TIL about terminal lucidity, a phenomenon in which patients with degenerated brains from neurodegenerative diseases such as Alzheimer's suddenly regain lucidity, personality and memory before death. There is no known medical explanation for this phenomenon.

Both my grandma's passed from Alzheimer's. One was confused and scared like yours, and the other reverted to almost infant like happiness. Both where sad in there own ways, but the terrified look you described is haunting. To me it seemed like she was in a near constant state of panic attack. Lot of talk of reckoning too (she wasn't religious at all), which I also experienced with my happy grandmother's next door neighbor. She was deeply terrified and confused from her Alzheimers and she swore I was Jesus Christ there to save her from "demons". On Easter one year when I was ~17 she escaped the staff restraining her and ran after me, litteraly banging on the elevator door as it closed yelling "Jesus dont leave me, you have to save me! They are hurting me here!"

Alzheimer's is a fucking creepy and tragic disease.

/r/todayilearned Thread Parent Link - en.wikipedia.org