Although it is advisable to consult with a physician about this, the following includes some possible explanations for your mother's sensation of frequently feeling cold. In aging individuals, skin commonly becomes thinner and loses some of the fatty cushion that functions to protect skin against injury. This can also describe why some people become more sensitive to weather conditions, as well as hot and cold temperatures. In addition, if your mother has experienced any weight loss or nutritional deficiencies, such as low iron, she can also be more affected by the cold. You may also want to check her temperature to see if she has a fever or elevated body temperature. As already noted, in order to have a better understanding if this cold sensitivity is medically related, it is important to consult with her physician and a nutritionist or dietician as soon as possible. If the doctor rules out all medical explanations, then it is possible that your mother's perception of being cold is caused by sensory acuity issues. Dementias are the result of an injured brain, and they can cause a person to believe or sense that something is true when there is no evidence for it. If your mother thinks that she is cold, the best remedy is to be as supportive as possible. For example, providing her with a warm sweater or a soft blanket is a good idea, and also can function in two other ways - it will demonstrate that you are helping to make her warm, and the tactile stimulation will benefit her sensory system in that it will offer a sense of comfort and safety. Sometimes the feel of a warm cup of tea can act as a way to soothe an individual and give them a sense of warmth. Be as creative as possible and always validate her concerns before redirecting her onto more positive subjects.
My mother-in-law was cold & hot. We would add covers for cold. Her feet were especially cold at nites. When she was hot she would start taking her clothes off. This was very difficult to handle, but what I would try to do is convert her to something else like "let's go for a walk, go to the kitchen for a treat & have a snack, etc.. This is one of the symptoms & I just handled it the best I could. I didn't know about this "site" until now.
Yes mother said she is cold all the time and it is 85 temp outside. She is 86 years old.
My father-in-law had the same thing. Last winter, he kept saying he was cold while the house is hot with the heater already. The caregiver just added more blanket so it covers his legs also. I think this is insecurity. Also for advanced Alzheimer's patient like my FIL, he has trouble to understand the temperature. For example, in the winter, he has no idea he cannot wear a t-shirt outside and has to be told it is freezy outside and he needs a coat or hat. Even now he still has trouble with temperature and cannot express why he feels hot or cold. It is up to the caregivers to see if it is indeed cold and help him out. I don't know how bad is your mom's dementia, but it is advanced, she will have trouble to know about how hot or how cold it is. She may be able to tell you she does not feel good or she is cold, but it may not be as it. The caregiver or family has to make his/her own judgment to act accordingly.
Just my 2 cents.