I think what would need to happen is:

Find an activity that does not help with PTSD or symptoms.

Find an activity that does.

Take two groups of both left and right hand people.

Have one group do the activity that doesn't help and one that does (placebo group.) Also, you would need equal amount of lefties and righties in each group.

This would have to be done for a certain period of time, then stopped to find good results. I would then do the test over again!

It would be interesting!

Bec