You know as well as I do that there is a great deal of evidence that Reagan was declining precipitously during his second term. Regarding Alzheimer's, we know he was formally diagnosed by 1994, just five years after he left office. Alzheimer's isn't a virus you catch one day -- it develops over time. We also know he was barely visible his last two years in office, and there are reports going back to 1986 that Reagan didn't even seem to know his own name during meetings with him. Shit man, his own son has even said something was wrong with him and he wasn't all there halfway through his time in office.

You can argue that it's inconclusive as to whether he was suffering from diagnosable Alzheimer's, dementia or both while still in office, but it's pretty clear he was well into his congitive decline in1987 when Bork was nominated. I'd say in all likelihood, he was already developing Alzheimers and so would many others.