In other care facilities and in hospitals, too, “wanderers” with dementia are believed to have spread the virus and caused outbreaks — but what are administrators to do? They can’t just lock people up.

“Stay in your room,” the nursing aides tell Mr. Williams. But he doesn’t stay. Whenever he gets out, an aide redirects him back to his armchair.

Mr. Williams speaks to his wife, Bev, most evenings after dinner, on the phone, but then he forgets.

He also forgets the time his wife drove to the nursing home and tried to talk with him through the window — and he couldn’t hear her, and the whole thing was so confusing. “Why don’t you just come in?” he asked. Back near the start of the pandemic, his family sent him a small cardboard cutout of her image, but then he started talking to the cardboard and trying to feed it, so the staff took it away.

Even those who stay free of the virus have suffered disproportionately from the disruptions of pandemic life. Dementia responds well to routine: rigid, time-blocked schedules and familiar faces. But the pandemic has shown us, and warned us, how quickly the fragile channels of dementia care — the muddled blend of formal and informal networks that sustain those routines — can collapse under strain.

When a daily routine falls apart, a person with dementia can seem to fall apart, too. Around the country, geriatricians describe an acceleration of decline — one that they say has not yet been captured and construed by academic literature, but that they see play out in the bodies and minds of their patients. People with dementia are losing things faster than they should: weight, words, functional abilities, their remaining sense of self.

But the question I have been chasing for the last year is different. I wanted to understand what it feels like to live through this terribly disorienting time inside a mind that is already deeply disoriented.

Read more in the New York Times.