Common, maybe not, but not uncommon either. A fair number of people with dementia simply do not recognise themselves in mirrors (quite possibly because because the image in the mirror doesn't look as they remember themselves). Personally, I would simply remove all non-essential mirrors or cover them.
My OH would glimpse himself in the mirror and be really frightened about the 'other man in the house'.I did as Jennifer pa suggested. All mirrors removed I'm afraid. I think however often you tell a Dementia sufferer it is their reflection, they will never believe you. One other point -my OH was so distressed by the 'other man' in the mirror, he tried to break it-luckily it just cracked-but it could have been very dangerous.
My husband is convinced the person in the mirror is someone trying to take his keys,
wallet etc. This leads to shouting and screaming episodes. Very hard to calm him down afterwards, usually try distraction such as a cup of tea !
My husband saw himself in a full length mirror when he was in an assessment unit and turned to me and said there was a man over there with a shirt on the same as his.
He then statewide to wave at the man who of course waved back and he chatted to him but then thought he had gone deaf because he could not hear him. I cried and laughed at the same time. He showed no distress which was a relief.
I went to a very informative talk about dementia and it was explained that as a dementia progresses the person affected won't recognise themselves in the mirror. This is because in their minds, they are usually in their middle age. Therefore the 'old person' in the mirror can't possibly be them. Hope this helps.
My mum went through a phase where the reflection upset her and (she was in hospital at the time) the mirror was covered.
By the time she moved to her care home she was not so concerned. The lift has a mirror in the back and when we used to go into the lift on a trip out she'd see the lady in the mirror and say hello - once she told me that the woman in the mirror looked like her sister! She wasn't wrong! I cried and laughed too Jaymor
I have noticed Mum doing this in photographs. We got married in August, and showed her the photographs a few weeks after the wedding. We showed her a photo of herself, and she said who's that? She doesn't recognise herself in photo's.