Here is the design of a clinical trial:

Official Title: Effects of Sulforaphane on Cognitive Function in Patients With Frontal Brain Damage: Study Protocol for a Randomized Controlled Trial

Included conditions:
- Frontal Lobe Dysfunction

Study Armgroups:
- {'label': 'sulforaphane', 'type': 'EXPERIMENTAL', 'description': 'To evaluate the effect of sulforaphane treatment on the cognitive deficits of patients with frontal brain damage', 'interventionNames': ['Drug: sulforaphane']}
- {'label': 'placebo', 'type': 'PLACEBO_COMPARATOR', 'description': 'To evaluate the effect of sulforaphane treatment on the cognitive deficits of patients with frontal brain damage', 'interventionNames': ['Drug: placedo']}

Interventions:
- {'type': 'DRUG', 'name': 'sulforaphane', 'description': 'To evaluate the effects of sulforaphane on the cognitive improvement of patients with frontal brain damage', 'armGroupLabels': ['sulforaphane']}
- {'type': 'DRUG', 'name': 'placedo', 'description': 'To evaluate the effects of sulforaphane on the cognitive improvement of patients with frontal brain damage', 'armGroupLabels': ['placebo']}

Primary Outcomes:
- {'measure': 'Changes from baseline cognitive tests scores at 3 months', 'description': 'The battery of cognitive tests include different domains of cognitive tests, higher scores indicates better cognition.', 'timeFrame': 'Week 1 and week 12.'}

Please estimate the sample size based on the assumption: 
80% power, two-sided p value of 0.05, 20% inflation for dropout and loss of patients to follow-up, SD in total scores estimated at 14 at 0 and 3 months.
Sample size
        Sample size calculation will be carried out using the SAS software. Since there were no previous studies of sulforaphane in patients with frontal brain damage, we estimated the sample size based on our unpublished study of sulforaphane treatment on cognitive impairment for other diseases (ClinicalTrials.gov: NCT02880462). 90 was calculated as the number necessary to detect an average difference of 18.5 in multiple cognitive domains between baseline and 3 months in the treatment group, and of 11.9 in the placebo groups at 80% power with a two-sided p value of 0.05. These calculations include a 20% inflation for dropout and loss of patients to follow-up. SD in total scores are estimated at 14 at 0 and 3 months. However, without knowledge of the within-person correlation between data points, it is impossible to predict the increase in power calculation.