Not long after her father, Peace Corps architect Sargent Shriver, announced he had Alzheimer’s in 2003, Maria Shriver sought to make a documentary about the disease.

No network wanted to do it.

Five years later, circumstances have changed, to the point where HBO has not only picked up Shriver’s original idea, but expanded it into a four-part series called “The Alzheimer’s Project,” with a host of multimedia components, including a book, DVDs and YouTube videos.

More and more people know someone who has been diagnosed with Alzheimer’s, Shriver says. “We are aging; the baby boomers are coming into their 60s. And so I think the timing of this is right.”

Alzheimer’s is on the national agenda, the subject of a recent study group chaired by Newt Gingrich and Bob Kerrey, and it’s all the more relevant with President Obama’s recent lifting of restrictions on stem cell research and efforts to reform health care. Shriver hopes Obama will go further, and make “the brain a priority of his focus, like President Kennedy did with the moon” — the subject of massive research to unlock its mysteries.

“Alzheimer’s is the most expensive disease we have,” she says, “and the research shows that it will singlehandedly break the healthcare system if we don’t have a cure.”

The first documentary, “The Memory Loss Tapes,” debuting May 10, profiles seven people living with Alzheimer’s, in various stages. “Momentum in Science,” looks at the advances in research. ” ‘Grandpa, Do You Know Who I Am?’ With Maria Shriver” focuses on grandchildren coping with their grandparents’ illness. And “Caregivers” profiles those who witness their loved one’s descent.

HBO was among the networks that rejected Shriver’s first pitch, but Sheila Nevins, head of its documentary division, called Shriver two years ago and said she was ready to do the project, similar in scope to the pay cabler’s “Addiction” series. Produced by John Hoffman and executive produced by Shriver, the Alzheimer’s project is sponsored by the National Institute on Aging, among others.

“I am in a much better place today to be executive producing this, to be involved in this and to be able to talk about it than I ever was in 2004,” Shriver allows. “That shows you, once again, that there is a higher power that is managing these things.”

The most personal portion of the series is “Grandpa,” based on Shriver’s children’s book, “What’s Happening to Grandpa?” and her own experiences with her father. The doc features the stories of a half-dozen children and their grandparents, including a 15-year-old girl who has to deal with her grandmother’s mood swings, and discovers that playing Elvis Presley recordings for the woman helps soothe her agitation.

In the project, Shriver shares a moment she regards as a turning point in how she has accepted her father’s diagnosis. It was when she stood with him on the lawn of his home and her father told her to listen to how serene the sound of water was. In truth, it was the sound of traffic, and after trying to correct him, Shriver eventually went along with it. The message: Go with the flow.

“When anyone has a loved one who gets diagnosed with Alzheimer’s, you don’t want it to be, so you keep correcting the person,” she says. “You want them to be who they were, not who they are.”

Her father, now 93, was an instrumental force not only in the Peace Corps but also in Lyndon Johnson’s Great Society programs, and was George McGovern’s running mate in 1972. He still looks “dashing” and “has a smile on his face,” Shriver says. She says it took her some time to accept the fact he did not recognize her.

“I tell him who I am and he is like, ‘Oh, great to see you.’ I don’t try to have the same kind of conversations we once had. It is, ‘Look at the weather. It is pretty outside.’ You have different conversations, different expectations, or none at all.”

Shriver says her own children “are good with my dad, but they are very vocal about, ‘Gee, I hope you don’t get like that.’ ” Following research that shows diet may be a contributor to the disease, Shriver says she takes things like Omega-3, and otherwise relies on “hope and exercise.”

She also has a new perspective on the best way for a family to respond — such as whether to put a parent in an assisted living home.

“I have really come to learn that none of us can come to judge the path of another,” she says. “It is so emotional and so personal, and for many families, it is financial. As I get older, I think the less judgmental we are as individuals, the better off we are in life, particularly in judging families dealing with Alzheimer’s.”