Dementia patients need care 24 hours a day, which is a great burden for their families. [Photo by Zou Hong / China Daily]

Hiring a helper is impossible, because few housemaids are willing to take care of someone with dementia.

Nursing homes are also out of the question, because the family often doesn't trust caregivers they can't supervise, especially when the patient cannot speak out if he is mistreated. In addition, most can't afford such care.

Cao can only get a short break on weekends when her son is not busy with work and comes to help.

"Only caregivers of dementia patients know how hard it is," says Zi Nuo, 52, in Zhuhai, Guangdong province, whose 79-year-old mother suffers from vascular dementia caused by diminished blood supply to the brain.

"People with dementia forget what they've done or said very quickly. You never know what they will do the next minute, and they need to be guarded 24 hours a day."

Her mother was diagnosed in 2010 at a mid-stage, and the condition has deteriorated quickly. She now cannot remember anyone, including herself. She is moody, and sometimes even violent.

She wakes up frequently and yells during the night, a common symptom in severe cases, and suffers from incontinence, often in the middle of the night.

Twice, the afflicted woman has damaged the door lock, and left the apartment alone. Now Zi has installed a specially designed door lock.

The physical and mental exhaustion have caused depression and high blood pressure for Zi.

However, Zi feels lucky that she is young enough to endure the physical and psychological pressure for her mother's sake, because many caregivers she knows are the seniors' spouses.

A 76-year-old Beijing resident, who asked to be identified as Peng, has been taking care of her 75-year-old husband with dementia for a decade. Their children don't live with them.

Diagnosed in 2004, her husband now has lost almost all abilities, except to walk when dragged. Peng has developed severe high blood pressure, heart disease and depression.

She refuses suggestions to send her husband to a nursing home, saying those facilities lack professional and devoted care.

Since 2009, she has been able to get a housemaid willing to help, for 4,000 yuan a month ($654). Sometimes, she is able to enjoy short travels.

Not everyone is as lucky.

Beijing resident Cao says if her son is away, she doesn't dare go to hospitals even if she's sick.

Zi, who looks after the mother in Zhuhai alone because her daughter and brother live in other cities far away, says although there is a supermarket in her community, she buys most things online.

"We are tied to the patients," Cao says. "I just hope there will be someone who can help, and let me get a break, even if only for a while."