When it happens
Usually starts during moderate-stage dementia.
Why it happens
As dementia slowly robs self-awareness, the person becomes less inhibited, losing both the memory of how he or she once behaved as well as a sense of social norms. It's as if an internal filter on what's polite behavior or not is turned off. Examples: Undressing in public, saying inappropriate things (rude comments, cursing), staring at strangers, making inappropriate sexual advances, masturbating in public.
What you can do
Know that some behaviors aren't what they look like. People with dementia who are losing language skills often express themselves with actions. For example, someone who unzips his pants may need to use the restroom. A person who disrobes may be hot. Someone who hurls a stream of foul language may feel stressed.
Notice what else is going on when a behavior occurs; something about the environment may be triggering a reaction in the form of this inappropriate behavior. Pay attention to the noise level, who's present, the time of day, whether the person has eaten or used the bathroom. Jot down this information if an odd behavior happens more than once.
Ignore these behaviors where possible. Reacting to them -- especially with outrage or disapproval -- may only egg on or upset the person.
React with calm reassurance. The person may be acting out because he or she feels uncomfortable, insecure, or overwhelmed by noise (such as in a public place).
Try reacting to sexual behaviors counterintuitively -- by providing extra touching and affection. Rub the hands or shoulders, smile, hug. The person may be expressing a (nonsexual) need for affection and human contact.
Distract, if possible, by changing the scene (moving to another room, going outside) or the activity.
Take strangers aside and explain, "Please excuse Mother; she has dementia and isn't fully aware of her actions." (Some people make up small cards they can silently pass to wait staff, store clerks, and others that explain the same message.)
For chronic undressers, try difficult-to-remove clothing, such as challenging fasteners (like small buttons) or tops that zip or button in back.
Don't try to reason the person into proper behavior: "We don't do that in public!" or "Mind your manners!" The person with dementia cannot follow that line of logic.