It seems two popular pastimes in Hong Kong - mahjong and tai chi - have more than just sweeping hand movements in common. A recent study indicates they can both keep elderly minds sharp. In a paper published in the American Journal of Geriatric Psychiatry, Hong Kong Institute of Education researchers suggest integrating mahjong and tai chi into regularly scheduled activities at nursing homes can halt or slow down cognitive decline, even for those suffering from significant dementia. Played three times a week for two to three months, these activities - which were considered by the researchers as cognitively demanding - showed evidence of long-term benefits for the mind. And they may be more effective than less cognitively demanding activities such as beading and making other simple handicrafts. Researchers chose 110 ageing residents from nine Hong Kong nursing homes and randomly assigned them to mahjong, tai chi and handicrafts groups, with the latter as the control group. The participants practised their assigned activity for one hour, three times a week, for a total of 12 weeks. All groups had an instructor and were helped by the researchers' assistants. The elderly's cognitive performance was tested up to nine months after completing the programme, and those who did tai chi and mahjong scored well in the Mini Mental State Examination, which assesses cognitive impairment through arithmetic, orientation and memory. The strongest improvement was seen in short-term memory. Depression is a risk factor ... simple, regular activities can help Professor Cheng Sheung-tak The study is the first randomised and controlled trial investigating the effects of both playing mahjong and practising tai chi among old dementia patients. Tai chi, a slow-moving exercise derived from traditional Chinese medicine and martial arts, requires a person to memorise a sequence of moves. In the study, frail patients practised a seated version of tai chi. Mahjong, meanwhile, was invented in the mainland more than 2,000 years ago in the court of the King of Wu. According to Chinese folklore, it was created by a beautiful but isolated maiden who wanted to amuse herself to ease her loneliness. After carving and painting hundreds of tiles made of bamboo and ivory, she invited her handmaidens to play. Lending credence to the maiden's cure for loneliness, the research team published a similar study late last year, concluding that regular mahjong playing (three times a week) could reduce depressive symptoms in ageing persons with mild dementia. Professor Cheng Sheung-tak, the lead researcher and head of psychology and gerontology at the institute, says isolation, loneliness and the lack of activities can cause depression among nursing home residents. "Depression is a risk factor for cognitive decline. The idea is that simple, regular activities can help," he says. Cheng stresses that the type of mahjong played by the participants in the study was different to the addictive, competitive game played by gamblers. "Our mahjong was in the form of an exercise, with no competitive or gambling elements," he says. According to Cheng, about 8 per cent Hong Kong's elderly population reside in nursing homes. While many of these facilities offer leisure activities to residents, most do not offer them on a regular basis and they do not engage residents who may be suffering from dementia or depression. "Activities may be restricted to a small number of keen residents - people who would do it anyway," says Cheng. In 2007, it was estimated that 345 million people in Asia play mahjong regularly. In the West, mahjong has even become a popular solitary online game, although it bears little resemblance to the Cantonese four-player version that is so popular in Hong Kong.