More details might help, but, sometimes, it's difficult to do, because, we may not know exactly where they are coming from. You might talk to her doctor and ask for guidance. Or read a lot about dementia and how it impacts some people.
Some people who have dementia get angry due to delusions or hallucinations. They may believe things that are not true and we have no idea how they got the ideas. But, disagreeing with them normally causes them to get upset. Also, going into strange or loud places can scare them and cause agitation. Having to change their clothes or take a bath upsets some. They are easily chilled and may have very sensitive skin that doesn't take the feel of water very well. Loud or aggressive voices might frighten them, as well.
To work out what triggers anything (hay fever, diarrhoea, heart flutters etc) the usual system is to maintain a detailed diary until you have enough instances of the problem. Then you look back through the diary to see if you can find a repetition before hand of something that may be a trigger. For example, it took me far too long to work out that even tiny amounts of chili triggered diarrhoea for me a day later, and a diary would have been a good idea. However it’s a lot of work to do in detail, and may not help if there are in fact many triggers.
Perhaps when an anger episode happens, you could look back to check for things that are common triggers for other people and that happened beforehand. Then make a note of them and the time between the potential trigger and the anger. Then see if there is a pattern. Doing this for a couple of weeks might be useful, and might at least help you to feel that it isn’t all random and not controllable at all.
My mother doesn't seem to feel the heat and she is in early stages of Dimentia. I personally run cold and her room would read 74+ (I am roasting) and she will ask if the heat is on. This is definitely a recent development for her.
My husband in 6 years into an Alzheimers diagnosis and he is always cold, has been for two to three years now. House temp is 74 and he is wearing 3 knit shirts, a heavy winter coat, ski gloves, and woolen cap. He never seems to get warm enough. Sits in front of our wood stove, with the fire blazing, yet always wants ice cream, go figure!
Nana, one thing to look out for is an urinary tract infection. Such an infection can cause many strange things such as anger in a dementia patient. The test for the infection is fairly easy, if the patient cooperates.
Some people who have dementia get angry due to delusions or hallucinations. They may believe things that are not true and we have no idea how they got the ideas. But, disagreeing with them normally causes them to get upset. Also, going into strange or loud places can scare them and cause agitation. Having to change their clothes or take a bath upsets some. They are easily chilled and may have very sensitive skin that doesn't take the feel of water very well. Loud or aggressive voices might frighten them, as well.
Perhaps when an anger episode happens, you could look back to check for things that are common triggers for other people and that happened beforehand. Then make a note of them and the time between the potential trigger and the anger. Then see if there is a pattern. Doing this for a couple of weeks might be useful, and might at least help you to feel that it isn’t all random and not controllable at all.