A man sits in a corridor as he waits for news of his wife who is suspected of having COVID-19 at the Dr. Norberto Raul Piacentini Hospital in Lomas de Zamora, Argentina, May 1, 2021. (AP Photo/Natacha Pisarenko) AP — Researchers are trying to unravel why some COVID-19 survivors suffer “brain fog” and other problems that can last for months, and new findings suggest some worrisome overlaps with Alzheimer’s disease. One study of older adults in Argentina found a surprising amount of dementia-like changes in memory and thinking for at least six months after a bout with the coronavirus — regardless of the severity of their infection. Other researchers found Alzheimer’s-related proteins in the blood of New Yorkers whose COVID-19 triggered brain symptoms early on.