A case of perilymphatic fistula caused by surgical drilling with preserved normal hearing.

We introduce our horrible experience of lateral semicircular canal exposure due to unintended drilling during left facial nerve decompression. Nearly half of the canal was drilled-out, however, the membranous labyrinth was preserved and the defect was covered with temporal fascia. Immediately after surgery, the patient complained of vertigo with right beating nystagmus. However, the patient could hear an audible tuning fork sound and the Weber-test showed left-sided deviation. The vertigo gradually subsided and the facial palsy was completely recovered 3 months after the surgery. One and half years later, the patient spent a normal life with normal hearing nevertheless after this terrifying episode.

Pseudo-spontaneous nystagmus in lateral semicircular canal benign paroxysmal positional vertigo: Correlation with bow and lean test in a pitch plane.

OBJECTIVES: We investigated the incidence and characteristics of pseudo-spontaneous nystagmus (PSN) in benign paroxysmal positional vertigo involving the lateral semicircular canal (LC-BPPV) and evaluated the correlation between PSN and the bow and lean test. METHODS: We examined nystagmus in the sitting position using video-oculography goggles in 131 LC-BPPV patients. The positioning test and bow and lean test were also performed. Patients were divided into canalolithiasis and cupulolithiasis groups according to the character of nystagmus. In each group, the incidence and direction of PSN, correlation with the bow and lean test, and treatment outcome were analyzed. RESULTS: PSN was observed in 25 cases (19.1%) in LC-BPPV patients, 7 of which were canalolithiasis and 18 of which were cupulolithiasis (p = 0.098). Of the 25 patients with PSN, 21 (84%) exhibited nystagmus consistent with the lean test whereas 4 (16%) exhibited nystagmus consistent with the bow test. In patients with PSN, nystagmus was observed in the bow and lean test in all cases (23/23), but in patients without PSN, no nystagmus was observed in 13 cases (13/87) in the bow and lean test (p = 0.048). The number of barbecue maneuvers performed until the end of treatment was 1.4 ± 0.7 in patients with PSN and 1.4 ± 0.9 in those without PSN (p = 0.976). CONCLUSION: We identified PSN in patients with LC-BPPV irrelevant of subtype. Moreover, all patients with PSN showed nystagmus in the bow and lean test. The direction of PSN was mostly consistent with that of the lean test (21/25, 84%). The presence of PSN was not related to the treatment outcome in this study.

Significance of high signal intensity in the endolymphatic duct on magnetic resonance imaging in ears with otological disorders.

BACKGROUND: High signal intensity in the endolymphatic duct (ED) is occasionally observed on magnetic resonance imaging (MRI) in ears that have otological disorders. OBJECTIVE: The signal intensity (SI) in the ED on post-contrast MRI was investigated in subjects with various otological disorders, and the meaning of high SI in the ED was evaluated. MATERIAL AND METHODS: 392 patients with otological disorders and 21 controls without otological symptoms underwent 3 T MRI. The SIs of the ED and the cerebellum were measured, the SI ratio (SIR) was calculated, and ears with SIR ≥4 were identified. RESULTS: A high SIR was identified in the ED of 3.7% of ears affected by definite Meniere's disease (dMD), 100% of ears affected by large vestibular aqueduct syndrome (LVAS), and 7.1% of ears with no otological symptoms. On the whole, a significant relationship was found between the existence of vestibular or cochlear EH and the SIR in the ED. CONCLUSION: The MRI finding of high SI in the ED may indicate the mechanism of inner ear disturbances in ears with otological disorders, especially in those with LVAS, and it may suggest an underlying disorder in some ears in which otological symptoms are not apparent.

Quantitative Analysis of Saccade Gain in Video Head Impulse Testing.

OBJECTIVE: To quantitatively analyze corrective saccade (CS) gain and further characterize the specific relationship between vestibulo-ocular reflex (VOR) gain and CS gain in patients with vestibular loss and healthy controls. STUDY DESIGN: Prospective combined with retrospective study. SETTING: Affiliated Sixth People's Hospital, Shanghai Jiao Tong University. SUBJECTS AND METHODS: Forty patients with unilateral vestibular loss and 40 participants with normal vestibular function were subjected to video head impulse testing (vHIT). The analysis of the horizontal semicircular canal VOR and CS gains was based on individual head impulses. RESULTS: The patient group had significantly higher CS gain and lower VOR gain than the control group (P < .001). While there was no significant correlation between VOR and CS gains in the control group after adjusting for age and sex (P = .689), VOR gain negatively correlated with CS gain in the patient group (r = -0.853, P < .001). The specific relationship between VOR and CS gains was characterized as y = -1.17x + 1.12 (x: VOR gain, y: CS gain; r2 = 0.732, P < .001) in the patient group. CONCLUSIONS: In healthy participants, CS was not correlated with VOR gain, suggesting that CS is not due to VOR hypofunction. In patients with unilateral vestibular loss, CS was closely associated with VOR gain and can almost correct gaze position errors required for visual stabilization. CS gain could be an important indicator to diagnose vestibular loss and help physicians identify abnormal vHIT curves caused by artifacts and irregular practices.

Clinical Characteristics of Patients with Cochlear Fistulas Caused by Chronic Otitis Media with Cholesteatoma.

OBJECTIVES: To analyze the clinical characteristics of cochlear fistulas (CFs) and propose a new fistula classification system with regard to the cochlea. MATERIALS AND METHODS: A retrospective chart review was conducted between January 2008 and December 2015 to identify patients who had undergone surgery for cholesteatoma with an associated CF. The following data were collected: preoperative symptoms, findings of temporal bone computed tomography (TBCT), fistula stage, cholesteatoma classification, surgical technique, and pre- and postoperative pure-tone audiometry. RESULTS: We analyzed a total of 159 patients, out of which 9 (5.7%) were diagnosed with a CF. The average duration of the chronic otitis media was 19.8 years. Cholesteatomas that induced CF rarely existed in the nonaggressive state; recurrent otorrhea was observed in all but one of our subjects. All the patients with CF had a distinct origin of cholesteatoma that developed from the retraction of posterior pars tensa; further, 88.9% cholesteatomas extended to and filled the sinus tympani. Preoperative audiometry revealed total hearing loss in 4 (44.4%) patients. Further, five patients with residual hearing before surgery had stage I fistulas, and the bone conduction thresholds remained stable after surgery. CONCLUSION: Cochlear fistulas were often detected in patients with (1) a history of chronic otitis media (exceeding 10 years), (2) frequently recurring otorrhea, and (3) pars tensa cholesteatomas that extended to the posterior mesotympanum and filled the sinus tympani. Such patients can suffer from potentially severe and irreparable sensorineural hearing loss.

Application of Cervical Vestibular-Evoked Myogenic Potentials in Adults with Moderate to Profound Sensorineural Hearing Loss: A Preliminary Study

Abstract Introduction The cochlea and the vestibular receptors are closely related in terms of anatomy and phylogeny. Patients with moderate to profound sensorineural hearing loss (MPSHL) should have their vestibular organ functions tested. Objective To evaluate the incidence of vestibular abnormalities in patients with MPSHL and to study the correlation between the etiology of hearing loss (HL) and a possible damage to the labyrinth. Methods A case-control retrospective study was performed. In the case group, 20 adults with MPSHL of known etiology were included. The control group was composed of 15 adults with normal hearing. The case group was divided into 4 subgroups based on the etiology (bacterial meningitis, virus, vascular disease, congenital). Cervical vestibular-evoked myogenic potentials (cVEMPs) were used to rate the saccular function and lower vestibular nerve. Results The study was performed in 70 ears, and it highlighted the presence of early biphasic P1-N1 complex in 29 (71.5%) out of 40 ears in the study group, and in all of the 30 ears in the control group (p = 0.001). Regarding the presence or absence of cVEMPs among the four subgroups of patients with MPSHL, the data were statistically significant (p < 0.001). The comparison between the latencies and amplitude of P1-N1 in case and control groups from other studies and in the four subgroups of cases in the present study did not detect statistically significant differences. Conclusion The present study demonstrates that patients with MPSHL have a high incidence of damage to the labyrinthine organs, and it increases the current knowledge about the etiopathogenesis of sensorineural HL, which is often of unknown nature.

Can miR-34a be suitable for monitoring sensorineural hearing loss in patients with mitochondrial disease? A case series.

Purpose: We aimed at evaluating the feasibility of using MicroRNA (miR)-34a and miR-29b to detect inner ear damage in patients with mitochondrial disease (MD) and sensorineural hearing loss (SNHL).Material and Methods: Three patients with MD and SNHL and seven healthy control subjects were included in this case series. MD patients underwent pure tone audiometry (PTA), distortion product otoacoustic emission (DPOAE) and auditory brain response tests to investigate the specific cochlear and retrocochlear functions; control patients underwent PTA. MiR-34a and miR-29b were extracted from blood in all subjects included in the study. The expression of miR-34a and miR-29b in MD patients and healthy controls were statistically compared, then the expression of these two miRs was compared with DPOAE values.Results: In MD patients, miR-34a was significantly up-regulated compared to healthy controls; miR-34a and DPOAEs were negatively correlated. Conversely, miR-29b was up-regulated only in the youngest patient who suffered from the mildest forms of MD and SNHL, and negatively correlated with DPOAEs.Conclusion: In MD patients, miR-34a and miR-29b might be a marker of inner ear damage and early damage, respectively. Additional studies on larger samples are necessary to confirm these preliminary results.

Inner ear pressure evaluation using wideband tympanometry in children with Large Vestibular Aqueduct Syndrome (LVAS): A pilot study.

OBJECTIVE: To investigate middle ear function in children with Large Vestibular Aqueduct Syndrome (LVAS) to explore the feasibility of measuring inner ear pressure using Wideband tympanometry (WBT). METHODS: 13 young children with LVAS were recruited. WBT and other audiological measurements i.e., Auditory Steady State Response (ASSR), Auditory Brain Stem Response (ABR), and Distorted Product Otoacoustic Emissions (DPOAE) were performed. Absorbance under ambient and peak pressure were compared with normative data, and analyzed using a one sample t-test. RESULTS: Average absorbance in children with LVAS was significantly lower than normative data under ambient pressure at 1000, 1189, 1296, 2000 Hz and 4000 Hz. Absorbance under peak pressure was also significantly lower at 707, 794, 917, 1000, 1189, 1297, 1498 and 2000 Hz. However, absorbance was higher than standard values above 4000 Hz under ambient and peak pressure. It was also higher under ambient pressure at frequencies below 500 Hz. CONCLUSION: The special characteristics of middle ear function found in children with Large Vestibular Aqueduct Syndrome (LVAS) indicate that WBT offers a sensitive and non-invasive method to evaluate inner ear pressure indirectly.

Video Head Impulse Test in Labyrinthine Fistula due to Middle Ear Cholesteatoma.

OBJECTIVES: To assess and monitor lateral semicircular canal (LSC) function over time in patients affected by chronic otitis media with cholesteatoma (CHO) complicated by fistula of LSC (LSC-F) before and after surgery using video Head Impulse Test (vHIT). MATERIALS AND METHODS: Eight patients aged 18-67 years affected by CHO with imaging-ascertained LSC-F were included in this preliminary prospective study. The following protocol has been applied: oto-microscopic diagnosis with patient's history; computed tomography scan of the temporal bone; surgery with concomitant resurfacing of LSF-F; audiological and vestibular evaluation before surgery (T0) and at 30 days (T1), 6 months (T2), and 1 year after surgery (T3). vHIT was used to assess vestibulo-ocular reflex (VOR) in LSC. RESULTS: None of the patients showed deterioration of bone conduction hearing levels during the different time of evaluation. Three patients showed a reduced VOR gain and catch-up saccades at T0, with VOR gain normalization at T2. This finding remained stable at the 1-year follow-up. The VOR gain in the nonaffected side generally experienced an increase, paralleled by the normalization on the affected side, with statistically significant correlation. The subjects with normal vHIT before surgery did not show any variation following surgery. CONCLUSION: vHIT allows the assessment of LSC function in case of fistula. The adopted surgical fistula repair did not induce deterioration of the auditory or LSC function, but indeed, it could prevent worsening and help promoting recovery to the normal function.

Audiological and Vestibular Findings in Subjects with MELAS Syndrome.

OBJECTIVES: The mitochondrial DNA (mtDNA) point mutation m.3243A>G is known to express the following two syndromes among others: maternally inherited diabetes and deafness (MIDD) and mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). Sensorineural hearing loss (SNHL) is the most frequent symptom in individuals harboring the m.3243A>G mutation. However, dysfunction of the vestibular organs has been scarcely examined. Therefore, the present study aimed to study the impact of the m.3243A>G mutation on the inner ear. MATERIALS AND METHODS: A total of 8 subjects harboring the blood-verified m.3243A>G mutation underwent thorough audiological and vestibular examinations, including tone and speech audiometry, video head impulse test (vHIT), ocular and cervical vestibular-evoked myogenic potential (oVEMP and cVEMP), and full otoneurological examination. The subjects also answered a Dizziness Handicap Inventory (DHI) questionnaire. RESULTS: SNHL was identified in all the 8 subjects, with a mean pure-tone average-4 (PTA-4) of 59 dB. Speech discrimination score (n=7) ranged from 24% to 100% (mean 74%), and vHIT (n=42) detected pathology in nine lateral semicircular canals (SCCs), five posterior SCCs, and one anterior SCC, whereas three measurements were inconclusive. All oVEMPs (n=14 ears) were absent, nine cVEMPs were absent, and two were inconclusive. Based on the DHI scores, 6 subjects reported none to mild dizziness, 1 reported moderate, and 1 reported severe dizziness. CONCLUSION: Our study population had pathological findings from every audiological and vestibular end organs. The results indicated that the pathological findings originated from within the end organs themselves and not within the superior and inferior vestibular or cochlear nerve.

Recovery of ocular and cervical vestibular evoked myogenic potentials after treatment of inner ear diseases.

Purpose: This study aimed to assess the clinical value of ocular vestibular evoked myogenic potential (oVEMP) and cervical vestibular evoked myogenic potential (cVEMP) for monitoring the rehabilitation of vestibular function in patients treated for peripheral vertigo. Materials and methods: Fifteen patients who had been diagnosed with peripheral vertigo and showed no VEMP response on the affected side but exhibited symptom alleviation and VEMP responses after therapies were retrospectively enrolled. We analyzed the restoration and parameters of their VEMP response. Results: After treatment, six patients with sudden sensorineural hearing loss showed VEMP recovery, including two with both oVEMP and cVEMP recovery, three with oVEMP recovery only, and one with cVEMP recovery only. Two patients with Meniere's disease (MD) showed cVEMP recovery, while the other three MD patients showed oVEMP recovery. Three patients with herpes zoster oticus exhibited cVEMP recovery. One patient with vestibular neuritis exhibited cVEMP recovery. Among the patients with cVEMP and/or oVEMP restoration, most patients presented normal VEMP parameters; however, some patients showed abnormal VEMP parameters after treatment. Conclusion: Combined oVEMP and cVEMP are objective tools for assessing vestibular otolithic end organ function during dynamic functional recovery from vestibular diseases.

Perilymphatic Fistulas and Superior Semi-Circular Canal Dehiscence Syndrome.

Perilymphatic fistulas (PLF) and superior semi-circular canal dehiscence syndrome (SCDS) are 2 conditions that can present with sound and/or pressure-induced vertigo. PLF should be suspected in cases of trauma or surgery, while a spontaneous PLF is a diagnosis of exclusion. Research is ongoing to identify an ideal biomarker for perilymph. The diagnosis of SCDS continues to evolve with further research into vestibular-evoked myogenic potentials, electrocochleography, and higher resolution CT imaging. Treatment advances include the transmastoid approach, smaller middle fossa craniotomies, and usage of endoscopes. Temporal bone studies have furthered the understanding of pressure dynamics within the ear and how this relates to recommendations for repair versus alternative treatments such as round window plugging.

Superior Canal Dehiscence Syndrome: Relating Clinical Findings With Vestibular Neural Responses From a Guinea Pig Model.

HYPOTHESIS: In superior canal dehiscence (SCD), fluid displacement of the endolymph activates type I vestibular hair cells in the crista of the affected canal and thus irregular superior canal (SC) neurons in Scarpa's ganglion, which provides the neurophysiological basis for the clinical presentation of SCD. BACKGROUND: Patients with SCD display sound- and vibration-induced vertigo/nystagmus and increased amplitudes of vestibular evoked myogenic potentials. METHODS: Extracellular recordings from n = 25 primary vestibular neurons of 16 female guinea pigs were analyzed. We recorded from the same vestibular neuron before, during and after creating the dehiscence and after closing the dehiscence. Neurobiotin labeling was employed in n = 11 neurons. RESULTS: After SCD, previously unresponsive irregular SC neurons displayed a stimulus-locked increase in discharge during application of air-conducted sound (ACS) or bone-conducted vibration (BCV) for a broad range of frequencies (ACS: 200-4000 Hz; BCV: 500-1500 Hz). This typical response was only observed for irregular SC neurons (n = 19), but not regular SC neurons, or irregular/regular horizontal canal neurons (n = 2 each), and was abolished after closing the dehiscence. Eleven irregular SC neurons responsive to ACS and/or BCV were traced back to calyx synapses in the central crista of the affected superior canal by neurobiotin labeling. CONCLUSIONS: Stimulus-locked activation of irregular SC neurons by ACS and BCV is the neurophysiological basis for sound- and vibration-induced vertigo/nystagmus and increased VEMP amplitudes in SCD. The results of the present study help to improve vestibular diagnostics in patients with suspected SCD.

Different clinical presentation of intralabyrinthine schwannomas - a systematic review / Diferentes apresentações clínicas do schwannoma intralabiríntico --- uma revisão sistemática

Abstract Introduction: Intralabyrinthine schwannoma is a rare, benign tumor that affects the most terminal portions of the vestibular and cochlear nerves. This tumor can be classified into 10 subtypes, according to its inner ear location. Objective: To carry out a comprehensive review of the most frequent auditory manifestations secondary to the intralabyrinthine schwannoma, describing the possible underlying pathophysiological mechanisms. Methods: Systematic review of the literature until October 2017 using the PubMed, Web of Science and Scopus databases. The inclusion criteria were clinical manifestations of the intralabyrinthine schwannoma. Three researchers independently assessed the articles and extracted relevant information. The description of a case of an intravestibular subtype intralabyrinthine schwannoma with multiple forms of clinical presentations was used as an example. Results: Twenty-seven studies met our inclusion criteria. The most common intralabyrinthine schwannoma subtype was the intracochlear, followed by the intravestibular type. All the cases demonstrated hearing loss, usually progressive hearing loss. Conclusion: The diagnosis of intralabyrinthine schwannomas is based on high-resolution magnetic resonance imaging and should be included in the differential diagnosis of patients with vestibulocochlear complaints. Although there are approximately 600 cases in the literature, we still lack a detailed description of the clinical evolution of the patients, correlating it with MRI findings of temporal bones and tumor subtype.

Resumo Introdução: Schwannoma intralabiríntico é um tumor benigno, raro, que afeta as porções mais terminais dos nervos vestibular e coclear. Este tumor pode ser classificado, de acordo com sua localização na orelha interna, em 10 subtipos. Objetivo: Realizar uma revisão abrangente das manifestações auditivas mais frequentes secundárias ao schwannoma intralabiríntico e descrever os possíveis mecanismos fisiopatológicos subjacentes. Método: Revisão sistemática da literatura até outubro de 2017 nas bases de dados PubMed, Web of Science e Scopus. O critério de inclusão foi manifestações clínicas do schwannoma intralabiríntico. Três pesquisadores avaliaram de forma independente os artigos e extraíram informações relevantes. Exemplificamos com a descrição de um caso de schwannoma intralabiríntico subtipo intravestibular com múltiplas formas de apresentações clínicas. Resultados: Vinte sete estudos contemplaram nossos critérios de inclusão. O subtipo do schwannoma intralabiríntico mais comum encontrado foi o intracoclear, seguido pelo intravestibular. Todos os casos apresentaram alteração auditiva, normalmente perda auditiva progressiva. Conclusão: O diagnóstico de schwannomas intralabirínticos baseia-se em exames de ressonância magnética de alta resolução e deve ser incluído no diagnóstico diferencial de pacientes com queixas vestibulococleares. Apesar de termos aproximadamente 600 casos na literatura, ainda nos falta descrição detalhada da evolução clínica dos pacientes em correlação com achados na ressonância magnética de ossos temporais e o subtipo tumoral.

Isolated horizontal canal hypofunction differentiating a canalith jam from an acute peripheral vestibular loss.

OBJECTIVES: To describe a unique case of acute vertigo presenting with spontaneous horizontal nystagmus (SHN) and a clinical picture consistent with right acute peripheral vestibular loss (APVL) in which an isolated hypofunction of a horizontal semicircular canal (HSC) permitted to detect a spontaneous canalith jam and treat the patient accordingly. METHODS: Case report and literature review. RESULTS: A 74-year old woman presented with acute vertigo, left-beating SHN and a clinical picture consistent with right APVL. Nevertheless, vestibular evoked myogenic potentials were normal with symmetrical amplitudes and the video head impulse test (vHIT) revealed an isolated hypofunction of the right HSC. After repeated head shakings, the supine roll test evoked bilaterally a positioning paroxysmal geotropic horizontal nystagmus suggesting benign paroxysmal positional vertigo involving the non-ampullated arm of the right HSC. vHIT and caloric testing confirmed restitution of HSC function after repositioning maneuvers. CONCLUSIONS: In case of acute vertigo with SHN, a complete functional assessment of vestibular receptors and afferents should always be given in order to avoid misdiagnosis. Canalith jam should be considered in case of spontaneous nystagmus and isolated canal hypofunction.

Different clinical presentation of intralabyrinthine schwannomas - a systematic review.

INTRODUCTION: Intralabyrinthine schwannoma is a rare, benign tumor that affects the most terminal portions of the vestibular and cochlear nerves. This tumor can be classified into 10 subtypes, according to its inner ear location. OBJECTIVE: To carry out a comprehensive review of the most frequent auditory manifestations secondary to the intralabyrinthine schwannoma, describing the possible underlying pathophysiological mechanisms. METHODS: Systematic review of the literature until October 2017 using the PubMed, Web of Science and Scopus databases. The inclusion criteria were clinical manifestations of the intralabyrinthine schwannoma. Three researchers independently assessed the articles and extracted relevant information. The description of a case of an intravestibular subtype intralabyrinthine schwannoma with multiple forms of clinical presentations was used as an example. RESULTS: Twenty-seven studies met our inclusion criteria. The most common intralabyrinthine schwannoma subtype was the intracochlear, followed by the intravestibular type. All the cases demonstrated hearing loss, usually progressive hearing loss. CONCLUSION: The diagnosis of intralabyrinthine schwannomas is based on high-resolution magnetic resonance imaging and should be included in the differential diagnosis of patients with vestibulocochlear complaints. Although there are approximately 600 cases in the literature, we still lack a detailed description of the clinical evolution of the patients, correlating it with MRI findings of temporal bones and tumor subtype.

Clinical and Physiologic Predictors and Postoperative Outcomes of Near Dehiscence Syndrome.

OBJECTIVE: To identify predictors of near dehiscence (ND) or thin rather than dehiscent bone overlying the superior semicircular canal in patients with signs and symptoms suggestive of superior semicircular canal dehiscence syndrome (SCDS), as well as postoperative outcomes. STUDY DESIGN: Retrospective case-control study. SETTING: Tertiary referral center. PATIENTS: All 288 patients who underwent middle cranial fossa approach for repair of SCDS (1998-2018) were reviewed for cases of ND. Demographics, symptoms, and clinical signs including nystagmus, ocular vestibular-evoked myogenic potential (oVEMP) amplitude, cervical vestibular-evoked myogenic potential (cVEMP) thresholds, and low-frequency air-bone gap were compared before and after surgery. MAIN OUTCOME MEASURE: Presence of preoperative ND and postoperative symptoms and physiologic measures. RESULTS: Seventeen cases of ND (16 patients, 17 ears) and 34 cases (34 ears) of frank SCDS were identified. ND cases differed from frank dehiscence cases in that they were less likely to have nystagmus in response to ear canal pressure or loud sounds, OR = 0.05 (95% CI 0.01-0.25) and Valsalva, OR = 0.08 (0.01-0.67), smaller peak-to-peak oVEMP amplitudes, OR = 0.84 (0.75-0.95), and higher cVEMP thresholds, OR = 1.21 (1.07-1.37). Patients with ND had similar symptoms to those with frank SCDS before surgery, and after surgery had outcomes similar to patients with frank SCDS. CONCLUSIONS: In patients with symptoms consistent with SCDS, predictors of ND include absence of nystagmus in response to pressure/loud sounds, greater cVEMP thresholds, and smaller oVEMP amplitudes. We propose ND is on a spectrum of dehiscence that partially accounts for the diversity of clinical presentations of patients with SCDS.

Anatomical basis of drug delivery to the inner ear.

The isolated anatomical position and blood-labyrinth barrier hampers systemic drug delivery to the mammalian inner ear. Intratympanic placement of drugs and permeation via the round- and oval window are established methods for local pharmaceutical treatment. Mechanisms of drug uptake and pathways for distribution within the inner ear are hard to predict. The complex microanatomy with fluid-filled spaces separated by tight- and leaky barriers compose various compartments that connect via active and passive transport mechanisms. Here we provide a review on the inner ear architecture at light- and electron microscopy level, relevant for drug delivery. Focus is laid on the human inner ear architecture. Some new data add information on the human inner ear fluid spaces generated with high resolution microcomputed tomography at 15 µm resolution. Perilymphatic spaces are connected with the central modiolus by active transport mechanisms of mesothelial cells that provide access to spiral ganglion neurons. Reports on leaky barriers between scala tympani and the so-called cortilymph compartment likely open the best path for hair cell targeting. The complex barrier system of tight junction proteins such as occludins, claudins and tricellulin isolates the endolymphatic space for most drugs. Comparison of relevant differences of barriers, target cells and cell types involved in drug spread between main animal models and humans shall provide some translational aspects for inner ear drug applications.

Performing and analysing tone-induced cervical and ocular vestibular-evoked myogenic potentials in traumatic and non-traumatic vestibular pathology.

OBJECTIVE: This paper discusses our technique of carrying out cervical and ocular vestibular-evoked myogenic potential testing in a single position. The described technique allows for a symmetrical, natural flexion of the neck muscles, which is helpful as many of our patients have suffered traumatic deceleration injures. METHODS: Patients with suspected vestibular pathology referred by specialists were sequentially assessed in a tertiary referral neuro-otology unit within a teaching hospital using our technique and our previously established normative database. All patients underwent standardised vestibular assessment in addition to cervical and ocular vestibular-evoked myogenic potential assessment. Our normative data are in keeping with that reported by other centres. RESULTS: Many of the patients had abnormal vestibular-evoked myogenic potentials, which is in line with a history suggesting otolithic disease. CONCLUSION: Both cervical and ocular vestibular-evoked myogenic potentials offer several parameters for detecting abnormalities. The technique reported enables us to assess patients in an accurate fashion whether or not they have suffered traumatic neck injuries.