I am not a fan of pinning such generalizations to an age. Rather I would prefer that people take cognitive tests every 5 or 10 years to see how they are doing.

I am not a fan of pinning such generalizations to an age. Rather I would prefer that people take cognitive tests every 5 or 10 years to see how they are doing. If the numbers start dropping I would prefer that one finds out why and does not accept theories from doctors. Make people present empirical data and provide potential suggestions for slowing cognitive decline and then compare the results against expectations. If there is a large deviation find out why. As just one example there are now petscans that can do a decent job of finding damage from silent micro-strokes and we are finding out that damage can occur from low blood pressure at older ages which runs counter to accepted theories of degradation and risks.