Red flags alerting a posterior cranial fossa tumor from audiovestibular perspectives - a review

BACKGROUND

There is no comprehensive and up-to-date overview of audiovestibular approach to the posterior fossa tumors in the literature.

OBJECTIVE

This paper reviewed the literature relating to tumors at the posterior cranial fossa to find red flags alerting a posterior fossa lesion from audiovestibular perspectives.

METHODS

This review was developed from articles published in those journals listed on the journal citation reports. Through the PubMed database, Embase, Google Scholar, and Cochrane library, 60 articles were finally obtained based on the PRISMA guidelines for reporting reviews.

RESULTS

The presence of one red flag indicates a positive predictive value of 33% for detecting a posterior fossa lesion. Clinical features, namely, 1) mid-frequency sudden sensorineural hearing loss (SNHL), 2) bilateral sudden SNHL, and 3) rebound nystagmus may indicate a posterior fossa lesion, representing one, two, and three red flags, respectively.

CONCLUSION

Those with 1) mid-frequency sudden SNHL, 2) bilateral sudden SNHL, and 3) rebound nystagmus trigger one, two, and three red flags, respectively, alerting clinicians the possibility of a posterior fossa lesion, which warrant MR imaging to exclude life-threatening or treatable conditions.

SIGNIFICANCE

Patients with posterior fossa tumors may have potential life-threatening outcome.

A case of sudden hearing loss in a patient with chronic myelomonocytic leukemia

Chronic myelomonocytic leukemia is a myeloid stem cell disease characterized by an abnormal production and accumulation of monocytic cells in association with other signs of myeloproliferation. Extramedullary manifestations of CMML are common and can affect the spleen, liver skin, and lymph nodes. However, otologic manifestations are extremely rare and could have occurred from either direct leukemic infiltration, hemorrhage of the cochlea, labyrinth, leukostasis, or infection. There is no standard treatment protocol for sensorineural hearing loss in CMML patients. More research is needed to improve the understanding of the pathogenesis of this condition, in order to provide better treatment options.

Utilizing Single Cell RNA-Sequencing to Implicate Cell Types and Therapeutic Targets for SSNHL in the Adult Cochlea

OBJECTIVE

To identify genes implicated in sudden sensorineural hearing loss (SSNHL) and localize their expression in the cochlea to further explore potential pathogenic mechanisms and therapeutic targets.

STUDY DESIGN

Systematic literature review and bioinformatics analysis.

DATA SOURCES

The following sources were searched from inception through July 2, 2020: PubMed-NCBI, MEDLINE, Embase, CINAHL, Cochrane Library, ClinicalTrials.gov, OpenGrey, GreyNet, GreyLiterature Report, and European Union Clinical Trials Registry. PubMed-NCBI and MEDLINE were additionally searched for human temporal bone histopathologic studies related to SSNHL.

METHODS

Literature review of candidate SSNHL genes was conducted according to PRISMA guidelines. Existing temporal bone studies from SSNHL patients were analyzed to identify the most commonly affected inner ear structures. Previously published single-cell and single-nucleus RNA-Seq datasets of the adult mouse stria vascularis, as well as postnatal day 7 and 15 mouse cochlear hair cells and supporting cells, were utilized for localization of the SSNHL-related genes curated through literature review.

CONCLUSIONS

We report 92 unique single nucleotide polymorphisms (SNPs) in 76 different genes that have been investigated in relation to SSNHL in the literature. We demonstrate that a subset of these genes are expressed by cell types in the adult mouse stria vascularis and organ of Corti, consistent with findings from temporal bone studies in human subjects with SSNHL. We highlight several potential genetic targets relevant to current and possible future SSNHL treatments.

Investigational Medicinal Products for the Inner Ear: Review of Clinical Trial Characteristics in ClinicalTrials.gov

BACKGROUND

The previous 30 years have provided information on the mechanisms of cell death in the inner ear after noise exposure, ototoxic drug injury, and during aging, and clinical trials have emerged for all of these acquired forms of hearing loss. Sudden hearing loss is less well understood, but restoration of hearing after sudden hearing loss is also a long-standing drug target, typically using steroids as an intervention but with other agents of interest as well.

PURPOSE

The purpose of this review was to describe the state of the science regarding clinical testing of investigational medicinal products for the inner ear with respect to treatment or prevention of acquired hearing loss.

DATA COLLECTION AND ANALYSIS

Comprehensive search and summary of clinical trials listed in the National Library of Medicine (www.

CLINICALTRIALS

gov) database identified 61 clinical trials.

RESULTS

Study phase, status, intervention, and primary, secondary, and other outcomes are summarized for studies assessing prevention of noise-induced hearing loss, prevention of drug-induced hearing loss, treatment of stable sensorineural hearing loss, and treatment of sudden sensorineural hearing loss.

CONCLUSION

This review provides a comprehensive summary of the state of the science with respect to investigational medicinal products for the inner ear evaluated in human clinical trials, and the current challenges for the field.

Global and local brain connectivity changes associated with sudden unilateral sensorineural hearing loss

Recent studies suggest that even moderate sudden sensorineural hearing loss (SSNHL) causes reduction of gray matter volume in the primary auditory cortex, diminishing its ability to react to sound stimulation, as well as reorganization of functional brain networks. We employed resting-state functional MRI (rs-fMRI), in conjunction with graph-theoretical analysis and a newly developed functional "disruption index," to study whole-brain as well as local functional changes in patients with unilateral SSNHL. We also assessed the potential of graph-theoretical measures as biomarkers of disease, in terms of their relationship to clinically relevant audiological parameters. Eight patients with moderate or severe unilateral SSNHL and 15 healthy controls were included in this prospective pilot study. All patients underwent rs-fMRI to study potential changes in brain connectivity. From rs-fMRI data, global and local graph-theoretical measures, disruption index, and audiological examinations were estimated. Mann-Whitney U tests were used to study the differences between SSNHL patients and healthy controls. Associations between brain metrics and clinical variables were studied using multiple linear regressions, and the presence or absence of brain network hubs was assessed using Fisher's exact test. No statistically significant differences between SSNHL patients and healthy controls were found in global or local network measures. However, when analyzing brain networks through the disruption index, we found a brain-wide functional network reorganization (p < 0.001 as compared with controls), whose extent was associated with clinical impairment (p < 0.05). We also observed several functional hubs in SSNHL patients that were not present in healthy controls and vice versa. Our results demonstrate a brain involvement in SSNHL patients, not detectable using conventional graph-theoretical analysis, which may yield subtle disease clues and possibly aid in monitoring disease progression in clinical trials.

Oral Corticosteroid Therapy For Sudden Sensorineural Hearing Loss And Factors Affecting Prognosis

BACKGROUND

Sudden sensorineural hearing loss (SSNHL) is considered an otologic emergency globally. Aetiology is unknown in most cases but still the disease is believed to be caused by inflammation of the cochlea; therefore, steroids are considered beneficial due to their anti-inflammatory effect.

METHODS

This study was conducted on 62 patients of sudden sensorineural hearing loss (SSNHL) in Ayub Medical Complex, Abbottabad. The patients were given prednisolone and their response to the therapy was monitored. Factors like age of the patient, gender, degree of hearing loss and duration of symptoms at initial presentation were recorded and their effect of response of the patient was also noted.

RESULTS

The research subjects were 62 patients. Majority of the patients suffered from moderate to moderately severe hearing loss. Age and gender did not influence the response to the treatment. While the patients who presented earlier after the onset of disease and the patients who had milder degree of hearing loss at presentation had a better response to therapy.

CONCLUSIONS

Oral corticosteroid therapy is a good therapeutic option for the treatment of sudden sensorineural hearing loss (SSHNL). The response to therapy is better in patients with milder hearing loss and those who present early to the otologist for treatment.

Biomarkers Suggesting Favorable Prognostic Outcomes in Sudden Sensorineural Hearing Loss

Sudden sensorineural hearing loss (SSNHL) is a medical emergency, making detailed examination to determine possible causes and early treatment important. However, etiological examinations in SSNHL do not always reveal a cause, and several factors have been found to affect treatment outcomes. Various studies are being performed to determine the prognosis and effects of treatment in patients who experience sudden hearing loss, and to identify biomarkers associated with this condition. Embase, PubMed, and the Cochrane database were searched using the key words SSNHL, prognostic, and biomarker. This search identified 4 articles in Embase, 28 articles in PubMed, and 36 in the Cochrane database. Of these 68 articles, 3 were duplicates and 37 were unrelated to the research topic. After excluding these articles, the remaining 28 articles were reviewed. Factors associated with SSNHL were divided into six categories: metabolic, hemostatic, inflammatory, immunologic, oxidative, and other factors. The associations between these factors with the occurrence of SSNHL and with patient prognosis were analyzed. Low monocyte counts, low neutrophil/lymphocyte ratio (NLR) and monocyte/high-density lipoproteins (HDL) cholesterol ratio (MHR), and low concentrations of fibrinogen, platelet glycoprotein (GP) IIIa, and TNF-α were found to be associated with good prognosis. However, these factors alone could not completely determine the onset of and recovery from SSNHL, suggesting the need for future basic and clinical studies.

Research progress in refractory sudden hearing loss: steroid therapy

Sudden sensorineural hearing loss (SSNHL) is a common condition with a rapid onset, and its worldwide frequency is increasing each year. Importantly, a significant number of patients with SSNHL do not respond to initial treatment, which is termed refractory sudden hearing loss (RSHL), and further treatment is not standardized in terms of type, duration, administration route, and concentration of topical steroid therapy. Dexamethasone and methylprednisolone are effective in treating RSHL, and salvage treatment typically consists of 2 weeks of steroid therapy followed by 3–6 months of follow-up. Near-continual steroid perfusion appears to be more effective than intermittent steroid injection. Furthermore, several novel therapeutic regimens have shown promising results in small-scale studies. However, the optimum treatment needs to be confirmed in larger randomized controlled trials.

[The significance of vestibular function assessment in sudden deafness]

Hearing loss caused by cochlear damage is the main symptom of sudden deafness (SD). Some patients also suffer from vestibular symptoms. In recent years, more attention has been paid to the vestibular dysfunction in patients with SD. The lesions could involve the whole inner ear in SD patients with and without vertigo. Comprehensive evaluation of vestibular function may help us understand the extent of lesions in sudden deafness and analyze the pathogenesis of disease. A less involvement of inner ear lesion may indicate a better hearing recovery.

[Character of early tinnitus about sudden deafness]

OBJECTIVE

To study the clinical characteristics of early tinnitus in patients with sudden deafness.

METHOD

Forty-seven patients with sudden deafness and early tinnitus recieved subjective review and filled out classified questionnaire of tinnitus. By pure tone audiometry and tinnitus matching test, we obtain the distribution, quantity and matching loudness of tinnitus patients.

RESULT

(1) Objective examination: the most common frequencies of tinnitus were 8000 Hz and 4000 Hz. The most common numbers were two frequencies. The matching loudness was (16.63 ± 8.37) dB. (2) Subjective examination: the tinnitus was monotone (74.0%), sustained (89.0%), third level loudness (45.0%), third level annoying (60.0%), high frequency (83.0%), sound of cicadas (66.7%). The most influencing factors were hearing (28.2%) and mood (29.5%). (3) Relationship between tinnitus and pure tone hearing threshold curve: there was a significant correlation between the frequency of pure tone audiometry and the matching loudness of tinnitus (r = -0. 370, P < 0.01). There was no significant correlation between the frequency of pure tone tinnitus and the matching loudness of tinnitus (r = -0.083, P > 0.05).

CONCLUSION

(1) The results of subjective examination were consistent with those of objective examination. (2) The tinnitus should be considered in the early treatment of sudden deafness.

[Part of the vertebral artery in patients with sudden deafness]

OBJECTIVE

To explore the characteristics of vertebral artery system in the patients with sudden deafness by using digital subtraction angiography (DSA).

METHOD

Thirty-four cases of sudden deafness with vertebrobasilar artery ischemia confirmed by the color doppler ultrasound were undergone DSA in both side. The characteristics of vertebral artery, basal artery and before-cerebellum artery were analysis before specific therapy.

RESULT

There is no related complication were occurred among 34 cases. Side vertebral artery was blocked in 2 cases, atherosclerosis was found in 5 cases. The right cerebellar artery anterior and the left cerebellar artery posterior were found filling defect or minor change in 29.4% (10/34) and 35.3% (12/34) of the patients, respectively. The right and the left arteria auditiva interna were found filling defect or minor change in 64.7% (22/34) and 73.5% (25/34) of the patients, respectively. After specific therapy, 8 cases were cured, the hearing of 9 cases were markedly improved, the hearing of 12 cases were improved efficient and 5 patients have no hearing improvement, the total effective rate was 85.3%.

CONCLUSION

The arteria auditiva interna and inferior anterior arteria cerebelli caused inner ear ischemia were found in the patients with sudden deafness. The using of vasodilator may have satisfactory and positive curative effect in the therapy of sudden deafness.

[Functional connectivity of resting-state functional magnetic resonance imaging observation of the right side of the auditory cortex of sudden deafness]

OBJECTIVE

Positively related to functional connectivity using resting state fMRI functional connectivity method to observe the right of sudden deafness of auditory cortex in patients with brain.

METHOD

We selected the right side of the 12 cases of patients with sudden deafness resting state fMRI data acquisition, positive correlation function for the observation about the right of sudden deafness patients using the method of functional connectivity brain auditory cortex and the brain regions to connect brain map, and matched the normal hearing group the difference.

RESULT

The right side of sudden deafness in patients with valid data for the seed point of A I bilateral. The brain was activated network included bilateral transverse gyrus, superior temporal gyrus, insula, cingulate gyrus and supplementary motor area. Brain networks were activated like a normal person, but there were differences between the two.

CONCLUSION

The right side of the deafness of A I seed point the functional connectivity of the auditory system is still mainly confined to the auditory system, but the local auditory cortex functional reorganization occurs.

[Moderate and severe sudden deafness treated with low-energy laser irradiation combined with auricular acupoint sticking]

OBJECTIVE

To test the therapeutic effect on moderate and severe sudden deafness treated with low-energy laser irradiation on acupoint and external auditory canal combined with auricular point sticking (APS) and as compared with electroacupuncture.

METHODS

Two hundred and fifty-eight cases of moderate and severe sudden hearing loss were randomly divided into an observation group 1, an observation group 2 and a control group, 86 cases in each group. In three groups, 10% low molecular Dextran 500 mL were used for intravenous infusion. Based on the above treatment, the observation group 1 was treated with low-energy laser irradiation on acupoint and external auditory canal (such as Ermen (TE 21), Tinggong (SI 19) and Tinghui (GB 2)), combined with APS at Gan (liver), Shen (kidney) and Neifenmi (endorine), etc. The observation group 2 was treated with electroacupuncture at the same acupoints as those point irradiation in observation group 1. Fifteen days made one session. The therapeutic effects were evaluated after one and two sessions.

RESULTS

After two sessions, The cured rate was 40.7% (35/86) in observation group 1 and 38.4% (33/86) in observation group 2,which were superior to 25.6% (22/86) in control group (both P < 0.05). Compared with one session, the therapeutic effects after two sessions were better in two observation groups (both P < 0.05), but there was no significant difference between two groups (both P > 0.05). In comparison of the improvements of frequency audiometry and auditory function, the two observation groups were better than those in control group (P < 0.05, P < 0.01), and the improvements after two sessions were better in two observation groups (both P < 0.01).

CONCLUSION

Both of low-energy laser irradiation on acupoint and external auditory canal combined with APS and electroacupuncture are able to decrease frequency audiometry, improve auditory function, and the therapeutic effects are better with prolongation of treatment time. The clinical efficacy of above two the rapies on moderate and severe sudden deafness is superior remarkably to that of conventional treatment. The therapy of low-energy laser irradiation on acupoint and external auditory canal combined with APS can replace the electroacupuncture therapy in treating moderate and severe sudden deafness.

[Compliance with diagnostic MRI in the workup of sudden sensorineural hearing loss]

INTRODUCTION

Sudden sensorineural hearing loss (SSNHL] can be the presenting symptom of an acoustic neurinoma. High sensitivity and specificity rates define magnetic resonance imaging (MRI) of the brain and internal acoustic canal as the gold standard for the diagnosis of retro-cochlear pathologies. A previous study revealed low compliance rates (49%] for performing an MRI after an episode of SSNHL; 15% of patients who had an MRI were diagnosed with a retro-cochlear pathology.

AIM OF STUDY

To evaluate current compliance rates for performing an MRI of the brain and internal acoustic canal after an episode of SSNHL.

MATERIAL AND METHODS

The study cohort included 41 patients, 24 females and 17 male, with an average age of 49.8 +/- 16.8 years (range, 16-78 years), who were diagnosed with SSNHL and admitted for treatment between December 2009 and June 2010.

RESULTS

Two months after discharge from hospitalization, only 29 patients (70.7%) returned for the scheduled followup. Only 21 patients (51.2% of those admitted) had an MRI of the brain and internal acoustic canal, as was recommended upon their discharge. Three of those who had an MRI were diagnosed with a retro-cochlear pathology. In 20 patients [48.8%) who did not perform an MRI, a retro-cochlear pathology could not be ruled out.

CONCLUSIONS

Compliance rates for performing an MRI after an episode of SSNHL haven't changed in recent years. The main reason seems to be poor patients' compliance, as well as their general practitioners and health insurance companies. Ruling out retro-cochlear pathologies by means of MRI is highly important and considered common medical practice. Guidelines regarding the importance of MRI after an episode of SSNHL should be updated and reinforced.

[Three-dimensional fluid attenuated inversion recovery imaging at 3T MRI in sudden deafness: its findings and relationship with the prognosis]

OBJECTIVE

To investigate inner ear of patients with sudden deafness with three-dimensional fluid attenuated inversion recovery (3D FLAIR) MRI, and the relationship between the results of 3D FLAIR and the prognosis.

METHODS

Twenty-three patients with sudden deafness received 3D FLAIR at 3T MRI, and the signals of inner ear were recorded. Hearing levels were evaluated at initial visit and after treatment. The relationship between 3D FLAIR findings and hearing prognosis was evaluated.

RESULTS

Eight patients with sudden deafness showed high signals in the affected cochlea on 3D FLAIR, the others of affected cochlea and all of contralateral cochlea showed no signal on 3D FLAIR. The age, sex, affected side, period to initial visit and initial audiogram had no difference between cochlea no signal group and high signal group. The average auditory threshold (x±s) in cochlea high signal group (90±21) dB HL was significant higher than that in cochlea no signal group (60±28) dB HL, P<0.05 at patients' discharge. After treatment, in cochlea no signal group, two cases' hearing was complete recovered, remarkable improvement in five cases, slight improvement in two cases and no change in six cases. In cochlea high signal group, hearing was slight improvement in one case and no change in seven cases. The prognosis was significant difference between two groups. Five of seven patients with vertigo and sudden deafness showed high signal in affected side vestibule on 3D FLAIR, and the hearing of whom had no change after treatment.

CONCLUSION

3D FLAIR can show high signal in affected inner ear in sudden deafness patients, and which is related to a poor hearing prognosis.

3D-FLAIR MRI findings in patients with low-tone sudden deafness

CONCLUSION

The findings suggest that alterations in the composition of inner ear fluid play important roles in the development of low-tone sudden deafness (LTSD). High-intensity signals on three-dimensional fluid attenuated inversion recovery (3D-FLAIR) may reflect an increased concentration of protein in the inner ear due to the increased permeability of blood vessels. Disordered blood flow in the inner ear is associated with an increased permeability of the blood-labyrinth barrier. Therefore, the disordered blood flow in the cochlea may be closely related to the pathophysiological mechanisms of LTSD.

OBJECTIVES

The 3D-FLAIR sequence has been used to detect alterations in the composition of inner ear fluid. The purpose of this study was to report imaging findings in cases of LTSD.

METHODS

3D-FLAIR magnetic resonance imaging was performed in five women with nonrecurrent-type LTSD.

RESULTS

Three of the five patients (60%) showed high-intensity signals in the cochlear basal turn on precontrast 3D-FLAIR. Postcontrast enhancement was not prominent in any patient. In patient 1, the cochlea of the unaffected side showed high-intensity signals. No patients had such signals in the vestibulae or the semicircular canals.

Multivariate analysis of hearing outcomes in patients with idiopathic sudden sensorineural hearing loss

CONCLUSIONS

Contralateral hearing loss is significantly correlated with poor hearing outcomes in patients with idiopathic sudden sensorineural hearing loss (ISSNHL).

BACKGROUND

The hearing outcome in patients with ISSNHL was analyzed using multiple variables.

METHODS

A retrospective chart review was conducted using 89 patients with ISSNHL. Patients within 40 dB HL of average hearing levels and/or patients whose hearing loss was restricted to low frequencies were excluded. The influence of pre-existing conditions on hearing outcome was analyzed using a polytomous universal model. Pre-existing conditions analyzed included hyperglycemia, hypercholesterolemia, hypertension, and contralateral hearing loss. In addition, the severity of hearing loss, age group, and the existence of vertigo were analyzed concomitantly.

RESULTS

Hearing recovery was significantly reduced in patients with a past history of contralateral hearing loss.

[Genetic constitution analysis of idiopathic sudden hearing loss]

OBJECTIVES

The purpose of this research is to understand the etiology of sudden hearing loss due to genetic factors in Turkish people. Determination of these genetic factors and better understanding of molecular pathogenesis may guide more realistic planning and treatment recommendations.

PATIENTS AND METHODS

Forty patients (Group 1; 19 males, 21 females; mean age 37.9+/-15.6 years; range 9 to 76 years) who presented with sudden hearing loss to the Ear, Nose and Throat Clinic of Medical Faculty Hospital of Cumhuriyet University between January 2008 and June 2009, and were diagnosed with sudden hearing loss through history, physical examination and review of audiometric findings, and 20 healthy volunteers (Group 2; 14 males, 6 females; mean age 31.7+/-4.4 years; range 24 to 43 years) for the control group were included in this study. All Patients were evaluated by the genetic clinic for the GJB2, GJB3, GJB6 and WFS1 gene using multiplex ligation-dependent probe amplification (MLPA) method mutation analysis.

RESULTS

No difference was found in the peripheral blood sample analyses of the two groups at WFS1 exon 8 and connexin 26, 30 and 31 gene zones using the MLPA method with respect to heterozygous mutation (p=0.291, p>0.05). In four patients in group 1 heterozygous mutation was detected at the target gene zone. Heterozygous mutation was in the WFS1 exon 8 zone in two patients; and in the WFS1 exon 1 zone in other two patients.

CONCLUSION

Sudden hearing loss studies in the future should include connexin 26, connexin 30 and other gene mutations that may affect the function of the gap-junction located in the region of the cochlea stria vascularis (stV), basal membrane (BM), spiral limbus (Li) and spiral ligament (SL). These studies should be performed on larger series, and should include family members of patients with sudden hearing loss.

3 Tesla magnetic resonance imaging obtained 4 hours after intravenous gadolinium injection in patients with sudden deafness

CONCLUSION

3 Tesla (3T) magnetic resonance imaging (MRI) performed 4 h after intravenous gadolinium (Gd) injection provides sufficient anatomic resolution of the inner ear fluid spaces in sudden deafness. The signal intensity ratio (SIR) between the cochlea and cerebellum may be a good indicator of disruption of the blood-labyrinthine barrier.

OBJECTIVES

We evaluated the inner ear 4 h after intravenous Gd injection to determine whether 3T MRI enables the acquisition of images of the affected inner ear in sudden deafness.

METHODS

Ten patients underwent 3T MRI scanning 4 h after intravenous Gd injection. Three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) MRI was performed.

RESULTS

The SIR varied from 0.45 to 2.17 in 11 affected ears and from 0.43 to 1.48 in 9 unaffected ears. The difference of contrast (affected ear vs unaffected ear) could be detected in five of the nine patients with unilateral sudden deafness. The Gd distribution was recognized in the vestibule of 10 affected ears and in the cochlea of 5 affected ears, in which no significant hydrops was observed. In the remaining vestibules and cochleas of affected ears, the Gd enhancement was too faint to evaluate the endolymphatic hydrops.

Enhancement pattern of the normal facial nerve at 3.0 T temporal MRI

The purpose of this study was to evaluate the enhancement pattern of the normal facial nerve at 3.0 T temporal MRI. We reviewed the medical records of 20 patients and evaluated 40 clinically normal facial nerves demonstrated by 3.0 T temporal MRI. The grade of enhancement of the facial nerve was visually scaled from 0 to 3. The patients comprised 11 men and 9 women, and the mean age was 39.7 years. The reasons for the MRI were sudden hearing loss (11 patients), Méniàre's disease (6) and tinnitus (7). Temporal MR scans were obtained by fluid-attenuated inversion-recovery (FLAIR) and diffusion-weighted imaging of the brain; three-dimensional (3D) fast imaging employing steady-state acquisition (FIESTA) images of the temporal bone with a 0.77 mm thickness, and pre-contrast and contrast-enhanced 3D spoiled gradient record acquisition in the steady state (SPGR) of the temporal bone with a 1 mm thickness, were obtained with 3.0 T MR scanning. 40 nerves (100%) were visibly enhanced along at least one segment of the facial nerve. The enhanced segments included the geniculate ganglion (77.5%), tympanic segment (37.5%) and mastoid segment (100%). Even the facial nerve in the internal auditory canal (15%) and labyrinthine segments (5%) showed mild enhancement. The use of high-resolution, high signal-to-noise ratio (with 3 T MRI), thin-section contrast-enhanced 3D SPGR sequences showed enhancement of the normal facial nerve along the whole course of the nerve; however, only mild enhancement was observed in areas associated with acute neuritis, namely the canalicular and labyrinthine segment.

An animal model for the analysis of cochlear blood flow [corrected] disturbance and hearing threshold in vivo

Impairment of cochlear blood flow (CBF) is considered to be important in inner ear pathology. However, direct measurement of CBF is difficult and has not been investigated in combination with hearing function. Six guinea pigs were used to show feasibility of an animal model for the analysis of cochlear microcirculation by intravital microscopy in combination with investigation of the hearing threshold by brainstem response audiometry (ABR). By the application of sodium nitroprusside (SNP), CBF was increased over 30 min. Reproducibility of measurements was shown by retest measurements. Mean baseline velocity of CBF was 109 +/- 19 mum/s. Vessel diameters had a mean value of 9.4 +/- 2.7 mum. Mean hearing threshold was 19 +/- 6 dB. In response to SNP, CBF velocity increased significantly to 161 +/- 26 mum/s. Mean arterial pressure decreased significantly to 36 +/- 11 mmHg. After the end of the application, CBF velocity recovered to a minimum of 123 +/- 17 microm/s. Within the retest, CBF velocity significantly increased to a maximum of 160 +/- 31 microm/s. Second recovery of CBF velocity was 125 +/- 14 mum/s. Within the second retest, CBF increased significantly to 157 +/- 25 microm/s. ABR thresholds did not change significantly. The increase in blood flow velocity occurred in spite of substantial hypotension as induced by a vasodilator. This may explain the fact that ABR threshold remained unchanged reflecting a maintained blood supply in this part of the brain. This technique can be used to evaluate effects of treatments aimed at cochlear microcirculation in inner ear pathologies.

3D-FLAIR magnetic resonance imaging in the evaluation of mumps deafness

A 6-year-old boy suffered acute profound right side deafness after his classmates had mumps. Although his salivary glands were not swollen, he had high levels of anti-mumps IgM and IgG antibodies. The three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) procedure applied to magnetic resonance imaging (MRI) showed high signals in the right cochlea and vestibule. This indicated hemorrhage or a high concentration of protein in the right inner ear. This is the first case demonstrating a high 3D-FLAIR MRI signal of the inner ear in a patient with mumps deafness. Our findings suggest that 3D-FLAIR MRI may help to identify and define labyrinthitis in mumps deafness.

Magnetic Resonance Imaging Findings in Sudden Sensorineural Hearing Loss

OBJECTIVE

To investigate the role of magnetic resonance imaging (MRI) in the diagnosis of sudden sensorineural hearing loss (SSNHL).

METHODS

Fifty-four consecutive patients affected by SSNHL were investigated using brain MRI. MRI was performed with an eight-channel phased-array head coil to study the entire audiovestibular pathway and the whole brain. The protocol study consisted of a high-resolution study of the temporal bone, internal auditory canal (IAC), cerebellopontine angle (CPA), and brainstem combining 2 mm thin-slice axial T(2)-weighted two-dimensional fast spin echo (FSE) and fluid-attenuated inversion recovery (FLAIR) sequences, pre- and postcontrast (gadolinium-diethylenetriamine pentaacetic acid) administration fat-suppressed axial T(1)-weighted two-dimensional FSE sequences, and a T(2)*-weighted three-dimensional Fourier transformation-constructive interference in steady state sequence (FT-CISS) , with 0.4 mm ultrathin partitions. The rest of the brain was studied with a 4 mm axial T(2)-weighted FLAIR sequence.

RESULTS

Thirty-one of 54 (57%) cases of SSNHL presented with MRI abnormalities. In 6 of 54 cases, the detected abnormality was directly correlated to the clinical picture (2 labyrinthine hemorrhage, 1 cochlear inflammation, 1 acoustic neuroma, 1 arachnoid cyst of the CPA, and 1 case of white matter lesions in the pons, compatible with demyelinating plaques along the central audiovestibular nervous pathway, as the first expression of multiple sclerosis).

CONCLUSIONS

An extensive MRI study of the audiovestibular nervous pathway and of the whole brain, pre- and postparamagnetic contrast administration, is recommended to rule out the wide spectrum of abnormalities that can cause SSNHL.

Leptomeningeal carcinomatosis: An unusual cause of sudden onset bilateral sensorineural hearing loss

We report a 66-year-old woman who developed sudden-onset bilateral sensorineural deafness due to leptomeningeal carcinomatosis involving the vestibulocochlear nerves. The clinical and diagnostic features of leptomeningeal carcinomatosis are discussed.

Pathology and Pathophysiology of Idiopathic Sudden Sensorineural Hearing Loss

BACKGROUND

The cause and pathogenesis of idiopathic sudden sensorineural hearing loss remain unknown. Proposed theories include vascular occlusion, membrane breaks, and viral cochleitis.

AIMS

To describe the temporal bone histopathology in 17 ears (aged 45-94 yr) with idiopathic sudden sensorineural hearing loss in our temporal bone collection and to discuss the implications of the histopathologic findings with respect to the pathophysiology of idiopathic sudden sensorineural hearing loss.

METHODS

Standard light microscopy using hematoxylin and eosin-stained sections was used to assess the otologic abnormalities.

RESULTS

Hearing had recovered in two ears and no histologic correlates were found for the hearing loss in both ears. In the remaining 15 ears, the predominant abnormalities were as follows: 1) loss of hair cells and supporting cells of the organ of Corti (with or without atrophy of the tectorial membrane, stria vascularis, spiral limbus, and cochlear neurons) (13 ears); 2) loss of the tectorial membrane, supporting cells, and stria vascularis (1 ear); and 3) loss of cochlear neurons only (1 ear). Evidence of a possible vascular cause for the idiopathic sudden sensorineural hearing loss was observed in only one ear. No membrane breaks were observed in any ear. Only 1 of the 17 temporal bones was acquired acutely during idiopathic sudden sensorineural hearing loss, and this ear did not demonstrate any leukocytic invasion, hypervascularity, or hemorrhage within the labyrinth, as might be expected with a viral cochleitis.

DISCUSSION

The temporal bone findings do not support the concept of membrane breaks, perilymphatic fistulae, or vascular occlusion as common causes for idiopathic sudden sensorineural hearing loss. The finding in our one case acquired acutely during idiopathic sudden sensorineural hearing loss as well as other clinical and experimental observations do not strongly support the theory of viral cochleitis.

CONCLUSION

We put forth the hypothesis that idiopathic sudden sensorineural hearing loss may be the result of pathologic activation of cellular stress pathways involving nuclear factor-kappaB within the cochlea.

Sudden deafness in vertebrobasilar ischemia: clinical features, vascular topographical patterns and long-term outcome

BACKGROUND AND PURPOSE

The aim of this study is to document the clinical features and natural history of sudden deafness associated with vertebrobasilar ischemia (VBI) and to describe the vascular topographic patterns of ischemic lesions on brain MRI associated with sudden deafness based on data collected from a prospective acute stroke registry.

METHODS

From 364 consecutive cases of VBI diagnosed by clinical features and brain MRI between January 2000 and September 2003, 29 patients were identified as having sudden deafness as a symptom of VBI.

RESULTS

In our series, the incidence of sudden deafness following VBI is 8.0% (29/364). Hearing loss occurred unilaterally (n=27) or bilaterally (n=2). All but one had vertigo as an associated symptom. Nine patients (31%) presented with an isolated audiovestibular loss initially and subsequently had delayed neurological deficits. Nearly a half of patients (14/29: 48%) showed cochlear features of hearing loss. Seventeen (81%) of 21 patients who were followed for at least 1 year after onset of sudden deafness had a recovery of hearing partially (n=10) or completely (n=7). The improvement rate of hearing loss in patients with profound hearing loss was significantly lower than that in patients with less than profound hearing loss (40% vs. 89%, P<0.01). In addition to infarction in the territory of anterior inferior cerebellar artery (n=23), cerebellar infarction in the territory of the medial branch of posterior inferior cerebellar artery (n=4) or an isolated brainstem infarction (n=2) was also associated with sudden deafness.

CONCLUSION

An isolated sudden deafness with cochlear audiometric features can be the initial presentation of VBI. Sudden deafness due to VBI often has a good outcome. There is topographic heterogeneity of ischemic lesions on brain MRI in patients with sudden deafness due to VBI.

Sudden deafness with vertigo as a sole manifestation of anterior inferior cerebellar artery infarction

Sudden deafness without associated neurological symptoms and signs is typically attributed to a viral inflammation of the labyrinth. Although sudden deafness occurs with anterior inferior cerebellar artery (AICA) infarction, the deafness is usually associated with other brainstem or cerebellum signs such as crossed sensory loss, lateral gaze palsy, facial palsy, Horner syndrome or cerebellar dysmetria. An 84-year-old woman suddenly developed right-sided tinnitus, hearing loss, vertigo and vomiting. Audiometry and electronystagmography documented absent auditory and vestibular function on the right side. T2-weighted and diffusion-weighted MRI showed a tiny infarct in the right lateral inferior pontine tegmentum. AICA occlusion can cause sudden deafness and vertigo without brainstem or cerebellar signs.

Magnetic Resonance Imaging Findings in the Auditory Pathway of Patients With Sudden Deafness

OBJECTIVES

The objectives of this study were to evaluate magnetic resonance imaging (MRI) findings of patients with sudden sensorineural hearing loss (SSNHL) and to grade the findings based on their clinical importance.

STUDY DESIGN

A prospective clinical study.

SETTING

A tertiary referral center (university hospital).

PATIENTS

MRI findings of 82 consecutive patients with SSNHL fulfilling the inclusion criteria.

MAIN OUTCOME MEASURES

We studied 1.0-T MR images that were analyzed by one experienced neuroradiologist.

RESULTS

Of the six cases (7%) in which clearly hearing loss was obviously associated with the observed pathology, four patients had an acoustic neuroma in the internal auditory canal or cerebellopontine angle, one patient had changes at the level of pons, and one patient had an obliterated internal carotid artery. Of the six other patients (7%) in which MRI revealed changes that suggest a possible etiology to hearing loss, two patients showed a demyelinating process and four patients showed blood vessel abnormalities such as caroticocavernous fistula, abnormally locating vertebral or basilar artery, and a venous angioma.

CONCLUSIONS

Enhanced MR imaging seems to be a useful examination in patients with SSNHL. The aim should not be only to exclude specific retrocochlear etiologies, but by appropriate techniques, MRI could reveal both peripheral and central abnormalities.

Cortical representation of hearing restoration in patients with sudden deafness

To characterize brain activity in response to auditory stimuli during recovery from acute hearing loss, fMRI was performed at two time points in 11 patients with sudden deafness in the right ear, and 10 subjects with normal hearing. In the acute phase, right-ear auditory stimulation induced only a small response in the auditory cortex, limited to the left hemisphere. In the recovery phase, the auditory response was more extensive than in the acute phase. Stimulation of the left ear induced a more extensive response in the left than right hemisphere in both acute and recovery phases, which differed from the pattern in normal subjects. The changes in cortical activation patterns were seen within 1 week of sudden deafness. Thus, alteration of cortical response in deafness occurs earlier than suggested by previous reports.

[Hyperbaric oxygen treatment in sudden hearing loss after unsuccessful medical treatment]

OBJECTIVES

We evaluated the efficacy of hyperbaric oxygen (HBO) treatment in patients with sudden hearing loss unresponsive to medical treatment.

PATIENTS AND METHODS

Fifty-one patients (37 males, 14 females; mean age 37 years; range 9 to 63 years) with sudden hearing loss were treated with HBO following unsuccessful medical treatment. Time elapsed from the occurrence of sudden hearing loss ranged between 15 to 45 days. Treatment included two sessions daily for the first three days, followed by a single daily session, to make 20 sessions of 90 minutes. Treatment was discontinued because of early recovery in two patients. Audiometric examinations were made at the end of every five sessions. The patients were classified according to age, gender, and audiogram curves.

RESULTS

The mean hearing thresholds were 75.3 dB and 65.6 dB before and after treatment, respectively. Recovery was rated as complete in two patients (3.9%), moderate in two patients (3.9%), mild in 19 patients (37.25%), and as no recovery in 28 patients (54.9%). No significant differences were found between the patient groups in terms of improvement and hearing gain (p>0.05).

CONCLUSION

We propose that HBO be resorted to when other means of medical treatment prove unsuccessful in patients with sudden hearing loss.

[Cochlear hemorrhage. Unusual cause of sudden sensorineural deafness]

Sudden sensorineural hearing loss (SNHL) caused by intralabyrinthine hemorrhage is a rare entity usually associated to patients with previous pathological factors, such as blood dyscrasias, anticoagulant therapy and local hemorrhagic pathologies. We report the first-published case of sudden-onset deafness due to cochlear hemorrhage in a patient with no previous pathologies. We describe the history, diagnosis and follow-up of this patient in comparison to others previously published.

Non-functioning posterior communicating arteries of circle of Willis in idiopathic sudden hearing loss

Most cases of sudden hearing loss have no identifiable cause. A link between compensatory blood flow through the circle of Willis and recovery from sudden hearing loss has, however, been suggested. We assessed 22 patients with sudden hearing loss who had no cerebrovascular disease, and 41 controls matched for age and sex. We took ultrasonographic doppler flow measurements of the extracranial carotid and vertebrobasilar systems and independent audiological measurements. 12 patients with sudden hearing loss, compared with four controls had bilateral non-functioning posterior communicating arteries (p=0.00019). Our findings suggest a strong association between a non-functioning posterior communicating artery of the circle of Willis and sudden hearing loss.

Idiopathic sudden sensorineural hearing loss: temporal bone histopathologic study

We microscopically examined the temporal bones of 12 ears with idiopathic sudden sensorineural hearing loss (iSSNHL), 10 ears with presbycusis, 11 ears with normal hearing, and 8 unaffected contralateral ears of patients with iSSNHL. The degeneration of the spiral ligament, vascular stria, hair cells, dendrites, and apical spiral ganglion cells was greater in ears with iSSNHL than in the other groups. The apical ganglion cells were significantly more affected than the basal ganglion cells, and the spiral ganglion cell loss increased as a function of duration of iSSNHL. Cochlear ossification was found in 1 ear with iSSNHL, and hydrops in 2. These findings suggest a viral rather than a vascular or ruptured inner ear membrane origin for iSSNHL.

An overlap syndrome with features of atypical Cogan syndrome and Wegener's granulomatosis

A 48 year old women developed serous otitis, scleritis, myalgia, vertigo, polyneuropathy, crescentic glomerulonephritis, general cerebral dysrythmia, hilar adenopathy, and retroorbital granulomatous inflammation. Pulmonary manifestations were absent and antibodies against neutrophilic cytoplasmic antigens (ANCA) could not be detected. The clinical picture was classified as an overlap syndrome with features of both atypical Cogan syndrome and Wegener's granulomatosis. The patient responded to treatment with high dose corticosteroids and pulse cyclophosphamide.

Cogan's syndrome

Work originating in the 1940s led to the characterization of a rare, chronic inflammatory disorder with a unique predilection for the cornea and vestibuloauditory apparatus, now called Cogan's syndrome (CS) after the ophthalmologist who first described it. CS occurs primarily in young adults and typically presents with interstitial keratitis (IK) and Ménière's-like episodes developing within several months of each other. The inflammatory process may target other ocular sites, and the disease itself may be accompanied by aortitis or a Takayasu's-like or medium-sized vessel vasculitis. Morbidity in CS results from deafness and complications from cardiovascular disease. Most evidence suggests that the ocular and vestibuloauditory manifestations are not a consequence of vasculitis but rather mediated by other immunologic mechanisms, possibly organ-specific autoimmunity. The cornerstone of treatment in CS is corticosteroids, topically for IK and systemically for inner ear dysfunction. Early corticosteroid therapy appears to be critical for reversing hearing loss. Cochlear implants can partially restore auditory function and have been a salvation for patients who suffer from deafness as a result of permanent cochlear damage.

The etiology of idiopathic sudden sensorineural hearing loss. Experimental herpes simplex virus infection of the inner ear

HYPOTHESIS

Experimentally induced herpes simplex virus type 1 (HSV-1) labyrinthitis provides a suitable model for idiopathic sudden sensorineural hearing loss (ISSHL).

BACKGROUND

Viral labyrinthitis has been postulated to play a role in the pathophysiology of ISSHL. Circumstantial evidence is pointing at members of the herpes virus family. Experimental viral labyrinthitis elicited by various virus families leaves a virus-specific pattern of cochlear damage. Herpes viruses provide the best matching pattern in the distribution of cochlear damage when compared with ISSHL postmortem cochlear histopathology.

METHODS

Herpetic viral labyrinthitis was induced in guinea pigs using perilymphatic inoculation with HSV-1. A control group was inoculated with the culture medium only. Infection was confirmed by the measurement of HSV antibodies. Hearing was monitored. Cochlear damage was evaluated by light and electron microscopy.

RESULTS

In all HSV-1 inoculated animals, rapid loss of hearing occurred. Seroconversion took place, but no systemic manifestations of herpetic infection were observed. The control group showed no cochlear or systemic symptoms. When comparing cochlear histopathology in ISSHL to experimental viral HSV-1 labyrinthitis, strong similarities were found: degeneration of the stria vascularis, destruction of the organ of Corti, loosening of the tectorial membrane, and inflammatory changes in neural structures.

CONCLUSIONS

Based on clinical and histopathologic characteristics, experimental HSV-1 labyrinthitis provides a suitable model of ISSHL.

[In-depth study of the causes of sudden deafness. Physiopathological mechanisms and their reversal]

This article deals with an investigative work done by the AA. with the aim of determine the final cause of sudden sensorial deafness. Three causes are accepted as source of sudden deafness: viral infections, the tear away of labyrinthine membranes and the vascular theory. An increase in antibody titer suggest a viral origin. The labyrinthine membranes split has been observed at times when performing an exploratory tympanotomy. But circulatory troubles are hardly diagnosed, even with histopathological evidences of vascular upsets in temporal bones belonging to patients who suffered from an auditory stroke, because there are no diagnostic tests for "in vivo" control. Our intend is to investigate on the physiopathology of unforeseen deafness and also try to know the possible mechanisms of reversion of this calamitous pathology. We use, as investigative method of actual vascular changes in sudden deafness, the following; the speed analysis of the blood flow furnished by the A. labyrinthi through echography Doppler color transcranialis and angiography and magnetic resonance (Angio-MR). Both procedures are non invasive and harmless. We comment the findings of 13 patients. And find out, in 4 cases, an important trouble of the arterial vertebrobasilaris flow. The A. labyrinthi, a branch of the A. cerebelli inferior anterior (ACIA) and/or A. basilaris--rarely from the A. cerebelli inferior posterior (ACIP)--showed a heavy hypoplasy of these vessels, stenosis or complete blockage. In 2 of cases, 4 months later, a new exploration of the Doppler flow and angio-MR, was performed, and detected an improvement of the vertebrobasilar flow, in both instances. In those patients with an evident recovery of the hearing, it was attributed to these two compensatory mechanisms: 1) reversal of the flow at the level of cicle of Willis, at the expense of development of A. communicans posterior, and 2) cessation of the vertebral A. spasm and decrease of the vessel's tortuosity so improving the blood flow.

Patterns of neural degeneration in the human cochlea and auditory nerve: implications for cochlear implantation

Although the identity of all the variables that may influence speech recognition after cochlear implantation is unknown, the degree of preservation of spiral ganglion cells is generally considered to be of primary importance. A series of experiments in our laboratories, directed at quantification of surviving spiral ganglion cells in the profoundly deaf, evaluation of the predictive value of a variety of clinical parameters, and the evaluation of the consequences of implantation in the inner ear, is summarized. Histologic study of the inner ears of patients who were deafened during life demonstrated that the cause of deafness accounted for 57% of the variability of spiral ganglion cell counts. Spiral ganglion cell counts were highest in individuals deafened by aminoglycoside toxicity or sudden idiopathic deafness and lowest in those deafened by postnatal viral labyrinthitis, congenital or genetic deafness, or bacterial meningitis. Study of the determinants of degeneration of the spiral ganglion revealed that degeneration is most severe in the basal compared with the apical turn and more severe when both inner and outer hair cells are absent. Unlike the findings in some experimental animal studies, no survival advantage of type II ganglion cells could be identified. There was a strong negative correlation between the degree of bony occlusion of the cochlea and the normality of the spiral ganglion cell count. However, even in specimens in which there was severe bony occlusion, significant numbers of spiral ganglion cells survived. A strong positive correlation between the diameter of the cochlear, vestibular, and eighth cranial nerves with the total spiral ganglion cell count (p < 0.001) was found. This would suggest that modern imaging techniques may be used to predict residual spiral ganglion cell population in cochlear implant candidates. Trauma from implantation of the electrode array was studied in both cadaveric human temporal bone models and temporal bones from individuals who received implants during life. A characteristic pattern of damage to the lateral cochlear wall and basilar membrane was identified in the upper basal turn. New bone formation and perielectrode fibrosis was common after cochlear implantation. Despite this significant trauma and reaction, there is no firm evidence that further degeneration of the spiral ganglion can be predicted as a consequence.

Molecular temporal bone pathology: II. Ramsay Hunt syndrome (herpes zoster oticus)

In 1907 J. Ramsay Hunt suggested that herpes zoster oticus resulted from a geniculate ganglionitis; however, many contemporary authors believe that this disorder represents a neuritis or polycranial neuropathy. Herpes varicella-zoster viral (VZV) DNA was identified, using the polymerase chain reaction, in archival celloidin-embedded temporal bone sections from two patients who clinically had Ramsay Hunt syndrome (herpes zoster oticus). The presence of VZV was confirmed by sequencing the PCR products. These experiments demonstrated that VZV genomic DNA was present in the geniculate ganglion of the side with facial paralysis and cutaneous recrudescence in both patients and in the clinically unaffected side in patient 1. In addition, patient 2 had a sudden hearing loss and was found to have VZV genomic DNA in sections from the affected side containing the spiral ganglion, Scarpa's ganglion, organ of Corti, and macula of the saccule. No VZV genomic DNA was identified in temporal bone sections from five patients with Bell's palsy and ten patients without evidence of otologic disease. In this study, the histopathology of these two cases yielded complementary information regarding the role of VZV in herpes zoster oticus. These data suggest that in patients with Ramsay Hunt syndrome, latent VZV is located in the geniculate ganglia and may be present in the auditory and vestibular primary afferent ganglia in some patients.

Management of 1000 vestibular schwannomas (acoustic neuromas): clinical presentation

OBJECTIVE

Despite good knowledge of the key symptoms of vestibular schwannomas and their significance for surgical results, the evolution of symptoms and signs and their relation to tumor extension still need thorough investigation.

METHODS

From 1978 to 1993, operations were performed by the same surgeon (M.S.) on 1000 vestibular schwannomas at the Neurosurgical Department of Nordstadt Hospital. The vestibular schwannomas were diagnosed in 962 patients, including 522 female patients (54%) and 440 male patients (46%); the mean age was significantly higher in female patients (47.6 yr) than in men (45.2 yr). We focused our analysis on the incidence of subjective disturbances versus objective morbidity, on the sequence of symptom onset, and on symptom duration and symptomatology versus tumor size and extension.

RESULTS

The most frequent clinical symptoms were disturbances of the acoustic (95%), vestibular (61%), trigeminal (9%), and facial (6%) nerves. Symptom duration was 3.7 years for hearing loss, 1.9 years for facial paresis, and 1.3 years for trigeminal disturbances. Symptom incidence and duration did not strictly correlate with tumor size. Key symptoms of various tumor extension classes precipitated the diagnosis, such as trigeminal disturbances in large tumors with brain stem compression or tinnitus in small neuromas. In cases of trigeminal or facial nerve symptoms, the overall duration of symptomatology was much shorter. According to the subjective perception of the patients, between only one- and two-thirds of nerve disturbances were noticed. Patients with preoperative deafness had become deaf either chronically (23%) or suddenly (3%); even in cases of moderate hearing deficit that lasts a long time, deafness can occur suddenly. The rate of tinnitus was higher in hearing than in deaf patients; however, deafness does not mean relief from tinnitus, because this symptom persists in 46% of preoperatively deaf patients. Vestibular disturbances most often occur as some unsteadiness while walking or as vertigo, and the symptoms frequently are fluctuating, not constant.

CONCLUSION

Differences in tumor biology can be underestimated and are not visible on radiological scans. For example, intrameatal tumors, despite their small size, present with a duration of symptoms that is representative of the larger tumors and are most frequently associated with vestibular symptoms and with tinnitus. Large tumors with brain stem compression present with relatively shorter symptom durations and at a younger age; both factors are suggestive of especially fast tumor growth. The clinical findings presented in this study promote new consideration of the dynamics of tumor growth and of the affected neural tissues.

[Clinical and electron microscopy study of sudden deafness treatment with the 10% HES 200/0.5 and pentoxifylline combination]

The incidence of sudden hearing loss has increased. The pathogenetic mechanisms are still unknown, but viral infections and vascular phenomena with acute impairment of microvascular perfusion are thought to play a major role. Infusion of hydroxyethyl starch (HES) is used as a regimen to treat sudden hearing loss. In our clinic, anaphylactic reactions due to HES have not been observed so far. However, the use of HES is still discussed controversially due to long-term storage of HES molecules in tissue and due to high incidence of long-lasting pruritus. In a retrospective analysis of 118 patients treated with HES for sudden hearing loss, we observed pruritus starting in 64% of patients one to three weeks after therapy. This symptom with a duration between two weeks and four months was refractory to medical interventions. During therapy with HES improvement of hearing was observed in 75% of patients, in 62% improvement of hearing persisted still at the end of the observation period (7 months post infusionem). Light and electron microscopic assessment of human skin biopsies of one patient after treatment with HES showed storage of HES especially within dermal macrophages. Pathogenetically a pathway independent of histamin seems responsible for the induction of pruritus. Accordingly, classic antihistaminic drugs had no therapeutic effect in our patients. Dextran is used as an alternative to hydroxyethyl starch. In contrast to HES, the often mentioned higher incidence of severe anaphylactic reactions due to dextran has dramatically decreased with hapten inhibition (after preinjection of monovalent haptendextran Promit).(ABSTRACT TRUNCATED AT 250 WORDS)

Value of Gd-DTPA-enhanced MR imaging of the labyrinth in patients with sudden hearing loss

Recent reports describe labyrinthine enhancement on MRI as a highly specific sign of labyrinthine disease. This paper reports 44 patients with unilateral sensorineural hearing loss (SNHL) and laboratory evidence of cochlear damage investigated with Gd-enhanced MR imaging. Enhancement of the cochlea was observed in only one patient with a lesion at the fundus of the internal auditory canal (IAC) that extended into the cochlea after Gd-DTPA administration. In one more patient, MR imaging demonstrated large vestibular aqueducts as underlying cause for his hearing loss, but no enhancement of the labyrinth was observed. No abnormal signal intensity on precontrast MR scans nor pathologic enhancement of the membranous labyrinth were identified in the other 42 patients. Gd-enhanced MR imaging appears to be insensitive in demonstrating labyrinthine disease and normal examination findings in a patient with sudden SNHL cannot exclude damage at the cochlear level.

The significance of herpes viral latency in the spiral ganglia

To better understand the pathogenesis of idiopathic sudden hearing loss (ISHL), the possibility of latent virus infection in the spiral ganglion cell was considered. Only few spiral ganglion cells showed positive viral antigen after systemic guinea pig-specific cytomegalovirus (GPCMV) inoculation indicating the absence of hearing loss but the possibility of a subsequent latent infection. By using a modern molecular biological technique we have detected the herpes simplex virus type-1 (HSV-1) DNA in human spiral ganglia. The concept of establishing viral latency in the spiral ganglion cells with periods of reactivation fits with the clinical picture seen in ISHL, even though the mechanism of reactivation still remains unclear.

[Progressing cases from low tone sudden deafness to Menière's disease--cochlear impairment in the so-called pre-Menière's disease period]

Among 80 patients with low tone sudden deafness (LTSD) who visited our department over the past 15 years, there were 6 cases (7.5%) who subsequently progressed to Menière's disease. The clinical and audiological processes of the 6 patients were studied in detail and the following results were obtained. (1) In these 6 patients, the time between onset of LTSD and the diagnosis of Menière's disease ranged from 4 months at the shortest to 6 years and 8 months at the longest, 2 years and 9 months on average. (2) Two pattern types were seen in the change from LTSD to Menière's disease: changing within a short period of time after recurrence of an LTSD-like attack, and changing after more than one year without recurrent attack. (3) The monoattack-nonrecovered type of LTSD and the recurrent type of LTSD within three months after the onset (short-term prognosis) frequently progressed to Menière's disease. (4) There were no close relationships between subjective symptoms and audiological features in the pre-Menière's disease period (from the onset of LTSD to the recurrence of vertigo with cochlear symptoms). (5) The 6 patients showed various audiogram shapes at the time of progression to Meniere's disease; 3 cases with the slightly rising type, 1 with the high frequency-impaired type, and 2 with the moderate, gradual and flat type. (6) Of the 6 patients, 3 had good hearing during long term observation. At least 2 patients seemed to have the mild type of Menière's disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Sudden loss of hearing and vestibular function, muscular weakness, and multiple white matter lesions in preschool children

Sudden cochlear hearing loss, occurring successively or simultaneously in both ears, was observed in four unrelated preschool children. Vestibular testing could be carried out in three patients and showed complete bilateral loss of function. All patients had a mildly retarded motor development due to nonprogressive muscular weakness. On MR imaging all patients showed multiple periventricular and subcortical white matter lesions. These lesions were not clearly progressive in one patient examined repeatedly over 6 years. Virological, bacteriological, immunological, and metabolic examinations were normal in all patients. Muscle biopsy showed morphologically abnormal mitochondria in two and lipid storage in one patient. No indications have been found for a disturbed functioning of the muscle mitochondria. The identical pattern and course of the disease in these patients suggests a new nosological entity, the aetiology of which can only speculatively be attributed to a vascular process associated with a mitochondriopathy.

[Experimental studies of ischemia of the cochlea. Part 3: Pathophysiology]

Selective interruption of cochlear blood flow is possible without operative manipulations in the middle or inner ear. By fitting a magnet into the external auditory canal and injecting iron filings into the cephalic vein is it possible to obtain an impaired inner ear in otherwise healthy experimental animals that can be kept alive for any length of time. The hearing loss induced by the ischemia normally remains unchanged over a period of weeks. The highly vascularised areas of the cochlea, namely the spiral ligament, the vascular stria, the spiral prominence and the root cells in the external spiral sulcus, as well as the spiral limbus were all clearly degenerated, but to different degrees. Pronounced vacuolisation of cells, degeneration of tissue, reduction of cellular elements, stasis in large and small blood vessels and morphological disorganisation were observed. The organ of Corti showed no changes worthy of note. On revascularisation of the spiral ligament and the spiral limbus with resumption of function, the organ of Corti can return to normal activity again. Repeat blood flow disturbances can also lead to recurrent sudden hearing loss and intermittent loss of hearing.