Here is the design of a clinical trial:

Official Title: The Efficacy and Appropriateness of Ball Blankets on Insomnia in Depression in Outpatient Clinics

Included conditions:
- Insomnia Due to Mental Disorder

Study Armgroups:
- {'label': 'Experimental arm AB (Ball blanket + TAU)', 'type': 'EXPERIMENTAL', 'description': 'Participants will be randomized into either sequence AB or BA each lasting four weeks.\n\nPatients that are randomized to the AB sequence receive intervention A (Protac Ball BlanketTM 7 kg Flexible) in the first two weeks and treatment B treatment as usual (TAU) in the second period.', 'interventionNames': ['Device: Protac Ball BlanketTM (7kg Flexible)']}
- {'label': 'Experimental arm BA (TAU + Ball blanket)', 'type': 'EXPERIMENTAL', 'description': 'Patients that are randomized to the BA sequence receive treatment B (TAU) in the first period and intervention A in the second period (Protac Ball BlanketTM 7kg Flexible).', 'interventionNames': ['Device: Protac Ball BlanketTM (7kg Flexible)']}

Interventions:
- {'type': 'DEVICE', 'name': 'Protac Ball BlanketTM (7kg Flexible)', 'description': 'All patients will wear a MotionLogger Micro Watch from Ambulatory Monitoring Inc. NY in all four weeks during all 24hours of the day.', 'armGroupLabels': ['Experimental arm AB (Ball blanket + TAU)', 'Experimental arm BA (TAU + Ball blanket)'], 'otherNames': ['MotionLogger Micro Watch from Ambulatory Monitoring Inc. NY']}

Primary Outcomes:
- {'measure': 'Changes in total night time sleep (TST) measured by actigraphy (Micro MotionLogger Watch)', 'description': 'The investigators will detect the change in total night time sleep in minutes (actual sleep time, excluding sleep latency and wakes after sleep onset) by comparing the means of the difference in TST for each participant between period A and B or B and A', 'timeFrame': 'Four weeks'}

Please estimate the sample size based on the assumption: 
The power calculation assumes a paired t test with a significance level (alpha) of 0.05 and a power of 0.80. The differences in sleep duration are assumed to be normally distributed.
Sample size
        The power calculation is based on data from a pilot study (NÂ =â8) as we have not identified any studies investigating the effects of ball blankets on TST in depressed patients.
        The main outcome will be changes in total night-time sleep with and without PBB estimated by the means of the differences between the periods for each participant. The null hypothesis is that there is no change in sleep duration. In the pilot study, the mean sleep duration appeared normally distributed and the mean sleep duration without a ball blanket was 420âmin. The standard deviation of the difference between the sleep duration with and without a ball blanket was 42âmin. Based on the potential clinical gains, we aim to be able to detect a change in total sleep duration of 20âmin. Assuming that the differences in sleep duration with and without a ball blanket is normally distributed, we performed power calculations for a paired t test, and with an alfaâ=â0.05 and powerâ=â0.80 the minimum required sample size is NÂ =â37. To take into account dropout rates, we aim to include 45 patients.