Anyway, there's a term I've learned recently: "sundowning". This seems to be a noted phenomenon with dementia patients, a marked worsening of their behaviour in the evening and at night. I'm not convinced: Mum is capable of odd behaviour on bright sunny mornings as well. To my mind, the undressing could equally be a response to the early darkness outside at this time of year and the fact that she's bored and cannot stimulate herself with books or TV.
I just caught Mum putting her nightie on at 8pm, which isn't unreasonable except that I'm still thinking of driving down South tonight. So I asked her to dress again. She managed to put on an entirely different outfit, since she had no idea what she was wearing 5 minutes before even though the discarded clothes were laid out on the bed in front of her. She started talking to me from inside her room and I asked her what was wrong. She told me that I was confusing her, asking her all these questions. I hadn't said anything since asking her to dress again.
Now, I've noticed for a few years that Mum will often start a conversation with "As I said to you..." or "Do you remember I told you...?" when discussing something entirely new to me, and she'll often respond to me with "You keep telling me that" when I know for a fact I've never in my life said that thing before. I've suspected for a while that Mum is having conversations in her head without me, but tonight's episode was a clear example. Poor thing, I'm bad enough to live with - Mum's plagued by phantom Gregs, too.