The correct answer to this question is False. There are several types of dementia, and unfortunately, not all of them are able to be cured. One type is Alzheimer's disease, which can affect memory loss, communication skills, and the ability to think. Though it is progressive, there is no cure with it.
This also goes for Lewy Body disease. Though both have no cure, there are a number of treatments that can be done to help curve the side effects and progression that comes with these types of dementia's. However, medical conditions that can lead to dementia, such as a deficiency of vitamin B12, do have a cure.