If the person has advanced dementia and/or is completely resistant

In later stages of dementia, the person may no longer be capable of insight into the fact that they've been incontinent. They may wake up and say, "Oh, you must have spilled water in my bed." An hour later, they may forget even that.

At this stage of impairment, Robbins says, the person may remain cooperative. Or the person may begin to refuse therapies such as scheduled bathroom visits -- or may even try to remove a diaper. It can be difficult to convince someone in late-stage dementia about the importance of following doctor's orders or staying clean. By this point, there are usually other behavioral problems going on as well.

It's often not helpful to try to reason with someone who has late-stage dementia. Often their beliefs are fixed, and your attempt to change their mind will be met with anger rather than as new information to consider.