Yesterday Derek read of our attempts to pin down a starting date for mum's dementia. He wrote the following in an email to me:

When Greg, Mum and Dad visited the UK in 2000 we all noticed that she was no longer the mother, mother-in-law and grandmother who we had known and last seen over Christmas 1992. Whereas previously if Janet had been preparing a meal Mum would have been in the middle of it, helping and contributing, she was now content to let others get on with things while she sat quietly by. We took Dad to a nearby restaurant for his birthday and Mum seemed confused both by the surroundings and what was happening (to be fair, so did Dad – but then he always did). She also needed help with the menu and in remembering what she had ordered for the meal. There was clearly something missing which meant that she allowed others to take charge of events in a way she would not have done previously – going with the flow and not being fully aware of the detail. Rebecca became very aware of this and gave Mum, along with the rest of us, the Mini Mental State Examination (MMSE) under the guise of needing the practice. From memory Mum’s score was around the mid 20s which is a clear warning sign that something is happening, bearing in mind that the median score is 29, and 26 or less is taken as evidence of dementia.

In October 2001 I visited Sydney in order to be present (with Greg) when the clinical psychologist presented the results of the 6 months assessment Mum had undergone; he was clearly of the opinion that mental deterioration had occurred and was in progress. He prescribed a drug, I cannot remember its name but it was very new at the time. Whether it was ever obtained and taken I do not know. The word Alzheimer’s hung in the air, although nobody said it and, of course, the only definitive diagnosis is post mortem. I do not remember either Mum or Dad asking many, if any, questions of the psychologist. The reasons for this could be many including an unwillingness to face what was an appalling future, a lack of knowledge/understanding of the disease and implications or, in Mum’s case, possibly her disengagement was such that she was content to let others take charge and therefore she didn’t need to know.

As you know, the level of educational attainment (in its widest sense) is a mitigating factor against Alzheimer’s and while I had always thought that this was merely a masking of symptoms, Rebecca tells me that there is some evidence that it goes deeper than this and can have an effect on the disease itself. Bob has achieved a higher level of education that Mum ever did and continued for longer; indeed his hobby continues to stretch his creativity and problem solving skills. My overall impression of Mum has been that she switched her brain off when she left school and while this is clearly a gross simplification, I suspect that the element of truth which rests in it is that of an absence of intellectual development stretching/testing throughout her life. This is a long way round to saying that I suspect that her disease had started pre 2000, but that its progress was inhibited by her educational level and she was able to mask its effects from the family by subtle confabulation. During our visit for their sixtieth wedding anniversary, the confabulation had ceased to be subtle and had become self evident.

On the basis of the above, I believe that Mum was about Bob's current age when AD started but that his educational attainment and current activities offer him a great deal more protection than Mum had. We will have to wait and see how things develop with him.

Another fact to bear in mind is that the average time from diagnosis to death is eight years, and given that the sufferers eventually lose the ability to recognise either food, cutlery (and its purpose) or hunger, I do not expect Mum and Dad’s underlying level of fitness to be an overriding factor.

This puts the start date back to 2000 or even before - given that dementia of some variety was diagnosed then by Rebecca. As Derek says, Alzheimer's disease per se can only be definitively diagnosed post mortem. And his observation that death follows diagnosis by an average of eight years means that in only a couple more years mum will be on borrowed time, doubly so.