A study led by Professor Elmar Graessel of Friedrich-Alexander University of Erlangen-Nurnberg in Germany, shows that two hours' activity a day, singing, gardening, bowling, doing crosswords and Sudoku can arrest the progress of dementia.

The cognitive and functional ability of patients, selected at random at five nursing homes in group activities, did not worsen over the year-long project. Whereas the thinking skills and ability to perform tasks deteriorated among fellow residents who did not join in activities. 

According to Professor Graessel, the activity sessions, known as MAKS, were "at least as good" for cognitive function and twice as good for daily living tasks, as treatment with cholinesterase inhibitors, the usual treatment for dementia.