Prevent it from happening? If it is to abolish, everytime pt will have to underwent your procedure? If it is to prevent, is it one time for the life?
Is this condition unberable so they have to see a doctor? Or is it just annoying?
It is not a life threatening condition but it will reduce your ability to do something and degrade the quality of your life. The procedure is to desensitize the sensitivity to some type of stimulus that occurs frequently. After the procedure, the susceptible people won't feel or feel less sick when encountering the situation. This is an one time procedure for a long time benefit. How long? we do not know. Preliminary data showed several months during which the subjects were followed. The proposed study is to follow a year. There will be dropouts during this period especially in control group because they will feel the same as before. The statistician guessed a dropout rate of 20% was reasonable and the sample size would be increased by 20% to account for the loss. I am not sure if this is a good idea because we do not know if there will be any useful information in dropouts.

All my questions are to query necessary info to see I can help design the study.
I can see you have such experiences. Thanks.

It is hard without knowing much about the condition. If you can give a description aout the condition in amedical way without revealing it, it'll be helpful.
Sorry, I can't find something comparable.

Setting up a good control is the key. It could be non-treatment, or medically treated group if you claim your procedure is more favorable. I'd also love to know in what way it is more favorable.
the control will be simply not treated. Non-stressful and no medication and it has a long lasting effect.

Study can also be dsigned for a combination therapy compared with single modlity in the future once you effective is established.

Phase III has to be a placebo design?

The outcome, is complete or partial alleviatuon of that feeling. Souds like your claim is partial. There might be role of conbination therapy.
The practical clinical significance is set to at least a 50% reduction in their sickness for the same condition of the stimulus.

The measureMent is the grading score. Yes.

The inclusion critrior will be very tricky and critical. If you are able to grade, e.g. In a scale of 5, I would only select grade 4 only. Because it is subjective, the extremes are not reliable. Choose pts of same level of severity allows you to compare your "score changes" with less bias, because the amptitude of change may be different from grade 5 and grade 1. Grade 1 just doesn't have equal room to improve as grade 5.
Our scale is 20 maximum. 10 will be moderate. Any one who is greater or equal to 10 will be selected. It is impossible to have the same severity across all subjects.

Other point to consider when choosing patients.

these are the group of population you hav e to think:patients who tolerates the "feeling " well and never sought medical help, patients who tried medicatioin but never worked or not satisfied and thus give trying medication, and pts who always use medicatiosan because it helps albeit limited. Depending on your goal of study, you choose different group of people. Try to limit your subjects to an identical group.

We don't want to compare with other procedures or with medications.
Once inclusion criterior is set, then recruit, and randomized into two groups.
It is impossible to have all subjects ready then to randomize them. Rather we will generate the sequence of the random number and the subjects recruited will be assigned to these sequence of numbers in a orderly manner. Not sure if this is a right description.