Audiovestibular Function Deficits in Vestibular Schwannoma

The Influence of Asymmetric Hearing Loss on Peripheral and Central Auditory Processing Abilities in Patients With Vestibular Schwannoma

OBJECTIVES

Asymmetric or unilateral hearing loss (AHL) may cause irreversible changes in the processing of acoustic signals in the auditory system. We aim to provide a comprehensive view of the auditory processing abilities for subjects with acquired AHL, and to examine the influence of AHL on speech perception under difficult conditions, and on auditory temporal and intensity processing.

DESIGN

We examined peripheral and central auditory functions for 25 subjects with AHL resulting from vestibular schwannoma, and compared them to those from 24 normal-hearing controls that were matched with the AHL subjects in mean age and hearing thresholds in the healthy ear. Besides the basic hearing threshold assessment, the tests comprised the detection of tones and gaps in a continuous noise, comprehension of speech in babble noise, binaural interactions, difference limen of intensity, and detection of frequency modulation. For the AHL subjects, the selected tests were performed separately for the healthy and diseased ear.

RESULTS

We observed that binaural speech comprehension, gap detection, and frequency modulation detection abilities were dominated by the healthy ear and were comparable for both groups. The AHL subjects were less sensitive to interaural delays, however, they exhibited a higher sensitivity to sound level, as indicated by lower difference limen of intensity and a higher sensitivity to interaural intensity difference. Correlations between the individual test scores indicated that speech comprehension by the AHL subjects was associated with different auditory processing mechanisms than for the control subjects.

CONCLUSIONS

The data suggest that AHL influences both peripheral and central auditory processing abilities and that speech comprehension under difficult conditions relies on different mechanisms for the AHL subjects than for normal-hearing controls.

Vestibular Schwannoma: Long-term Outcome of the Vestibular Function After Stereotactic Radiosurgery

Objective

Evaluation at long term of the impact of the stereotactic surgery (SRS) on the vestibular function in vestibular schwannoma (VS) patients.

Study design and setting

Retrospective study in a tertiary referral center.

Patients

Fifty-one VS patients were included (34 females;17 males), aged from 41 to 78 years treated exclusively with SRS.

Intervention

Vestibular function was assessed before SRS and with median time interval of 14 (FU1) and 25 (FU2) months after treatment. Vestibular evaluation included: history, clinical vestibular examination, videonystagmography, head impulse test (v-HIT) and cervical vestibular evoked myogenic potentials (c-VEMPS).

Results

Before SRS, caloric testing (Caloric) was impaired in 77%; after treatment, in 92% (FU1) and 77% (FU2). Lateral HIT was decreased in 22% before SRS, in 39% at FU1 and FU2. C-VEMPS were absent in 50% before SRS, in 76% at FU1 and, FU2. Before SRS, no statistically significant association was found between asymptomatic and symptomatic patients with respect to the results of Caloric, v-HIT and c-VEMPS. This lack of association was also seen after SRS, at FU1 and FU2.

Conclusion

Our study showed that the impairment of the vestibular function might be attributed to the VS itself as well as to the radiation of the inner ear during SRS. The lateral SSC at low frequencies and the saccular function seem to be more involved with the time.

[Clinical characteristics of acoustic neuroma patients with normal hearing]

Objective:To analyze the clinical characteristics of unilateral acoustic neuroma（AN） with normal hearing, so as to provide evidence for early identification AN. Methods:Clinical datas from 73 patients of unilateral AN with normal hearing of Otorhinolaryngology Head and Neck Surgery of Beijing Tiantan Hospital affiliated of Capital Medical University from August 2019 to April 2022 admitted to department were retrospectively analyzed. All patients underwent pure tone audiometry（PTA）, speech discrimination score（SDS）, auditory brainstem response（ABR）, distortion product otoacoustic emission（DPOAE） and head enhanced MRI. Results:The incidence of normal hearing among patients with AN was 10.7%. Male∶female=1∶2.2; the mean age of the patients was（37.3±9.4） years; the mean tumor size was（24.2±11.2） mm. Tinnitus was the most common reason for visit; the patients who had headache and dizziness had larger tumors. Surgery was the main treatment, and the patients who underwent surgery had larger tumors than those of follow-up. Heterogeneous tumors were the most common type of MRI, homogeneous tumors were smaller than heterogeneous and cystic tumors. The sensitivity of ABR in the diagnosis of AN with normal hearing was 95.9%, and that of ≥20 mm tumors was 100%; prolonged Ⅴ-waves were the most common, patients with Ⅴ-wave deletion had larger tumors than those with normal or prolonged Ⅴ-waves. Patients who had the longer the Ⅴ-wave and the longer difference between Ⅰ-Ⅴ wave had larger tumors. DPOAE was not elicited at full frequency in 11 patients. There was no statistically significant difference in age among patients with different symptoms, treatments, types of MRI, ABR and DPOAE. Conclusion:AN of normal hearing was most common in 30-39 years old women. Patients had different symptoms, phenotypes of MRI and ABR. Patients with normal hearing who had tinnitus, dizziness, headache, facial paraesthesia, and recovery after sudden haring loss can be further examination of ABR and DPOAE for early identification AN. The sensitivity of ABR in diagnosis of hearing normal AN was 95.9%, and the abnormal type of Ⅴ-wave is related to tumor size.

Treated large posterior fossa vestibular schwannoma and meningioma: Hearing outcome and willingness-to-accept brain implant for unilateral deafness

Background/Objective

To compare functional hearing and tinnitus outcomes in treated large (~ 3 cm) vestibular schwannoma (VS) and posterior fossa meningioma cohorts, and construct willingness-to-accept profiles for an experimental brain implant to treat unilateral hearing loss.

Methods

A two-way MANOVA model with two independent variables (tumor type; time from treatment) and three dependent variables (hearing effort of tumor ear; abbreviated Speech, Spatial, and Qualities of Hearing scale (SSQ12); Tinnitus Functional Index (TFI)) was used to analyze data from VS (N = 32) and meningioma (N = 50) patients who were treated at a tertiary care center between 2010 and 2020. A query to probe acceptance of experimental treatment for hearing loss relative to expected benefit was used to construct willingness-to-accept profiles.

Results

Tumor type was statistically significant on the combined dependent variables analysis (F[3, 76] = 19.172, p < .0005, Wilks' Λ = 0.569). Meningioma showed better outcome for hearing effort (F[1, 76] = 14.632, p < .0005) and SSQ12 (F[1, 76] = 16.164, p < .0005), but not for TFI (F[1, 76] = 1.247, p = .268) on univariate two-way ANOVA analyses. Superior hearing effort and SSQ12 indices in the short-term (< 2 years) persisted in the long-term (> 2 years) (p ≤ .017). At the 60% speech understanding level, 77% of respondents would accept an experimental brain implant.

Conclusion

Hearing outcome is better for posterior fossa meningioma compared to VS. Most patients with hearing loss in the tumor ear would consider a brain implant if the benefit level would be comparable to a cochlear implant.

Level of Evidence

2.

Relationship between Signal Intensity of the Labyrinth and Cochleovestibular Testing and Morphologic Features of Vestibular Schwannoma

Objectives The aim of this article was to evaluate the relationship between signal intensity of the labyrinth and vestibulocochlear function and morphologic features of vestibular schwannoma (VS).

Design Cross-sectional Study.

Setting Tertiary referral center.

Participants Fifty-four patients with sporadic, untreated VS.

Main Outcome Measure Signal intensity of the cochlea and vestibule (SIRc and SIRv: signal intensity of cochlea/vestibule compared with cerebellar signal intensity; AURc and AURv: SIRc/SIRv of the affected side compared with the unaffected side) in 1.5T T2-weighted images was correlated with size (Hannover classification), cystic status, distance from the fundus of the internal auditory canal, video head impulse test (vHIT), and audiometry.

Results Signal intensity of the vestibule was higher than that of the cochlea (p < 0.01). Large tumors had lower SIRc than smaller tumors (p = 0.03); Hannover T1 tumors had higher SIRc (p < 0.01), SIRv (p < 0.01), AURc (p < 0.01) and AURv (p < 0.01) than the rest; heterogenous and cystic tumors had higher SIRv than solid large tumors (p = 0.02); superior vestibular nerve pattern on vHIT had higher SIRv and AURv than inferior vestibular nerve and mixed patterns (p = 0.03 and 0.004, respectively); and there was a weak correlation between AURv and speech discrimination (r = 0.33, p = 0.04).

Conclusion A more abnormal signal intensity of the labyrinth is associated with larger size and solid status of VS. There was a positive relationship between signal intensity of the labyrinth and speech discrimination scores on audiogram.

Evaluation of Vestibular Function in Diagnosis of Vestibular Schwannomas

Vestibular schwannomas (VS) are benign tumors of the vestibular nerve. The common first symptoms are hearing loss and tinnitus, followed by imbalance, vertigo, and facial nerve involvement. The subjective symptoms of VS patients are not consistent with the severity of vestibular lesions and the results of vestibular tests, which often interfere with clinicians' diagnoses. Thus, the main screening and diagnostic methods for VS are audiometry and magnetic resonance imaging (MRI), ignoring the evaluation of vestibular function at the source of pathological lesions. With the development and improvement of vestibular evaluation technology and its wide application in the clinic, modern vestibular examination technology can reflect the severity and frequency of vestibular lesions and compensation from multiple perspectives, providing an objective basis for the diagnosis and treatment of vestibular diseases. In this report, we review the results and characteristics of vestibular tests in VS patients and further clarify the clinical value of vestibular function assessment in the diagnosis and treatment of VS.

The Preoperative Diagnostic Value of MRI and Otoneural Tests in Acoustic Neuroma

Objectives

To determine the preoperative diagnostic accuracy of MRI and otoneural tests (ONT) for acoustic neuroma (AN) in a cohort of unselected patients with pontocerebellar angle tumors. To find a convenient way to screening out the potential asymptomatic AN patient earlier.

Design

This diagnostic accuracy study was performed in a central hospital and included a consecutive sample of unilateral incipient pontocerebellar angle tumor patients referred for MRI and ONT before surgery. Different AN features of MRI and ONT were collected and concluded into preoperative diagnostic variables or variable combinations. Those of MRI and ONT are analyzed and compared with biopsy results by multivariable receiver operating characteristic (ROC) analysis. The early-stage group, the course of which is 1 year or less, was separately computed and compared.

Results

Eighty-three subjects were collected from June 2013 to June 2019; 62 were confirmed AN postoperatively by biopsy, whereas others are not AN. The area under the curve (AUC) of MRI was 0.611, whereas the AUC of ONT was 0.708. In the early-stage group, the AUC of MRI was 0.539, and the AUC of ONT was 0.744.

Conclusions

ONT was able to identify more subjects affected by unilateral incipient AN than MRI preoperatively. Given that ONT is a functional test for internal auditory canal nerves, it is an optimal screening test for AN patients because it provides more information than MRI for the further clinical plan. It is particularly noteworthy for identifying asymptomatic AN patients and for early stage. Therefore, it may help more patients from unnessesary surgery. Furthermore, an MRI follow-up is suggested if the patient was found alert in ONT.

Optimized preoperative determination of nerve of origin in patients with vestibular schwannoma

In vestibular schwannoma (VS) patients hearing outcome and surgery related risks can vary and depend on the nerve of origin. Preoperative origin differentiation between inferior or superior vestibular nerve may influence the decision on treatment, and the selection of optimal treatment and counselling modalities. A novel scoring system based on functional tests was designed to predict the nerve of origin for VS and was applied to a large number of consecutive patients. A prospective, double blind, cohort study including 93 patients with suspected unilateral VS was conducted at a tertiary referral centre. Preoperatively before tumor resection a functional test battery [video head-impulse test (vHIT) of all semicircular canals (SCC)], air-conducted cervical/ocular vestibular evoked myogenic potential tests (cVEMP, oVEMP), pure-tone audiometry, and speech discrimination was applied. Sensitivity and specificity of prediction of intraoperative finding by a preoperative score based on vHIT gain, cVEMP and oVEMP amplitudes and asymmetry ratios was calculated. For the prediction of inferior vestibular nerve origin, sensitivity was 73% and specificity was 80%. For the prediction of superior vestibular nerve origin, sensitivity was 60% and specificity was 90%. Based on the trade-off between sensitivity and specificity, optimized cut-off values of - 0.32 for cVEMP and - 0.11 for oVEMP asymmetry ratios and vHIT gain thresholds of 0.77 (anterior SCC), 0.84 (lateral SCC) and 0.80 (posterior SCC) were identified by receiver operator characteristic curves. The scoring system based on preoperative functional tests improves prediction of nerve of origin and can be applied in clinical routine.

Volume quantification of endolymphatic hydrops in patients with vestibular schwannoma

•

Origin of vestibular symptoms in patients with VS is unknown.

•

Intratympanic gadolinium-enhanced MRI could confirm labyrinthine lesion in VS.

•

The volume percentage of the endolymphatic space was more accurate than the area percentage for assessing vestibular EH.

•

Vestibular symptoms in patients with VS may originate from peripheral lesions.

Objective

The origin of vestibular symptoms in patients with vestibular schwannoma (VS) is uncertain. We used intratympanic gadolinium-enhanced magnetic resonance imaging (MRI) to confirm the labyrinthine lesions in patients with VS and to explore the features of endolymphatic hydrops (EH) in these patients.

Methods

In total, 66 patients diagnosed with unilateral VS were enrolled in this study and underwent intratympanic gadolinium-enhanced MRI. The borders of the vestibule and endolymph were mapped on the axial MRI images, and the area and volume of vestibule and endolymph were automatically calculated using Osirix software, and the area and volume percentage of vestibular endolymph were obtained.

Results

The area and volume percentages of vestibular endolymph on the affected side were significantly larger than those on the healthy side (both p < 0.001). Using Kendall's W test, we found that the area and volume percentages of vestibular endolymph on the affected side were consistent (p < 0.001), but the consistency was moderate (k = 0.574). The healthy side was also consistent (p < 0.001), and the degree of consistency was moderate (k = 0.444). We used 19.1% as the cut-off point to distinguish the presence or absence of vestibular EH; that is, the volume percentage of vestibular endolymph that was more than 19.1% were defined as the subgroup with hydrops, while the subgroup without hydrops included patients with a baseline level below 19.1%. No volume classification for vestibular EH was proposed. Based on this standard, 11/66 (16.7%) of the patients with VS in this study had vestibular EH. Conclusions.

The volume percentage of the vestibular endolymph was more accurate than the area percentage for assessing vestibular EH. Using 19.1% as the cut-off point to distinguish the presence or absence of vestibular EH, we found that 16.7% of patients with VS had varying degrees of vestibular EH. We believe that the vestibular symptoms in patients with VS may originate from the peripheral lesions.

Video Head Impulse Test to Preoperatively Identify the Nerve of Origin of Vestibular Schwannomas

BACKGROUND

Identification of the nerve of origin in vestibular schwannoma (VS) is an important prognostic factor for hearing preservation surgery. Thus far, vestibular functional tests and magnetic resonance imaging have not yielded reliable results to preoperatively evaluate this information. The development of the video head impulse test (vHIT) has allowed a precise evaluation of each semicircular canal, and its localizing value has been tested for some peripheral vestibular diseases, but not for VS.

OBJECTIVE

To correlate patterns of semicircular canal alteration on vHIT to intraoperative identification of the nerve of origin of VSs.

METHODS

A total 31 patients with sporadic VSs were preoperatively evaluated with vHIT (gain of vestibule-ocular reflex, overt and covert saccades on each semicircular canal) and then the nerve of origin was surgically identified during surgical resection via retrosigmoid approach. vHIT results were classified as normal, isolated superior vestibular nerve (SVN) pattern, isolated inferior vestibular nerve (IVN) pattern, predominant SVN pattern, and predominant IVN pattern. Hannover classification, cystic component, and distance between the tumor and the end of the internal auditory canal were also considered for analysis.

RESULTS

Three patients had a normal vHIT, 12 had an isolated SVN pattern, 5 had an isolated IVN pattern, 7 had a predominant SVN pattern, and 4 had a predominant IVN pattern. vHIT was able to correctly identify the nerve of origin in 89.7% of cases (100% of altered exams).

CONCLUSION

The pattern of semicircular canal dysfunction on vHIT has a localizing value to identify the nerve of origin in VSs.

MRI based volumetric measurements of vestibular schwannomas in patients with neurofibromatosis type 2: comparison of three different software tools

Neurofibromatosis type 2 is a neurogenetic disorder with an incidence of about 1:33.000. Hallmarks are bilateral benign vestibular schwannomas, which can lead to deafness or brainstem compression. Volumetric tumor measurements are essential to assess the efficacy of new therapies. We present a statistical and methodical comparison of three volumetric image analysis tools. We performed volumetric measurements on phantoms with predefined volumes (0.1 to 8.0 ml) and tumors seen on 32 head MRI scans from eight NF2 patients with BrainLab, ITK-Snap, or OsiriX. The software was compared with regard to accuracy and reproducibility of the measurements and time required for analysis. The mean volume estimated by all three software programs differed significantly from the true volume of the phantoms, but OsiriX and BrainLab gave estimates that were not significantly different from each other. For the actual tumors, the estimated volumes with all three software tools showed a low coefficient of variability, but the mean volume estimates differed among the tools. OsiriX showed the shortest analysis time. Volumetric assessment of MRI images is associated to an intrinsic risk of miscalculation. For precise volumes it is mandatory to use the same volumetric tools for all measurements.

Video Head Impulse Test in Vestibular Schwannoma: Relevance of Size and Cystic Component on Vestibular Impairment

OBJECTIVES

Tumor factors that influence vestibular function in vestibular schwannoma (VS) have not been properly described. We evaluated whether cystic VSs have different vestibular function than solid VS. Tumor size on vestibular function was also evaluated.

STUDY DESIGN

Cross-sectional study.

SETTING

Tertiary referral center.

PATIENTS

Forty-one cases of sporadic, untreated VS.

INTERVENTION

Evaluation with video head impulse test and MRI.

MAIN OUTCOME MEASURES

Tumors were classified as solid, heterogeneous, or cystic and by size using the Hannover classification. Vestibulo-ocular reflex (VOR) gain was correlated to tumor size and cystic status.

RESULTS

Large VS had worse VOR gain than small lesions (p < 0.001). Cystic lesions had lower VOR gain than all other tumors (p = 0.001), Hannover T3 and T4 (p = 0.014), Hannover T4 (p = 0.015), solid tumors (p < 0.001), solid Hannover T3 and T4 (p = 0.003), and solid Hannover T4 (p = 0.008). Heterogeneous VSs had lower VOR gain compared to solid tumors (p = 0.02), solid Hannover T3 and T4 (p = 0.08), and solid Hannover T4 (p = 0.14). Heterogeneous and cystic VSs had lower VOR gain than solid tumors (p < 0.001), solid Hannover T3 and T4 (p = 0.004), and solid Hannover T4 (p = 0.02). VOR gain of solid T4 lesions was not significantly lower than solid Hannover T1-T3 (p = 0.33).

CONCLUSION

Cystic status is directly associated with a worse vestibular dysfunction. Size did not significantly impact vestibular function in solid VS.

Is Asymmetric Hearing Loss a Risk Factor for Vestibular Dysfunction? Lesson From Big Data Analysis Based on the Korean National Health and Nutrition Survey

OBJECTIVE

The purpose of this study was to investigate whether asymmetric hearing loss affects vestibular function.

STUDY DESIGN

Retrospective cross-sectional study.

PATIENTS

Data from the 2010 Korean National Health and Nutrition Survey for adults aged 40 years or more were used.

INTERVENTIONS

The modified Romberg test and pure-tone audiometry were performed. Data were analyzed using a complex sample χ test of independence and complex sample logistic regression analysis.

MAIN OUTCOME MEASURES

Vestibular dysfunction and hearing thresholds.

RESULTS

The overall prevalence of vestibular dysfunction was 3.3% (95% confidence interval [CI], 2.5-4.3%). In adults more than 40 years of age, multivariate linear regression analyses showed that the odds ratio (OR) of vestibular dysfunction was 3.067 times higher than the reference for a 30-dB difference in hearing thresholds between both ears (CI, 1.481-6.351; p = 0.007) after adjusting for factors associated with vestibular dysfunction. Among these individuals, the risk of equilibrium disturbance was higher in the presence of low-frequency asymmetric hearing loss (OR, 2.148; CI, 1.216-3.793; p = 0.009); on the other hand, high-frequency asymmetry did not lead to a higher risk.

CONCLUSIONS

As low-frequency asymmetric hearing thresholds tend to coexist with vestibular dysfunction in adults, those with asymmetric hearing loss should be closely monitored.

[Preoperative determination of nerve of origin in patients with vestibular schwannoma. German version]

BACKGROUND

Vestibular schwannoma (VS) is a benign tumor that develops in the internal auditory canal and the cerebellopontine angle, potentially diminishing hearing or balance. Most VS tumors arise from one of two vestibular branches: the superior or inferior vestibular nerve. Determining the specific nerve of origin could improve patient management in terms of preoperative counseling, treatment selection, and surgical decision-making and planning. The aim of this study was to introduce a novel scoring system that was designed to determine the nerve of origin.

METHODS

The nerve of origin was predicted based on video head impulse assessments of all semicircular channels, together with cervical/ocular vestibular-evoked myogenic potential tests. The acquired data were entered into a scoring system developed to allocate the tumor origin. Finally, the nerve of origin was definitively determined intraoperatively.

RESULTS

The novel scoring system was applied to 5 consecutive patients undergoing surgical VS treatment. In one case, no determination was possible. In all other cases, the preoperatively predicted tumor origin was the same as the origin determined during surgery.

CONCLUSION

The scoring system predicts the nerve of origin and will be evaluated in a larger prospective cohort study of VS patients in the near future.

Sensorineural hearing loss in patients with vestibular schwannoma correlates with the presence of utricular hydrops as diagnosed on heavily T2-weighted MRI

PURPOSE

The purpose of this study was to assess whether the volume of the vestibular endolymphatic space correlates with the degree of hearing loss using heavily T2-weighted fast imaging employing steady-state acquisition with cycle phase (FIESTA-C) MRI.

MATERIALS AND METHODS

A total of 23 patients with vestibular schwannoma, as diagnosed on typical image findings, who underwent FIESTA-C MRI were included. There were 13 women and 10 men with a mean age of 63.5±9.3 (SD) years (range: 49-88years). Two radiologists independently evaluated the volume of the utricle and saccule. Correlation between tumor volume, vestibular endolymphatic space volume and degree of hearing loss - as evaluated with the levels of pure-tone average and speech recognition threshold - were searched for.

RESULTS

The mean saccular, utricular and tumor volumes were 3.17±1.1 (SD) mm³ (range: 1.45-5.7mm³), 14.55±5 (SD) mm³; (range: 6.6-23.9mm³) and 17.4±5.5 (SD) mm³; (range: 8.3-25.4mm³), respectively. There was a moderate correlation between the volume of the utricle and the degree of hearing loss as evaluated with the levels of pure-tone average (rho=0.5; P=0.015) and speech recognition threshold (rho=0.58; P=0.004). There were no significant correlations between saccular and tumor volumes and the degree of hearing loss.

CONCLUSION

The volume of the utricle in patients with obstructive vestibular schwannoma moderately correlates with the degree of hearing loss.

Facial nerve schwannomas presenting with vestibular dysfunction: a case series

Facial nerve schwannomas (FS) can symptomatically mimic vestibular schwannomas (VS). In addition, FS can be difficult to distinguish from VS on magnetic resonance imaging (MRI). Although disequilibrium is not uncommon in patients with FS, no previous studies have investigated the vestibular function in such patients. Three cases of FS presented vestibular dysfunction as measured with caloric test, video head impulse test (VHIT), and vestibular evoked myogenic potentials (VEMPs). All patients in this study had a considerable affection of the vestibular function as assessed by the vestibular test panel. Audiovestibular evaluation of FS provides important information that may influence treatment strategy. As VS, FS should be evaluated with vestibular tests prior to intervention.

An international comparison of diagnostic and management strategies for vestibular schwannoma

Objective

To compare international diagnostic and management strategies for vestibular schwannoma (VS).

Methods

A web-based questionnaire was sent to 130 otolaryngologists, mainly identified through the European Skull Base Society. It contained questions on general information including guideline usage as well as questions on diagnosis (focussing on selection of patients for MRI) and management of VS, including case scenarios. Descriptive statistics were reported.

Results

Thirty-six otolaryngologists working in 11 different countries completed the questionnaire (response rate: 28%). Guidelines for diagnosis and management of VS are used by 44% and 42% of respondents, respectively. In the diagnostic strategy for VS, different types and combinations of audiovestibular function tests are used when deciding whether a patient should undergo an MRI. Respondents apply 18 different definitions of asymmetrical hearing loss. Variation was also apparent from reported considerations on management of VS. Most respondents (84%) prefer a wait-and-scan strategy in case of a small intrameatal VS (Koos 1). Variety in management strategies increases for patients with a medium to large sized VS (Koos 2, 3 and 4). The details of each management strategy (wait-and-scan, microsurgery, stereotactic radiosurgery and fractionated radiotherapy) also differ among respondents.

Conclusions

A large variation in diagnostic and management strategies for VS was identified between respondents. More evidence and/or consensus seem warranted to reduce uncertainties for patients, and differences in outcome and costs that might result from the variety of strategies currently being applied.

Electronic supplementary material

The online version of this article (10.1007/s00405-018-5199-6) contains supplementary material, which is available to authorized users.

The prediction of the tumor size of a vestibular schwannoma by clinical performance and vestibular function tests

PURPOSE

To investigate the relationship between vestibular schwannoma (VS) size and the dysfunction and compensation of the vestibular system.

METHODS

One hundred fifty-two patients with unilateral VS were investigated using multiple auditory-vestibular function tests such as audiometry, sensory organization test (SOT), caloric test, cervical vestibular-evoked myogenic potential (cVEMP) test, and ocular VEMP (oVEMP) test.

RESULTS

In this study, 89% of patients with unilateral VS had mild to severe hearing loss on the involved side. All patients showed higher threshold values or no response in the cVEMP and oVEMP tests, which both exhibited a lower response rate on the affected side than on the unaffected side. Patients with a tumor size ≥ 30 mm had significantly lower equilibrium scores for condition 5 and condition 6 of the SOT, which were associated with vestibular dysfunction, higher rates of canal paresis in the caloric test, and lower response rates in the cVEMP and oVEMP tests on the affected sides, compared with the results of patients with a tumor size ≤ 14 mm and patients with a tumor size of 15-29 mm.

CONCLUSIONS

A diameter > 30 mm may be the critical threshold at which vestibular function is affected and vestibular compensation is interfered with by a VS tumor. Functional performance of the vestibular system can help clinicians predict the size of a tumor and provide a basis for the development of treatment protocols.

Unusual discovery of a vestibular schwannoma following eradication therapy for Mycobacterium abscessus

A young man with cystic fibrosis in his early 30s presented to accident and emergency with acute onset unilateral lower motor neuron facial palsy, hearing loss and impaired balance following Mycobacterium abscessus eradication induction therapy. The hearing loss and impaired balance developed over a 3-day period prior to the onset of facial palsy. Further investigation with a CT scan and MRI scan led to a diagnosis of vestibular schwannoma. The facial palsy resolved with steroid treatment; however, the hearing loss is irreversible, which has had a profound impact on his life and career. This case is intriguing as the cause and association of events are unclear. A working diagnosis of incidental Bell's palsy and unilateral hearing loss caused by the vestibular schwannoma was applied. However, the onset of these symptoms in relation to M. abscessus eradication induction therapy promotes discussion.

Cochlear Dysfunction is not Common in Human Meningioma of the Internal Auditory Canal

HYPOTHESIS

Cochlear dysfunction is not common in human meningioma of the internal auditory canal.

BACKGROUND

Meningiomas arising from the cerebellopontine angle and internal auditory canal typically cause hearing loss. Cochlear dysfunction is known to contribute to sensorineural hearing loss induced by vestibular schwannoma, the most common tumor of the internal auditory canal. Detailed cochlear histopathology in meningioma has not been reported.

METHODS

Retrospective analysis of cochlear histopathology in five unoperated and five operated meningiomas of the internal auditory canal identified after screening human temporal bone collections from three academic medical centers.

RESULTS

While some dysfunction of all analyzed cochlear cell types was identified, a predominant or exclusive loss of hair cells was not observed in any meningioma. Only 14.3% of temporal bones showed significantly more hair cell damage on the side of the tumor when compared with the contralateral ear; cochlear neuronal damage was more prevalent in meningiomas. The incidence of hydrops, perilymphatic precipitate, or endolymphatic precipitate was low.

CONCLUSIONS

Substantial cochlear damage in human meningioma of the internal auditory canal is not common. This may explain the anecdotal hearing improvement observed after surgical resection of meningioma. Our findings underline the importance of developing therapeutic strategies to prevent cochlear neuronal degeneration due to tumors of the internal auditory canal.

Diagnosis of retrocochlear lesions with emphasis on expansion of the cerebellopontine angle

The correct diagnosis of CPA tumours is a relatively common issue in both neurological and ENT practice, the omission of which can have serious consequences for the patient. Properly set clinical guidelines and diagnostic protocols are key aspects of good clinical practice. In the case of CPA tumours, two options are available: the first is diagnosis with the help of an ABR as the primary tool for determining the group of patients with a possible tumour; the second is an MRI scan of the posterior cranial fossa. With an appropriately set diagnostic protocol in place, and despite the 40% chance of failure of the ABR to detect tumours less than or equal to 1 cm, similar treatment results can be achieved with much higher cost efficacy in case of primary ABR testing.