***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: 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 Abstract . The present study compares the efficacy and safety of betahistine dihydrochloride to that of a placebo in recurrent vertigo result ing from Meniere 's disease ( MD ) or in paroxysmal positional vertigo ( PPV ) of probable vascular origin . The design was double-blind , multicentre and parallel-group r and omised . Eleven Italian centres enrolled 144 patients : 75 of the patients were treated with betahistine ( 41 MD/34 PPV ) and 69 with placebos ( 40 MD/29 PPV ) . The betahistine dosage was 16 mg twice per day for 3 months . Compared to the placebo , betahistine had a significant effect on the frequency , intensity and duration of vertigo attacks . Associated symptoms and the quality of life also were significantly improved by betahistine . Both the physician 's judgement and the patient 's opinion on the efficacy and acceptability of the treatment were in agreement as to the superiority of betahistine . The effective and safe profile of betahistine in the treatment of vertigo due to peripheral vestibular disorders was confirmed A double-blind , cross-over , placebo-controlled study of betahistine dihydrochloride ( 12 mg , t.i.d . ) was carried out in patients with vertigo of peripheral vestibular origin . Twenty-four patients completed the study , which consisted of two six-week treatment periods . The patients were diagnosed as suffering from Menière 's disease ( 15 patients ) , vertigo due to other ( specified ) causes ( five patients ) , or vertigo of unknown origin ( four patients ) . Patients were examined by the investigator at the start of the study and were re-assessed at three-weekly intervals . In addition , they recorded the nature , frequency and severity of their symptoms on diary cards . Both the incidence and severity of dizziness ( the predominant presenting complaint ) were found to be significantly reduced during betahistine treatment ( p = 0.004 ) . The occurrence of nausea and vomiting was also significantly reduced during betahistine treatment ( p = 0.014 and 0.036 respectively ) . There were no statistically significant differences in the results of audiometric or vestibulometric tests , or in the severity of tinnitus or deafness , between the two treatment periods . The overall comparisons of the two periods made by both the patients and the investigator were significantly in favour of betahistine ( p less than 0.001 ) . All diagnostic groups responded favourably to betahistine , confirming the efficacy of betahistine in the symptomatic treatment of peripheral vestibular vertigo . No unwanted signs or symptoms were reported The effects of betahistine hydrochloride ( Serc ) on the clinical features of Ménière 's disease were assessed in two double-blind , placebo-controlled , cross-over clinical studies . The diagnosis was based on a peripheral , fluctuating , recruiting , cochlear ( sensorineural ) deafness in one or both ears , tinnitus ( usually of low tone ) and paroxysmal attacks of rotational vertigo . Appropriate auditory and vestibular analyses confirmed the diagnosis . Twenty-four patients were admitted to the studies after careful screening over two- and -a-half years . Twenty-two patients completed the studies , ten of whom received betahistine and placebo for eight weeks each whereas the remaining twelve were given betahistine and placebo for twelve weeks each . the dose of betahistine was the same ( 16 mg . t.i.d . ) in both studies . Daily symptom score cards kept by all patients throughout the studies showed a statistically significant preference for betahistine over placebo with regard to vertigo ( p = 0 - 025 ) , tinnitus ( p = 0 - 010 ) and fullness of the ear ( p = 0 - 036 ) . Symptom scores of deafness and vomiting indicated trends in favour of betahistine but these did not attain statistical significance . Objective measurements of deafness ( mean db . loss ) , however , showed a highly significant improvement in favour of betahistine , when compared with placebo ( p less than 0 - 001 ) . Vestibular testing revealed no important difference between betahistine and placebo . No unwanted effects or adverse reactions attributable to betahistine were observed during the studies WHEN VERTIGO , associated with Meniere 's syndrome , becomes intractable and incapacitating , the patient becomes a c and i date for surgery . This is not a pleasant outlook for the patient , nor for the treating physician . As a consequence , there has been an incessant but yet unrewarding search for a satisfactory medical treatment . Williams 1 recently reported : Neither the definition , the diagnosis nor the dysfunction of Meniere 's disease is much clearer now than when Meniere first described the condition in 1861 .... On the basis of recently acquired information , we may define Meniere 's disease as a disorder of a predisposed stria vascularis , possibly in response to a hypothalamic stimulus , with the local synthesis of toxic amounts of histamine and possibly of norepinephrine , producing in the stria vascularis the picture of the slow stage of shock , increased hydrodynamic pressure in the endolymphatic system , loss of hearing , and , secondarily , attacks of vertigo , nausea and vomiting . In a 
    Output:
    
None of the trials showed any effect of betahistine on hearing loss .
No adverse effects were found with betahistine .
REVIEW ER 'S CONCLUSIONS There is insufficient evidence to say whether betahistine has any effect on Menière 's disease