During the 11 years that Margaret Albus lived with Alzheimer's disease, the worst moment came in the middle of one night, when she called out to her daughter, panic-stricken: "I just want to know who I am."
"I am almost crying now," said Becky Albus, a 53-year-old optician who was looking after her elderly parents that weekend. "I would have done anything not to let her be scared."
Margaret Albus died on Dec. 31, 2009, at the age of 86. But she had mentally slipped away a decade before. She had seven children.
"It's the disease of the long goodbye. It's a perfect description," said another daughter, Elaine Albus, 51, a team leader for a Minnesota business improvement company.
"The fear in her eyes, it's hard to watch over and over again," she said. "There's nothing you can do about the terror but say, 'Mom, it's all right. We'll take care of you.'"
All seven of Margaret's middle-aged children -- four sisters and three brothers -- are at increased risk for developing Alzheimer's disease.
A decade ago, they volunteered to be part of a study at the University of Wisconsin to find genetic markers for the disease that today affects 5 million Americans.
The goal of the study, the largest of its kind, is to identify people in middle age and follow them in the hopes of learning how the disease develops.
Scientists hope that if they can find markers to predict eventual onset, they can develop early interventions.
"This is a terrible disease and to have a parent or anyone in the family [with Alzheimer's] leaves an indelible mark," he said. "The loss of identity and loss of personality -- we have an organ called the brain that is who we are."
The disease affects so many people that when the study was announced 10 years ago, the institute got 600 phone calls in the first 24 hours.
"We never had to recruit, that's how much interest there was in the study," he said. "And people have traveled large distances to be a part of it."
Now, the study includes 1,500 participants with a mean age of 53, including all seven of the Albus siblings. The hardest part has been finding those who don't have a family history -- and a compelling reason to participate -- for a comparison group, according to Sager.
Risk factors for the disease include increasing age and abnormalities in the apolipoprotein E gene (APOE), which is on chromosome 19 and has three different alleles, or alternative purposed, like those for eye and hair color.
One -- the e4 allele -- is associated with increased risk. Not all who have this gene will go on to get the disease, but they are more susceptible.
APOE was first recognized for its importance in lipoprotein metabolism and cardiovascular disease, but has more recently been studied for its role in the onset of Alzheimer's disease.
About 44 percent of the study participants have APOE abnormalities. They have more than double the risk of the general population, 15 to 20 percent of whom have that gene sequencing.
"The disease is more prevalent in women because they live longer," said Sager.
Disease onset is typically in the late 70s and early 80s. By age 85, 30 to 50 percent of adults have symptoms.
Margaret Albus, a homemaker, raised her large family in the small Wisconsin town of Lady Smith, where her husband Roger ran a business that made conveyers for farm equipment.
But when she reached 75, her memory began to fail. After tests revealed she had Alzheimer's disease, the siblings called a family conference.
"All of us kids came from wherever we lived and sat around the table," remembers Elaine. "We all knew there was something wrong with Mom, but to have it confirmed is awful. On the ride back I was with one of my sisters who also live in the Twin Cities and we cried. There is nothing you can really do."
"Mom just sat in the meeting, kind of like it wasn't about her," said Elaine. "She never really remembered getting the diagnosis."
Her family meant everything to her, but eventually, Margaret Albus didn't even remember who her children were.
"Once in a while she would say, 'Elaine,' and I would look at her. Wow, where did that come from?" said Elaine. "Sometimes she would know you and sometimes she wouldn't. It's really hard to see your parents -- someone to talk to about what's going on in your life -- and then they're not there anymore."
The Albus children know that one day this may be their fate. Some of them have already bought long-term care insurance and they talk about looking into nursing homes and assisted care facilities after reaching retirement.
"I kind of feel like it's for sure, out of seven of us, a couple of us are going to get it," said Elaine. "So you have to keep telling yourself it could be you, and be prepared for it."
But they say they keep their sense of humor.
"In my family it's become a natural thing to do," she said. "Every time someone forgets, we say, 'It's starting already.' We say we will get rooms next to each other. It's a little bit of denial, joking with each other."
"I fully expect that I will be in a facility," said Elaine, who is single and doesn't have children. "I want my nieces and nephews to get me in early enough. My one big fear is being one of those cat ladies, and the social services come in, and I am living in garbage with animals all over the place."
The Albus family had both the money and manpower to look after their mother, so care giving was not as stressful as it is for some families.
At first, Roger Albus looked after his wife, but soon, the siblings set up a weekend schedule to help give their father some relief.
"Six years ago, Dad was totally stressed out," said Elaine.
Kathy Cronick, 48 and the youngest, lives in Lady Smith. She checked in on her parents each day, handling the shopping and doctors' visits.
The others, who lived across Minnesota and Wisconsin, two or three hours away, set up a rotation, staying with their parents on weekends.
"I cannot imagine how a smaller family does it with not so many people to pitch in," she said. "It would be much more stressful."
Cronick said Alzheimer's disease is "always in the back of my mind.
"But there's nothing you can do about it and there are no cures, so what happens, happens. I just hope I forget quickly," she said. "I know it was really scary to see my Mom, but I don't dwell on it."
The siblings said they were lucky because their mother was "an easy person and always good natured," which is not always the case with Alzheimer's patients.
"She was unhappy when we took the car keys away, then we told her we were going to get the car to get fixed and she accepted that," said Elaine Albus. "I hear others have a personality change or become totally violent."
"As Mom would say, 'We are blessed.' And as awful as it was, it could have been so much worse," she said.
But things started to get more difficult.
"Eventually my dad started not sleeping well and worried about Mom getting up," said Elaine. "We convinced him to get overnight help so he could get a solid night's sleep and they could hear when she wandered."
They blocked off stairs and put locks high on doors so their mother couldn't open them. Her husband put wind chimes on the bedroom door so that he could hear it opening and closing.
Until their mother got pneumonia and died in the hospital, the family was able to keep her at home, where their father, now nearly 94, still lives on his own. "He's pretty sharp for his age," said Elaine.
"Right until the end, she knew Dad was someone important to her, though she didn't know who he was," said Becky Albus. "But we feel really blessed we didn't have to put her in a nursing home."
Some of the Albus siblings are happier about the poking and prodding of the Alzheimer's study than others.
Researchers took fasting blood samples, weight and measurements. Every two or three years, they are subjected to periodic mental tests, repeating word lists and solving math problems.
The follow-up continues "until they lose their funding or make some discovery," according to Elaine.
The study will compare its data, is looking at factors that might contribute to the onset of Alzheimer's, such as lifestyle choices and diet. Exercise is thought to be protective. They keep track of monitor cognition, years of education, biochemical parameters in the blood and rising levels of homocysteine, an amino acid associated with dementia.
"There is good data to suggest that midlife obesity, high levels of cholesterol in midlife and a host of other things that occur in midlife that increase the risk 20 or 30 years later," said study director Sager.
Participants are not told the results of all these tests, and the institute has filed a certificate of confidentiality with the National Institutes of Health, so that personal data can never be released and have an impact on insurance decisions.
At information sessions, Sager and his colleagues tell families like the Albuses, "There's no guarantee [the study] will help you one bit, but we hope your children will be the beneficiary of the research."
"At first, I naively thought this will save Mom -- they'd figure something out," said Becky Albus. "But it was quickly obvious that wasn't going to happen. And it probably won't happen for us either."
But the study has been "remarkable," said Elaine Albus. "I think we are all doing this because we loved our Mom. Mom can't benefit, but we might be able to benefit my 13 nieces and nephews."
"Its' very frightening to know that as the baby boomers age, there will be so many who get Alzheimer's," said her sister, Kathy. "We just wanted to do what we could to help."
To learn more about the work that researchers are doing to untangle the mysteries of neurocognitive disorders, visit the website of the Cleveland Clinic Neurological Institute's Lou Ruvo Center for Brain Health here and the Keep Memory Alive (KMA) website here.