"My head's not worth stink."

That is a direct quote from my mother, and I think it aptly sums up her illness. One day her mind was sharp as a tack; she was in control and taking care of my dad, his medical appointments, and all his medications - and then, slowly, she began to lose it. Some time in the past two years, her doctor tells us, she had a ministroke, due to high cholesterol and blood pressure. What happened, we suspect, was that she was so worried about my dad's health that she stopped taking her own medications.

The dementia started so gradually that my sister and I hardly noticed it at first; little things, like the times of medical appointments, slipped right out of her head. She also had strange "moments," like when I took them to see Christmas lights and I made a wrong turn and took us home the long way. My mom became panicky and kept repeating the question, "Do you know where we are?" over and over, then reassuring herself, "Oh yes, this looks familiar," even though we were on a road we hadn't taken before.

That kind of thing progressed to repeating herself more and more often - not the way middle-aged or elderly people do, in an absentminded kind of way, but like this: the same question, over and over, every three to five minutes. She also began to obsess - she might pull a prescription from the doctor out of her purse and look at it quizzically on the drive home, replace it, pull it out again five or six times. Eventually, she forgot how to write checks, even though she'd managed their finances for 62 years. She forgot to fix lunch or cook dinner; we signed them up for Meals on Wheels, which she refers to as "Wheels on Meals." She would call me three or four times in an evening with the same question, unaware she'd already called. I started screening her calls, and I found that if I didn't phone her back right away, she would simply forget she'd ever called me at all.

And yet there are days, particularly when she goes to the doctor, that she can somehow pull it together and almost seem like her old self. We might even have a conversation. On Christmas Day, at our family dinner at my house, she was amazingly calm, happy, and normal-seeming - until she thought she'd lost the checks that she'd brought to give me and my sister. Then the obsessing started - she went in and out of her purse in a panicked way.

A social worker told me that if there was one thing she'd like all families to know about dementia, it's this: it comes and goes.