Gurkov 2012.

Methods	Allocation: prospective, randomised, double‐blind, multicentre, placebo‐controlled trial Follow‐up after 4, 8, 12 and 16 weeks Design: RCT
Participants	Number: n = 74 Age/gender: age 19 to 74 years, 19 females in the active group (n = 38), 17 females in the placebo group (n = 36) Setting: 3 centres: Departments of Oto‐Rhino‐Laryngology, Head and Neck Surgery, Ludwig Maximilians University of Munich and Johann Wolfgang Goethe University of Frankfurt, Germany Eligibility criteria: diagnosis of definite Ménière's disease according to the AAO‐HNS criteria (Grade I), including 2 or more definite, spontaneous episodes of vertigo of 20 minutes or longer, audiometrically documented hearing loss on at least 1 occasion, tinnitus or aural fullness in the treated ear and exclusion of other causes, 2 or more vertigo attacks per month in the last 2 months and treatment with betahistine for the last 3 months without subjective vertigo control Exclusion criteria: bilateral Ménière's disease, previous destructive or surgical therapy (e.g. gentamicin instillation or endolymphatic sac surgery) and age below 18 years Baseline characteristics: in the active group mean age 57, mean disease duration 43 months, Ménière's disease stage III and IV 19 and 5 participants, canal paresis 27.3%. In the placebo group mean age 52, mean disease duration 57 months, Ménière's disease stage III and IV 17 and 5 participants, canal paresis 29.1%
Interventions	Intervention group: Meniett device Comparator group: placebo device Use of additional interventions: pre‐existing medical therapy with daily doses of 48 mg to 72 mg of betahistine
Outcomes	Primary outcome: vertigo score, number of definite vertigo days and number of sick days Secondary outcomes: activity score, number of vertigo‐free days, hearing threshold and caloric stimulus induced slow phase nystagmus velocity
Notes	‐ Treatment duration: 16 weeks ‐ Comparison between 4 weeks before treatment and last 4 weeks of treatment ‐ Placebo device used slight pressure pulse generation of 2 cm H2O ‐ Observation period of 1 month after insertion of ventilation tube ‐ No funding, but the Meniett device was provided by Medtronic Xomed ‐ Additional (pre‐study) medication allowed of 48 to 72 mg/day betahistine
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	154 patients met the inclusion criteria but 74 were accepted to participate in the study; unclear reasons for the non‐participation of 80 patients
Allocation concealment (selection bias)	Low risk	Method of randomisation is not described ("... a total of 74 patients accepted, and were individually randomised into either the active treatment group or the placebo group..."). A 4‐week observation period was used after insertion of the ventilation tube for all participants
Blinding (performance bias and detection bias) All outcomes	Low risk	Double‐blind, adequately and explicitly described
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Flow chart and description of drop‐outs presented, but without adequate descriptions of drop‐outs and treatment failure. No intention‐to‐treat analysis
Selective reporting (reporting bias)	Low risk	Adequate descriptions of methods and results at different follow‐ups. Adequate presentation of data. No statistical analysis between follow‐up periods, but authors supplied additional raw data on request
Other bias	Unclear risk	Use of slight pressure pulse of 2 cm H2O in the placebo group; the possibility of a small therapeutic effect cannot be completely ruled out
Grading: AAO‐HNS diagnosis	Low risk	Grade 1
Grading: AAO‐HNS outcome measurement	Low risk	The AAO‐HNS criteria for 'control of vertigo' are not used, but the frequency of vertigo is calculated using cumulative vertigo scores and number of vertigo days. Data from the 4‐week interval before the treatment were compared with the 4‐week period at the end of the 16‐week treatment