That’s strange. I had a great aunt who died at age 104 and was both deaf and blind! She was clear as a bell until last two yrs.
Your aunt would be labeled an Outlier:
An outlier is an observation that lies an abnormal distance from other values in a random sample from a population. In a sense, this definition leaves it up to the analyst (or a consensus process) to decide what will be considered abnormal.
Hopefully, you got some of her family DNA.