Her family has called every nursing home and healthcare centre for the elderly in Woodlands, but Madam Ng Kum Ho, 68, remains missing - 10 days after she left home.
Her Members of Parliament, including National Development Minister Khaw Boon Wan, have posted appeals for residents to look out for her.
Madam Ng's daughter, Madam Emily Lee, 40, a housewife and babysitter, told The New Paper that her mother suffers from Parkinson's disease and has high blood pressure.
Madam Ng left home on Jan 3, and has not returned since.
"Her memory has been problematic, as she has started to forget things," said Madam Lee.
"I'm afraid she's lost and unable to recall anything."
Memory dysfunction is one of the symptoms of Parkinson's disease, according to the World Parkinson's Education Program website.
Madam Lee went to the market on Jan 3 at about 10am to buy her mother lunch, but when she returned to her unit at Woodlands Ring Block 628B at 11am, Madam Ng was no longer there.
"At first I didn't think much about it, because she sometimes takes the newspaper to read at the void deck," said Madam Lee. "But she did not return after an hour, and it was only then that I got worried."
A missing person's report was lodged with the police that evening.
Madam Lee, her husband, cousin and about four friends have been looking for Madam Ng since.
"Every morning from 9am to 11am, we split up, and walk and drive around the blocks and the parks in Woodlands looking for her," she said.
"I've also called every nursing home and eldercare centre in Woodlands, but none of them has seen her."
Madam Ng's son died in 2013 from a heart attack at age 38, leaving Madam Lee as her only surviving child.
"My mother needs to take medicine three times a day," said Miss Lee. "It has been 10 days. I'm very worried."
She also approached the Members of Parliament for Sembawang GRC for help on Jan 6.
Mr Khaw and Mr Vikram Nair, both MPs of Sembawang GRC, have since posted pictures of Madam Ng on their Facebook accounts urging residents to look out for her.
Mr Joseph Tan, 48, the founder of Crime Library Singapore, said that of the 900 cases of missing persons a year that he handles, 95 per cent are found.
Madam Lee said: "Someone called me saying she was spotted near the Civic Centre (along Woodlands Avenue 5). But when I went down, she wasn't there."
She added that Madam Ng was last wearing a brown checkered shirt and grey shorts.
She usually carries an umbrella and a small bag, and has little money on her.
"I hope we find her soon," said Madam Lee.
"We are getting very worried, especially since she needs to take her medicine."
From 2008 to 2012, an average of 2,500 people were reported missing each year.
This article was first published on Jan 13, 2015.
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