Here is the design of a clinical trial:

Official Title: CURATE.AI Optimised Digital COgnitive Rehabilitation Therapy (COR-Tx) for Post Brain Radiotherapy Patients: CURATE.AI COR-Tx Mixed-methods Feasibility Clinical Trial

Included conditions:
- Cognitive Decline

Study Armgroups:
- {'label': 'CURATE.AI', 'type': 'EXPERIMENTAL', 'description': 'A cognitive evaluation and a Digital Diagnostic (DD) session performed anytime before radiotherapy will serve as the baseline. After the radiotherapy treatment, which can last between 1 to 6.5 weeks, patients will have a variable recovery time (0 to 4 weeks). Subsequently, patients will be subject to a cognitive evaluation and a DD session, right before starting the Digital Intervention (DI) training. This training will comprise ten weeks of DI (three 10-15 minute sessions per week). Patients will complete cognitive evaluations and DD sessions at the end of DI, and 16 and 32 weeks after the end of DI.', 'interventionNames': ['Device: CURATE.AI']}

Interventions:
- {'type': 'DEVICE', 'name': 'CURATE.AI', 'description': 'CURATE.AI will be utilised to provide personalised training intensity recommendations (low, medium or high) to the patients during the digital cognitive test battery DI session. The difficulty of each task will be modulated by CURATE.AI by adjusting the frequency of critical events that demand evaluation and/or response.', 'armGroupLabels': ['CURATE.AI']}

Primary Outcomes:
- {'measure': 'Patient acceptability of the digital cognitive test battery DI/DD obtained during a semi-structured interview', 'description': 'Qualitative summary of patient acceptability of the digital cognitive test battery DI/DD', 'timeFrame': 'One visit 60 minutes (at the end of the 10 week intervention)'}
- {'measure': 'Patient adherence to the DI/DD', 'description': 'Percentage of completed DI/DD sessions', 'timeFrame': 'up to 12 months'}
- {'measure': 'Patient attrition rate to the DI/DD', 'description': 'Percentage of patients that drop out of DI/DD', 'timeFrame': 'up to 12 months'}
- {'measure': 'Percentage of CURATE.AI profiles successfully created and applied', 'timeFrame': 'up to 12 months'}
- {'measure': 'Timely delivery of DI/DD at indicated time points', 'description': 'Percentage of DI/DD sessions successfully delivered by study team at indicated time points', 'timeFrame': 'up to 12 months'}
- {'measure': 'Digital intervention limited efficacy', 'description': 'Change in cognitive performance as measured by the standard of care cognitive evaluations pre-post digital intervention', 'timeFrame': 'up to 12 months'}
- {'measure': 'Digital diagnostic limited efficacy', 'description': 'Correlation between standard of care cognitive evaluations scores and digital diagnostic scores', 'timeFrame': 'up to 12 months'}

Please estimate the sample size based on the assumption: 
No formal assumptions on significance level, power, or missing/dropout rate were made.
Sample size
        We intend to recruit 15 participants for this study. As this is a feasibility clinical trial with no prior data, we did not perform formal sample size calculations. However, this sample size is based on the number of patients who can be practically and logistically recruited within the period of this feasibility trial that will allow for a reasonable signal to expand to a larger RCT.