Over the last 2000 years, have any Popes been recorded as going senile?

by bluefrite

I was thinking about what would happen if the leader of the catholic church was diagnosed with dementia, alzeimer's, etc. Obviously these diseases were discovered/diagnosable (relatively)only recently, but what would happen if/when a Pope is diagnosed with a disease of this nature?

[deleted]

As far as I'm aware, no pope is known to have suffered from any such ailment.