According to a study published in the New England Journal of Medicine, board games are tops among several mental activities that help to prevent dementias associated with aging. The study followed its senior subjects for over 20 years, tracking their activities and the incidence of dementia as they aged. Playing board games four times a week reduced the risk of dementia by 74%, better than playing a musical instrument (69%), playing chess (47%), or reading (35%). The beneficial effects were enhanced by frequent play, but doing a mental activity even one time per week was associated with a 7% reduction in the risk of dementia.