Here is the design of a clinical trial:

Official Title: Epley Manoeuvre for Posterior Semi-circular Canal Benign Paroxysmal Positional Vertigo in People With Multiple Sclerosis: Protocol of a Randomized Controlled Trial

Included conditions:
- Benign Paroxysmal Positional Vertigo
- Multiple Sclerosis

Study Armgroups:
- {'label': 'Epley Manoeuvre', 'type': 'EXPERIMENTAL', 'description': 'Epley manoeuvre in participants with Multiple Sclerosis who suffer from benign paroxysmal positional vertigo. Only one administration.', 'interventionNames': ['Procedure: Epley Manoeuvre']}
- {'label': 'Sham Manoeuvre', 'type': 'SHAM_COMPARATOR', 'description': 'The second group will received a sham manoeuvre. However after the experimental intervention ends, this groups will also receive Epley manoeuvre.', 'interventionNames': ['Procedure: Sham Manoeuvre']}

Interventions:
- {'type': 'PROCEDURE', 'name': 'Epley Manoeuvre', 'description': 'This manoeuvre is constituted by five steps. In the first step, while the patient is in supine posture the head will be positioned 45 degrees turned towards the unaffected ear and the head slightly overhang on the edge of the couch. In this second step maintaining the previous position of the head, physiotherapist will turn head 45 degrees turned towards the affected ear. Next, in the third step, the whole body will turn until is located 135 degrees from the baseline supine position. In the fourth step, while the head keeps turned to the affected ear the subject will be incorporated until he is sitting. In the fifth step, while the subject is seated with the head in neutral position the chin will be bended 20 degrees. Each procedure will be held among 30 seconds or two minutes, while the dizziness or the nystagmus vanish. The intervention will be conducted at the Physical Therapy Department of the University of Sevilla (Spain).', 'armGroupLabels': ['Epley Manoeuvre'], 'otherNames': ['canalith repositioning procedure for posterior semi-circular canal']}
- {'type': 'PROCEDURE', 'name': 'Sham Manoeuvre', 'description': 'The sham manoeuvre consist is going to star with the participant in a neutral seated position. Sum to it, head is rotated 45 degrees towards the unaffected vestibule. After that, the participant will be guided by the physiotherapist to a lateral decubitus position towards the affected side on which his nose will be pointing above. To conclude, the seated position will be reached again without head rotation. Each position of the sham manoeuvre will be maintained along one minute. During all the process the videonystagmography glasses will be dressed by participants and they will be indicated not to close eyes in the intervention. After the execution of the manoeuvre, also this group will be evaluated 48 hours after. The intervention will be conducted at the Physical Therapy Department of the University of Sevilla (Spain).', 'armGroupLabels': ['Sham Manoeuvre']}

Primary Outcomes:
- {'measure': 'Changes in the conversion of a positive to a negative Dix Hallpike Test', 'description': 'The performance of Dix Hallpike Test consists on a participant sit on a table and the head is turn 45 degrees towards the tested side. Once this position is stablished, the evaluator is going to laid back the participant in a quick movement sum to a neck extension of 20 degrees with the affected ear down. Throughout the process subject will be indicated to keep eyes open to allow the search of nystagmus. If torsional nystagmus or vertigo appears while the head is down it is indicative of posterior canal benign paroxysmal positional vertigo.', 'timeFrame': 'Baseline, immediately after intervention and 48 hours after intervention.'}

Please estimate the sample size based on the assumption: 
one-tailed hypothesis, Î± error of 0.05, statistical power of 80%, estimated dropout rate of 15%
Sample size calculation
        The sample size was calculated using the G*Power software (V.3.1.7; Kiel University, Kiel, Germany).50 The sample size has been calculated as 80 participants for a one-tailed hypothesis, with an Î± error of 0.05, size effect of d=0.8, statistical power of 80% and an estimated dropout rate of 15%.51 52