Long-term efficacy of triple semicircular canal plugging in the treatment of patients with ipsilateral delayed endolymphatic hydrops.

This study aims to explore the long-term efficacy of triple semicircular canal plugging (TSCP) in the treatment of intractable ipsilateral delayed endolymphatic hydrops (DEH), so as to provide an alternative therapy for this disease. Forty-eight patients diagnosed with ipsilateral DEH referred to vertigo clinic of our hospital between Dec. 2010 and Dec. 2017, were included in this study for retrospective analysis. All patients were followed up for 2 years. Vertigo control and auditory functions were measured and analyzed. Pure tone audiometry, caloric test, and vestibular evoked myogenic potential (VEMP) were performed in two-year follow-up. Forty-five patients who accepted intratympanic gentamicin (26.7 mg/mL) twice given one week apart were selected as a control group. The total control rate of vertigo in TSCP group was 97.9% (47/48) in the two-year follow-up, with complete control rate of 83.3% (40/48) and substantial control rate of 14.6% (7/48). The rate of hearing loss was 22.9% (11/48). The total control rate of vertigo in intratympanic gentamicin group was 80.0% (36/45), with complete control rate of 57.8% (26/45) and substantial control rate of 22.2% (10/45), and the rate of hearing loss was 20.0% (9/45). The vertigo control rate of TSCP was significantly higher than that of intratympanic gentamicin (χ2 = 6.01, p < 0.05). There was no significant difference of hearing loss rate between two groups. (χ2 = 0.12, p > 0.05). TSCP, which can reduce vertiginous symptoms in patients with intractable ipsilateral DEH, represents an effective therapy for this disorder.

cVEMP correlated with imbalance in a mouse model of vestibular disorder.

BACKGROUND: Cervical vestibular evoked myogenic potential (cVEMP) testing is a strong tool that enables objective determination of balance functions in humans. However, it remains unknown whether cVEMP correctly expresses vestibular disorder in mice. OBJECTIVE: In this study, correlations of cVEMP with scores for balance-related behavior tests including rotarod, beam, and air-righting reflex tests were determined in ICR mice with vestibular disorder induced by 3,3'-iminodipropiontrile (IDPN) as a mouse model of vestibular disorder. METHODS: Male ICR mice at 4 weeks of age were orally administered IDPN in saline (28 mmol/kg body weight) once. Rotarod, beam crossing, and air-righting reflex tests were performed before and 3-4 days after oral exposure one time to IDPN to determine balance functions. The saccule and utricles were labeled with fluorescein phalloidin. cVEMP measurements were performed for mice in the control and IDPN groups. Finally, the correlations between the scores of behavior tests and the amplitude or latency of cVEMP were determined with Spearman's rank correlation coefficient. Two-tailed Student's t test and Welch's t test were used to determine a significant difference between the two groups. A difference with p < 0.05 was considered to indicate statistical significance. RESULTS: After oral administration of IDPN at 28 mmol/kg, scores of the rotarod, beam, and air-righting reflex tests in the IDPN group were significantly lower than those in the control group. The numbers of hair cells in the saccule, utricle, and cupula were decreased in the IDPN group. cVEMP in the IDPN group was significantly decreased in amplitude and increased in latency compared to those in the control group. cVEMP amplitude had significant correlations with the numbers of hair cells as well as scores for all of the behavior tests in mice. CONCLUSIONS: This study demonstrated impaired cVEMP and correlations of cVEMP with imbalance determined by behavior tests in a mouse model of vestibular disorder.

Effect of caffeine on vestibular evoked myogenic potential: a systematic review with meta-analysis / Efeito da cafeína no potencial evocado miogênico vestibular: uma revisão sistemática com metanálise

Abstract Introduction: Caffeine can be considered the most consumed drug by adults worldwide, and can be found in several foods, such as chocolate, coffee, tea, soda and others. Overall, caffeine in moderate doses, results in increased physical and intellectual productivity, increases the capacity of concentration and reduces the time of reaction to sensory stimuli. On the other hand, high doses can cause noticeable signs of mental confusion and error induction in intellectual tasks, anxiety, restlessness, muscle tremors, tachycardia, labyrinthine changes, and tinnitus. Objective: Considering that the vestibular evoked myogenic potential is a clinical test that evaluates the muscular response of high intensity auditory stimulation, the present systematic review aimed to analyze the effects of caffeine on vestibular evoked myogenic potential. Methods: This study consisted of the search of the following databases: MEDLINE, CENTRAL, ScienceDirect, Scopus, Web of Science, LILACS, SciELO and ClinicalTrials.gov. Additionally, the gray literature was also searched. The search strategy included terms related to intervention (caffeine or coffee consumption) and the primary outcome (vestibular evoked myogenic potential). Results: Based on the 253 potentially relevant articles identified through the database search, only two full-text publications were retrieved for further evaluation, which were maintained for qualitative analysis. Conclusion: Analyzing the articles found, caffeine has no effect on vestibular evoked myogenic potential in normal individuals.

Resumo Introdução: A cafeína pode ser considerada a droga mais consumida por adultos em nível mundial, podendo ser encontrada em inúmeros alimentos, como no chocolate, café, chá, refrigerante e outros. Em geral, a cafeína em doses moderadas, produz ótimos rendimentos físico e intelectual, aumenta a capacidade de concentração e diminui o tempo de reação aos estímulos sensoriais. Por outro lado, doses elevadas podem causar sinais perceptíveis de confusão mental e indução de erros em tarefas intelectuais, ansiedade, nervosismo, tremores musculares, taquicardia, alterações labirínticas e zumbido. Objetivo: Considerando que o potencial evocado miogênico vestibular é um teste clínico que avalia a resposta muscular decorrente de estimulação auditiva de alta intensidade, a presente revisão sistemática objetivou analisar o efeito da cafeína sobre o potencial evocado miogênico vestibular. Método: A formulação deste trabalho consistiu na busca dos estudos nas seguintes bases de dados: MEDLINE, CENTRAL, ScienceDirect, Scopus, Web of Science, LILACS, SciELO e Clinical-Trials.gov. Adicionalmente, a literatura cinzenta também foi pesquisada. A estratégia de busca incluiu termos relacionados à intervenção (consumo de cafeína ou café) e ao desfecho primário (potencial evocado miogênico vestibular). Resultados: A partir de 253 registros potencialmente relevantes identificados através da busca nas bases de dados, apenas duas publicações em texto completo foram recuperadas para avaliação mais aprofundada, sendo estas mantidas para a análise qualitativa. Conclusão: Diante dos artigos encontrados a cafeína não tem efeito sobre o potencial evocado miogênico vestibular em sujeitos normais.

The Follow-Up Role of the Vestibular Evoked Myogenic Potential Test in Meniere's Disease.

Despite some proposed roles for the diagnostic impact of the cervical vestibular evoked myogenic potential test in the patients with Meniere's disease, the role of this test as an objective instrument in following up the patients with Meniere's disease who underwent. Intratympanic steroid injection is not cleared. In a prospective study, thirty-one adult patients with definite one-sided Meniere's disease with vertigo as main complaint refractory to medical treatments for three months, were selected. Patients underwent three times of intratympanic dexamethasone injection with one-week intervals. We performed cervical vestibular evoked myogenic potential test at first and four weeks after the last injection for all participants. We followed the patients for one year. The study results were analyzed with the chi-square test. Cervical vestibular evoked myogenic potential test could not be recorded in 26 patients (83.9%), and the test results were abnormal in the remaining 5 patients. The results were abnormal in the healthy ear of 32.3% of the patients. Despite the clinical improvement of the symptoms after intratympanic injection, the test results were not changed. Cervical vestibular evoked myogenic potential test could not be recorded in the majority of the patients with Meniere's disease; while it is usually recorded in normal ears. On the other hand, results of the cervical vestibular evoked myogenic potential test do not change during the early phase after treatment and could not be a good option for follow up and evaluating the response in this situation.

Effect of caffeine on vestibular evoked myogenic potential: a systematic review with meta-analysis.

INTRODUCTION: Caffeine can be considered the most consumed drug by adults worldwide, and can be found in several foods, such as chocolate, coffee, tea, soda and others. Overall, caffeine in moderate doses, results in increased physical and intellectual productivity, increases the capacity of concentration and reduces the time of reaction to sensory stimuli. On the other hand, high doses can cause noticeable signs of mental confusion and error induction in intellectual tasks, anxiety, restlessness, muscle tremors, tachycardia, labyrinthine changes, and tinnitus. OBJECTIVE: Considering that the vestibular evoked myogenic potential is a clinical test that evaluates the muscular response of high intensity auditory stimulation, the present systematic review aimed to analyze the effects of caffeine on vestibular evoked myogenic potential. METHODS: This study consisted of the search of the following databases: MEDLINE, CENTRAL, ScienceDirect, Scopus, Web of Science, LILACS, SciELO and ClinicalTrials.gov. Additionally, the gray literature was also searched. The search strategy included terms related to intervention (caffeine or coffee consumption) and the primary outcome (vestibular evoked myogenic potential). RESULTS: Based on the 253 potentially relevant articles identified through the database search, only two full-text publications were retrieved for further evaluation, which were maintained for qualitative analysis. CONCLUSION: Analyzing the articles found, caffeine has no effect on vestibular evoked myogenic potential in normal individuals.

Effect of betel nut chewing on the otolithic reflex system.

OBJECTIVE: This study investigated the effect of betel nut chewing on the otolithic reflex system. METHODS: Seventeen healthy volunteers without any experience of chewing betel nut (fresh chewers) and 17 habitual chewers underwent vital sign measurements, ocular vestibular-evoked myogenic potential (oVEMP), and cervical VEMP (cVEMP) tests prior to the study. Each subject then chewed two pieces of betel nut for 2min (dosing). The same paradigm was repeated immediately, 10min, and 20min after chewing. On a different day, 10 fresh chewers masticated chewing gum as control. RESULTS: Fresh chewers exhibited significantly decreased response rates of oVEMP (53%) and cVEMP (71%) after dosing compared with those from the predosing period. These abnormal VEMPs returned to normal 20min after dosing. In contrast, 100% response rates of oVEMP and cVEMP were observed before and after masticating chewing gum. In habitual chewers, the response rates of oVEMP and cVEMP were 32% and 29%, respectively, 20min after dosing. CONCLUSION: Chewing betel nuts induced a transient loss of the otolithic reflexes in fresh chewers but may cause permanent loss in habitual chewers. SIGNIFICANCE: Chewing betel nuts can cause a loss of otholitic reflex function. This creates a risk for disturbed balance and malfunction, for instance, during driving.

Refractory episodic vertigo: role of intratympanic gentamicin and vestibular evoked myogenic potentials / Vertigem refratária episódica: papel da gentamicina intratimpânica e potencial evocado miogênico vestibular

Abstract Introduction: Even today, the treatment of intractable vertigo remains a challenge. Vestibular ablation with intratympanic gentamicin stands as a good alternative in the management of refractory vertigo patients. Objective: To control intractable vertigo through complete saccular and horizontal canal vestibular ablation with intratympanic gentamicin treatment. Methods: Patients with refractory episodic vertigo were included. The inclusion criteria were: unilateral ear disease, moderate to profound sensorineural hearing loss, and failure to other treatments. Included patients underwent 0.5-0.8 mL of gentamicin intratympanic application at a 30 mg/mL concentration. Vestibular ablation was confirmed by the absence of response on cervical vestibular evoked myogenic potentials and no response on caloric tests. Audiometry, electronystagmography with iced water, and vestibular evoked myogenic potentials were performed in all patients. Results: Ten patients were included; nine patients with Meniere's disease and one patient with (late onset) delayed hydrops. Nine patients showed an absent response on vestibular evoked myogenic potentials and no response on caloric tests. The only patient with low amplitude on cervical vestibular evoked myogenic potentials had vertigo recurrence. Vertigo control was achieved in 90% of the patients. One patient developed hearing loss >30 dB. Conclusions: Cervical vestibular evoked myogenic potentials confirmed vestibular ablation in patients treated with intratympanic gentamicin. High-grade vertigo control was due to complete saccular and horizontal canal ablation (no response to iced water in electronystagmography and no response on cervical vestibular evoked myogenic potentials).

Resumo Introdução: Ainda hoje, o controle da vertigem intratável permanece um desafio. A ablação vestibular com gentamicina intratimpânica permanece como uma boa alternativa no tratamento de pacientes com vertigem refratária. Objetivo: Controlar a vertigem intratável por meio de ablação vestibular completa dos canais sacular e horizontal com gentamicina intratimpânica como tratamento. Método: Pacientes com vertigem refratária episódica foram incluídos. Os critérios de inclusão foram doença unilateral da orelha, perda auditiva neurossensorial de moderada a profunda e fracasso com outros tratamentos. Os pacientes incluídos receberam uma aplicação de 0,5-0,8 mL de gentamicina intratimpânica com concentração de 30 mg/mL. A ablação vestibular foi confirmada pela ausência de resposta no teste de potencial evocado miogênico vestibular cervical (PEMVc) e nenhuma resposta nas provas calóricas. Audiometria, eletronistagmografia com água gelada e potencial evocado miogênico vestibular foram realizados em todos os pacientes. Resultados: Ao todo, dez pacientes foram incluídos: nove com doença de Ménière e um com hidropisia tardia. Nove pacientes apresentaram ausência de resposta no teste de potencial evocado miogênico vestibular e nenhuma resposta na prova calórica. O único paciente com baixa amplitude no PEMVc apresentou recorrência da vertigem. O controle da vertigem foi obtido em 90% dos pacientes. Um paciente desenvolveu perda auditiva > 30 dB. Conclusões: O PEMVc confirmou ablação vestibular nos pacientes tratados com gentamicina intratimpânica. O alto grau de controle da vertigem foi devido à ablação completa do sáculo e canal horizontal (sem resposta à água gelada na eletronistagmografia e ausência de resposta no PEMVc).

Refractory episodic vertigo: role of intratympanic gentamicin and vestibular evoked myogenic potentials.

INTRODUCTION: Even today, the treatment of intractable vertigo remains a challenge. Vestibular ablation with intratympanic gentamicin stands as a good alternative in the management of refractory vertigo patients. OBJECTIVE: To control intractable vertigo through complete saccular and horizontal canal vestibular ablation with intratympanic gentamicin treatment. METHODS: Patients with refractory episodic vertigo were included. The inclusion criteria were: unilateral ear disease, moderate to profound sensorineural hearing loss, and failure to other treatments. Included patients underwent 0.5-0.8mL of gentamicin intratympanic application at a 30mg/mL concentration. Vestibular ablation was confirmed by the absence of response on cervical vestibular evoked myogenic potentials and no response on caloric tests. Audiometry, electronystagmography with iced water, and vestibular evoked myogenic potentials were performed in all patients. RESULTS: Ten patients were included; nine patients with Meniere's disease and one patient with (late onset) delayed hydrops. Nine patients showed an absent response on vestibular evoked myogenic potentials and no response on caloric tests. The only patient with low amplitude on cervical vestibular evoked myogenic potentials had vertigo recurrence. Vertigo control was achieved in 90% of the patients. One patient developed hearing loss >30dB. CONCLUSIONS: Cervical vestibular evoked myogenic potentials confirmed vestibular ablation in patients treated with intratympanic gentamicin. High-grade vertigo control was due to complete saccular and horizontal canal ablation (no response to iced water in electronystagmography and no response on cervical vestibular evoked myogenic potentials).

Assessment of D-methionine protecting cisplatin-induced otolith toxicity by vestibular-evoked myogenic potential tests, ATPase activities and oxidative state in guinea pigs.

To date, inadequate study has been devoted to the toxic vestibular effects caused by cisplatin. In addition, no electrophysiological examination has been conducted to assess cisplatin-induced otolith toxicity. The purposes of this study are thus two-fold: 1) to determine whether cervical vestibular-evoked myogenic potentials (VEMPs) and ocular VEMPs are practical electrophysiological methods of testing for cisplatin-induced otolith toxicity and 2) to examine if D-methionine (D-met) pre-injection would protect the otolith organs against cisplatin-induced changes in enzyme activities and/or oxidative status. Guinea pigs were intraperitoneally treated once daily with the following injections for seven consecutive days: sterile 0.9% saline control, cisplatin (5 mg/kg) only, D-met (300 mg/kg) only, or a combination of d-met (300 mg/kg) and cisplatin (5 mg/kg), respectively, with a 30 minute window in between. Each animal underwent the oVEMP and cVEMP tests before and after treatment. The changes in the biochemistry of the otolith organs, including membranous Na(+), K(+)-ATPase and Ca(2+)-ATPase, lipid peroxidation (LPO) levels and nitric oxide (NO) levels, were also evaluated. In the cisplatin-only treated guinea pigs, the mean amplitudes of the oVEMP tests were significantly (p<0.05) decreased when compared to the other three groups. In guinea pigs receiving both D-met and cisplatin, the amplitudes of their oVEMP tests were significantly larger (p<0.05) than those of the cisplatin-only group, but smaller (p<0.05) than those of the saline control or D-met-only group. However, no significant difference of the amplitudes of cVEMP tests was noted among the four groups. In comparison with the other three groups, the cisplatin-only group had the lowest (ps<0.05) mean Na(+), K(+)-ATPase and Ca(2+)-ATPase, and the highest (ps<0.05) LPO and NO levels. The oVEMP tests were feasible for the evaluation of cisplatin-related otolith dysfunction. D-Met attenuated the reduced ATPase activities and increased oxidative stress induced by cisplatin toxicity in the otolith organs.

Glycerol affects vestibular-evoked myogenic potentials and pure-tone hearing in patients with Ménière's disease.

CONCLUSION: The pure-tone audiometry results following glycerol administration indicated a positive effect on cochlear endolymphatic hydrops. Glycerol cervical vestibular-evoked myogenic potential (cVEMP) tests are a useful means of diagnosing saccular hydrops. There was no correlation between cVEMP and audiological results. OBJECTIVE: To document the changes in pure-tone hearing outcomes and cVEMPs in patients with Ménière's disease (MD) and 10 healthy volunteers before and after oral administration of glycerol. METHODS: Twenty-nine study group subjects were chosen with complaints of vertigo. cVEMP testing and pure-tone hearing level testing were performed before and at 1, 2, and 3 h after administration of glycerol. RESULTS: The means of the latencies, amplitudes, and difference ratio in 20 normal subject ears were determined. Based on these values, 9/29 MD-affected (MDA) ears (31%) had a unilaterally absent cVEMP. Compared with difference ratio values of the control groups there were significant differences in both latencies and amplitudes in MDA ears after glycerol administration. Before glycerol administration, there were significant differences between control and MDA ears on mean values of pure-tone hearing outcomes. Twenty patients in the MDA group showed significant pure-tone hearing outcomes after glycerol administration.

Mechanisms of sharp wave initiation and ripple generation.

Replay of neuronal activity during hippocampal sharp wave-ripples (SWRs) is essential in memory formation. To understand the mechanisms underlying the initiation of irregularly occurring SWRs and the generation of periodic ripples, we selectively manipulated different components of the CA3 network in mouse hippocampal slices. We recorded EPSCs and IPSCs to examine the buildup of neuronal activity preceding SWRs and analyzed the distribution of time intervals between subsequent SWR events. Our results suggest that SWRs are initiated through a combined refractory and stochastic mechanism. SWRs initiate when firing in a set of spontaneously active pyramidal cells triggers a gradual, exponential buildup of activity in the recurrent CA3 network. We showed that this tonic excitatory envelope drives reciprocally connected parvalbumin-positive basket cells, which start ripple-frequency spiking that is phase-locked through reciprocal inhibition. The synchronized GABA(A) receptor-mediated currents give rise to a major component of the ripple-frequency oscillation in the local field potential and organize the phase-locked spiking of pyramidal cells. Optogenetic stimulation of parvalbumin-positive cells evoked full SWRs and EPSC sequences in pyramidal cells. Even with excitation blocked, tonic driving of parvalbumin-positive cells evoked ripple oscillations. Conversely, optogenetic silencing of parvalbumin-positive cells interrupted the SWRs or inhibited their occurrence. Local drug applications and modeling experiments confirmed that the activity of parvalbumin-positive perisomatic inhibitory neurons is both necessary and sufficient for ripple-frequency current and rhythm generation. These interneurons are thus essential in organizing pyramidal cell activity not only during gamma oscillation, but, in a different configuration, during SWRs.

Effect of caffeine on cervical vestibular-evoked myogenic potential in healthy individuals.

INTRODUCTION: Caffeine is the most common psychoactive drug in use around the world and is found at different concentrations in a variety of common food items. Clinically, a strong association between caffeine consumption and diseases of the vestibular system has been established. Cervical vestibular-evoked myogenic potential (cVEMP) is an electrophysiological test that is used to assess the sacculocollic pathway by measuring changes in the vestialibulocollic reflex. AIM: The present study aimed to evaluate the effect of an acute dose of caffeine on the vestibulocollic reflex by using cVEMP. METHOD: A prospective experimental study was performed in which healthy volunteers were submitted to the test before and after the intake of 420 mg of caffeine. The following parameters were compared: p13 and n23 latencies and p13-n23 amplitude. RESULT: No statistically significant difference was found in the test results before and after caffeine use. CONCLUSION: The vestibulocollic reflex is not altered by caffeine intake.

The influence of caffeine on calorics and cervical vestibular evoked myogenic potentials (cVEMPs).

BACKGROUND: Prior to undergoing vestibular function testing, it is not uncommon for clinicians to request that patients abstain from caffeine 24 hr prior to the administration of the tests. However, there is little evidence that caffeine affects vestibular function. PURPOSE: To evaluate whether the results from two tests commonly used in a clinical setting to assess vestibular function (i.e., calorics and the cervical vestibular evoked myogenic potential [cVEMP]) are affected by caffeine. RESEARCH DESIGN: Subjects were tested with and without consuming a moderate amount of caffeine prior to undergoing calorics and cVEMPs. STUDY SAMPLE: Thirty young healthy controls (mean = 23.28 yr; females = 21). Subjects were excluded if they reported any history of vestibular/balance impairment. DATA COLLECTION AND ANALYSIS: The Variotherm Plus Caloric Irrigator was used to administer the water, while the I-Portal VNG software was used to collect and analyze subjects' eye movements. The TECA Evoked Potential System was used for the cVEMP stimulus presentation as well as for the data collection. During cVEMP collection, subjects were asked to monitor their sternocleidomastoid muscle contraction with a Delsys EMG monitor. IBM SPSS Statistics 20 was used to statistically analyze the results via paired t-tests. RESULTS: Analysis of the data revealed that ingestion of caffeine did not significantly influence the results of either test of vestibular function. CONCLUSIONS: The results revealed that a moderate amount of caffeine does not have a clinically significant effect on the results from caloric and cVEMP tests in young healthy adults. Future research is necessary to determine whether similar results would be obtained from individuals with a vestibular impairment, as well as older adults.

Effect of caffeine on cervical vestibular-evoked myogenic potential in healthy individuals / O efeito da cafeína no potencial evocado miogênico vestibular cervical em indivíduos saudáveis

INTRODUCTION: Caffeine is the most common psychoactive drug in use around the world and is found at different concentrations in a variety of common food items. Clinically, a strong association between caffeine consumption and diseases of the vestibular system has been established. Cervical vestibular-evoked myogenic potential (cVEMP) is an electrophysiological test that is used to assess the sacculocollic pathway by measuring changes in the vestialibulocollic reflex. AIM: The present study aimed to evaluate the effect of an acute dose of caffeine on the vestibulocollic reflex by using cVEMP. METHOD: A prospective experimental study was performed in which healthy volunteers were submitted to the test before and after the intake of 420 mg of caffeine. The following parameters were compared: p13 and n23 latencies and p13-n23 amplitude. RESULT: No statistically significant difference was found in the test results before and after caffeine use. CONCLUSION: The vestibulocollic reflex is not altered by caffeine intake. .

INTRODUÇÃO: A cafeína é a droga psicoativa mais consumida no mundo e está contida, em diferentes concentrações, em diversos alimentos consumidos no dia a dia. Clinicamente, nota-se um envolvimento importante do seu consumo com as doenças do sistema vestibular. O VEMP cervical é um exame eletrofisiológico que avalia a via sáculo-cólica, determinando alterações no reflexo vestíbulo-cólico. OBJETIVO: O objetivo deste trabalho é avaliar a interferência do uso agudo de cafeína no reflexo vestíbulo-cólico através do cVEMP. MÉTODO: Foi realizado um estudo experimental prospectivo, no qual voluntários saudáveis se submeteram ao exame antes e depois do uso de 420 mg de cafeína, sendo comparados os seguintes parâmetros: latência de p13 e de n23 e interamplitude p13-n23. RESULTADO: Após a comparação dos dados não houve diferença estatisticamente significante entre os exames antes e após o uso da droga. CONCLUSÃO: Não foi observada influência da cafeína no reflexo vestíbulo-cólico. .

The effect of alcohol on cervical and ocular vestibular evoked myogenic potentials in healthy volunteers.

OBJECTIVE: We investigated the effect of alcohol on the cervical and ocular vestibular evoked myogenic potentials (cVEMPs and oVEMPs). As alcohol produces gaze-evoked nystagmus (GEN), we also tested the effect of nystagmus independent of alcohol by recording oVEMPs during optokinetic stimulation (OKS). METHODS: The effect of alcohol was tested in 14 subjects over multiple rounds of alcohol consumption up to a maximum breath alcohol concentration (BrAC) of 1.5‰ (mean 0.97‰). The effect of OKS was tested in 11 subjects at 5, 10 and 15deg/sec. RESULTS: oVEMP amplitude decreased from baseline to the highest BrAC level by 27% (range 5-50%, P<0.001), but there was no significant effect on oVEMP latency or cVEMP amplitude or latency. There was a significant negative effect of OKS on oVEMP amplitude (16%, P=0.006). CONCLUSIONS: We found a selective effect of alcohol on oVEMP amplitude, but no effect on the cVEMP. Vertical nystagmus elicited by OKS reduced oVEMP amplitude. SIGNIFICANCE: Alcohol selectively affects oVEMP amplitude. Despite the effects of alcohol and nystagmus, both reflexes were reliably recorded in all subjects and conditions. An absent response in a patient affected by alcohol or nystagmus indicates a vestibular deficit.

[On the mechanism of ikaron-1 anti-naupathia action].

Pneumomicroinjection of vestibuloprotector ikaron-1 (Russia) in specific neurons of the medial vestibular nucleus (MVN) was studied in cats immobilized by muscle relaxants using microelectrode devices. The original preparation had a direct effect on the majority of MVN neurons (95 %). Thirty four neurons of 37 cells (92 %) developed an inhibitory response, only one cell (3 %) was activated and 2 neurons (5 %) were areactive. Therefore, the inhibitory reaction to the preparation was 34 times more often than excitatory. An investigation of the MVN neurons activity evoked by adequate stimulation of the vestibular apparatus showed that ikaron-1 attenuates the evoked response in 92 % cells. This phenomenon could be behind the ikaron-lantinaupathia action.

Hearing loss and vestibular dysfunction among children with cancer after receiving aminoglycosides.

BACKGROUND: Children undergoing cancer therapy often receive aminoglycosides to treat febrile neutropenia or gram-negative infections. The magnitude of the risk of developing aminoglycoside-induced ototoxicity and the dose threshold at which that risk significantly increases are unknown. PROCEDURE: Eligible cancer patients received the aminoglycoside amikacin at Children's Medical Center between 2004 and 2007. They were aged 3-8 years; were without prior hearing loss; had no platinum-based chemotherapy, cranial radiation, nor bone marrow transplant; and received no loop diuretics within 6 weeks of testing. Consenting patients underwent complete hearing and vestibular testing. RESULTS: We tested 23 patients who had significant amikacin exposure. Three (13%) had abnormal hearing tests, and four (17%) had subclinical vestibular dysfunction; none had both. Of those with hearing loss, two were known to have developed hearing loss after aminoglycoside exposure, but the third had moderate to severe high-frequency sensorineural hearing loss bilaterally that had been undiagnosed. We observed clear dose-dependent ototoxicity; of the eight patients who received amikacin for a cumulative total of more than 50 days, five (68%) developed toxicity. Similarly, of the seven who received a cumulative total of more than 1,200 mg/kg, five developed toxicity. CONCLUSIONS: These data highlight the risks of prolonged aminoglycoside administration and warrant further validation in a larger group of patients. Patients to be treated with prolonged aminoglycoside therapy may benefit from prospective hearing screening.

Effects of acute administration of ketorolac on mammalian vestibular sensory evoked potentials.

The nonsteroidal antiinflammatory drug (NSAID) ketorolac is a candidate for use as a supplemental analgesic during major surgery in anesthetized rodents. The use of ketorolac during surgery is believed to reduce the anesthetic dose required to achieve and maintain an adequate surgical plane, thus improving the physiologic condition and survival of animals during long experimental procedures. Ketorolac has reported side effects that include dizziness, ear pain, hearing loss, tinnitus, and vertigo in humans, but ketorolac has not been reported to affect the vestibular system in animals. To investigate this possibility, we evaluated the acute effects of ketorolac on vestibular compound action potentials in C57BL/6 mice. Linear vestibular sensory-evoked potentials (VsEP) were recorded during the administration of ketorolac at doses 3 to 14 times the effective analgesic dose. VsEP results for ketorolac were compared with those from a control group maintained under anesthesia for the same period. Ketorolac did not significantly affect the temporal profiles of response latencies and amplitudes or the rate of change in response measures over time between controls and ketorolac-treated mice. These findings demonstrate that ketorolac can be used as an analgesic to supplement anesthesia in mice without concerns of modifying the amplitudes and latencies of the linear VsEP.

Effect of standard-dose Betahistine on endolymphatic hydrops: an MRI pilot study.

This study aimed to assess whether standard-dose Betahistine (48 mg daily) exerts an effect upon the degree of endolymphatic hydrops in patients with Menière's disease using a retrospective case series in the setting of a tertiary neurotology referral centre. In six patients with definite unilateral Menière's disease, the degree of cochlear and vestibular endolymphatic hydrops was assessed before and after treatment with a standard dose of Betahistine (48 mg daily), using high-resolution 3 T MR imaging after intratympanic contrast medium application. The treatment duration was 3-7 months (mean 5 months), and the patients were followed-up for 6-29 months (mean 11 months). In the study cohort, the standard dose of Betahistine did not have an MR morphologically measurable beneficial effect on the degree of endolymphatic hydrops. The results indicated no effect of standard-dose Betahistine on endolymphatic hydrops found on high-resolution MR imaging. Possible explanations are: (1) insufficient dosage or duration of treatment with betahistine, (2) insufficient resolution of the MR imaging technique, and (3) insufficient length of follow-up. Further studies addressing these issues are warranted.

Furosemide-loading vestibular evoked myogenic potential testing can suggest developing bilateral involvement of unilateral Meniere's disease.

CONCLUSIONS: Patients with positive results of furosemide-loading vestibular evoked myogenic potential (F-VEMP) testing in the unaffected ears of unilateral Meniere's disease have a high incidence of developing bilateral lesions. OBJECTIVE: To clarify the meaning of positive results of F-VEMP testing of the unaffected ear of patients with unilateral Meniere's disease. METHODS: Twenty-five patients with unilateral Meniere's disease were investigated in this study. The positive group consisted of 6 patients with positive results of F-VEMP testing in the contralateral ear and the negative group consisted of 19 patients with negative results. The incidence of contralateral involvement was compared in both groups by the Kaplan-Meier method. RESULTS: Contralateral involvement was seen in three cases (50%) in the positive group after 2, 12, and 26 months and in three cases (16%) in the negative group after 27, 56, and 78 months. The positive group had a higher incidence of contralateral involvement than the negative group (p = 0.0017, according to a log-rank test).