Husband has done this a few times, never have seen it before, he has ALZ/DEM. Sometimes does this with open hands and sometimes with closed fists. The closed fists was done when he got angry with our daughter, open hands was as he was coming down the hall to ask me a question.
This is an education along the journey, so many of us are in this together, even though we don't know one another...so glad this is here.