Lisa Smith is the picture of vibrant aging. She's bright, lively and outgoing, a trim 89-year-old who lives alone, golfs three times a week and goes to chair exercise class on other days. She plays bridge online and keeps up with politics.
And her forgetfulness has gotten to the point that she has posted notes in her airy Placer County home to remind herself of a few basics.
"Turn Off Stove and Oven," reads the note posted in her kitchen. "Lock Your Doors," read the note that used to hang just inside her front door.
"Turn Off the Water," read a sign she took down not long ago. It was a reminder not to repeat the incident of a year ago in which she got up in the middle of the night to make cocoa, forgot to turn off the kitchen tap or make sure the sink was unplugged and woke up hours later to a house flooded with water.
"I'll say to my friends, 'I can't think,' " said Smith, who relocated from New Orleans in 1998. "They say they can't, either. I can't tell what's normal."
Diagnosed two years ago with mild cognitive impairment, which can progress to full-blown Alzheimer's disease, Smith in some ways represents the shape of the Alzheimer's epidemic to come.
A growing number of people with dementia already live alone more than 800,000 across the country and 72,000 in California, according to a new Alzheimer's Association report. Half of them have no specific caregiver.
With the aging of the independent-minded baby boom generation, which has been more likely to forgo childbearing and more apt to divorce, those numbers are expected to soar.
"It's not surprising, if you think about the seniors you know," said Bill Fisher, chief executive officer of the Alzheimer's Association of Northern California. "There will be people who are divorced or widowed or never partnered. Maybe their children live across the country. They're not living with family."
While an estimated 5.4 million Americans already have Alzheimer's, a progressive wasting of the brain that is the leading cause of dementia, that number is expected to triple to 16 million by 2050.
But in some ways, dementia remains a hidden problem. As many as half of the people with Alzheimer's will go to their graves undiagnosed, said Fisher, in large part because they think extreme forgetfulness is a normal problem of old age.
"Most of the people we deal with are adult children reaching out to us, concerned about their parents' forgetfulness," said Dale Masters, a manager with the Sacramento area senior referral service A Place for Mom.
"They don't remember to eat properly. They don't remember to hydrate properly. They don't remember to take their medications properly.
"And the parents typically think everybody else has the problem. They think they're OK living alone and don't need assistance."
Living longer and alone
U.S. census figures indicate that in 2010, almost 30 percent of people 65 and older lived by themselves, up from only 9 percent in 1950. Fully 40 percent of women in that age group, as well as 19 percent of men, were widowed. Among the oldest old people 85 and older 80 percent of women lived alone.
Only 4 percent of the elderly lived in skilled nursing facilities.
Those statistics dovetail with aging experts' forecast for the baby boom: More people will live longer, spending more years living alone and, if possible, remaining in their own homes.
Lou Bordisso Jr. would prefer to stay at home, too. Only 58, the retired psychotherapist was diagnosed two years ago with early stage Alzheimer's disease. He moved home from Vallejo to the Sacramento area and until recently was able to share a live-in caregiver with his elderly father.
Now his father is in a nursing home and although Bordisso doesn't yet require full-time care, he knows he needs help in several areas.
"My finances became a problem several months ago," he said. "I was writing out a check and couldn't remember how to make an S for the seven on the check amount line.
"I've given up night driving already because my vision is impaired, and I have poor spatial judgment. Without a caregiver, I won't be able to go to meetings at night. I won't be able to drive over and see my dad at night.
"I'm quite forgetful about taking medications. Sometimes, I take too many. I've had to put a yellow sticky note on the box saying, 'Don't Take Me.' "
As a result, Bordisso is assessing whether to turn to assisted living now, before his dementia worsens. Another option for many people in the early stages of Alzheimer's is part-time care in the home, which costs an average of $20 an hour.
The math of elder care becomes daunting as Alzheimer's progresses. The average cost of California nursing home care is $70,000 a year but the cost of round-the-clock private home health aides can surge past $160,000 a year.
On a limited scale, said Masters, "home care is a good first step. Things can be done to make an older person successful at home even with dementia.
"We can take care of their nutrition, hydration and medication management. We can go in and throw away spoiled food. And we'll have the family take the financial things off the plate.
"But a lot of the time, families are in denial."
'Taking my chances'
For millions of families, aging and forgetful relatives who live alone are a crisis waiting to happen.
They could fall and break fragile bones. They could accidentally double up on powerful medications or forget to take them altogether. They could wander from home, lost and confused. They could leave a skillet on a hot stove, causing a house fire.
"Very early on, you've got to pair up the person with dementia with someone who can make decisions for them," said Fisher. "Because they won't be good decision-makers themselves for long.
"It's the nature of the disease. It's insidious and subtle in its progression. You know the crisis is coming, but you don't know when. There's not a crisp line."
Divorced more than three decades ago, Lisa Smith remains close to her five grown children, who are scattered across the country, as well as a circle of friends.
Her dementia diagnosis threw her for a loop.
"You know the horror stories," she said. "I got very anxious. What's going to happen to me? I got very stressed, and that made me more forgetful. I was becoming more reclusive. I was very depressed.
"And then I realized that everybody has something going on with them. I'm healthy. I can do things other 89-year-olds can't do. I guess that kind of rationalizing was healing for me."
Then she accidentally flooded the house.
"It scared my children when that happened," she said. "It scared me, too."
Her family insisted that a home care aide visit weekly to check on her, monitor her medications and make sure she was eating properly. Her children have also discussed the possibility of Smith moving to a seniors care facility.
But she'd like to stay in the home she's filled with antiques and framed family photos.
"I don't want to leave this place if I can help it," she said. "They're right. I should probably think about it.
"I know I'm taking my chances here."