Apologies in advance for long post, trying to give the full picture.
Mum is in her 90s and has been getting a bit more forgetful in the last few years but was functioning fine and lived independently. Then last summer she passed out, fell and suffered a nasty fracture. She also hit her head and may or may not have had a brief concussion. Head was MRI'd and no stroke, but some 'white patches' suggesting previous mini infarcts.
She was in hospital for several weeks and though never got as far as 'delirium' was definitely very weak and seemed to be declining generally. Came home , carers arranged (2 visits per day, they are really good and reliable) and seems to have picked up in strength and alertness.
However. We have noticed she is
a) forgetful in that we tell her something (that she wants to know) and it goes out of her head, she needs to be told again
and b) she seems to be confused about the timeline of the past year, what happened before and since she was in hospital, and sometimes seems to forget that the things she can't do now are since her fall, and because of her fall, and for example thinks she has been doing things she can't do any more, in recent months.
She is quite tired and sleepy a fair bit of the time and sometimes I think she just can't be bothered to think/remember about things, because now with carers and close involvement by her two adult children (we have activated £ PoA etc) she doesn't have to, and she does seem to enjoy being looked after.
She's not gaga, she still does her online shopping (but not as well as she used to, and often forgets to look at the shopping list the carer writes out for her). She makes her own phone calls to arrange appointments still.
But she has definitely lost flexibility of mind, and as above, is now quite vague and forgetful. But I don't know if this is a disease process or just natural ageing at this point. And I don't know at what point there would be anything to be gained from assessment/investigation/diagnosis.
I am loath to suggest yet more investigations unless there was a clear benefit. She had to have her heart assessed after her fall, and she is in the process of a skin cancer diagnosis/treatment, and each visit to a doctor/hospital is a major palaver - for her, and I'll be honest, for us as well (she is 3 hours away from me so it involves a couple of days at least out of my life to take her when its my 'turn'.
Clearly if she was not safe at home it would be a different matter, but day-to-day she manages fine. She has a set routine (has had for years really, there's just less variety now) , well aware of what time things should happen. She is aware she is getting forgetful, and keeps everything written in a diary to know eg when the gardener is coming etc - she has always done this but she knows she is more reliant on things being written down.
So very interested to hear other people's experiences with cognitive decline and pursuing an assessment, in very late life.