My Mum is 83 and was diagnosed 13 years ago. Since November last year she has been sleeping a lot more. She is usually wakes by 10.30 am has breakfast then sleeps on and off through the afternoon. The evenings are sometimes difficult when she goes into this 'Sundowner' phase, where the parkinsons's dementia gets the better of her and she becomes confused and disorientated. This is very distressing, last night she asked to use the phone to speak to her Mum (dead for over 50 years!). She was asleep by 10/10.30pm. Our district nurse says to just go with it, so that's what I do. Not saying that that's the best advice for everyone but it works for Mum.