MIL “shooshing” female family members; anyone else seen this?

"Mom, this situation seems to be hard on you and your hearing, so lets move YOU into another room where it is quieter" Might do the trick! If there is no one to "Shoosh" and she is getting some time out she may come around.. but of course with dementia there are no promises.

Sometimes changes in hearing make higher pitched voices much more annoying; think of seniors who are "nervous" with their grandchildren playing in the house. I haven't known anyone who actually shushed anyone but I have known a couple of people who asked the kids to play outside and in one case left the house because a cousin with a high pitched voice was visiting.

Chalk it up to her decline. You may want her evaluated to see if she is now entering the world of full blown Dementia. For now, thats what I would tell people.

The "shushing" people up has been a lifelong behavior in my mom. When she feels a loss of control over people's speech and actions, or thinks she's "out of the loop" in any way, she feels anxious; thus triggering the shushing behavior. Like she thinks she has the right to shut people up. With dementia added to the mix, it got much worse. Yes, it's annoying and embarrassing. When my father was hospitalized and dying, she thought visitors were "too loud" when they really weren't at all. My dad, ill or not, was always delighted to receive friends and family, and that was part of the problem: it wasn't all about her. One time with family present in Dad's room, she was so disruptive I asked Mom if she wanted to leave, and she said (indignantly), "Yes!" Lol! I escorted her from the room. Problem diffused! At least for the moment. Once my father passed, that particular behavior diminished, and since then she exhibits a series of paranoid delusions, one after the other. sigh