Alzheimer on set, back-date provable ?

[eas-lab at absamail.co.za]

Hi,
  some medical conditions which are caused by physical 'actions'
can be back-dated.  eg. date of death can be determined after death,
by measureing and calculating the known rate of certain physical
proccesses.

How would I 'prove' (what I already know) that a person was in
advanced dementia two years ago ?

Thanks for any answers/advice (possibly also Cc:ed ).


-- Chris Glur.