She is a 90-year-old widow with mild Alzheimer’s disease, and her son is begging her, for safety’s sake, to give up something she considers essential to her independence and sense of control.

“You can’t take it away from me,” she told him recently. “It’s all I’ve got.”

Eliandric

This may sound like a classic confrontation with an elderly mother who won’t give up her car. But it’s in fact about a loaded .38-caliber handgun that she keeps wrapped in a scarf in her top dresser drawer in a Southern California retirement community.

She says she needs it for protection. Her son is afraid that she will get angry or confused and shoot someone — possibly him. “I’d rather eat barbed wire than deal with this,” said her son, Chuck, who asked that his last name not be used to avoid drawing the retirement community into his dispute with his mother.

Like cars, guns symbolize independence and individualism to many Americans. In states where gun ownership is a way of life, the elderly population is as likely as anyone to be armed and, in the view of many family members and professionals who care for the elderly, possibly dangerous.

With the 85-and-older population growing faster than any group in the country, gun ownership among the very old is increasingly a concern of adult children, who worry that elderly parents will commit suicide or shoot someone they mistake for an intruder.

Geriatric care managers in several Western states said they regularly work with families struggling to persuade aging parents with dementia to surrender guns.

“We are a big gun-rights state and a lot of older people do have guns, and some of them have dementia,” said Dawn Savattone, a geriatric care manager in Phoenix who said she gets about one case a month involving guns. She is now working with a family of a gun-owner in her early 80s with paranoia.

“They’re afraid to go to the house to help her,” she said of the woman’s children.

More than a quarter of people ages 65 and older own guns, according to the National Firearms Survey of 2004.

The Veterans Health Administration launched a public awareness campaign about gun access by dementia patients after an 83-year-old veteran pulled a pistol from his pocket in August 2000 and shot a doctor in a V.A. hospital emergency room in Salisbury, N.C.

The agency found in 2004 that 40 percent of veterans with mild to moderate dementia had a gun in their homes. The V.H.A. also issued guidelines for doctors to use to help family members keep guns away from relatives with dementia or mental illness.

Families find little help in the law when trying to pry guns away from impaired family members. Only 11 states require a license to buy a gun — Iowa is the one exception west of the Mississippi — so it is difficult to impose restrictions, as states do for driving, based on age or impairment in places where gun ownership is highest. The Supreme Court’s ruling last month striking down Chicago’s handgun ban as unconstitutional — and a similar 2008 ruling involving the District of Columbia — are likely to chill state and local efforts to restrict gun ownership.

The federal Brady Act bars gun sales to anyone adjudicated mentally “defective,” a legal process few children want to put parents through. Even if they did, most older people bought their guns years ago, and Dennis Henigan, a vice president of the Brady Center to Prevent Gun Violence, said there is no “systematic way for the authorities to find out if they have guns.”

Many home health agencies have stepped into this vacuum, requiring elderly people to remove guns from their homes as a condition of sending aides to assist them. Some enforce the policy only against those with dementia.

“If there’s someone mentally impaired, we don’t want rifles, we don’t want handguns anywhere in the residence,” said Don Irish, who heads Family Home Care Inc., with offices in Arizona and California. “We’re not going to put any of our workers in harm’s way,” he said.

While there are few reports of elderly gun owners shooting relatives or caregivers, older white males have the highest suicide rate in the country, and 71 percent of the time they use a gun, according to a 2003 study in the American Journal of Geriatric Psychiatry.

Another study by the Centers for Disease Control and Prevention found 11 cases of caregivers shooting and killing victims 80 and older from 2003 to 2007. The most common scenario was a husband killing a wife.

In response to a reporter’s inquiry, the National Rifle Association forwarded a statement regarding gun ownership and the frail elderly: “Our NRA basic courses focus on educating all gun owners regardless of age. They also teach gun owners the importance of storing guns so they are never accessible to untrained or unauthorized individuals.”

Families of frail, elderly gun owners wind up doing a lot of improvising. Chuck in Southern California says he has thought of removing the bullets from his mother’s gun while she is out. Ms. Savattone, the Phoenix care manager, said some of her clients tried taking their parents’ guns on the sly, but the parents called the police and reported that their children stole their guns.

In many cases, care managers say, the guns have deeply sentimental meanings to elderly owners.

A Billings, Mont., widow with early Alzheimer’s treasured her guns as reminders of her late husband, who carried them when tending sheep and shooting predators on a ranch they left long ago, recalled care manager Seth Blades.

In the end, the family used a home care agency’s prohibition on guns as leverage. “They gave her an ultimatum: either give it up or you go into a facility that doesn’t let you have a gun,” Mr. Blades said.

She handed over the gun.