Normal audiologic presentations in patients with acoustic neuroma: An evaluation using strict audiologic parameters

Presbycusis and Hearing Preservation in Observed Vestibular Schwannomas

OBJECTIVE

We reviewed a cohort of patients with untreated sporadic vestibular schwannoma (VS) and examined the relationship between high-frequency hearing loss (HFHL) in the non-VS ear and long-term hearing outcomes in the VS-affected ear. We hypothesized that the progression of HFHL is associated with accelerated hearing decline in sporadic VS.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary center.

PATIENTS

We studied 102 patients with sporadic VS diagnosed from 1999 to 2015 with ≥5 years of observation (median, 6.92; interquartile range, 5.85-9.29). Sixty-six patients had AAO-HNS class A/B hearing at presentation and were included in analysis.

INTERVENTIONS

Audiometry, serial magnetic resonance imaging for observation of VS.

MAIN OUTCOME MEASURES

Four-frequency pure tone average (PTA) and word recognition scores (WRS) in the VS-affected ear. Decline in high-frequency PTA (average of thresholds at 4000, 6000, and 8,000 Hz) was defined as ≥10 dB during the study period. Decline in WRS was defined as ≥10%.

RESULTS

Compared with those without, patients with progressive HFHL in the non-VS ear were more likely to experience a decline in WRS in the VS ear (80% vs. 54%, p = 0.031). However, the same group showed no difference (52% vs. 41%, p = 0.40) in decline in PTA of the VS ear.

CONCLUSIONS

Patients with observed VS who experience progressive HFHL in the non-VS ear are more likely to experience significant declines in speech understanding in the VS-affected ear over time. Patients with a history of presbycusis may have an increased risk of losing serviceable hearing because of sporadic VS.

Bilateral Vestibular Schwannomas in a Patient with Ring Chromosome 22: Case Report and Review of the Literature

INTRODUCTION

Ring chromosome 22 (r[22]) can lead to the development of intracranial tumors such as meningiomas, neurofibromas, and schwannomas similar to neurofibromatosis 2 (NF2).

CASE PRESENTATION

An 18-year-old female with r(22) and a history of global development delay and cognitive impairment presented with sudden hearing loss. MRI revealed bilateral vestibular schwannomas. Given documented audiologic decline in the patient's hearing, the larger tumor was treated with CyberKnife fractionated stereotactic radiosurgery, and the smaller tumor is being monitored.

CONCLUSION

This case provides further evidence that patients with r(22) can develop clinical features of NF2, including the development of bilateral vestibular schwannomas, and should be monitored for hearing disturbances starting in puberty as a warning sign for these tumors.

The Influence of Vestibular Schwannoma Tumor Volume and Growth on Hearing Loss

OBJECTIVE

To ascertain the relationship among vestibular schwannoma (VS) tumor volume, growth, and hearing loss.

STUDY DESIGN

Retrospective cohort study.

SETTING

Single tertiary center.

SUBJECTS AND METHODS

Adults with observed VS and serviceable hearing at diagnosis were included. The primary outcome was the development of nonserviceable hearing as estimated using the Kaplan-Meier method. Associations of tumor volume with baseline hearing were assessed using Spearman rank correlation coefficients. Associations of volume and growth with the development of nonserviceable hearing over time were assessed using Cox proportional hazards models and summarized with hazard ratios (HRs).

RESULTS

Of 230 patients with VS and serviceable hearing at diagnosis, 213 had serial volumetric tumor data for analysis. Larger tumor volume at diagnosis was associated with increased pure-tone average (PTA) (P < .001) and decreased word recognition score (WRS) (P = .014). Estimated rates of maintaining serviceable hearing at 6 and 10 years following diagnosis were 67% and 49%, respectively. Larger initial tumor volume was associated with development of nonserviceable hearing in a univariable setting (HR for 1-cm³ increase: 1.36, P = .040) but not after adjusting for PTA and WRS. Tumor growth was not significantly associated with time to nonserviceable hearing (HR, 1.57; P = .14), although estimated rates of maintaining serviceable hearing during observation were poorer in the group that experienced growth.

CONCLUSION

Larger initial VS tumor volume was associated with poorer hearing at baseline. Larger initial tumor volume was also associated with the development of nonserviceable hearing during observation in a univariable setting; however, this association was not statistically significant after adjusting for baseline hearing status.

Audiological Evaluation of Vestibular Schwannoma Patients with Normal Hearing

Objective: To evaluate the audiological aspects of vestibular schwannoma (VS) patients with normal hearing. Study Design: Retrospective study. Setting: Quaternary referral center for skull base pathologies. Patients: The records on 4,000 patients who had been diagnosed with VS between 1986 and December 2017 were retrospectively reviewed. The patients included in the study were the ones who complied with the strict audiological normality criteria, as follows: a pure tone hearing threshold (at the 6-octave-spaced frequencies from 250 to 8,000 Hz) ≤25 dBHL; a word recognition score >90%; and interaural differences ≤10 dB at each frequency. Interventions: Auditory brainstem response (ABR) testing and radiological imaging. Main Outcome Measures: The incidence of normal objective hearing among VS patients, and the diagnostic utility of the ABR and the effect of tumor size and site on the response. Results: The incidence of normal hearing among VS patients was 4.2%. Tinnitus and vertigo were the most common symptoms across tumor grades; 5.6% of the tumors were large and giant tumors. The ABR yielded a sensitivity of 73.6%, with a false negative rate of 26.3% using a cutoff point of 0.2 ms for interaural latency differences. Conclusions: The diagnosis of VS should not be based on audiometric thresholds alone. Alarming signs of VS should be clear to the physician in order not to miss or delay the diagnosis of the disease. The ABR is useful in the diagnosis of VS, but normal results do not exclude the occurrence of the disease in patients with normal hearing.

ABR in the diagnosis of vestibular schwannomas: a meta-analysis

PURPOSE

The aim of this study is to rigorously evaluate the role of auditory brainstem response (ABR) testing in the diagnosis of vestibular schwannomas (VS).

MATERIALS AND METHODS

Searches were conducted in multiple online databases, supplemented by hand searches. From the studies chosen for final inclusion, relevant data were extracted and meta-analysis of pooled data was performed.

RESULTS

623 studies were identified from which 43 met inclusion criteria for analysis (1978 to 2009) including 3314 patients. Pooled sensitivity for ABR detection of vestibular schwannomas was 93.4% (95% CI 92.6-94.3, P=0.0000). For tumors less than 1cm (8 studies, 176 patients) sensitivity was 85.8% (95% CI 80.6-90.1, P=0.0116). For tumors greater than 1cm (6 studies, 251 patients) pooled sensitivity was 95.6% (95% CI 93.1-98.2, P=0.0660). Sensitivity of ABR to detect extracanalicular tumors was higher than for intracanalicular tumors, though pooled data were not statistically valid. Pooled specificity (8 studies, 2432 patients) was 82.0% (95% CI 80.5-83.6, P=0.0000).

CONCLUSIONS

Although MRI remains the gold standard, emerging trends towards more conservative management coupled with limited financial resources may prompt many clinicians to review the role of ABR testing in screening for retrocochlear pathology. In light of the high sensitivity and specificity of ABR testing for VS, we strongly urge its reconsideration as a useful diagnostic tool for patients with clinically suspected VS.

Atypical clinical presentations of vestibular schwannomas

A significant number of patients with vestibular schwannomas present atypically, with none of the classical symptoms of unilateral sensorineural hearing loss, tinnitus, and/or dysequilibrium. The aim of this study is to highlight those patients with unusual clinical symptoms.

STUDY DESIGN

The clinical data of all patients who presented to the vestibular schwannoma clinic at Beaumont Hospital over the past 12 years was prospectively recorded in a computerized database. This paper reviews the atypical presenting symptoms.

RESULTS

Three hundred ninety-eight patients were included in this study. A total of 3.7% of patients presented with atypical symptoms only.

CONCLUSION

A significant subgroup, 3.7% in our study, did not present with the audiovestibular symptoms classically associated with vestibular schwannoma. Clinician awareness of the atypical clinical symptoms may lead to earlier detection of these lesions.

[Clinical tumoral size dissociation in acoustic neuroma: reality or measure distortion?]

INTRODUCTION

In this study we have analyzed (i) the audiometric frequencies more often affected in acoustic neuroma (AN), (ii) the percentage of patients presenting normal hearing and those with sudden hearing loss, (iii) if there is a correlation between tumor size and hearing loss, and (iv) the relationship between clinical and radiological parameters and audiological data.

METHODS AND MATERIAL

Retrospective study of 81 patients undergoing surgical removal of a sporadic AN.

RESULTS

The highest threshold in the tumor's ear was found at 8000 Hz, and the highest interaural difference at 4000 Hz. The percentage of patients presenting normal hearing and sudden hearing loss was 2.5% and 9%, respectively. No significant association was found between tumor size and hearing loss, preoperative facial palsy or Vth cranial nerve deficit. There was a significant association between the degree of hearing loss and Vth cranial nerve deficit, and between hearing loss and preoperative facial palsy.

CONCLUSIONS

The association between hearing loss and Vth cranial nerve deficit, and between hearing loss and preoperative facial palsy is independent the size of the tumour.

Acoustic neuroma. Assessment and management

Acoustic neuroma results from abnormal proliferation of Schwann cells. These tumors originate in the region of Scarpa's ganglion at the junction of peripheral and central myelin of the vestibular nerve located in the internal auditory canal (IAC). The bony confine of the IAC houses the VII and the VIII cranial nerves. The presence of tumor mass compresses these structures. The growing tumor mass may also prolapses into the cerebellopontine angle (CPA). With continued growth, the tumor eventually compresses on the brain stem and cerebellum. Despite the benign nature of these tumors, the clinical course of this disease may be fraught with complications.

Preoperative versus postoperative role of vestibular-evoked myogenic potentials in cerebellopontine angle tumor

OBJECTIVE/HYPOTHESIS

Vestibular-evoked myogenic potential (VEMP) examination was performed on patients with a cerebellopontine angle (CPA) tumor to evaluate its clinical role.

METHODS

Patients with a CPA tumor were subjected to caloric test and VEMP examination. Follow-up study was performed 1 year after the surgery.

RESULTS

Six (69%) of the 9 tumors did not exhibit either caloric response or VEMP on the lesioned side. Three patients received tumor excision and all tumors involved both the superior and inferior vestibular nerves. Two (22%) of the 9 tumors had normal caloric responses but no VEMP. One underwent surgical excision, and the tumor originated from the inferior vestibular nerve. In the follow-up study, only 1 patient with epidermoid cyst presented complete recovery of caloric response and VEMP, whereas in the other 3 patients with vestibular schwannoma, the responses were all absent persistently.

CONCLUSION

Before surgery, VEMP test can be used to predict the nerve of origin and to formulate the best surgical approach. After surgery, VEMP test can be used to define the nature of the tumor (compressing or infiltrating the nerve) and disclose the residual function of the inferior vestibular nerve.

[Asymptomatic acoustic neurinoma associated with hypophyseal macroadenoma]

The widespread use of gadolinium-enhanced MRI (Gd-MRI) in our hospitals has supposed an increase in detection of asymptomatic acoustic neuromas (AN) as incidental finding. Concurrent primary intracranial tumors of different cell types are extremely uncommon.

CLINICAL CASE

A 23 year-old woman complained of irregular menstrual cycles and galactorrhea for two years. A Gd-MRI scan showed a pituitary macroadenoma and an AN of 1.4 cm. with intracanalicular and cisternal extension. The patient did not have any otologic or neuro-otologic symptoms or signs. Audiograms revealed bilateral normal hearing. The results of acoustic reflex test and electronystagmographic caloric tests were normal. The AN underwent radiosurgery treatment.

DISCUSSION

The literature about atypical AN is reviewed, giving a particular concern on asymptomatic cases. We only have found one case of association between AN and pituitary adenoma. The real prevalence of AN in general population is discussed.