Here is the design of a clinical trial:

Official Title: Breathing, Relaxation, Attention Training, & Health in Older Adults

Included conditions:
- Mild Cognitive Impairment
- Healthy Aging

Study Armgroups:
- {'label': 'RFB+VSOP (MCI)', 'type': 'EXPERIMENTAL', 'description': 'For home-based RFB+VSOP: The investigators will instruct subjects to do 10-minutes of app- guided paced breathing at RF daily; for select days, there will be VSOP training immediately following RFB.\n\nA total of 8 weeks intervention. The investigators will extend the intervention for additional two weeks for make-up sessions.', 'interventionNames': ['Behavioral: RFB', 'Behavioral: VSOP']}
- {'label': 'IR+VSOP (MCI)', 'type': 'ACTIVE_COMPARATOR', 'description': 'The control IR strategy will be used, set-up of which will be the same as the RFB + VSOP intervention group with IR replacing RFB. A total of 8 weeks intervention. The investigators will extend the intervention for additional two weeks for make-up sessions.', 'interventionNames': ['Behavioral: VSOP', 'Behavioral: IR']}
- {'label': 'IR only (MCI)', 'type': 'PLACEBO_COMPARATOR', 'description': 'Participants randomized to this condition will receive weekly in-person check-in visits, and perform daily 10-minute IR, so that the number of treatment contacts (though not duration) will be equivalent. A total of 8 weeks intervention. The investigators will extend the intervention for additional two weeks for make-up sessions.', 'interventionNames': ['Behavioral: IR']}
- {'label': 'RFB+VSOP (HC)', 'type': 'OTHER', 'description': 'this is a new healthy control intervention arm used for testing adherence related items.\n\nFor home-based RFB+VSOP: The investigators will instruct subjects to do 10-minutes of app- guided paced breathing at RF daily; for select days, there will be VSOP training immediately following RFB.\n\nA total of 8 weeks intervention. The investigators will extend the intervention for additional two weeks for make-up sessions.', 'interventionNames': ['Behavioral: RFB', 'Behavioral: VSOP']}

Interventions:
- {'type': 'BEHAVIORAL', 'name': 'RFB', 'description': 'The RFB protocol entails a combination of 8 weekly, in-lab training sessions using HRV biofeedback software (Physiocom, Seattle, WA) and daily paced breathing homework using a mobile-based HRV biofeedback app (Inner Balance, HeartMath, LLC, CA).', 'armGroupLabels': ['RFB+VSOP (HC)', 'RFB+VSOP (MCI)']}
- {'type': 'BEHAVIORAL', 'name': 'VSOP', 'description': 'The investigators will use the INSIGHT online program (Posit Science). The platform will be built for our study, including 5 tasks (Eye for detail, Peripheral challenge, Visual sweep, Double decision, Target tracker) that practice different cognitive processes with PS/A as the shared domain.', 'armGroupLabels': ['IR+VSOP (MCI)', 'RFB+VSOP (HC)', 'RFB+VSOP (MCI)']}
- {'type': 'BEHAVIORAL', 'name': 'IR', 'description': 'Guided imagery relaxation, equal in dose and frequency to RF practice, will be used to control for relaxation effects that may occur via RFB (which could provide an alternative explanation for outcomes). IR activities will be facilitated using the Insight Timer mobile-based app, which emphasizes the use of visualization and imagery strategies to help the body relax.', 'armGroupLabels': ['IR only (MCI)', 'IR+VSOP (MCI)']}

Primary Outcomes:
- {'measure': 'change of ANS flexibility at 2 months from baseline', 'description': 'A composite score developed via central autonomic networks and heart rate variability at rest and in response to a challenging cognitive stressor. Higher indicates better ANS flexibility. No max/min.', 'timeFrame': '2 months post-baseline'}
- {'measure': 'change of ANS flexibility at 8 months from baseline', 'description': 'A composite score developed via central autonomic networks and heart rate variability at rest and in response to a challenging cognitive stressor. Higher indicates better ANS flexibility. No max/min.', 'timeFrame': '8 months post-baseline'}
- {'measure': 'change of ANS flexibility at 14 months from baseline', 'description': 'A composite score developed via central autonomic networks and heart rate variability at rest and in response to a challenging cognitive stressor. Higher indicates better ANS flexibility. No max/min.', 'timeFrame': '14 months post-baseline'}
- {'measure': 'change of cognition at 2 months from baseline', 'description': 'A composite score in executive function computed from Executive Abilities: Measures and Instruments for Neurobehavioral Evaluation and Research (EXAMINER). No min/max; higher score indicates higher executive function. Z-transformation will be calculated.\n\nVisual episodic memory computed from Brief Visuospatial Memory Test-Revised (BVMT-R). Age normative percentile scores range from 0-100, higher indicating better memory. Z-transformation will be calculated.\n\nA composite score will be a mean Z-score of composite score of EXAMINER and percentile score of BVMT-R.', 'timeFrame': '2 months post-baseline'}
- {'measure': 'change of cognition at 8 months from baseline', 'description': 'A composite score in executive function computed from Executive Abilities: Measures and Instruments for Neurobehavioral Evaluation and Research (EXAMINER). No min/max; higher score indicates higher executive function. Z-transformation will be calculated.\n\nVisual episodic memory computed from Brief Visuospatial Memory Test-Revised (BVMT-R). Age normative percentile scores range from 0-100, higher indicating better memory. Z-transformation will be calculated.\n\nA composite score will be a mean Z-score of composite score of EXAMINER and percentile score of BVMT-R.', 'timeFrame': '8 months post-baseline'}
- {'measure': 'change of cognition at 14 months from baseline', 'description': 'A composite score in executive function computed from Executive Abilities: Measures and Instruments for Neurobehavioral Evaluation and Research (EXAMINER). No min/max; higher score indicates higher executive function. Z-transformation will be calculated.\n\nVisual episodic memory computed from Brief Visuospatial Memory Test-Revised (BVMT-R). Age normative percentile scores range from 0-100, higher indicating better memory. Z-transformation will be calculated.\n\nA composite score will be a mean Z-score of composite score of EXAMINER and percentile score of BVMT-R.', 'timeFrame': '14 months post-baseline'}

Please estimate the sample size based on the assumption: 
Alpha = 0.025, 3 measurement time points (baseline, post-intervention, 12-month follow-up), 20% attrition rate.
Sample size
        Sample estimation is based on the effect of RFB+VSOP combined intervention on two primary outcomes (ANS flexibility and cognition/IADL) by comparing to other groups (IR+VSOP control and IR control only). Literature indicates the following information related to deciding the effect size: (1) a moderate to large effect (using Hedgesâ g = 0.83) of HRVB (including RFB) on stress regulation measures [17], (2) a small to moderate effect of VSOP on cognition, (3) correlation between ANS measures (Ï2 = 11.70, r = 0.44) [7, 64], and (4) correlations between ANS measures and cognition (pooled r = 0.16) [65]. We estimate alpha = 0.025 (correct for two comparisons: combined intervention group with VSOP+IR control, as well as with the IR control group), and 3 measurement time points: baseline, post-intervention assessment, and 12-month follow-up. A sample size of 96 will be able to detect a small effect (d = 0.20). We further estimate a 20% attrition rate at the 12-month follow-up (in another local longitudinal study of cognitively healthy older adults Dr. Lin conducted [66], the attrition rate was less than 20% for up to a 5-year follow-up), and we will use a sample size of 114 (n = 38 per group).