That's an interesting point, but do you think you're implying that people who are content even if they have alzheimers or a damaged hippocampus aren't technically intelligent?
I don’t think it’s unfair to say that catastrophic conditions like those make you _less_ intelligent, they’re feared and loathed for good reasons.
I also don’t think all that many people would be seriously content to lose their minds and selves this way, but everyone is able to fear it prior to it happening, even if they lose the ability to dread it or choose to believe this is not a big deal.