Here is the design of a clinical trial:

Official Title: The Effect of Vestibular Exercise, With or Without Medication, in Managing Residual Dizziness After Successful Repositioning Maneuvers in Patients With Benign Paroxysmal Positional Vertigo

Included conditions:
- Vestibular Disorder

Study Armgroups:
- {'label': 'Group A', 'type': 'EXPERIMENTAL', 'description': 'Group A will be provided with Exercise-based vestibular rehabilitation (VR) twice per day for a period of 4 weeks;', 'interventionNames': ['Behavioral: Exercise-based vestibular rehabilitation']}
- {'label': 'Group B', 'type': 'EXPERIMENTAL', 'description': 'Group B will be prescribed with Betahistine 12mg, twice daily for 7 days;', 'interventionNames': ['Drug: Betahistine']}
- {'label': 'Group C', 'type': 'EXPERIMENTAL', 'description': 'Group C will receive an combination of Exercise-based VR plus Betahistine.', 'interventionNames': ['Drug: Betahistine', 'Behavioral: Exercise-based vestibular rehabilitation']}

Interventions:
- {'type': 'DRUG', 'name': 'Betahistine', 'description': 'Betahistine is used in the treatment of and vertigo.', 'armGroupLabels': ['Group B', 'Group C']}
- {'type': 'BEHAVIORAL', 'name': 'Exercise-based vestibular rehabilitation', 'description': 'Exercise-based vestibular rehabilitation (VR) has proven to be an effective way for managing dizziness by relieving symptoms and improving balance and postural stability.', 'armGroupLabels': ['Group A', 'Group C']}

Primary Outcomes:
- {'measure': 'Balance function', 'description': 'Balance function, measured by computerized dynamic posturography.', 'timeFrame': 'Change from baseline, at 4 weeks, 8 weeks and 12 weeks postrandomisation'}

Please estimate the sample size based on the assumption: 
80% power, alpha level of 0.05 (two-tailed test), 20% loss during follow-up period.
Sample size calculation
        The study sample size was based on the VAP measure (one of the primary outcomes), which is a useful clinical tool for assessing a patientâs limitations in activities and participation due to vertigo, dizziness and unsteadiness. The validation of VAP in patients who complained of dizziness or imbalance showed the minimum detectable change (MDC) for the VAP was 0.58, with an SE of 0.21.39 In this study, a VAP difference of 0.6 will be considered clinically meaningful. Thus, to detect an MDC of 0.6 for the VAP with 80% power (alpha level of 0.05, two-tailed test), 55 subjects per group will be required. Although there are three groups in this study, controlling for the type I error rate is not needed because our hypotheses are: (1) VR will be superior to betahistine (Group A vs Group B) and (2) VR will be non-inferior to VR plus betahistine (Group A vs Group C); therefore, only two comparisons will be executed. Allowing for a 20% loss during the follow-up period, a total sample of 183 (61 per group) will be required for the current study.