Loss of memory, confusion, anxiety, losing the ability to do everyday things and to look after yourself, losing your personality, all gradually getting worse; (my experience with my mother).
Personally, I do not think it is a life worth living, although this is a very harsh view.
Why have you asked this question?
I’m curious too...you can get a medical description from anywhere...and what are people here going to say? Certainly no one is going to say that it is nothing to worry about, take a pill and all will be well. Unfortunately.
I put 'dementia' into the search box at the top of this page, here's the result: https://forum.alzheimers.org.uk/search/52086/?q=dementia&o=date
reading these posts and all the recent posts and archived posts here on TP may give you some appreciation of how much dementia means to the folk who have shared their experiences so generously, some at particularly challenging times in their lives
Seriously, OP, please explain your "research" to us, because just signing up to put a question into the room without any background info isn't the best etiquette.