Last of these posts.
Thank you Chrisite47 for this article. It is precisely what I have been searching for.
Alzheimer’s disease and anesthesia
from Frontiers in Neuroscience.
Caution: This is a clinical paper and so it is difficult for a layman like me to read.
Article here:
dropbox.com/s/u4hurdsicjlrg...
The paper presents evidence of persistent post operative FOG in Alzheimer's patients. In so doing it looks at the formation a number of enzymes which increase the likelihood of neurofibrillary tangles and the the formation of Tau protein, both of which are implicated in PSP. They evidence that the temperature drop in the brain whilst being sedated exacerbates this process.
But they conclude:
"Overall, epidemiological evidence establishing a link between
anaesthetic exposure and the risk of AD [Alzheimer's Disease] remains controversial, with some studies finding an increased risk after anesthesia-exposure, and others finding no risk.
So for me, in summary, best avoided if you can, but not necessarily harmful.