***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Objective Betahistine is a histamine H1-receptor agonist and H3-receptor antagonist that is administered to treat Menière ’s disease . Despite widespread use , its pharmacological mode of action has not been entirely eluci date d. This study investigated the effect of betahistine on guinea pigs at dosages corresponding to clinical ly used doses for cochlear microcirculation . Methods Thirty healthy Dunkin-Hartley guinea pigs were r and omly 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 clinical ly 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 Thirty-seven patients suffering from vertigo associated with vertebrobasilar insufficiency participated in our prospect i ve , single-center , double-blind , comparative study . Patients were r and omly allocated to treatment with placebo ; betahistine ( 12 mg betahistine dimesylate , one tablet three times daily ) ; or the fixed combination of 20 mg cinnarizine and 40 mg dimenhydrinate ( one tablet three times daily ) for 4 weeks . The primary efficacy end point was the decrease of the mean vertigo score ( S(M ) ) , which was based on the patients ' assessment s of 12 individual vertigo symptoms after 4 weeks of treatment . Patients treated with the fixed combination showed significantly greater reductions of S(M ) as compared to patients receiving placebo ( p < .001 ) or the reference therapy betahistine ( p < .01 ) . The vestibulospinal parameter lateral sway ( Unterberger 's test ) improved to a significantly greater extent in patients taking the fixed combination as compared to those receiving placebo ( p < .001 ) . No serious adverse event was reported in any therapy group . The tolerability of the fixed combination was judged as very good or good by 91 % ( betahistine , 73 % ; placebo , 82 % ) . In conclusion , the fixed combination proved to be statistically more effective than the common antivertiginous drug betahistine in reducing vertebrobasilar insufficiency-associated vertigo symptoms A double-blind , placebo-controlled , clinical study was performed to assess the effects of oral betahistine hydrochloride ( Serc ) on mental impairment and physical disability in patients with established cerebrovascular disease . Fifty-three patients were admitted to the study during 18 months . Forty-five patients completed the study . They received either betahistine 24 mg daily or placebo for eight weeks . Clinical assessment s of general functional activity were done and a battery of nine mental function tests was administered pretreatment and at two-weekly intervals during therapy . The results were analysed statistically using distribution-free tests . Significant differences were demonstrated between betahistine and placebo at week 8 of treatment for associate learning , digit retention , general knowledge , orientation , sentence learning and simple arithmetic . These differences were consistently in favour of betahistine at or close to the 5 % level of significance . The results of the remaining mental function tests showed no significant differences between betahistine and placebo , but trends were in favour of the former . General functional activity assessment s also demonstrated that betahistine-treated patients were significantly better than those on placebo ( P less than or equal to 0.05 ) . No untoward side-effects were noted during the study 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 , r and omised , 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 r and omisation 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 ; IS RCT N no IS RCT N44359668 A double-blind , placebo-controlled , cross-over clinical trial was performed to assess the effect of betahistine hydrochloride ( Serc ) in Ménière 's disease . The diagnosis was based on paroxysmal attacks of rotational vertigo , with tinnitus , and a fluctuating sensori-neural deafness , together with the results of auditory and vestigular tests . Twenty-eight patients were admitted to the trial over 3 years . Twenty-two patients completed the trial . In total , they received betahistine 32 mg daily , for a period of 16 weeks , and placebo also for the same length of time , preceded in every case by a 4-week pre-treatment period . Daily symptom score cards were kept . There was a statistically significant improvement in favour of the drug with regard to vertigo , tinnitus and deafness . Vertigo was the most responsive symptom . No adverse reactions were observed Objective : The purpose of this study was to determine the prevalence and incidence of  vestibular vertigo in the general population and to describe its clinical characteristics and associated factors . Methods : The neurotologic survey had a two-stage general population sampling design : nationwide modified r and om digit dialing sampling for participation in the German National Telephone Health Interview Survey 2003 ( response rate 52 % ) with screening of a r and om sample of 4,869 participants for moderate or severe dizziness or vertigo , followed by detailed  neurotologic interviews  developed through piloting and validation ( n = 1,003 , response rate 87 % ) . Diagnostic criteria for vestibular vertigo were rotational vertigo , positional vertigo , or recurrent dizziness with nausea and oscillopsia or imbalance . Vestibular vertigo was detected by our interview with a specificity of 94 % and a sensitivity of 88 % in a concurrent validation study using neurotology clinic diagnoses as an accepted st and ard ( n = 61 ) . Results : The lifetime prevalence of vestibular vertigo was 7.8 % , the 1-year prevalence was 5.2 % , and the incidence was 1.5 % . In 80 % of affected individuals , vertigo result ed in a medical consultation , interruption of daily activities , or sick leave . Female sex , age , lower educational level , and various comorbid conditions , including tinnitus , depression , and several cardiovascular diseases and risk factors , were associated with vestibular vertigo in the past year in univariate analysis . In multivariable analysis , only female sex , self-reported depression , tinnitus , hypertension , and dyslipidemia had an independent effect on vestibular vertigo . Conclusions : Vestibular vertigo is common in the general population , affecting more than 5 % of adults in 1 year . The frequency and health care impact of vestibular symptoms at the population level have been underestimated Objective . The purpose of this study is to evaluate the effects of betahistine in addition to Epley maneuver on the quality of life of patients with posterior semicircular canal benign paroxysmal positional vertigo ( BPPV ) of the canalithiasis type . Study Design . Double-blind , r and omized , controlled clinical trial . Setting . Academic university hospital . Subjects and Methods . Seventy-two patients were enrolled in the study . The first group was treated with Epley maneuver only . The second group received placebo drug 2 times daily for 1 week in addition to Epley maneuver , and the third group received 24 mg betahistine 2 times daily for 1 week in addition to Epley maneuver . The effectiveness of the treatments was assessed in each group as well as between them by analyzing and comparing data of 4 different vertigo symptom scales . Results . Epley maneuver , alone or combined with betahistine or placebo , was found to be very effective with a primary success rate of 86.2 % . The symptoms were significantly reduced in group 3 patients overall , and those patients younger or older than 50 years of age who had hypertension , with symptom onset < 1 month , and with attack duration of less than a minute did significantly better with the combination of betahistine 48 mg daily . Conclusion . Betahistine in addition to Epley maneuver is more effective than Epley maneuver alone or combined with placebo with regard to improvement of symptoms in certain patients . However , future clinical studies covering more patients to investigate the benefit of medical treatments in addition to Epley maneuver are needed OBJECTIVE To assess the prevalence of ear , nose and throat ( ENT ) symptoms experienced by individuals living in Scotl and , and their use of GP or hospital services for these problems . METHODS A cross-sectional postal self-completed question naire was sent to a r and om sample of 12,100 households throughout Scotl and . 15,788 individuals aged 14 + years living in the 7244 households who returned the question naire ( adjusted response rate 64.2 % ) participated in the study . RESULTS Roughly a fifth of respondents reported currently having hearing difficulties , including difficulty following conversations when there is background noise and hearing problems causing worry or upset ; few wore a hearing aid regularly . A fifth reported noises in head or ears ( tinnitus ) lasting more than five minutes . In the previous year , between 13 and 18 % of respondents reported persistent nasal symptoms or hayfever , 7 % sneezing or voice problems and 31 % had at least one episode of severe sore throat or tonsillitis . Nearly 21 % of all respondents reported ever having had dizziness in which things seemed to spin around the individual ; 29 
    Output:
    
Low quality evidence suggests that in patients suffering from vertigo from different causes there may be a positive effect of betahistine in terms of reduction in vertigo symptoms .
Betahistine is generally well tolerated with a low risk of adverse events .