Alzheimer's disease had erased 68-year-old Thomas Earl Thomas's memory. He mistook his wife of 39 years for his sister. He watched a blank television screen and complained that it was a rerun. Seeking his dead mother, he sometimes wandered to his childhood home, long since occupied by others.

When his family could no longer care for him in 2002, it found what appeared to be the perfect solution: Ridgefield Retirement in Marion, situated along an interstate in southwest Virginia. It was close to home. It looked clean and well-maintained -- and more important, his family said, the Ridgefield staff showed them a "lockdown" wing designed for Alzheimer's residents. The back doors to the unit were equipped with alarms. The front door could be exited only by punching a code into a keypad.

Thomas, they assured, would be safe at the 126-bed home.

"They said: 'He can't go very far. We got people watching,' " said his son, Randall Thomas.

Thomas Earl Thomas was among a growing pool of potential customers increasingly sought by assisted living facilities: dementia patients who need supervision but who are not sick enough to live in nursing homes. The facilities have marketed themselves aggressively to such families, offering safe, round-the-clock care in a less institutionalized setting than a nursing home.

For many families, assisted living is a good alternative. But despite their marketing, the homes often are ill-prepared to deal with the unpredictable and challenging behavior of residents with dementia, records show.

Eleven days after moving in, Thomas slipped outside undetected on a chilly, overcast night. Clad in moccasins and his favorite flannel shirt, the slender man wandered lost along Interstate 81 near the home. A driver used a cell phone to report a man standing in the middle of the highway. Eight minutes later, Thomas was dead, knocked out of his slippers by a truck that never stopped, according to police.

The chasm between what some assisted living facilities promise to do to protect people with dementia and what they deliver has become a serious concern for advocacy groups.

"This is an enormous issue, and there is an enormous gulf between what marketing material advertises and what in fact is actually happening" to residents with Alzheimer's and other cognitive impairments, said Karen Love, founder of the Consumer Consortium on Assisted Living, a national nonprofit consumer group based in Falls Church.

Sharon Martin, administrator at Ridgefield since August, said that "there were a lot of mistakes" made at the facility under previous management but that the problems have been corrected.

Thomas was not the only dementia patient to die after a lapse in care at a Virginia assisted living facility, state records show. John Sagnier, 88, fell from a window at Sunrise in Falls Church in 1995. Carole Ann Petersen, 66, died after choking in 2001 while eating unsupervised at Manorhouse in Virginia Beach, which has since changed management. Three other patients strayed undetected and died from exposure to extreme heat or cold. One resident was struck by a car. Another was struck by a train not far from where Thomas died.

About 4.5 million Americans suffer from Alzheimer's and that number is expected to increase to 11.3 million by 2050. A range of other illnesses and conditions can trigger the same confusion, memory loss and poor judgment.

Nationally, assisted living operations have increasingly offered Alzheimer's care, said David Goldberg, executive vice president of Assisted Living University, a training organization for the industry. He said at least half of the larger facilities and a majority of newer homes have an Alzheimer's unit. The injuries and deaths have been isolated problems, Goldberg said, and the only way to guarantee safety for mentally impaired residents would be to constantly restrain them.

"Assisted living is not meant to be a prison," he said.

In recent years, Virginia, like many states, has acted to beef up safety in facilities that house dementia residents, in some cases requiring them to have at least two staff members on duty and have a method for monitoring security.

But records and interviews indicate that Virginia inspectors increasingly have reprimanded homes for taking in dementia patients who are too disabled to be in their care; for failing to have adequate staff and security systems to monitor those patients; for employing untrained caregivers; and for failing to protect agitated dementia residents from hurting one another.

Sunrise Senior Living, the nation's largest chain with more than 370 assisted living operations, markets special services for dementia sufferers: security systems, increased supervision and "safe and stimulating" surroundings for as much as $200 a day.

Licensing records on Sunrise facilities cite about 80 violations related to seriously mentally impaired residents from 2000 through early this year. At Sunrise of Reston in 2000, for example, a diabetic man living in the unit for impaired residents "was hospitalized due to dehydration and malnutrition resulting from facility staff failing to ensure the resident was eating and drinking," a state licensing official wrote.

In an internal e-mail written early last year, the head of the Virginia state licensing division characterized problems in general at Sunrise facilities as "very bad, high risk and inexcusable." Another administrator pointed out that the chain had made improvements, but also noted problems stemming from aging security systems and staff inaccurately assessing residents' impairments. That administrator added that "our greatest concern . . . is the number of recent wandering incidents."

Sarah Evers, Sunrise vice president for communications, said that the e-mail was more than a year old and that since then, Sunrise has taken many steps -- including upgrading security systems and rewriting policies -- to correct problems cited by the state.

Evers said that the "tens of thousands of satisfied residents and family members" reflect the company's operations in Virginia.

When Thomas Earl Thomas's relatives chose Ridgefield, they did not know that the home already had dozens of problems.

Ridgefield had failed to protect a female resident from sexual abuse by another resident and then put the aggressor in the dementia unit with other vulnerable residents, according to records. Inspectors had found medication errors and undertrained employees, and found that parts of the "safe, secure" unit for dementia residents had no protective devices on the windows.

"If we had known of any of those violations, he would not have been put in there," said Thomas's daughter, Rebecca Pavlick. "Those people . . . let my dad die."

On Dec. 13, 2002, Claudine Thomas stopped by to visit her husband on her way home from work. Later that evening, staff workers said they realized he was gone.

Workers called his relatives, and as they drove to Ridgefield, they saw the emergency vehicles along Interstate 81 where, they later learned, Thomas died.

State inspectors faulted the home for letting Thomas wander. Workers knew the front door to the dementia unit was regularly left open, records show. An insurance company for the home, which denied wrongdoing, agreed to pay the family $240,000 to settle a claim of wrongful death.

Ridgefield administrator Sharon Martin said the home has instituted major improvements in staffing and procedures, including a bracelet security system for mentally impaired residents. She noted that inspectors relicensed the home last fall after it had been targeted for revocation since July 2002.

Staff researcher Bobbye Pratt contributed to this report.

Alzheimer's patient Thomas Earl Thomas slipped out of Ridgefield Retirement, background, and wandered onto Interstate 81, where he was hit by a truck.Randall Thomas, holding his father's slipper, says home workers told him: "He can't go very far. We got people watching." His father left the home undetected.