When President Reagan announced he had Alzheimer's disease, Diana Friel McGowin felt two emotions: sadness over his condition and joy over the fact that he had gone public.

An early-stage Alzheimer's patient who is the author of "Living in the Labyrinth--A Personal Journey Through the Maze of Alzheimer's," McGowin, 57, knows firsthand of the emotional and psychic pain caused by the disease, a progressive degenerative disorder that attacks the brain and results in impaired memory, thinking and behavior.

But Reagan's announcement has suddenly made the nightmare of Alzheimer's easier to bear for the estimated 4 million U.S. patients and their families, she said.

"The entire Alzheimer community has been hoping for a long time that someone acclaimed by the world who is still alive and functioning would step up and say they have the disease," said McGowin, who will speak on Friday at the Alzheimer's Assn. of Orange County's annual conference, "Facing the Challenge."

"Families of other Alzheimer patients--Rita Hayworth, Norman Rockwell--announced it after they were gone because of the unwanted embarrassment (of the disease).

"So, while we always regret to hear we have another fellow traveler, at the same time, we are so very proud he is also standing up to be counted."

McGowin decided to go public with her diagnosis because she "couldn't live in shame for something for which there should \o7 be\f7 no shame," she said during a telephone interview from her Orlando, Fla., home. "Until Reagan made his announcement, I have been the one thrust into the spotlight because I \o7 won't\f7 shut up about it. I am an intense advocate."

When she discusses the "Patient's Perspective" at the Pan Pacific Hotel in Anaheim on Friday morning, McGowin hopes to show Alzheimer's care-givers and members of the health-care industry what one Alzheimer's patient can do for herself.

"I want them to understand how much they could do for us if they just put their mind to it," she said. "I will share my perspective mostly, but I will also share stories from other patients like me." (For seminar information, call (714) 283-1111.)

McGowin is especially proud of the support group she has founded for newly diagnosed Alzheimer's patients. "It has spread across the United States and Canada," she said.

"We get together, share stories, hints, tips, research information--anything we can get our hands on. And we give each other moral support, learn to laugh again."