Here is the design of a clinical trial:

Official Title: Assistive Robotic in the Elderly: Innovative Models in the Rehabilitation of the Elderly With Parkinson's Disease Through Technological Innovation

Included conditions:
- Parkinson Disease
- Frail Elderly
- Robotic Devices in Rehabilitation

Study Armgroups:
- {'label': 'control arm', 'type': 'ACTIVE_COMPARATOR', 'description': 'Ten traditional treatment sessions divided into 2 training sessions per week for 5 weeks', 'interventionNames': ['Other: control arm']}
- {'label': 'virtual reality games arm', 'type': 'EXPERIMENTAL', 'description': 'Ten technological treatment sessions divided into 2 training sessions per week for 5 weeks', 'interventionNames': ['Other: virtual reality games']}
- {'label': 'robotic treadmill arm', 'type': 'EXPERIMENTAL', 'description': 'Ten technological treatment sessions divided into 2 training sessions per week for 5 weeks', 'interventionNames': ['Other: robotic treadmill']}

Interventions:
- {'type': 'OTHER', 'name': 'control arm', 'description': 'Each session will include 50 minutes of traditional physical rehabilitation therapy', 'armGroupLabels': ['control arm']}
- {'type': 'OTHER', 'name': 'virtual reality games', 'description': 'Each session will include 30 minutes of traditional physical rehabilitation therapy followed by 20 minutes of robotic Tymo system (Tyromotion, Austria), a wireless static and dynamic platform, for evaluating and rehabilitating posture.', 'armGroupLabels': ['virtual reality games arm']}
- {'type': 'OTHER', 'name': 'robotic treadmill', 'description': 'Each session will include 30 minutes of traditional physical rehabilitation therapy followed by 20 minutes of robotic Walker View (TecnoBody, Italy) a treadmill equipped with a sensorized belt with eight load cells and a 3D camera', 'armGroupLabels': ['robotic treadmill arm']}

Primary Outcomes:
- {'measure': 'difference in falling risk among virtual reality games arm, robotic treadmill arm and control arm', 'description': 'falling risk will be evaluated by the Tinetti performance oriented mobility assessment (POMA). POMA test has two subscales, Balance and Gait sections. Total score is obtained by adding the scores of the two subscales (balance + gait) . Total score \\< 19 high fall risk, total score 19-24 medium fall risk, total score 25-28 low fall risk.', 'timeFrame': 'before treatment, at the end of treatment and 6, 12 and 24 months after the end of treatment'}

Please estimate the sample size based on the assumption: 
Statistical power of 80%, significance level of 0.05, three groups, 5 repeated assessments (baseline and 4 follow-ups), and a 25% dropout rate.
Sample size
        The Performance-Oriented Mobility Assessment (POMA) [27], a test widely used to assess walking ability and associated with equilibrium, is used to calculate the sample size [28]. Assuming a small effect size of 10% [29], it is estimated that the overall sample size needed to capture this effect size is of 153 subjects, assuming a statistical power of 80%, a significance level of 0.05, three groups and 5 repeated assessments (a baseline and 4 follow-ups) in an ANOVA model within-between interactions. Even assuming a 25% drop out rate, the total number required would be 195 subjects (65 for each arm).
        It is hypothesized that this sample dimension is more than sufficient to grasp a variation also for secondary outcomes for which a treatment effect size is assumed of a similar or higher entity than that identified for the primary outcome [30, 31].