Dreaming while awake

If Mother is not staying with me I call her at least once a day. I called her as usual on Friday and we spoke for a few minutes. She seemed lucid, but said that she had been dozing when I called because she had not slept well the previous night. Two hours later my phone rang, but I was unable to answer. When I checked she had left a voice mail saying "well, at least your message machine answers even if you don't....it's the only way I hear your voice". I called her back and asked what was wrong, she said she was fine. I asked if she remembered that we had spoken 2 hours earlier, she said she wasn't sure. I then asked why she had left the message saying that I wasn't speaking with her. She answered that she must have had a dream while awake in which I was not talking to her!