 years) and screening frequency (every 1 or 5 years). Simulated persons experience yearly age- and sex-specific probabilities of acquiring HL, and subsequent hearing aid uptake (0.5-8%/year) and discontinuation (13-4%). Quality-adjusted life-years (QALYs) were estimated according to hearing level and treatment status. Costs from a health system perspective include screening ($30-120; 2020 USD), HL diagnosis ($300), and hearing aid devices ($3690 year 1, $910/subsequent year). Data sources were published estimates from NHANES and clinical trials of adult hearing screening.

PARTICIPANTS

Forty-year-old persons in US primary care across their lifetime.

INTERVENTION

Alternative screening schedules that increase baseline probabilities of hearing aid uptake (base-case 1.62-fold; range 1.05-2.25-fold).

MAIN MEASURES

Lifetime undiscounted and discounted (3%/year) costs and QALYs and incremental cost-effectiveness ratios (ICERs).

KEY RESULTS

CD resulted in 1.20 average person-years of hearing aid use compared to 1.27-1.68 with the screening schedules. Lifetime total per-person undiscounted costs were $3300 for CD and ranged from $3630 for 5-yearly screening beginning at age 75 to $6490 for yearly screening beginning at age 45. In cost-effectiveness analysis, yearly screening beginning at ages 75, 65, and 55 years had ICERs of $39,100/QALY, $48,900/QALY, and $96,900/QALY, respectively. Results were most sensitive to variations in hearing aid utility benefit and screening effectiveness.

LIMITATION

Input uncertainty around screening effectiveness.

CONCLUSIONS

We project that yearly hearing screening beginning at age 55+ is cost-effective by US standards.

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.

The spatial percept of tinnitus is associated with hearing asymmetry: Subgroup comparisons

The spatial percept of tinnitus is hypothesized as an important variable for tinnitus subtyping. Hearing asymmetry often associates with tinnitus laterality, but not always. One of the methodological limitations for cross-study comparisons is how the variables for hearing asymmetry and tinnitus spatial perception are defined. In this study, data from two independent datasets were combined (n=833 adults, age ranging from 20 to 91 years, 404 males, 429 females) to investigate characteristics of subgroups with different tinnitus spatial perception focusing on hearing asymmetry. Three principle findings emerged. First, a hearing asymmetry variable emphasizing the maximum interaural difference most strongly discriminated unilateral from bilateral tinnitus. Merging lateralized bilateral tinnitus (perceived in both ears but worse in one side) with unilateral tinnitus weakened this relationship. Second, there was an association between unilateral tinnitus and ipsilateral asymmetric hearing. Third, unilateral and bilateral tinnitus were phenotypically distinct, with unilateral tinnitus being characterized by older age, asymmetric hearing, more often wearing one hearing aid, older age at tinnitus onset, shorter tinnitus duration, and higher percentage of time being annoyed by tinnitus. We recommend that careful consideration is given to the definitions of hearing asymmetry and tinnitus spatial perception in order to improve the comparability of findings across studies.

Evidence gaps in economic analyses of hearing healthcare: A systematic review

BACKGROUND

Hearing loss is a common and costly medical condition. This systematic review sought to identify evidence gaps in published model-based economic analyses addressing hearing loss to inform model development for an ongoing Lancet Commission.

METHODS

We searched the published literature through 14 June 2020 and our inclusion criteria included decision model-based cost-effectiveness analyses that addressed diagnosis, treatment, or prevention of hearing loss. Two investigators screened articles for inclusion at the title, abstract, and full-text levels. Data were abstracted and the studies were assessed for the qualities of model structure, data assumptions, and reporting using a previously published quality scale.

FINDINGS

Of 1437 articles identified by our search, 117 unique studies met the inclusion criteria. Most of these model-based analyses were set in high-income countries (n = 96, 82%). The evaluated interventions were hearing screening (n = 35, 30%), cochlear implantation (n = 34, 29%), hearing aid use (n = 28, 24%), vaccination (n = 22, 19%), and other interventions (n = 29, 25%); some studies included multiple interventions. Eighty-six studies reported the main outcome in quality-adjusted or disability-adjusted life-years, 24 of which derived their own utility values. The majority of the studies used decision tree (n = 72, 62%) or Markov (n = 41, 35%) models. Forty-one studies (35%) incorporated indirect economic effects. The median quality rating was 92/100 (IQR:72-100).

INTERPRETATION

The review identified a large body of literature exploring the economic efficiency of hearing healthcare interventions. However, gaps in evidence remain in evaluation of hearing healthcare in low- and middle-income countries, as well as in investigating interventions across the lifespan. Additionally, considerable uncertainty remains around productivity benefits of hearing healthcare interventions as well as utility values for hearing-assisted health states. Future economic evaluations could address these limitations.

FUNDING

NCATS 3UL1-TR002553-03S3.

Prognostic Value of Early Magnetic Resonance Imaging Patterns in Sudden Hearing Loss

INTRODUCTION

Sudden sensorineural hearing loss (SSHL) is a relatively frequent disease, but a sensitive marker or a reliable test to identify the underlying cause is still unavailable. Neuroradiology appears to offer the most promising tools, especially magnetic resonance imaging (MRI). In a recent study from our group, we explored the ability of MRI to detect subtle changes in the inner ear compartments by means of a 3D-fluid-attenuated inversion recovery sequence, aiming at identifying 3 distinct MRI patterns (haemorrhagic, inflammatory, brain-labyrinth barrier breakdown). In the present study, we contrasted the MRI patterns at onset with relevant prognostic factors, with the audiological features of each patient's SSHL and with treatment outcomes.

METHODS

In this retrospective study, we enrolled 50 adult subjects (54.61 ± 18.26 years) with SSHL. They underwent an MRI within 72 h from admission, and 5 audiological evaluations: at admission, on the 5th day after the start of medical therapy, at the end of the first cycle of hyperbaric oxygen therapy, then 1 and 6 months later.

RESULTS

Abnormalities of the MRI signal and/or post-contrast enhancement asymmetry of the cochlea ("pattern+ MRI") correlated with worse audiological outcomes at 1 month, but the different MRI patterns were not correlated with any specific prognostic model, despite rigid protocol settings. However, a significant difference was found for low-tone SSHL, which were always "pattern" negative at MRI (p = 0.01), and for profound SSHL which demonstrated a pattern+ MRI in 80% (p = 0.04). At the onset of SSHL, a pattern+ MRI was found in 29/50 cases (58.0%) and was related with lesser degree of recovery of pure-tone average at 1 month and lesser chance to retain the hearing threshold benefit in the long term. Given the limited numbers of patients enrolled so far, the relative impact of comorbidities on each MRI pattern remains uncertain. At 6 months, we observed a trend of greater and more stable recovery (p = 0.023) and less frequent recurrence of SSHL in patients with a normal MRI.

CONCLUSIONS

The 3 observed MRI patterns did not correlate consistently with specific audio-vestibular features or any peculiar aspect of the patient's clinical history. Larger series of patients with SSHL are needed, possibly from multicentric studies.

Hearing examinations in Southern Denmark (HESD) database: a valuable tool for hearing-related epidemiological research

OBJECTIVE

To introduce and document the recently established HESD (Hearing Examinations in Southern Denmark) database, including the necessary data preprocessing steps, and to describe the hearing loss (HL) characteristics of the study sample.

DESIGN

Clinical auditory information has been collected for approximately 20 years in the state-funded clinics of the Region of Southern Denmark. We reviewed these data and conducted extensive preprocessing through data selection, integration, cleaning, transformation, and classification. HL profiling was then assessed in terms of severity, asymmetry, configuration, site of lesion, and audiogram shape.

STUDY SAMPLE

The final number of complete audiograms available in the HESD database was 271,556, corresponding to detailed hearing information for 143,793 adults.

RESULTS

The distribution of HL characteristics differed significantly (p < 0.001) between men and women for all categories analysed. Clear differences were observed for asymmetry and audiogram configuration. However, both men and women had higher prevalence of unilateral, moderate, and sensorineural HL.

CONCLUSIONS

This work highlights the potential of the HESD database as a source of audiology-related epidemiological data. It can be used to evaluate the distribution of HL characteristics and also to investigate risk factors for HL and the associations between HL and other health outcomes.

Current imaging tools for vestibular schwannoma

PURPOSE OF REVIEW

Of the tumors found in the cerebellopontine angle (CPA), vestibular schwannomas are by far the most common. Modern diagnostic imaging enables excellent visualization of the CPA and detection of very small tumors while optimizing patient comfort and time. This review addresses the current imaging tools available for diagnosis of vestibular schwannomas.

RECENT FINDINGS

The current gold-standard imaging study for vestibular schwannomas is a gadolinium-enhanced T1-weighted MRI. The yield of this expensive study is only about 3-4% given the low incidence of vestibular schwannomas, thus there is utility in screening with noncontrast T2-weighted MRI, which is a quicker and more economical study.

SUMMARY

Vestibular schwannomas are best evaluated with gadolinium-enhanced T1-weighted MRI, which can detect tumors as small as 2-3 mm. Recent studies have found that the reported sensitivity and specificity of noncontrast MRI is almost equivalent to that of gadolinium-enhanced T1-weighted MRI. As such, this modality is increasingly being adopted by institutions for both diagnosis and surveillance of vestibular schwannomas and shows promise for broader implementation. Newer protocols, such as FLAIR and DTI may provide additional information and further aid preoperative counseling and surgical planning in the future.

Diagnostic Yield of MRI for Sensorineural Hearing Loss - An Audit

PURPOSE

Contrast-enhanced magnetic resonance imaging (CEMRI) of the head is frequently employed in investigations of sensorineural hearing loss (SNHL). The yield of these studies is perceptibly low and seemingly at odds with the aims of wise resource allocation and risk reduction within the Canadian healthcare system. The purpose of our study was to audit the use and diagnostic yield of CEMRI for the clinical indication of SNHL in our institution and to identify characteristics that may be leveraged to improve yield and optimize resource utilization.

MATERIALS AND METHODS

The charts of 500 consecutive patients who underwent CEMRI of internal auditory canal for SNHL were categorized as cases with relevant positive findings on CEMRI and those without relevant findings. Demographics, presenting symptoms, interventions and responses, ordering physicians, and investigations performed prior to CEMRI testing were recorded. Chi-squared test and t-test were used to compare proportions and means, respectively.

RESULTS

CEMRI studies revealed relevant findings in 20 (6.2%) of 324 subjects meeting the inclusion criteria. Pre-CEMRI testing beyond audiometry was conducted in 35% of those with relevant positive findings compared to 7.3% of those without (p < 0.001). Auditory brainstem response/vestibular-evoked myogenic potentials were abnormal in 35% of those with relevant CEMRI findings compared to 6.3% of those without (p < 0.001).

CONCLUSION

CEMRI is a valuable tool for assessing potential causes of SNHL, but small diagnostic yield at present needs justification for contrast injection for this indication. Our findings suggest preferred referral from otolaryngologists exclusively, and implementation of a non-contrast MRI for SNHL may be a better diagnostic tool.

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.

A parsimonious approach for screening moderate-to-profound hearing loss in a community-dwelling geriatric population based on a decision tree analysis

Background

Hearing loss is one of the most common modifiable factors associated with cognitive and functional decline in geriatric populations. An accurate, easy-to-apply, and inexpensive hearing screening method is needed to detect hearing loss in community-dwelling elderly people, intervene early and reduce the negative consequences and burden of untreated hearing loss on individuals, families and society. However, available hearing screening tools do not adequately meet the need for large-scale geriatric hearing detection due to several barriers, including time, personnel training and equipment costs. This study aimed to propose an efficient method that could potentially satisfy this need.

Methods

In total, 1793 participants (≥60 years) were recruited to undertake a standard audiometric air conduction pure tone test at 4 frequencies (0.5–4 kHz). Audiometric data from one community were used to train the decision tree model and generate a pure tone screening rule to classify people with or without moderate or more serious hearing impairment. Audiometric data from another community were used to validate the tree model.

Results

In the decision tree analysis, 2 kHz and 0.5 kHz were found to be the most important frequencies for hearing severity classification. The tree model suggested a simple two-step screening procedure in which a 42 dB HL tone at 2 kHz is presented first, followed by a 47 dB HL tone at 0.5 kHz, depending on the individual’s response to the first tone. This approach achieved an accuracy of 91.20% (91.92%), a sensitivity of 95.35% (93.50%) and a specificity of 86.85% (90.56%) in the training dataset (testing dataset).

Conclusions

A simple two-step screening procedure using the two tones (2 kHz and 0.5 kHz) selected by the decision tree analysis can be applied to screen moderate-to-profound hearing loss in a community-based geriatric population in Shanghai. The decision tree analysis is useful in determining the optimal hearing screening criteria for local elderly populations. Implanting the pair of tones into a well-calibrated sound generator may create a simple, practical and time-efficient screening tool with high accuracy that is readily available at healthcare centers of all levels, thereby facilitating the initiation of extensive nationwide hearing screening in older adults.

Evidence-Based Medicine in Otolaryngology Part 10: Cost-Effectiveness Analyses in Otolaryngology

Clinicians seek to pursue the most clinically effective treatment strategies, but costs have also become a key determinant in contemporary health care. Economic analyses have thus emerged as a valuable resource to both quantify and qualify the value of existing and emerging interventions and programs. Cost-effectiveness analyses estimate the benefits gained per monetary unit, providing insights to guide resource allocation. Herein, we delineate the related concepts and considerations to facilitate understanding and appraisal of these analyses, so as to better inform the stakeholders in our otolaryngology community.

Radiographic findings in young adults with asymmetric sensorineural hearing loss

PURPOSE

To evaluate radiographic findings in US Navy recruits found to have asymmetric sensorineural hearing loss (ASNHL) during routine medical screening.

MATERIALS AND METHODS

Retrospective analysis of US Navy recruits receiving screening audiometry and medical suitability evaluation from January 2011 to October 2016. Single-institution, institutional review board-approved study of US Navy recruits screened for hearing loss over a six-year period. All recruits with ASNHL were evaluated by an otolaryngologist and received diagnostic radiographic evaluation. Audiometric and imaging results were retrospectively reviewed for this population and compared to common screening criteria.

RESULTS

ASNHL was identified in 674 of 228,504 total recruits screened. This population was 91% male and between 17 and 29 years old (mean age 21.1). Six-hundred fifty-three (97%) met criteria for further ASNHL evaluation. Subjective hearing loss was reported in only 6% of patients. Six-hundred sixty-one (99%) received magnetic resonance imaging of the internal auditory canals. Intracranial pathology was identified in 43 (6.3%) patients and 2 (0.3%) had a causative intracranial lesion corresponding to ASNHL. No patients were found to have a vestibular schwannoma.

CONCLUSIONS

In a population of healthy young adults with audiometric proven ASNHL, 0.3% had radiographic proven intracranial pathology explaining the hearing loss. Intracranial masses may be less likely to cause ASNHL in this population; further research is needed to determine appropriate MRI screening methods for young adults with ASNHL.