Long-term prophylactic treatment of attacks of vertigo in Menière's disease--comparison of a high with a low dosage of betahistine in an open trial

Effects of high-dose betahistine on intractable dizziness in patients with uncompensated unilateral vestibulopathy

OBJECTIVE

In the present study, we examined the effects of high-dose betahistine on dizziness handicap inventory (DHI) scores in patients with unilateral vestibulopathy.

METHODS

An uncontrolled, open-label, multicenter clinical trial was conducted. Fifteen patients with unilateral vestibulopathy, such as vestibular neuritis, who complained of intractable dizziness for more than three months were enrolled. Initially, all patients were orally administered betahistine at a dose of 36 mg/day for four weeks, which is the standard dose and dosing period for the treatment of dizziness in Japan. The patients were then administered betahistine at a double dose of 72 mg/day for four weeks. Six patients who became aware of the benefits of high-dose betahistine were further administered betahistine at 72 mg/day for an additional 12 weeks (a total of 16 weeks). Perceived disability due to dizziness was assessed by DHI scores.

RESULTS

In all 15 patients, short-term administration with high-dose (72 mg/day) betahistine for four weeks, but not low-dose betahistine (36 mg/day) for four weeks significantly decreased DHI scores. In particular, in six responding patients with self-reported benefits after short-term administration with high-dose betahistine, long-term administration with high-dose betahistine for 16 weeks further significantly decreased DHI scores. However, DHI scores of the remaining nine non-responding patients were not changed after short-term administration with high-dose betahistine for four weeks.

CONCLUSION

Short-term administration with the standard dose and dosing period of betahistine did not improve DHI scores in the enrolled patients, indicating that they were not compensated for unilateral vestibulopathy with intractable dizziness. The present findings suggest that long-term administration with high-dose betahistine facilitates vestibular compensation to improve intractable dizziness in some, but not all patients with uncompensated unilateral vestibulopathy.

Effects of Betahistine on Vestibulo-Ocular Reflex in Normal Healthy Adults: A Randomized Double-Blind, Placebo-Controlled Trial

Introduction

Vertigo, or the perception of a spinning sensation, is a common symptom experienced by patients who are referred to Otorhinolaryngology clinics. Betahistine is a medication that has been widely used to treat vertigo and its accompanying symptoms. However, the effects of this medication on the vestibulo-ocular reflex (VOR) are still unknown. Initially, it was assumed that betahistine should be discontinued prior to any vestibular tests, particularly the video head impulse test (vHIT).

Method

Thirty young healthy adults were randomly divided into two equal groups for this randomized double-blind clinical study (betahistine 24 mg and placebo). Baseline pure-tone audiometry (PTA), tympanometry, and VOR measurements were taken, followed by experimental measurements at one hour, four hours, eight hours, and 24 hours after consumption. The video head impulse test (vHIT) was used to determine the VOR.

Result

Betahistine had no statistically significant effect on vestibulo-ocular reflex gain (F(4,140) = 0.601, p = 0.662). The gain variability across repetitive head impulses remained constant over time.

Conclusions

Betahistine has no effect on the vestibulo-ocular reflex. As a result, this medication can be taken prior to the vHIT procedure.

[Betahistine in vestibular disorders: current concepts and perspectives]

The goal of this paper is to review the pharmacological profile of betahistine and evidence for using it in the treatment of common vestibular disorders. Betahistine is a weak agonist for histamine H1 receptors and strong antagonist for histamine H3 receptors. It demonstrates the maximum benefit in different types of peripheral vertigo, especially in Meniere's disease. The best results in decreasing intensity of vertigo, frequency of attacks and stimulation of vestibular compensation were obtained in daily dose 48 mg during 3 months. In benign paroxysmal positional vertigo betahistine is used to treat residual dizziness after successful treatment of otolithiasis and to reduce the severity of vertigo during repositioning maneuvers. In vestibular neuritis betahistine stimulates central compensation during vestibular rehabilitation. A new once-daily drug formulation of modified-release betahistine is non-inferior to traditional and has a comparable safety profile, and could improve patient adherence. The implication of betahistine in the treatment of central vestibular disorders is under-researched. The efficacy of betahistine in increasing of vestibular compensation in post-stroke central vestibular disorders, persistent postural-perceptual dizziness and its role in vestibular migraine need further investigation.

In Vitro Physiological Effects of Betahistine on Cell Lines of Various Origins

Objectives

Betahistine is a histamine analog commonly prescribed for symptomatic treatment of vertiginous symptoms. In vitro studies have shown that betahistine was not toxic at the prescribed doses in a nasal epithelial cell line. However, the effect of betahistine on other cell types has not been studied. In this study, we aimed to investigate some of the physiological effects of betahistine on L929 fibroblast, A549 lung cancer, human umbilical vein endothelial (HUVEC), and Ishikawa endometrial cell lines.

Materials and Methods

Cellular proliferation was assed assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, apoptosis was evaluated by acridine orange-ethidium bromide staining, and cellular migration was assed assessed by scratch assay.

Results

Betahistine treatment (0.1-0.5 mg/mL, 24 hours) can inhibit cell proliferation and induce apoptosis in HUVEC, A549, Ishikawa, and L929 cell lines. Betahistine (≥0.1 mg/mL) significantly increased the number of apoptotic cells (HUVEC: 26.3%, A549: 17.3%, L929: 8.6%, and Ishikawa: 2.3%). Betahistine at doses over 0.1 mg/mL significantly suppressed the cell migration rate in all of the cell lines. In contrast, exposure to a low dose of betahistine (0.025 mg/mL) induced migration rates of HUVEC and Ishikawa cells by 81% and 48%, respectively.

Conclusion

Betahistine may alter the processes of cellular proliferation, apoptosis, and cellular migration in a cell line- and dose-dependent manner. In this sense, proliferative and metastatic properties of certain cancer cells can potentially be altered in response to betahistine treatment.

Effects of Betahistine on the Development of Vestibular Compensation after Unilateral Labyrinthectomy in Rats

Background: Vestibular compensation (VC) after unilateral labyrinthectomy (UL) consists of the initial and late processes. These processes can be evaluated based on the decline in the frequency of spontaneous nystagmus (SN) and the number of MK801-induced Fos-positive neurons in the contralateral medial vestibular nucleus (contra-MVe) in rats. Histamine H3 receptors (H3R) are reported to be involved in the development of VC. Objective: We examined the effects of betahistine, an H3R antagonist, on the initial and late processes of VC in UL rats. Methods: Betahistine dihydrochloride was continuously administered to the UL rats at doses of 100 and 200 mg/kg/day using an osmotic minipump. MK801 (1.0 mg/kg) was intraperitoneally administered on days 7, 10, 12, and 14 after UL, while Fos-positive neurons were immunohistochemically stained in the contra-MVe. Results: The SN disappeared after 42 h, and continuous infusion of betahistine did not change the decline in the frequency of SN. The number of MK801-induced Fos-positive neurons in contra-MVe significantly decreased on days 7, 10, and 12 after UL in a dose-dependent manner in the betahistine-treated rats, more so than in the saline-treated rats. Conclusion: These findings suggest that betahistine facilitated the late, but not the initial, process of VC in UL rats.

Diagnostic and therapeutic strategies for Meniere's disease of the Japan Society for Equilibrium Research

OBJECTIVE

We provided diagnostic and therapeutic strategies for Meniere's disease in accordance with Japanese Clinical Practice Guideline of Meniere's disease and delayed endolymphatic hydrops 2nd ed. Tokyo: Kanehara Shuppan; 2020 edited by the Japan Society for Equilibrium Research.

METHODS

The Committee for Clinical Practice Guidelines was entrusted with a review of the scientific literature on the above topic. Clinical Questions (CQs) concerning the treatment for Meniere's disease were produced, and the literature according to each of them including CQ was searched. The recommendations are based on the literature review and the expert opinion of a subcommittee.

RESULTS

Diagnosis criteria of Meniere's disease are classified into Meniere's disease with typical cochlear and vestibular symptoms, and atypical Meniere's disease with either cochlear symptoms or vestibular symptoms. Treatment of Meniere's disease was composed of lifestyle changes, medications such as anti-vertigo drugs and diuretics, middle ear positive pressure treatment, and selective destruction of the vestibule.

CONCLUSION

Meniere's disease is diagnosed based on clinical histories and examination findings after processes of differential diagnosis. Treatment option of the disease should be selected in order of invasiveness, according to the severity of the disease and the response to each treatment.

Conservative Treatment Possibilities of Ménière Disease, Involving Vertigo Diaries

Ménière disease is a disorder of the inner ear, characterized by rotational vertigo, hearing loss, tinnitus, and vegetative symptoms. The aim of the present research is to examine the effectiveness of betahistine and piracetam in the reduction of vertigo attacks in Ménière disease. To verify our hypothesis, 105 (31 male and 74 females, mean age [standard deviation], 57.4 [11.05]) adult patients with definite Ménière disease were enrolled in this investigation. Beside the analysis of the hospital records, the subjective complaints of the patients and the completed vertigo diaries were taken into consideration too. The statistical analysis was completed using the IBM SPSS version 24 software. Retrospective analysis, including a 12 years period was conducted. Based on our results, betahistine was successful in the reduction of attacks. Statistically significant decrease was achieved in frequency of dizziness (P = .000331) and vertigo (P < .00001) and in the duration of them (P = .000098), although in the mean power of them was not (P = .0887). The mean dose in the symptomatic treatment was determined as 87.5 ± 27.2 mg per day; however, there was no connection detected between the dose of the agent and the effectiveness of the symptomatic control. By using dual therapy (betahistine and piracetam), vertigo episodes appeared significantly less often (P = .027, Odds ratio: 4.9, 95% confidence interval: 1.2-20.2). Finally, it can be concluded that betahistine is effective in Ménière disease, but the daily dose of it should be set up for every patient individually. The advantage of the dual therapy was also confirmed.

Prediction of Unilateral Meniere's Disease Attack Using Inner Ear Test Battery

OBJECTIVES

In the clinical setting, a variety of inner ear test results are obtained from patients with unilateral Meniere's disease (MD). In this study, the authors use inner ear test results as parameters to illustrate the relationship between inner ear function and vertigo attack frequency.

DESIGN

We retrospectively enrolled 50 unilateral MD patients. In addition to clinical symptoms, the results of pure-tone audiometry and caloric, acoustic cervical vestibular-evoked myogenic potential (cVEMP), galvanic cVEMP, vibratory ocular VEMP (oVEMP), and galvanic oVEMP tests were collected via chart review. The multiple linear regression method was used to examine which independent variables have a statistically significant influence on vertigo attacks.

RESULTS

In affected ears, the abnormal rate of the caloric, acoustic cVEMP, galvanic cVEMP, vibratory oVEMP, and galvanic oVEMP tests was 74%, 76%, 48%, 34%, and 30%, respectively. According to the regression model, the abnormal galvanic cVEMP response and abnormal galvanic oVEMP response had significantly negative correlations with the frequency of vertigo attacks after logarithmic transformation. A predictive model for disease attack frequency using significant parameters and their regression coefficients was proposed: (Equation is included in full-text article.) CONCLUSIONS:: Using the proposed model with galvanic VEMP, clinicians could develop better strategies to manage vertigo attacks in patients with MD.

Betahistine in the Treatment of Peripheral Vestibular Vertigo: Results of a Real-Life Study in Primary Care

The present research was carried out with the objective to establish the clinical effect and safety of betahistine (48 mg daily), for the management of peripheral vestibular vertigo, in patients treated by primary care physicians in Colombia. An observational prospective cohort study was conducted including patients older than 15 years with clinical diagnosis of peripheral vestibular vertigo who were candidates to be treated with betahistine (48 mg daily). A sample size of 150 individuals was calculated, and weekly follow-ups were planned for 12 weeks. Rotatory movement sensation, loss of balance, and global improvement scale from 0 to 100 points were evaluated. Complete improvement was defined when the patient reached a level of 100 points. We calculated average weekly improvement, cumulative incidence of complete improvement, incidence rate of complete improvement, and the probability of complete improvement as a function of time. After the first week, the average improvement was 56.6 points (95% confidence interval [CI]: 50.4-62.7). At the end of week 12, it was 89.3 points (95% CI: 86.5-92.2). Sixty-one percent of the patients had achieved complete improvement at the end of the second week. After the sixth week, the percentage of cumulative improvement was 72%, and after 12 weeks of follow-up, the cumulative incidence of complete improvement was 73% (95% CI: 65%-80%). Based on the follow-up times, a complete improvement incidence rate of 16 cases per 100 people/week was calculated (95% CI: 13-19). We concluded that Betahistine (48 mg daily) has a positive effect, controlling the symptoms associated with benign paroxysmal vertigo, with an adequate safety profile.

The Vestibular System and Ageing

The world's population is ageing due to increased hygiene and improved medical care. Dizziness and imbalance frequently affect the elderly and is most common among individuals over the age of 60. In this age group approximately 30% of the population experience these debilitating symptoms at some point. They contribute to falls and frailty, which often result in hospitalization causing tremendous cost for the health care systems, and increased mortality. To make the matters worse balance disorders are often complex. Physicians face the difficulty of diagnosing the patient with the exact disorder especially since each disorder may manifest differently in each patient. In addition, several treatment options exist, however, with a low level of evidence. This chapter summarizes the underlying degenerative processes of the peripheral as well as the central vestibular system, diagnostic tools, the most common balance disorders in the elderly, and possible treatment options of these disorders.

[In vitro equivalence evaluation of betahistine generic medicinal products as a tool potentially determining the efficacy of pharmacotherapy]

AIM

To compare release parameters of various betahistine drugs in vitro using a comparative dissolution kinetics test.

MATERIAL AND METHODS

Objects of research are solid dosage forms (tablets) containing betahistine in a dose of 24 mg permitted for medical use in the Russian Federation. A method of comparative dissolution kinetics test was carried out as follows. The study was performed on a paddle stirrer at a speed of 50 rpm in three different pH dissolution media (pH 1.2, 4.5, 6.8), simulating the main sections of the digestive tract in which the active ingredient was decomposed, released and absorbed. This was performed in a quality controlled environment using a citrate buffer solution with pH 6.8. The time points for sampling the medium were 10 min, 15 min, 20 min and 30 min.

RESULTS

The results of betahistine release were significant (RSD<10%) for all time points, except the first time point (RSD<20%). Regardless of pH, there was a complete release (≥85% over 15 minutes, <10%) of betahistine from betaserc, 24 mg, tablets (manufactured by Mylan Laboratories SAS). The dissolution profiles of betahistine in other investigational drugs did not show complete drug release (parameter <85% in 15 minutes, <10%) in different pH media. Therefore, dissolution profiles of the studied drugs were not comparable to the reference profile.

CONCLUSION

Starting from 10 minutes, the reference drug of betahistine (betaserc, 24 mg) has a consistently higher release at different pH levels (representing the various stages of gastric digestion), vs. other studied generic analogues showing significantly lower levels of betahistine release. None of the studied drugs were found to be equivalent in vitro.

Betahistine Treatment in a Cat Model of Vestibular Pathology: Pharmacokinetic and Pharmacodynamic Approaches

This study is a pharmacokinetic (PK) and pharmacodynamics (PD) approach using betahistine doses levels in unilateral vestibular neurectomized cats (UVN) comparable to those used in humans for treating patients with Menière's disease. The aim is to investigate for the first time oral betahistine administration (0.2 and 2 mg/kg/day) with plasma concentrations of betahistine and its major metabolite 2-pyridylacetic acid (2-PAA) (N = 9 cats), the time course of posture recovery (N = 13 cats), and the regulation of the enzyme synthesizing histamine (histidine decarboxylase: HDC) in the tuberomammillary nuclei (TMN) of UVN treated animals (N = the same 13 cats plus 4 negative control cats). In addition the effect of co-administration of the lower betahistine dose (0.2 mg/kg/day) and selegiline (1 mg/kg/day), an inhibitor of the monamine oxidase B (MAOBi) implicated in betahistine catabolism was investigated. The PK parameters were the peak concentration (C_max), the time when the maximum concentration is reached (T_max) for both betahistine and 2-PAA and the area under the curve (AUC). The PD approach consisted at quantifying the surface support area, which is a good estimation of posture recovery. The plasma concentration-time-profiles of betahistine and 2-PAA in cats were characterized by early C_max-values followed by a phase of rapid decrease of plasma concentrations and a final long lasting low level of plasma concentrations. Co administration of selegiline and betahistine increased values of C_max and AUC up to 146- and 180-fold, respectively. The lowest dose of betahistine (0.2 mg/kg) has no effects on postural function recovery but induced an acute symptomatic effect characterized by a fast balance improvement (4–6 days). The higher dose (2 mg/kg) and the co-administration treatment induced both this acute effect plus a significant acceleration of the recovery process. The histaminergic activity of the neurons in the TMN was significantly increased under treatment with the 2 mg/kg betahistine daily dose, but not with the lower dose alone or in combination with selegiline. The results show for the first time that faster balance recovery in UVN treated cats is accompanied with high plasma concentrations of betahistine and 2-PAA, and upregulation of HDC immunopositive neurons in the TMN. The higher betahistine dose gives results similar to those obtained with the lower dose when co-administrated with an inhibitor of betahistine metabolism, selegiline. From a clinical point of view, the study provides new perspectives for Menière's disease treatment, regarding the daily betahistine dose that should be necessary for fast and slow metabolizers.

[How to manage vertigo in adult?]

The interrogation and the clinical examination are critical in the research of vertigo etiology. In the context of vertigo, the vital emergencies are of neurological and vascular origins. It is therefore necessary to be able to identify them quickly and simply. Vertigo is a symptom to relieve and the cause is to be diagnosed. Careful questioning combined with neurological examination, nystagmus study, Halmagyi test and skew deviation search are more reliable than imaging in the first 48hours to detect a stroke. There are 12% false negatives in cerebral MRI and 74% false negative in cerebral CT-scan in the first 48hours of an ischemic stroke. Labyrinth emergencies are infectious labyrinthitis, perilymphatic fistula and aeroembolism of the vestibule.

Effectiveness of betahistine (48 mg/day) in patients with vestibular vertigo during routine practice: The VIRTUOSO study

Background

Vestibular vertigo is associated with substantially reduced quality of life. Betahistine is effective in improving vertigo-associated symptoms, with longer treatment periods leading to greater improvements; however, it is not known whether these effects persist after treatment cessation.

Methods

VIRTUOSO was a prospective, multinational, non-comparative, post-marketing observational programme investigating the effectiveness of betahistine (48 mg/day) and the course of vertigo after the discontinuation of treatment. Patients with vestibular vertigo who were prescribed 48 mg/day betahistine were enrolled in Russia and Ukraine. Treatment duration was up to 2 months, and patients were followed up for 2 months after discontinuation of betahistine. Efficacy endpoints included clinical response (assessed by change in vertigo severity), monthly attack frequency, and physician and patient grading of overall clinical response and improvement of vertigo-associated symptoms.

Results

Overall, 309 patients were enrolled and 305 completed the study. Clinical response was rated as good, very good or excellent in 74.1% of patients at end of treatment, with vertigo severity significantly decreased from baseline (p < 0.001). Monthly vertigo attack frequency decreased significantly during the 2 months of treatment (p < 0.001 from baseline) and further decreased during the 2-month follow-up (p < 0.001 from end of treatment). Overall, clinical response was graded as good or excellent by 94.4% of physicians and 95.4% of patients. Clinical improvement was considered either good or excellent by 82.6–90.5% of physicians and patients for nausea, vomiting and faintness. Only one adverse event was reported, with no serious adverse events.

Conclusion

Our findings suggest that betahistine (48 mg/day) therapy is effective in treating vertigo in routine clinical settings. The observed effects persisted for 2 months after treatment cessation, suggesting that betahistine may facilitate lasting vestibular compensation.

Evidence and evidence gaps of medical treatment of non-tumorous diseases of the head and neck

Unfortunately, the treatment of numerous otolaryngological diseases often lacks of evidence base because appropriate studies are missing.

Whereas sufficient high-quality trials exist for the specific immunotherapy of allergic rhinitis and in a limited measure also for the angiotensin-converting enzyme inhibitor induced angioedema, the evidence for Menière’s disease or for pharmacotherapy of postoperative laryngeal edema is rather poor. This contribution will discuss the trial situation and evidence of the respective diseases.

Zebrafish models of human eye and inner ear diseases

Eye and inner ear diseases are the most common sensory impairments that greatly impact quality of life. Zebrafish have been intensively employed to understand the fundamental mechanisms underlying eye and inner ear development. The zebrafish visual and vestibulo-acoustic systems are very similar to these in humans, and although not yet mature, they are functional by 5days post-fertilization (dpf). In this chapter, we show how the zebrafish has significantly contributed to the field of biomedical research and how researchers, by establishing disease models and meticulously characterizing their phenotypes, have taken the first steps toward therapies. We review here models for (1) eye diseases, (2) ear diseases, and (3) syndromes affecting eye and/or ear. The use of new genome editing technologies and high-throughput screening systems should increase considerably the speed at which knowledge from zebrafish disease models is acquired, opening avenues for better diagnostics, treatments, and therapies.

Treatment of Meniere's disease with intratympanic dexamethazone plus high dosage of betahistine

PURPOSE

The aim of the present study was to assess if the combined therapy of intratympanic dexamethasone (ITD) and high dosage of betahistine (HDBH) is able to provide increased vertigo control compared to ITD alone in patients suffering from definite unilateral Meniere's disease (MD).

MATERIALS AND METHODS

Consecutive MD patients were enrolled and randomly divided in two groups, each comprising 33 cases. Group A received a combination of ITD and identical-appearing placebo pills while Group B received a combination of ITD and HDBH. ITD protocol consisted of three consecutive daily injections. HDBH comprised 144mg/day (48mg tid). The main outcome measures were: 1) vertigo class, pure tone average (PTA), speech discrimination score (SDS) and Functional Level Score (FLS) according to the American Academy of Otolaryngology-Head and Neck Surgery criteria; 2) complete and substantial vertigo control according to the Kaplan-Meier survival method.

RESULTS

Sixty two patients completed the 24-month follow-up. A complete vertigo control was achieved in 14 patients (44%) from Group A and in 22 patients (73.3%) from Group B, statistically significant (p=0.01). Complete vertigo relief is also significant according to the Kaplan-Meier method: p=0.027, log rank test. Substantial vertigo control was obtained in 21 patients (65.6%) in Group A and 27 patients (90%) in Group B. The difference is statistically significant, p=0.02. The difference is significant according to the Kaplan-Meier method: p=0.035, log rank test. No significant differences between hearing levels and tinnitus scores were demonstrated between the groups.

CONCLUSIONS

Our preliminary results demonstrate that complete and substantial vertigo control is significantly higher in patients treated with a combination of HDBH and ITD.

Betahistine decreases olanzapine-induced weight gain and somnolence in humans

Olanzapine's efficacy in schizophrenia is attributed to antagonism of dopamine and serotonin receptors. Olanzapine is also a potent histamine-H1 antagonist that results in weight gain and somnolence. Betahistine is a centrally acting histamine-H1 agonist, and therefore may reduce olanzapine's effect on histamine receptors in the brain. Olanzapine's high affinity for the histamine-H1 receptor warrants the use of high doses of betahistine. Forty-eight healthy women were recruited and randomized to receive either betahistine 144 mg/day or matching placebo for 4 weeks. Due to the high dose of betahistine, olanzapine was started only on the second week and titrated up to 10 mg/day, and co-administration continued for an additional 2 weeks. Only nominal differences in adverse events were noted between the treatment groups. Betahistine caused a 37% reduction in mean weight gain (1.24 kg in the betahistine arm vs. 1.93 kg in the placebo arm; p=.049) and 60% reduction in the mean increase in daytime Epworth sleepiness scores (1.82 units in the betahistine group vs. 3.57 units in the placebo group; p=.042). The present study suggests that betahistine-olanzapine co-administration, in healthy female subjects, yields an acceptable safety profile with mitigation of weight gain and somnolence. This should be further tested in a patient cohort.

Efficacy and safety of betahistine treatment in patients with Meniere's disease: primary results of a long term, multicentre, double blind, randomised, placebo controlled, dose defining trial (BEMED trial)

STUDY QUESTION

What is the long term efficacy of betahistine dihydrochloride on the incidence of vertigo attacks in patients with Meniere's disease, compared with placebo?

METHODS

The BEMED trial is a multicentre, double blind, randomised, placebo controlled, three arm, parallel group, phase III, dose defining superiority trial conducted in 14 German tertiary referral centres (for neurology or ear, nose, and throat). Adults aged 21-80 years (mean age 56 years) with definite unilateral or bilateral Meniere's disease were recruited from March 2008 to November 2012. Participants received placebo (n=74), low dose betahistine (2 × 24 mg daily, (n=73)), or high dose betahistine (3 × 48 mg daily, (n=74)) over nine months. The primary outcome was the number of attacks per 30 days, based on patients' diaries during a three month assessment period at months seven to nine. An internet based randomisation schedule performed a concealed 1:1:1 allocation, stratified by study site. Secondary outcomes included the duration and severity of attacks, change in quality of life scores, and several observer-reported parameters to assess changes in audiological and vestibular function.

STUDY ANSWER AND LIMITATIONS

Incidence of attacks related to Meniere's disease did not differ between the three treatment groups (P=0.759). Compared with placebo, attack rate ratios were 1.036 (95% confidence interval 0.942 to 1.140) and 1.012 (0.919 to 1.114) for low dose and high dose betahistine, respectively. The overall monthly attack rate fell significantly by the factor 0.758 (0.705 to 0.816; P<0.001). The population based, mean monthly incidence averaged over the assessment period was 2.722 (1.304 to 6.309), 3.204 (1.345 to 7.929), and 3.258 (1.685 to 7.266) for the placebo, low dose betahistine, and high dose betahistine groups, respectively. Results were consistent for all secondary outcomes. Treatment was well tolerated with no unexpected safety findings. Without a control group of patients who did not receive any intervention to follow the natural course of the disease, the placebo effect could not be accurately assessed and differentiated from spontaneous remission and fluctuation of symptoms.

WHAT THIS STUDY ADDS

Current evidence is limited as to whether betahistine prevents vertigo attacks caused by Meniere's disease, compared with placebo. The trial provides information on symptom relief on placebo intervention which is relevant for the design of future studies on potential disease modifying treatments in patients with Meniere's disease.

FUNDING, COMPETING INTERESTS, DATA SHARING

Support from the German Federal Ministry of Education and Research (BMBF support code 01KG0708). Potential competing interests have been reported in full at the end of the paper on thebmj.com. Data are available from the corresponding author (Michael.Strupp@med.uni-muenchen.de) or biostatistician (mansmann@ibe.med.uni-muenchen.de). Study registration EudraCT no 2005-000752-32; ISRCTN no ISRCTN44359668.

Menière's disease

Menière's disease (MD) is a chronic multifactorial disorder of the inner ear characterized by episodic vestibular symptoms associated with sensorineural hearing loss, tinnitus, and aural pressure. Epidemiologic and genomic evidence supports a genetic susceptibility with multiple biochemical pathways involved, including the endocrine system, innate immune response, and autonomic nervous system. Allergens, infectious agents, vascular events, or genetic factors could modify inner-ear homeostasis and trigger MD. The diagnosis of MD is based on clinical criteria and requires the observation of an episodic vertigo syndrome associated with low- to medium-frequency sensorineural hearing loss and fluctuating aural symptoms (hearing loss, tinnitus, and/or fullness) in the affected ear. Headache is also found during the attacks and bilateral involvement is found in 25-40% of cases. Audiologic and vestibular assessment is recommended to monitor the clinical course. The treatment of MD is symptomatic to obtain relief of vestibular episodes and preventive to limit hearing loss progression. Treatment options include sodium restriction, betahistine, intratympanic gentamicin, or steroids and eventually surgery, such as cochlear implantation.

[Diseases of the peripheral vestibular system: contribution of ENT medical diagnostics and therapy]

The most common types of vertigo caused by diseases of the peripheral vestibular system are benign paroxysmal positional vertigo (BPPV), Meniere's disease and vestibular neuritis. A thorough examination of the medical history and clinical examination are usually sufficient for the differential diagnostics. Treatment includes differentiated repositioning maneuvers, medicinal treatment and physiotherapy.

Pharmacotherapy of vestibular and cerebellar disorders and downbeat nystagmus: translational and back-translational research

There are currently eight groups of drugs for the pharmacotherapy of vertigo, nystagmus, and cerebellar disorders: antiemetics; anti-inflammatories, antimenieres, and antimigraineous medications; antidepressants, anticonvulsants, aminopyridines, and acetyl-DL-leucine ("the eight A's"). In acute unilateral vestibulopathy, corticosteroids improve the recovery of peripheral vestibular function, but there is not sufficient current evidence for a general recommendation. There is also insufficient evidence that 48 or 144 mg/day betahistine has an effect in Ménière's disease. Therefore, higher dosages are currently recommended; in animal studies, it was shown that betahistine increases cochlear blood flow. In vestibular paroxysmia, oxcarbazepine was effective (one yet not randomized controlled trial (RCT)). Aminopyridines are recommended for the treatment of downbeat nystagmus (two RCTs) and episodic ataxia type 2 (EA2, one RCT). There are so far no RCTs on vestibular migraine, so currently no treatment can be recommended. Acetyl-dl-leucine improves cerebellar ataxia (three observational studies); it also accelerates central compensation in an animal model of acute unilateral lesion, but RCTs were negative. There are ongoing RCTs on vestibular paroxysmia with carbamazepine (VESPA), acute unilateral vestibulopathy with betahistine (BETAVEST), vestibular migraine with metoprolol (PROVEMIG), benign paroxysmal positional vertigo with vitamin D (VitD@BPPV), EA2 with 4-aminopyridine versus acetazolamide (EAT-2-TREAT), and cerebellar ataxias with acetyl-DL-leucine (ALCAT).

Long-term outcome of vertigo and dizziness associated disorders following treatment in specialized tertiary care: the Dizziness and Vertigo Registry (DiVeR) Study

To investigate the long-term outcome of interdisciplinary treatment in a tertiary care neuro-otology institution after 2 years as part of the Dizziness and Vertigo Registry study. Risk factors associated with unfavourable outcome were assessed. 3113 consecutive patients with disorders of vertigo and dizziness were recruited prospectively between March 2010 and February 2012. Patients were clinically assessed and treated according to their diagnosis. Standardized instruments were used at baseline and at 2-year follow-up [Dizziness Handicap Inventory (DHI), Quality of Life Questionnaire, General Depression Scale, Stait-Trait Anxiety Index], as well as a custom health-related questionnaire. The primary outcome variable of this observational study was the change in DHI after 2 years. Patients suffered from phobic postural vertigo (23%), benign peripheral paroxysmal vertigo (14.4%), unilateral vestibulopathy (10.5%), central vestibular disorders (8%), Menière's disease (9.8%), vestibular migraine (6.9%), bilateral vestibulopathy (5.5%), and vestibular paroxysmia (3.1%). Mean disease duration was 4.6 ± 6.3 years. 1272 patients were available for follow-up, 1159 completed the DHI score. 72.1% of patients improved in DHI score from baseline to 2 years follow-up. Mean reduction in DHI score was 14 points (p = 0.02). Long-term outcome following diagnosis and treatment in a specialized tertiary care centre is good and persistent after 2 years. Risk factors for an unfavourable outcome were advanced age, severe disability, constant vertigo or dizziness, and concomitant back pain, while depression and anxiety did not contribute to this risk considerably.

Treatment of Menière's Disease

OPINION STATEMENT

Diagnosis of Menière's disease is made with a characteristic patient history, including discrete episodes of vertigo lasting 20 min or longer, accompanied by sensorineural hearing loss, which is typically low frequency at first, aural fullness, and tinnitus. Workup includes audiometry, a contrast enhanced MRI of the internal auditory canals, and exclusion of other diseases that can produce similar symptoms, like otosyphilis, autoimmune inner ear disease, perilymphatic fistula, superior semicircular canal syndrome, Lyme disease, multiple sclerosis, vestibular paroxysmia, and temporal bone tumors. A history of migraine should be sought as well because of a high rate of co-occurrence (Rauch, Otolaryngol Clin North Am 43:1011-1017, 2010). Treatment begins with conservative measures, including low salt diet, avoidance of stress and caffeine, and sleep hygiene. Medical therapy with a diuretic is the usual next step. If that fails to control symptoms, then the options of intratympanic (IT) steroids and betahistine are discussed. Next tier treatments include the Meniett device and endolymphatic sac surgery, but the efficacy of both is controversial. If the above measures fail to provide symptomatic control of vertigo, then ablative therapies like intratympanic gentamicin are considered. Rarely, vestibular nerve section or labyrinthectomy is considered for a patient with severe symptoms who does not show a reduction in vestibular function with gentamicin. Benzodiazepines and anti-emetics are used for symptomatic control during vertigo episodes. Rehabilitative options for unilateral vestibular weakness include physical therapy and for unilateral hearing loss include conventional hearing aids, contralateral routing of sound (CROS) and osseointegrated hearing aids.

Intratympanic dexamethasone versus high dosage of betahistine in the treatment of intractable unilateral Meniere disease

PURPOSE

The objective of our randomized, double-blind study was to compare the effectiveness of intratympanic (IT) dexamethasone versus high-dosage of betahistine in the treatment of patients with intractable unilateral Meniere disease (MD).

MATERIALS AND METHODS

Sixty six patients with definite unilateral MD were randomly divided in two groups: Group A received a combination of IT dexamethasone (DX) and identical-appearing placebo pills while Group B received a combination of high-dosage betahistine and IT saline. Intratympanic injections were repeated for three times with an interlude of 3days. High-dosage of betahistine entailed 144mg/day. Mean outcome measures consisted of vertigo control, pure tone average (PTA), speech discrimination score, Functional Level Score, Dizziness Handicap Inventory and Tinnitus Handicap Inventory.

RESULTS

Fifty nine patients completed the study and were available at 12months for analysis. In Group A complete vertigo control (class A) was attained in 14 patients (46.6%) and substantial control (class B) in 7 patients (20%). In Group B, 12 patients (41%) achieved complete vertigo control (class A), 5 patients (17%) substantial control (class B). There is no statistical difference in vertigo control between the two treatment groups. In Group A hearing was unchanged in 14 patients and improved in 4 patients, while in Group B hearing was unchanged in 16 patients and improved in 2 patients.

CONCLUSIONS

Our preliminary results demonstrate that high-dosage of betahistine achieved similar outcomes as IT dexamethasone in the control of vertigo and hearing preservation.

Effects and safety profile of betahistine in patients in the Russian contingent of OSVaLD, an open-label observational study in vestibular vertigo

BACKGROUND

We report here data from the >200 patients recruited in Russia to take part in OSVaLD, a 12-week, open-label, post-marketing surveillance study of the response to betahistine 48 mg/day in vertigo of peripheral vestibular origin carried out in a total of 13 countries.

METHODS

The primary efficacy endpoint was change in the Dizziness Handicap Inventory (DHI; 100-point scale). Changes in Hospital Anxiety and Depression Scale (HADS) and Medical Outcomes Study Short-Form 36, version 2 (SF-36v2(®)) scores were a priori secondary Outcomes.

RESULTS

Total DHI score improved by 43 points during betahistine treatment. This aggregate improvement was equally distributed across the three domains of the DHI (physical, emotional, and functional; P<0.0001 for main and subscore changes from baseline). Statistically significant improvements versus baseline were also observed in mean HADS scores for anxiety and depression (both P<0.0001), and in the Physical Component Summary and Mental Component Summary scores of the SF-36v2 (both P<0.0001 versus baseline). Only one suspected adverse drug reaction was recorded in the Russian safety population (n=204), indicating that betahistine was well tolerated in those patients.

CONCLUSION

Betahistine 48 mg/day was associated with clear improvements in well-configured and widely validated measures of health-related quality of life and an encouraging tolerability profile in patients in Russia who took part in OSVaLD.

Reappraisal of the glycerol test in patients with suspected Menière's disease

BACKGROUND

Recent advances in magnetic resonance imaging make it possible to visualize the presumed pathophysiologic correlate of Menière's disease: endolymphatic hydrops. As traditional diagnostic tests can provide only indirect evidence, they are hardly competitive in this respect and need to be rethought. This is done here for the glycerol test.

METHODS

The data of a previous retrospective analysis of the glycerol test in patients with suspected Menière's disease are reinterpreted using a simple model. The mean threshold reduction (MTR) in the frequency range from 125 to 1500 Hz (calculated from audiograms obtained immediately before and four hours after the glycerol intake) is used as the test statistic. The proposed model explains the frequency distribution of the observed MTR by the convolution of a Gaussian probability density function (representing measurement errors) with a template representing the frequency distribution of the true MTR. The latter is defined in terms of two adjustable parameters. After fitting the model to the data, the performance of the test is evaluated using receiver operating characteristic (ROC) analysis.

RESULTS

The cumulative frequency distribution of the observed MTR can be explained almost perfectly by the model. According to the ROC analysis performed, the capability of the currently used audiometric procedure to detect a glycerol-induced threshold reduction corresponds to a diagnostic test of rather high accuracy (area under the ROC curve greater than 0.9). Simulations show that methodological improvements could further enhance the performance.

CONCLUSIONS

Owing to their ability to reveal functional aspects without an obvious morphological correlate, traditional test for Menière's disease could be decisive for defining the stage of the disease. A distinctive feature of the glycerol test is that it is capable of determining, with high accuracy, whether the pathophysiologic condition of the inner ear is partially reversible. Prospectively, this could help to estimate the chances of specific therapies.

Betahistine exacerbates amikacin ototoxicity

OBJECTIVE

Betahistine augments cochlear blood flow and is currently used as an efficient therapeutic agent. Amikacin is used in a wide range of areas, but its ototoxic effect continues to be problematic. This study investigates the effect of betahistine on amikacin-induced ototoxicity.

METHODS

Thirty-two healthy rats were randomized to 4 groups of 8 rats in each group (amikacin, amikacin+betahistine, betahistine, and no treatment). Amikacin was administered intramuscularly to groups 1 and 2 for 14 days. Betahistine was delivered by oral gavage to groups 2 and 3 for 21 days. Distortion-product otoacoustic emissions (DPOAE) and auditory brainstem response (ABR) tests were conducted on all rats.

RESULTS

There were significant decreases in the DPOAE levels and significant increases in the ABR thresholds of the amikacin and amikacin+betahistine groups on the 7th, 14th, and 21st days, as compared to their basal values. The DPOAE levels of the amikacin+betahistine group significantly decreased on days 7, 14, and 21, and the ABR thresholds significantly increased on the same days, as compared to the amikacin group.

CONCLUSION

Our study implies that amikacin's ototoxic effects are augmented by the concurrent use of betahistine. Experimental and clinical research, supported by histopathological studies, is needed to affirm our findings.

Treatment of Vertigo: A Randomized, Double-Blind Trial Comparing Efficacy and Safety of Ginkgo biloba Extract EGb 761 and Betahistine

A multicenter clinical trial was performed to compare the efficacy and safety of Ginkgo biloba extract EGb 761 and betahistine at recommended doses in patients with vertigo. One hundred and sixty patients (mean age 58 years) were randomly assigned to double-blind treatment with EGb 761 (240 mg per day) or betahistine (32 mg per day) for 12 weeks. An 11-point numeric analogue scale, the Vertigo Symptom Scale—short form, the Clinical Global Impression Scales and the Sheehan Disability Scale were used as outcome measures. Both treatment groups were comparable at baseline and improved in all outcome measures during the course of treatment. There was no significant intergroup difference with regard to changes in any outcome measure. Numerically, improvements of patients receiving EGb 761 were slightly more pronounced on all scales. Clinical global impression was rated “very much improved” or “much improved” in 79% of patients treated with EGb 761 and in 70% receiving betahistine. With 27 adverse events in 19 patients, EGb 761 showed better tolerability than betahistine with 39 adverse events in 31 patients. In conclusion, the two drugs were similarly effective in the treatment of vertigo, but EGb 761 was better tolerated. This trial is registered with controlled-trials.com ISRCTN02262139.

[Cardinal symptom vertigo from the neurologist's perspective]

In most patients with vertigo, the first and clinically most important question posed to neurologists is whether it is a central or a peripheral syndrome. In more than 90 % of cases, this differentiation is made possible by systematically recording the patient history (asking about the type of vertigo, the duration, triggers and accompanying symptoms) and conducting a physical examination. Particularly in the case of acute vertigo disorders, a five-step procedure has proven useful: 1. A cover test to look for vertical divergence (skew deviation) as a central sign and component of the ocular tilt reaction (OTR); 2. Examination with and without Frenzel goggles to differentiate between peripheral vestibular spontaneous nystagmus and central fixation nystagmus; 3. Examination of smooth pursuit; 4. Examination of the gaze-holding function (particularly gaze-evoked nystagmus beating in the opposite direction to spontaneous nystagmus); 5. The head impulse test to look for a deficit in the vestibulo-ocular reflex (VOR). Considerable advances have been made in the pharmacotherapy of vertigo disorders during the last 10 years, including cortisone for the treatment of acute vestibular neuritis, betahistine as a high-dose long-term treatment for Menière's disease, carbamazepine to treat vestibular paroxysmia and aminopyridine for down- and upbeat nystagmus and episodic ataxia type 2.

[Vertigo in children and adolescents. Part 1: Epidemiology and diagnosis of peripheral vestibular disorders]

Migraine equivalents are the most common cause of vertigo in children and adolescents. Vertigo and balance disorders occur frequently in children during the course of otitis media, middle ear effusion and viral infections. If otitis media is associated with reduced hearing and vertigo, labyrinthitis must be considered. Craniocerebral injury is another important cause of vertigo in children. In contrast, spontaneous benign paroxysmal positional vertigo is rare among children. The isolated cases of endolymphatic hydrops that occur in children are usually secondary. Perilymph fistula can have congenital, infectious or trauma-related causes. The following characteristics are useful for differentiating between different vertiginous syndromes: type and duration of vertigo, triggering/aggravating/alleviating factors and accompanying symptoms. A neuro-ophthalmologic examination is essential to rule out central vestibular disorders.

The treatment and natural course of peripheral and central vertigo

BACKGROUND

Recent studies have extended our understanding of the pathophysiology, natural course, and treatment of vestibular vertigo. The relative frequency of the different forms is as follows: benign paroxysmal positional vertigo (BPPV) 17.1%; phobic vestibular vertigo 15%; central vestibular syndromes 12.3%; vestibular migraine 11.4%; Menière's disease 10.1%; vestibular neuritis 8.3%; bilateral vestibulopathy 7.1%; vestibular paroxysmia 3.7%.

METHODS

Selective literature survey with particular regard to Cochrane reviews and the guidelines of the German Neurological Society.

RESULTS

In more than 95% of cases BPPV can be successfully treated by means of liberatory maneuvers (controlled studies); the long-term recurrence rate is 50%. Corticosteroids improve recovery from acute vestibular neuritis (one controlled, several noncontrolled studies); the risk of recurrence is 2-12%. A newly identified subtype of bilateral vestibulopathy, termed cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS), shows no essential improvement in the long term. Long-term high-dose treatment with betahistine is probably effective against Menière's disease (noncontrolled studies); the frequency of episodes decreases spontaneously in the course of time (> 5 years). The treatment of choice for vestibular paroxysmia is carbamazepine (noncontrolled study). Aminopyridine, chlorzoxazone, and acetyl-DL-leucine are new treatment options for various cerebellar diseases.

CONCLUSION

Most vestibular syndromes can be treated successfully. The efficacy of treatments for Menière's disease, vestibular paroxysmia, and vestibular migraine requires further research.

Peripheral vestibular disorders

PURPOSE OF REVIEW

First, to update the diagnosis, pathophysiology, and treatment of the most frequent peripheral vestibular disorders. Second, to identify those disorders for which the diagnostic criteria are still deficient and treatment trials are still lacking.

RECENT FINDINGS

Bilateral vestibulopathy can be reliably diagnosed by the head-impulse test, caloric irrigation, and vestibular-evoked myogenic potentials. A new frequent subtype has been described: cerebellar ataxia, neuropathy, and vestibular areflexia syndrome. Benign paroxysmal positioning vertigo can be easily diagnosed and effectively treated. Vestibular neuritis is most likely caused by the reactivation of a herpes simplex type 1 infection; the inferior vestibular nerve subtype is now well established. More evidence is needed that the recovery can be improved by corticosteroids. Endolymphatic hydrops in Menière's disease can be depicted by high-resolution MRI after transtympanic gadolinium injection; a high-dosage and long-term prophylactic treatment with betahistine is evidently effective. Its mechanism of action is most likely an increase in the inner-ear blood flow. Vestibular paroxysmia is now a well established entity; carbamazepine is the treatment of first choice. Superior canal dehiscence syndrome can be reliably diagnosed; the best current treatment option is canal plugging.

SUMMARY

Although progress has been made in the diagnosis and treatment of most peripheral vestibular disorders, more state-of-the-art trials are needed on the treatment of bilateral vestibulopathy to prove the efficacy of balance training, of vestibular neuritis (in terms of recovery of peripheral vestibular function and central compensation), of vestibular paroxysmia to prove the effects of carbamazepine, and of Menière's disease to find the optimal dosage of betahistine.

Bayesian model selection techniques as decision support for shaping a statistical analysis plan of a clinical trial: an example from a vertigo phase III study with longitudinal count data as primary endpoint

Background

A statistical analysis plan (SAP) is a critical link between how a clinical trial is conducted and the clinical study report. To secure objective study results, regulatory bodies expect that the SAP will meet requirements in pre-specifying inferential analyses and other important statistical techniques. To write a good SAP for model-based sensitivity and ancillary analyses involves non-trivial decisions on and justification of many aspects of the chosen setting. In particular, trials with longitudinal count data as primary endpoints pose challenges for model choice and model validation. In the random effects setting, frequentist strategies for model assessment and model diagnosis are complex and not easily implemented and have several limitations. Therefore, it is of interest to explore Bayesian alternatives which provide the needed decision support to finalize a SAP.

Methods

We focus on generalized linear mixed models (GLMMs) for the analysis of longitudinal count data. A series of distributions with over- and under-dispersion is considered. Additionally, the structure of the variance components is modified. We perform a simulation study to investigate the discriminatory power of Bayesian tools for model criticism in different scenarios derived from the model setting. We apply the findings to the data from an open clinical trial on vertigo attacks. These data are seen as pilot data for an ongoing phase III trial. To fit GLMMs we use a novel Bayesian computational approach based on integrated nested Laplace approximations (INLAs). The INLA methodology enables the direct computation of leave-one-out predictive distributions. These distributions are crucial for Bayesian model assessment. We evaluate competing GLMMs for longitudinal count data according to the deviance information criterion (DIC) or probability integral transform (PIT), and by using proper scoring rules (e.g. the logarithmic score).

Results

The instruments under study provide excellent tools for preparing decisions within the SAP in a transparent way when structuring the primary analysis, sensitivity or ancillary analyses, and specific analyses for secondary endpoints. The mean logarithmic score and DIC discriminate well between different model scenarios. It becomes obvious that the naive choice of a conventional random effects Poisson model is often inappropriate for real-life count data. The findings are used to specify an appropriate mixed model employed in the sensitivity analyses of an ongoing phase III trial.

Conclusions

The proposed Bayesian methods are not only appealing for inference but notably provide a sophisticated insight into different aspects of model performance, such as forecast verification or calibration checks, and can be applied within the model selection process. The mean of the logarithmic score is a robust tool for model ranking and is not sensitive to sample size. Therefore, these Bayesian model selection techniques offer helpful decision support for shaping sensitivity and ancillary analyses in a statistical analysis plan of a clinical trial with longitudinal count data as the primary endpoint.

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.

Betahistine exerts a dose-dependent effect on cochlear stria vascularis blood flow in guinea pigs in vivo

OBJECTIVE

Betahistine is a histamine H(1)-receptor agonist and H(3)-receptor antagonist that is administered to treat Menière's disease. Despite widespread use, its pharmacological mode of action has not been entirely elucidated. This study investigated the effect of betahistine on guinea pigs at dosages corresponding to clinically used doses for cochlear microcirculation.

METHODS

Thirty healthy Dunkin-Hartley guinea pigs were randomly assigned to five groups to receive betahistine dihydrochloride in a dose of 1,000 mg/kg b. w. (milligram per kilogram body weight), 0.100 mg/kg b. w., 0.010 mg/kg b. w., 0.001 mg/kg b. w. in NaCl 0.9% or NaCl 0.9% alone as placebo. Cochlear blood flow and mean arterial pressure were continuously monitored by intravital fluorescence microscopy and invasive blood pressure measurements 3 minutes before and 15 minutes after administration of betahistine.

RESULTS

When betahistine was administered in a dose of 1.000 mg/kg b. w. cochlear blood flow was increased to a peak value of 1.340 arbitrary units (SD: 0.246; range: 0.933-1.546 arb. units) compared to baseline (p<0.05; Two Way Repeated Measures ANOVA/Bonferroni t-test). The lowest dosage of 0.001 mg/kg b. w. betahistine or NaCl 0.9% had the same effect as placebo. Nonlinear regression revealed that there was a sigmoid correlation between increase in blood flow and dosages.

CONCLUSIONS

Betahistine has a dose-dependent effect on the increase of blood flow in cochlear capillaries. The effects of the dosage range of betahistine on cochlear microcirculation corresponded well to clinically used single dosages to treat Menière's disease. Our data suggest that the improved effects of higher doses of betahistine in the treatment of Menière's disease might be due to a corresponding increase of cochlear blood flow.

[Receptor function of the semicircular canals. Part 2: pathophysiology, diseases, clinical findings and treatment aspects]

Perturbation of semicircular canal function may result in a pathological angular vestibulo-ocular reflex (aVOR). The resulting impairment in gaze stabilization is perceived as "vertigo" or "dizziness" and may occur following receptor function impairment of all three semicircular canals. The head impulse test reveals hidden (covert-catchup) or visible (overt-catchup) saccades in disturbances of semicircular function. Most peripheral vestibular disorders can be treated conservatively. There are surgical treatment options for some diseases, such as intractable benign paroxysmal positional vertigo and superior semicircular canal dehiscence. Vestibular training promotes central reorganization of the VOR. Impaired semicircular receptor function, in particular bilateral vestibulopathy, may affect spatial orientation and cognitive processes. Balance prostheses could serve as a replacement for receptors in the future.

Current treatment of vestibular, ocular motor disorders and nystagmus

Vertigo and dizziness are among the most common complaints with a lifetime prevalence of about 30%. The various forms of vestibular disorders can be treated with pharmacological therapy, physical therapy, psychotherapeutic measures or, rarely, surgery. In this review, the current pharmacological treatment options for peripheral and central vestibular, cerebellar and ocular motor disorders will be described. They are as follows for peripheral vestibular disorders. In vestibular neuritis recovery of the peripheral vestibular function can be improved by treatment with oral corticosteroids. In Menière's disease a recent study showed long-term high-dose treatment with betahistine has a significant effect on the frequency of the attacks. The use of aminopyridines introduced a new therapeutic principle in the treatment of downbeat and upbeat nystagmus and episodic ataxia type 2 (EA 2). These potassium channel blockers presumably increase the activity and excitability of cerebellar Purkinje cells, thereby augmenting the inhibitory influence of these cells on vestibular and cerebellar nuclei. A few studies showed that baclofen improves periodic alternating nystagmus, and gabapentin and memantine, pendular nystagmus. However, many other eye movement disorders such as ocular flutter opsoclonus, central positioning, or see-saw nystagmus are still difficult to treat. Although progress has been made in the treatment of vestibular neuritis, downbeat and upbeat nystagmus, as well as EA 2, state-of-the-art trials must still be performed on many vestibular and ocular motor disorders, namely Menière's disease, bilateral vestibular failure, vestibular paroxysmia, vestibular migraine, and many forms of central eye movement disorders.

Pharmacotherapy of vestibular and ocular motor disorders, including nystagmus

We review current pharmacological treatments for peripheral and central vestibular disorders, and ocular motor disorders that impair vision, especially pathological nystagmus. The prerequisites for successful pharmacotherapy of vertigo, dizziness, and abnormal eye movements are the "4 D's": correct diagnosis, correct drug, appropriate dosage, and sufficient duration. There are seven groups of drugs (the "7 A's") that can be used: antiemetics; anti-inflammatory, anti-Ménière's, and anti-migrainous medications; anti-depressants, anti-convulsants, and aminopyridines. A recovery from acute vestibular neuritis can be promoted by treatment with oral corticosteroids. Betahistine may reduce the frequency of attacks of Ménière's disease. The aminopyridines constitute a novel treatment approach for downbeat and upbeat nystagmus, as well as episodic ataxia type 2 (EA 2); these drugs may restore normal "pacemaker" activity to the Purkinje cells that govern vestibular and cerebellar nuclei. A limited number of trials indicate that baclofen improves periodic alternating nystagmus, and that gabapentin and memantine improve acquired pendular and infantile (congenital) nystagmus. Preliminary reports suggest suppression of square-wave saccadic intrusions by memantine, and ocular flutter by beta-blockers. Thus, although progress has been made in the treatment of vestibular neuritis, some forms of pathological nystagmus, and EA 2, controlled, masked trials are still needed to evaluate treatments for many vestibular and ocular motor disorders, including betahistine for Ménière's disease, oxcarbazepine for vestibular paroxysmia, or metoprolol for vestibular migraine.

High-dosage betahistine dihydrochloride between 288 and 480 mg/day in patients with severe Menière's disease: a case series

The objective of this study was to evaluate the clinical benefit and the side effects of high dosages of betahistine dihydrochloride (288-480 mg/day) in patients with severe Menière's disease (MD). In this case series 11 patients with MD who had not responded sufficiently to a dosage of 144 mg/day of betahistine dihydrochloride were treated on an individual basis with daily dosages between 288 and 480 mg of betahistine dihydrochloride. The number of attacks per month and the side effects were monitored. Non-parametric tests were used for statistical analysis. As a result, the frequency and the severity of vertigo were significantly reduced in all patients. The side effects were mild, self-limiting, and did not require any change in the treatment strategy. Despite the considerable limitations of an observational study--in particular in MD--high dosages of betahistine dihydrochloride between 288 and 480 mg/day seem to be effective in patients who do not sufficiently respond to lower dosages. Moreover, such dosages are well tolerated.

Which medication do I need to manage dizzy patients?

Vertigo and dizziness are not independent disease entities, but instead symptoms of various diseases. Accordingly, a variety of treatment approaches are required. Here we review the most relevant drugs for managing dizziness, vertigo, and nystagmus syndromes. It is important to differentiate symptomatic treatment of nausea and vomiting with, for example, dimenhydrinate and benzodiazepines, and prophylactic treatment of motion sickness with scopolamine from a causal therapy of the underlying disorders. Examples of such causal therapy include aminopyridines for downbeat nystagmus and episodic ataxia type 2; carbamazepine for vestibular paroxysmia, paroxsymal dysarthria and ataxia in multiple sclerosis, and superior oblique myokymia; betahistine, dexamethasone, and gentamicin for Menière's disease; gabapentin and memantine for different forms of acquired and congenital nystagmus; corticosteroids for acute vestibular neuritis and Cogan's syndrome; metoprolol and topiramate for vestibular migraine; and selective serotonin reuptake inhibitors such as paroxetine for phobic postural vertigo. The clinical entities are briefly described, the various medications are discussed in alphabetical order, and dosage, major side effects, contraindications, and alternative medications of each drug are displayed in boxes for easy reference.

New methods for diagnosis and treatment of vestibular diseases

Dizziness and vertigo are common complaints, with a lifetime prevalence of over 30%. This review provides a brief summary of the recent diagnostic and therapeutic advances in the field of neuro-otology. A special focus is placed on the clinical usefulness of vestibular tests. While these have markedly improved over the years, treatment options for vestibular disorders still remain limited. Available therapies for selected vestibular diseases are discussed.