Nobody talked about dementia when I was a kid. I didn’t even know what it was until I was in my 40s. And back then it was described as a kind of “brain fog” that affected octogenarians. It wasn’t something I thought about.

It began to get a good deal of attention about 20 years ago, perhaps because older baby boomers – the bulging demographic that has been dominating cultural concerns – were experiencing it.

Even then I wasn’t scared. I was healthy. And anyway, I imagined dementia as simply life without memory. You were basically living “in the here and now.” Wasn’t that supposed to be good?

As time passed, we learned more about it. And it became clear that it was – or could be – crippling, humiliating, and psychologically painful. It was, indeed, scary. Every bit as scary as cancer, and in one way (with the loss of self-awareness) perhaps worse.

So now, like most people my age, I dread dementia. And I have good reason to worry. Because it is becoming increasingly common with people in their 60s and 70s. It’s even popping up in 40-year-olds.

Perhaps because I’m prone to hypochondria, the fear of dementia flashes through my mind almost every day. If I lose my wallet or keys or especially forget why I’ve come into a room, I think, “This is it.”

Recently I heard that stumbling could be an early sign. And sure enough, I’ve been noticing that I do stumble now and then.

“This is weird,” I say to K as we walk through the city.

“Just pick up your feet!” she replies.

“It’s dementia,” I say. “Early onset.”

She laughs. “Not so early,” is her reply.