Dementia Support Group
Dementia is the progressive decline in cognitive function due to damage or disease in the brain beyond what might be expected from normal aging. Particularly affected areas may be memory, attention, language and problem solving, although particularly in the later stages of the condition, affected persons may be disoriented in time, place and person (not knowing who they...
I would talk to her doctors and see what anti-anxiety medications can be given to calm her down. More often than not, this is the route that the family has to take.
Is she taking any type of medications now? Is your mother in a facility? Don't take to heart what she's saying to you now? It's the disease that just makes them more miserable than they were before. Not fun though, I sympathize with you there.
One of the things that happens in dementia is damage to the executive portion of the brain. This controls "appropriate" behavior. For many people sexual behavior and thoughts go wild. The inhibitions are gone. This can also take the controls off everything else. My mom will say wild things about people.
So to answer your question I don't think dementia changes people. I think it just takes all of the filters off and you see what they were thinking deep inside.