A year ago, when a doctor finally diagnosed the brain disease that had been making it harder for her to walk without falling, Rona Zelniker told her son and daughter that she was going to end her life while she still could, before complete disability set in.

Her children were grateful for the way she prepared them, and for the time they had together at the end. "I must have cried 150 times in the last year," said Keith Zelniker, 32, her son. He scheduled off the week she was planning to die, writing on his work calendar, "bereavement time."

Zelniker felt anxiety about how she would end her life. She didn't want to swallow pills, only to wake up even worse off, with brain damage. A gun was out of the question.

Last fall, she contacted an organization she had found on the Internet - the Final Exit Network - which she described in a letter as "the answer to my prayers."

After reviewing her records and interviewing her, members of the network instructed her how to end her life quickly and painlessly, and an "exit guide" - a retired guidance counselor from Wynnewood - would come hold her hand.

Zelniker was enraged, but undeterred, in February when Georgia authorities charged four members of the Final Exit Network with assisted suicide, a felony. The Final Exit Network halted all trips to the bedside, fearful of more police sting operations.

"We were told all exits were off," said Leonora Vizer, 77, the Wynnewood guide, who had to stay home.

So on March 18, Rona Zelniker, one month shy of 61, with a progressive and incurable brain disease called Sporadic OPCA, ended her life alone, in the spare bedroom of her condominium, adjacent to the golf course, in an active-adult community in Monroe Township, Middlesex County, just off Exit 8 of the New Jersey Turnpike.

Zelniker pulled a clear plastic hood over her head, fastened the bottom around her neck with Velcro, opened two helium canisters with tubes leading into the hood, and soon enough was unconscious, and then dead, in her black recliner.

She was wearing a $6 golden necklace Keith had given her when he was 13. Inscribed on the heart was, "I love you, Mom. 1990."

By her side Zelniker left letters for police, friends and family.

"I hope that you all understand my need to die with dignity at the time and place of my choosing," she wrote. "It has not been easy for me these past months. My balance has become so bad and my legs so weak that I am in constant fear of falling and hurting myself . . . I am dropping almost everything. It is getting harder to speak and I am choking more frequently. My window of opportunity is narrowing rapidly and if I wait much longer, I will be at a nursing home's mercy. I could never live like that. I would not have done this if I had time left. Please know that I really don't want to leave my wonderful life, family and friends. I waited until the last possible moment."

She also wrote, because of the Georgia arrests, "I have to do this alone. Nobody should have to go through this unaccompanied, for fear of their friends and loved ones being arrested. I truly hope that one day, the laws will be changed and people like me will be able to die with dignity, with friends and loved ones by their side."

John Celmer, who ended his life last summer in Georgia, and whose death prompted the arrests of Final Exit Network members, was not terminally ill. He was disfigured from surgeries, skin grafts and cancer treatments for his jaw and would not leave the house.

"We're talking about a person who was cured of cancer," said John Bankhead, spokesman for the Georgia Bureau of Investigation. "Without the involvement of the Final Exit Network, he would likely still be here. The problem is they offer this as a viable alternative to people who are not terminally ill."

He stressed that this group isn't licensed, isn't trained, and operates in the shadows.

Georgia law - like nearly all states' - makes it a crime to assist in a suicide, and Bankhead said giving Celmer instructions on how to end his life, and emotional and physical support, qualified as assistance.

"He had no idea how to do it himself, and just by supporting him in his endeavor, they may have had the effect of actually pushing him," said Jay Lukowski, an attorney for Celmer's wife, who did not live with Celmer.

Georgia officials also say that exit guides holding Celmer's hands as he died could have prevented him from removing his hood had he wanted to change his mind.

Jerry Dincin, 78, a retired psychiatrist in Chicago and acting president of the Final Exit Network, said the struggle to allow people to control how and when they die will become "the human-rights issue of the 21st century."

"In his case," he added, "Mr. Celmer felt that he was very deformed, that he had half his face removed, and he would need several more operations which he did not want to have, and he definitely wanted to end his life."

"And the fact that his estranged wife didn't think he should is interesting, but doesn't determine anything. We believe people should decide for themselves."

As for the contention that exit guides restrained Celmer by holding his hands, Dincin said, "that is by far the stupidest thing of anything. It doesn't make any sense. By the time someone pulls that hood down over his face, we've asked them 20 times are they sure they want to do this, and we keep asking them. It's their decision. But we do hold their hand for the human contact of a compassionate presence at the last moment of life."

Larry Egbert, 81, the medical director for Final Exit Network, was one of the four arrested. He lives in Baltimore, was extradited to Georgia, and released on $66,000 bail.

As medical director, he said he reviewed medical records of people seeking aid in dying. He said his group always does an assessment and interview to make sure the person has a terminal or catastrophic illness, is mentally competent, and wants to go forward.

"Our mission is to allow people to have the right to control the way they die with dignity, with a minimum of discomfort and when they want," he said. "I'm proud of what I do. I've never felt more like a doctor than doing what I'm doing."

For 11 years, Oregon had been the only state allowing physician-assisted suicide. In that time, under the Death with Dignity Act, 405 people ended their lives, out of 330,000 deaths.

In Oregon, two doctors must certify that a person requesting aid in dying has six months to live. A person must make two requests to the state, 15 days apart, and be found to be mentally competent. Doctors then may prescribe a lethal dose of medicine. The dying person must ingest the pills without assistance.

Washington state voters approved a similar law in November and it went into effect in March. Also, in December, a Montana judge ruled the state constitution gives residents the right to a physician-assisted suicide, though the state has appealed.

The U.S. Supreme Court ruled in 1997 that the Constitution does not grant individuals such a right, and left the issue to the states.

Supporters of the Oregon law say it has improved care of the dying. More people in Oregon per capita use hospice, die at home rather than in institutions, and receive good pain management than in any other state, they say.

Advocates for better care of the dying say groups like the Final Exit Network are a consequence of our failure as a nation to support the dying and their families.

Bill Colby, the lawyer who represented Nancy Cruzan's family in its fight to have her feeding tube removed, the first right-to-die case to reach the Supreme Court in 1991, said that before America resolved how to help the few who choose to hastene their own deaths, it must first do a much better job comforting the millions with terminal and chronic diseases who want to go on living.

"It strikes me that a caring society would do a better job for its citizens than sending them to a secret room with a bag over their head and a tank of helium to exit this world," Colby said. "That solution is a failure for all of us."

Ira Byock, director of palliative care at Dartmouth-Hitchcock Medical Center and author of Dying Well, testified against an Oregon-like law being debated in New Hampshire.

The bill, he said, "has the veneer of respecting individual rights . . . but smacks of science fiction, not responsible social policy.

"In the context of uncontrolled pain, social isolation, financial devastation and the toll that an individual's illness takes on his or her family, a person's decision to commit suicide may be entirely rational," Byock added. "But doesn't that make it all the more tragic?"

The better solution, he said, is for America "to address the shameful deficiencies in care and support for the most ill, elderly and vulnerable."

Zelniker's illness, Sporadic OPCA, is an aggressive form of ataxia, a neurological disease that reduces the ability to stand, speak and swallow.

"There is no treatment or cure for the ataxias . . . but there are medications that can help and continue life," said Michael Parent, executive director of the National Ataxia Foundation. "We always encourage folks never to give up hope. We certainly don't advocate ending one's life."

Zelniker felt otherwise.

"I respect and admire those in my position who chose to live out the course of the disease," she wrote in a letter. "However, I see that as a choice."

On Dec. 5, Pat Eames, 79, who lives at the Quadrangle, a retirement community in Haverford, drove to Zelniker's home to interview her for Final Exit Network.

A retired attorney and general counsel at Wayne State University, Eames lives with her old college friend, Connie Hart, volunteers in the Quadrangle library, just finished directing a production of Arsenic and Old Lace.

Eames wants control at the end of her own life and decided, "Why shouldn't I pull my share of the load?" She held the hand of a New York woman as she died last year.

"Rona Zelniker . . . is a smart, articulate, opinionated lady," Eames wrote in her report Dec. 7. "She understands her situation and has researched her disease. She understands that it may progress quickly. She states that she is flatly unwilling to use a wheelchair, and intends to exit before that is necessary."

Eames had surgery planned at the time Zelniker wanted to die, so she handed off exit guide duties to Vizer, the former counselor who lives in Green Hill Condominium off City Avenue in Wynnewood.

Vizer spoke to Zelniker many times, but never met her. When Vizer heard about the arrests, and was told she couldn't be there to comfort Zelniker, "I was terrified for her," Vizer said. "I didn't know what Rona was going to do. When I called, she was calming me, 'Listen, I'm not going to let this stop me.' "

Zelniker did not bathe the last three days of her life.

"She was so scared that getting out of the shower she would fall, hurt something, and then her window of opportunity would end," her son said. "She wanted to do it when she was able to turn the helium on herself."

Keith and his sister, who supported her mother but didn't want her name used in a story, had a "slumber party" with their mother the weekend before she died. Zelniker's son-in-law and grandchildren came.

Keith and his sister stayed with their mother on Monday and Tuesday, said final goodbyes, and left at 10 p.m.

"She didn't want us to see her with a bag on her head and helium tanks next to her," Keith said. "She didn't want us to remember her that way. But even with the tanks and the bag, I would have liked to have been there, to hold her hand. But there were legal issues. She wouldn't allow it."

Keith worried his mother wouldn't have the strength to drag the helium tanks from the laundry room to the spare bedroom, and he had visions of her ending her life on the laundry room floor.

This made him angry.

"Things are so taboo," he said, "you have to do this backroom. This is like an abortion before Roe v. Wade."

Keith and his sister drove back Wednesday morning, and alerted the guard at the gate of the community, Greenbriar at Whittingham, that something might have happened to their mother.

Police came, investigated, and concluded no crime had occurred. After the funeral home removed the body that morning, Keith and his sister went back inside.

He took the helium tanks, in a box with balloons and happy faces printed on it, to a Dumpster. He hopes his mother died peacefully.

John Hansen-Flaschen, chief of pulmonary and critical care at the University of Pennsylvania Medical Center, said helium has legitimate medical uses, including in the intensive care unit to ease breathing through clogged airways because of its lighter density. But helium is always mixed with oxygen, he said.

Before the arrests, he said he had never heard of helium being used to end a life.

"I think it's quite possible that people would be very uncomfortable under one of these hoods," he said. "I don't think this should be sold as a surefire peaceful way to end your life. I'm skeptical."

Rona Zelniker managed every last detail of her death.

She emptied her closets to the Salvation Army. She changed her car title into Keith's name. She listed her condo with a Realtor, figuring it would take two months to begin showing it.

She shopped for the funeral home, and even bought a biodegradable urn for her ashes, which she left on the kitchen counter. In a three-page to-do list found near her body, she covered every detail, right down to the E-Z Pass: "Return tag, close account and get refund."

She even left an extra $20 and a note for the cleaning lady, Nalva, scheduled to come in two days, "to clean out the fridge and freezer."