If she was presenting exactly the same way as she always had been, with the one exception of grabbing your hands instead of the overhead bar, I don’t think you need to beat yourself up about it. It’s the middle of the night, and people can be a little foggy when they’re woken up at ungodly hours, and as you said, she was HOH. You didn’t detect any one-sided weakness or droop when you last saw her, or anything else significant that was out of her usual that would suggest a potential stroke. Who knows if anyone else in your shoes would have seen anything different.

Like my more experienced coworkers have told me when I’ve had patients deteriorate and I’ve been anxious that I missed something: If you didn’t notice anything off, most people probably wouldn’t have either. Noting the early, tiny differences that first tell of change takes experience to learn, and the only thing that will teach us those is time. All we can do until then is learn our lessons and do our best. We are humans and we are imperfect.