Tumors of the nervous system and hearing loss: Beyond vestibular schwannomas.

Hearing loss is a common side effect of many tumor treatments. However, hearing loss can also occur as a direct result of certain tumors of the nervous system, the most common of which are the vestibular schwannomas (VS). These tumors arise from Schwann cells of the vestibulocochlear nerve and their main cause is the loss of function of NF2, with 95 % of cases being sporadic and 5 % being part of the rare neurofibromatosis type 2 (NF2)-related Schwannomatosis. Genetic variations in NF2 do not fully explain the clinical heterogeneity of VS, and interactions between Schwann cells and their microenvironment appear to be critical for tumor development. Preclinical in vitro and in vivo models of VS are needed to develop prognostic biomarkers and targeted therapies. In addition to VS, other tumors can affect hearing. Meningiomas and other masses in the cerebellopontine angle can compress the vestibulocochlear nerve due to their anatomic proximity. Gliomas can disrupt several neurological functions, including hearing; in fact, glioblastoma multiforme, the most aggressive subtype, may exhibit early symptoms of auditory alterations. Besides, treatments for high-grade tumors, including chemotherapy or radiotherapy, as well as incomplete resections, can induce long-term auditory dysfunction. Because hearing loss can have an irreversible and dramatic impact on quality of life, it should be considered in the clinical management plan of patients with tumors, and monitored throughout the course of the disease.

Acoustic Reflexes in Aural Atresia Patients: Evidence of an Intact Efferent System?

OBJECTIVE: To record crossed acoustic reflex thresholds (xART's) postoperatively from patients after surgical repair of unilateral congenital aural atresia (CAA). To seek explanations for when xARTs can and cannot be recorded. We hope to understand the implications for this central auditory reflex despite early afferent deprivation. METHODS: Patients who underwent surgery to correct unilateral CAA at a tertiary academic medical were prospectively enrolled to evaluate for the presence of xART. Preoperative ARTs in the normal (non-atretic) ear, and postoperative ipsilateral ARTs (stimulus in the normal ear) and contralateral ARTs (stimulus in the newly reconstructed atretic ear; record in the normal ear) were measured at 500, 1000, and 2000 Hz. RESULTS: Four of 11 patients with normal ipsilateral reflex thresholds preoperatively demonstrated crossed acoustic reflexes postoperatively (stimulus in reconstructed ear; record from normal ear). Four other patients demonstrated normal ipsilateral thresholds preoperatively but did not have crossed reflexes postoperatively. No reflexes (pre- or postoperatively) could be recorded in 3 patients. Crossed reflex threshold is significantly correlated with the postoperative audiometric threshold. There was no correlation between ipsilateral and contralateral reflex thresholds. CONCLUSION: Crossed acoustic reflexes can be recorded from some but not all postoperative atresia patients, and the thresholds for those reflexes correlate with the postoperative pure tone threshold. The presence of acoustic reflexes implies an intact CN VIII-to-opposite CN VII central reflex arc despite early unilateral sound deprivation.

NLRP3 inflammasome activation in human vestibular schwannoma: Implications for tumor-induced hearing loss.

Vestibular schwannoma (VS) is the fourth most common intracranial tumor, arising from neoplastic Schwann cells of the vestibular nerve and often causing debilitating sensorineural hearing loss (SNHL) and tinnitus. Previous research suggests that the abnormal upregulation of inflammatory pathways plays a highly significant, though infrequently described role in VS pathobiology, and that VS-associated SNHL is due not only to mechanical compression of the auditory nerve but also to differences in the intrinsic biology of these tumors. We hypothesize that patients who present with poor hearing associated with VS experience a more robust inflammatory response to this tumor than VS patients who present with good hearing. To investigate this hypothesis, we conducted a comprehensive pathway analysis using gene expression data from the largest meta-analysis of vestibular schwannoma microarray data, comprising 80 tumors and 16 healthy peripheral nerves. We identified the NLRP3 inflammasome as a novel target worthy of further exploration in VS research and validated this finding at the gene and protein expression level in human VS tissue using qRT-PCR and immunohistochemistry. To date, NLRP3 inflammasome activation has not been reported in VS, and this finding may represent a new and potentially significant therapeutic avenue. Notably, after analysis of 30 VSs, we observe that overexpression of key components of the NLRP3 inflammasome is preferentially associated with tumors that produce increased hearing loss in VS patients. Therefore, therapeutic development for VS should include considerations for minimizing NLRP3-associated inflammation to best preserve hearing.

The Relationship between the Etiology of Profound Prelingual Sensorineural Hearing Loss and the Results of Vestibular-Evoked Myogenic Potentials

Abstract Introduction Cervical vestibular-evoked myogenic potentials (cVEMPs) are biphasic, short latency potentials, which represent the inhibition of the contraction of the sternocleidomastoid muscle (SCM) mediated by the saccule, the inferior vestibular nerve, the vestibular nuclei and the medial vestibular spinal tract. Objective To evaluate the response of cVEMPs in individuals with profound prelingual bilateral cochlear hearing loss. Methods A prospective case-control study. A total of 64 volunteers, divided into a study group (31 patients with profound prelingual sensorineural hearing loss) and a control group (33 subjectsmatched for age and gender with psychoacoustic thresholds of ≤ 25 dB HL between 500 and 8,000 Hz) were submitted to the cVEMP exam. The causes of hearing loss were grouped by etiology and the involved period. Results The subjects of the study group aremore likely to present changes in cVEMPs compared to the control group (35.5% versus 6.1% respectively; p = 0.003), with an odds ratio (OR) of 8.52 (p = 0.009). Itmeans that they had 8.52-fold higher propensity of presenting altered cVEMP results. There were no statistically significant differences between the latencies, the interamplitude and the asymmetry index. Regarding the etiology, there was a statistically significant difference when the cause was infectious, with an OR of 15.50 (p = 0.005), and when the impairment occurred in the prenatal period, with an OR of 9.86 (p = 0.009). Conclusion The present study showed abnormalities in the sacculocolic pathway in a considerable portion of individuals with profound prelingual sensorineural hearing loss due to infectious and congenital causes, as revealed by the cVEMP results. (AU)

Nervus Intermedius Guides Auditory Brainstem Implant Surgery in Children with Cochlear Nerve Deficiency.

OBJECTIVE: To investigate the anatomic features of the nervus intermedius and cranial nerve VII in children with cochlear nerve deficiency and to verify whether the nervus intermedius can provide an additional landmark to help guide placement of the auditory brainstem implant electrode. STUDY DESIGN: Case series with chart review. SETTING: Tertiary referral center. SUBJECTS AND METHODS: High-definition video was captured during retrosigmoid surgery in 64 children (mean age, 3.91 ± 2.83 years) undergoing auditory brainstem implant placement. These videos were examined with particular reference to the number and variety of nervus intermedius bundles and any associated facial nerve anomalies. RESULTS: Absence of cranial nerves VI, VII, and VIII was observed in 3, 6, and all 64 children, respectively. Fifteen children had several abnormalities of the facial nerve in the cerebellopontine angle. Anatomic identification of the facial nerve and the bundles composing the nervus intermedius was possible in 46 children. In 12 children, identification was possible with the assistance of intraoperative monitoring. The number of bundles composing the nervus intermedius varied from 1 to 6. The nervus intermedius and cranial nerve IX were useful landmarks for identifying the foramen of Luschka of the lateral recess. CONCLUSION: The nervus intermedius provides an additional landmark during auditory brainstem microsurgery since it was identified in all subjects. The nervus intermedius anatomy and its topographic relationship with the neurovascular structures around the foramen of Luschka have been described for the first time in children with cochlear nerve deficiency.

Hearing thresholds and FMRI of auditory cortex following eighth cranial nerve surgery.

OBJECTIVE: Determine whether auditory cortex (AC) organization changed following eighth cranial nerve surgery in adults with vestibular-cochlear nerve pathologies. We examined whether hearing thresholds before and after surgery correlated with increased ipsilateral activation of AC from the intact ear. STUDY DESIGN: During magnetic resonance imaging sessions before and 3 and 6 months after surgery, subjects listened with the intact ear to noise-like random spectrogram sounds. SETTING: Departments of Radiology and Otolaryngology of Washington University School of Medicine. SUBJECTS AND METHODS: Three patients with acoustic neuromas received Gamma Knife radiosurgery (GK); 1 patient with Meniere's disease and 5 with acoustic neuromas had surgical resections (SR); 2 of the latter also had GK. Hearing thresholds in each ear were for pure tone stimuli from 250 to 8000 Hz before and after surgery (3 and 6 months). At the same intervals, we imaged blood oxygen level-dependent responses to auditory stimulation of the intact ear using an interrupted single-event design. RESULTS: Hearing thresholds in 2 of 3 individuals treated with GK did not change. Five of 6 individuals became unilaterally deaf after SRs. Ipsilateral AC activity was present before surgery in 6 of 9 individuals with ipsilateral spatial extents greater than contralateral in 3 of 9. Greater contralateral predominance was significant especially in left compared to right ear affected individuals, including those treated by GK. CONCLUSION: Lateralization of auditory-evoked responses in AC did not change significantly after surgery possibly due to preexisting sensory loss before surgery, indicating that less than profound loss may prompt cortical reorganization.

Analysis of interpeak latencies of brainstem auditory evoked potential waveforms during microvascular decompression of cranial nerve VII for hemifacial spasm.

OBJECT: Microvascular decompression (MVD) of the facial nerve is an effective treatment for patients with hemifacial spasm. Intraoperative monitoring of brainstem auditory evoked potentials (BAEPs) during MVD can reduce the incidence of hearing loss. In this study the authors' goal was to evaluate changes in interpeak latencies (IPLs) of Waves I-V, Waves III-V, and Waves I-III of BAEP Waveforms I, III, and V during MVD and correlate them with postoperative hearing loss. To date, no such study has been performed. Hearing loss is defined as nonuseful hearing (Class C/D), which is a pure tone average of more than 50 dB and/or speech discrimination score of less than 50%. METHODS: The authors performed a retrospective analysis of IPLs of BAEPs in 93 patients who underwent intraoperative BAEP monitoring during MVD. Patients who did not have hearing loss were in Class A/B and those who had hearing loss were in Class C/D. RESULTS: Binary logistic regression analysis of independent IPL variables was performed. A maximum change in IPLs of Waves I-III and Waves I-V and on-skin change in IPLs of Waves I-V increases the odds of hearing loss. However, on adjusting the same variables for loss of response, change in IPLs did not increase the odds of hearing loss. CONCLUSIONS: Changes in IPL measurements did not increase the odds of postoperative hearing loss. This information might be helpful in evaluating the value of IPLs as alarm criteria during MVD to prevent hearing loss.

[Linear accelerator radiosurgery for the treatment of vestibular schwannoma]. / Radiocirugia con acelerador lineal en el tratamiento del schwannoma vestibular.

INTRODUCTION AND AIM: Radiosurgery is among the treatment options for patients with vestibular schwannoma. We present the experience in our institution in the treatment of this disease with this technique. PATIENTS AND METHODS: A retrospective study was made including 20 patients (11 women and 9 men; median age: 55.15 years-old) with vestibular schwannoma who received linear accelerator radiosurgery treatment since April 2005 until December 2008. Follow-up period was between 12 and 42 months, considering clinical examination of cranial nerves VII (House-Brackmann scale) and VIII (Gardner-Robertson scale) as well as radiological findings (considering tumor volume). For statistical analysis, the Fisher's exact test and logistic regression test were used. RESULTS: Certain worsening of hearing function was present in 25% of the patients. Five patients had large tumors at the moment of the treatment (equal or larger than 3.5 cm3), from which four deteriorated from headache, unsteady gait, dizziness/vertigo, facial numbness and tinnitus, with statistical significance (p < 0.05). From the first year of treatment on, there was a tumor volume decrease tendency, with no tumor growth in the medium/long term follow-up, achieving a local control rate of 100%. CONCLUSIONS: Radiosurgery has become an alternative in the treatment of patients with vestibular schwannoma of appropriate size, with high safety level, using low radiation doses, low rate of complications and good tumor control rate in the medium term follow-up.

The impact of tinnitus and vertigo on patient-perceived quality of life after cerebellopontine angle surgery.

BACKGROUND: Quality of life (QOL) has come into focus after treatment for cerebellopontine angle (CPA) lesions. OBJECTIVE: This study compared subjective (tinnitus, vertigo) and objective (hearing loss, facial palsy) results of CPA surgery with patient-perceived impairment of QOL. METHODS: A retrospective analysis of a consecutive series of 48 patients operated on for either a vestibular schwannoma or a meningioma in the CPA was performed. Patient's subjective impairment of QOL by tinnitus, vertigo, hearing loss, and facial nerve palsy was assessed by a visual analog scale (VAS). Objective facial nerve and hearing function were determined using House-Brackmann and Gardner-Robertson classification systems, respectively. RESULTS: The return rate of questionnaires was 64.4%, with mean follow-up time of 417.2 (+/- 46.4) days. Mean preoperative tinnitus score was 2.5 (+/- 0.5) and increased to 4.6 (+/- 0.7) postoperatively (P < .01). The vertigo score increased from 2.0 (+/- 0.3) to 5.8 (+/- 0.6) (P < .001). Pre- and postoperative values for hearing loss were 3.4 (+/- 0.6) and 5.9 (+/- 0.7), respectively (P < .01), and for facial nerve palsy 0.7 (+/- 0.4) compared with 3.1 (+/- 0.6) postoperatively (P < .01). House-Brackmann grade 1 or 2 was determined in 87.1% of patients before and in 80.6% after surgery. Serviceable hearing (Gardner-Robertson classes I-III) was found in 75% before and in 64.3% after surgery. CONCLUSION: Preservation of facial nerve and hearing function are not the only important criteria defining QOL after CPA surgery. Tinnitus and vertigo may have a significant underestimated impact on the patient's postoperative course and QOL.

[Evaluation with functional magnetic resonance imaging in 1 case of cochleovestibular nerve malformation in children before cochlear implantation and review of the literature].

OBJECTIVE: To evaluate the feasibility of cochlear implantation by functional magnetic resonance imaging (fMRI) in a patient with cochleovestibular nerve hypoplasia. METHOD: Audiometry, radiological examination and fMRI of the auditory cortex were performed to a 15-year-old boy with bilateral hearing loss before cochlear implantation. RESULT: Results of pure tone audiometry and auditory brainstem responses showed profound sensorineural hearing loss (SNHL). Transiently evoked otoacoustic emission was absent on both sides. High resolution computed tomography revealed the inner ear malformation (incomplete partition I) on both side. Oblique sagittal reconstruction in magnetic resonance imaging (MRI) showed the malformation of cochleovestibular nerve, fMRI demonstrated the activation of the right primary auditory cortex during 1-kHz monaural stimulation on the left side. No cortical activation appeared during the monaural right acoustic stimulation using the same sound pressure level. The child had subjective auditory response 1 month after cochlear implantation on his left side. CONCLUSION: fMRI would be an effective measure in the assessments for the cochlear implantation candidates, combining with audiometry and radiological examination, especially when MRI shows cochleovestibular nerve malformation in these patients.

Cerebellopontine angle arachnoid cyst containing ectopic choroid plexus--case report.

We present a rare and interesting case of a cerebellopontine angle cyst containing ectopic choroid plexus tissue in a 26 year-old female. Surgical resection was performed, and histological examination confirmed the presence of choroid plexus in the cyst wall. This is the first reported case of ectopic choroid plexus at the cerebellopontine angle in an adult. We present the case and review the literature.

Chronological changes in the eighth cranial nerve compound action potential (CAP) in experimental endolymphatic hydrops: the effects of altering the polarity of click sounds.

CONCLUSION: Using a guinea pig model of experimental endolymphatic hydrops, click sounds of altered polarity showed different latencies and amplitudes in hydropic compared with normal cochleae. Latency changes appeared as early as 1 week after endolymphatic obstruction. This method can help diagnose endolymphatic hydrops. OBJECTIVE: The goal of the study was to develop an objective electrophysiological diagnosis of endolymphatic hydrops. MATERIALS AND METHODS: Endolymphatic hydrops were created surgically in guinea pigs. The latency and the amplitude of the eighth cranial nerve compound action potential (CAP) for click sounds of altered polarity were measured up to 8 weeks after the surgery. RESULTS: At early stages after surgery, the latency for condensation clicks became longer, and at later stages the latencies for both condensation and rarefaction became longer. The discrepancy in the latencies for rarefaction and condensation click sounds (rarefaction minus condensation) became larger by the first week after surgery, but no further discrepancy occurred thereafter. Compared with latency changes, amplitude changes in the CAP were rapid and progressive following surgery, suggesting ongoing damage to hair cells.

Subacute onset of deafness and vertigo in a patient with leptomeningeal metastasis from ovarian cancer.

Ovarian carcinoma is a common gynecological malignancy. Distant metastases usually involve the liver and lung while neurological complications are rare. We describe the case of a 63-year-old woman diagnosed from an ovarian carcinoma with peritoneal seed, which was treated surgically and with chemotherapy. After 4 years she was admitted to our Department for the development of subacute right deafness, vertigo and imbalance. MRI revealed the presence of leptomeningeal carcinomatosis and an expansive formation in the right pontocerebellar angle, suggesting involvement of the right VIII cranial nerve. Examination of the cerebrospinal fluid disclosed the presence of neoplastic cells. Subsequently the patient rapidly deteriorated and eventually died. Involvement of VIII cranial nerve as the presentation of leptomeningeal carcinomatosis in ovarian carcinoma is rare. In the literature at least two other cases presented with deafness, suggesting that leptomeningeal carcinomatosis should be considered in the differential diagnosis when deafness appears in a cancer patient.

Remote tentorium meningioma causing sudden sensorineural deafness.

BACKGROUND: Sudden sensorineural deafness is a well-known symptom mostly of unknown etiology. CASE DESCRIPTION: A case of sudden sensorineural deafness is reported to be caused by a small, remote, ipsilateral tentorial meningioma not compressing the vestibulocochlear nerve or auditory tract. Surgical resection of the meningioma immediately restored the patient's hearing. CONCLUSION: The authors hypothesize that the sudden sensorineural deafness resulted from a growing meningioma inducing a neurovascular compression of the vestibulocochlear nerve, the vertebral artery already being in close relationship with the vestibulocochlear nerve in the premorbid phase. Resection of the meningioma allows for an autodecompression of this vascular conflict resulting in hearing restoration.

Objective findings with malpositioning of a nucleus 24RE(CA) cochlear implant.

BACKGROUND: Proper intracochlear placement of cochlear implant electrode arrays is believed to be important for optimum speech perception results. However, objective tests of cochlear implant function typically provide little or no information about the intracochlear placement of the array. We report the results for a variety of objective tests, including averaged electrode voltage (AEV) measurements, in a patient where the electrode array had folded up on itself during insertion. PURPOSE: To determine whether any of the objective measures provided evidence of incorrect electrode placement. RESEARCH DESIGN: Objective test data are reported for a patient with an incorrectly positioned electrode array, prior to and following reimplantation, and compared to data obtained in 42 patients with normal insertions. STUDY SAMPLE: One patient with an incorrectly placed electrode array, prior to and following reimplantation, and a sample of 42 implant recipients with correct insertions. INTERVENTION: The patient with the malpositioned electrode array was explanted and reimplanted. The results for the first and the second implant, with regards to objective test results, are compared. The results are also compared to the data obtained on 42 implant recipients with normal insertions. DATA COLLECTION AND ANALYSIS: The objective test data (primarily AEV data) are compared with AEV results obtained in 42 patients with normal electrode insertions. RESULTS AND CONCLUSIONS: Although the electrode array had folded up on itself during insertion, intraoperative electrode impedances and VIII nerve responses, as well as postoperative electrically evoked auditory brainstem responses, were within normal limits. However, averaged electrode voltages, obtained with the Nucleus Crystal Integrity Test system, were abnormal and consistent with a low-impedance pathway between the apical and middle portions of the electrode array.

Nerve of origin, tumor size, hearing preservation, and facial nerve outcomes in 359 vestibular schwannoma resections at a tertiary care academic center.

OBJECTIVE: To determine nerve of origin, tumor size, hearing preservation rates, and facial nerve outcomes in a retrospective cohort study of patients undergoing translabyrinthine (TL), middle cranial fossa (MCF), and retrosigmoid/suboccipital (SO) approaches to vestibular schwannomas (VS). STUDY DESIGN: Retrospective. METHODS: Chart review. RESULTS: Patient charts from 231 TL, 70 MCF, 53 SO, and 5 combined TL/SO procedures for VS were evaluated in 356 patients. The inferior vestibular nerve (IVN) was the nerve of origin in 84 of 359 cases (23.3%), while the superior vestibular nerve (SVN) was the nerve of origin in 36 patients (10%). In 239 of 359 cases (66.6%), the nerve of origin was not identified. Forty patients undergoing hearing preservation surgery had hearing results and nerve of origin data available for review. Functional hearing (<50dB PTA and >50% speech discrimination) was preserved in 10 of 15 patients (75%) with SVN tumors, while only 7 of 25 patients (28%) with IVN tumors retained functional hearing. Facial nerve outcomes and nerve of origin were recorded simultaneously in 109 patients. Seventy-one of 74 patients (95%) patients with IVN tumors achieved a House-Brackmann (HB) grade I-III, while 35 of 35 patients (100%) with SVN tumors retained HB I-III facial function. Looking at tumor size versus hearing preservation, functional hearing was preserved in 22 of 49 patients (45%) with <1-cm tumors, and 4 of 20 patients (20%) with 1- to 1.5-cm tumors. For all cases with documented facial nerve function, HB I-III were achieved in 96% of SO, 94% of MCF, and 88% of TL procedures. CONCLUSIONS: Our retrospective data indicated that IVN tumors were twice as common as SVN tumors. The nerve of origin did not affect facial nerve outcomes but did impact hearing preservation rates. Patients with tumors <1 cm in size had the best chance for hearing preservation. Overall facial nerve preservation was excellent with >90% achieving HB 1 to 3 function at final follow-up.

Tinnitus in vascular conflict of the eighth cranial nerve: a surgical pathophysiological approach to ABR changes.

Some forms of tinnitus are associated with a blood vessel being in close contact with the auditory nerve near its entrance into the brainstem. The outcome of operations for tinnitus, moving the blood vessel off the nerve (microvascular decompression operations, MVD) is less successful than microvascular decompression operations for other vascular conflict syndromes (hemifacial spasm, HFS, and trigeminal neuralgia, TGN). No generally accepted criteria exist for the selection of candidates for MVD for tinnitus. A pathophysiological approach for interpreting auditory brainstem response (ABR) changes is proposed as a basis for selection of tinnitus patients for the MVD operation. We followed changes in the ABR and the tinnitus in 78 patients with unilateral tinnitus, who had indications of having vascular conflicts of the eighth nerve. In 18 of these patients a blood vessel was removed of the auditory nerve and in 9 of these a correlation could be made between preoperative and postoperative clinical changes and ABR changes. In this retrospective study we found abnormalities in the amplitude of peak II and the interpeak latency (IPL) I-III of the ABR that were related to the duration of their tinnitus and its intensity. While no ABR changes could be detected during the first 2 years, after that period a decrease of the amplitude of peak II occurred, and a prolongation the IPL of peak I-III occurred in patients whose peak II had disappeared. The rate of IPL I-III increase slows down after 10 years. IPL I-III prolongation correlates with ipsilateral hearing loss at tinnitus frequency and worsens in time. This correlates with a worsening of the tinnitus associated with the worsening of the IPL I-III. Tinnitus frequency correlates to the frequency of maximal hearing loss and the more the hearing loss at tinnitus frequency the worse the tinnitus. Postoperative improvement of tinnitus correlated with postoperative improvement of peak II and postoperative improvement of hearing loss at the tinnitus frequency correlated with postoperative IPL I-III improvement. It is concluded that interpreting ABRs from a pathophysiological point of view can be beneficial for surgeons performing MVDs for tinnitus, especially with regard to timing of the surgery and interpretation of symptom presentation.

[Vestibulo-cochlear disturbances in the course of vaso-neural conflict of vestibule-cochlear nerve--diagnostic and therapeutic problems]. / Zespól zaburzen przedsionkowo-slimakowych na podlozu konfliktu naczyniowo-nerwowego nerwu przedsionkowo-slimakowego--problemy diagnostyczno-terapeutyczne.

INTRODUCTION: Symptoms encompassing sensorineural hearing loss, tinnitus and vertigo occur in many diseases of various origin. The diagnostics in such cases is especially difficult and often requires interdisciplinary cooperation. Despite of that many cases remain unexplained. MATERIAL AND METHOD: The two cases with above mentioned symptoms (52 year-old woman and 46 year-old man) with differentiated clinical course were presented. The woman for one year experienced left sided, extreme tinnitus with paroxysmal vertigo and dizziness. The man with sudden monolateral hearing loss and tinnitus that disappeared after corticosteroid therapy, complained about recurrence of fluctuating hearing loss and tinnitus accompanied by chronic instability. The diagnostics of hearing and balance organs was performed (pure tone audiometry, impedance audiometry, DPOAE, ABR, ENG) complemented with computed tomography and Nuclear Resonance. RESULTS: Female patient presented bilateral mild sensorineural hearing loss, more intensive on the left side, male patient right sided sensorineural hearing loss in the frequencies from 250 to 1500 Hz. The elongation of some peak values in ABR test (with bilaterally proper otoacoustic emissions) as well as partial canal paresis on the hearing loss side suggested primary diagnosis of neoplasmatic process. It was an indication to perform radiological diagnostics. The radiologic findings revealed the contact of vestibulo-cochlear nerve with the loop of cerebellar inferior anterior artery within the internal acoustic canal. CONCLUSIONS: The course of the disease and diagnostic tests do not provide characteristic data that let diagnose neuro-vascular conflict. One has to be aware of such possibility in patients with intensive vertigo and dizziness that do not improve after treatment when other causes do not justify the symptoms.

Cavernous malformation of the internal auditory canal.

Cavernous malformations of the internal auditory canal are a rare clinical entity that, however, should be considered in the differential diagnosis of intracanalicular masses. Even though this type of malformation is usually associated with an evident gadolinium enhancement at MR examination, in some patients, like in this case, the signal characteristics may be not sufficiently specific to allow the correct preoperative diagnosis. Nevertheless, the clinical history, in particular, a rapid onset of cranial nerve deficits, lead to the suspicion of a vascular malformation.